View Full Version : Going Linear with the Caiman
StanleyB
29-03-2010, 21:27
I have been thinking of trying out a CB radio linear power supply on a Caiman just to see what the results would be like. CB radioes need extremely low noise linear power supplies or high current capability. Unfortunately the CB radios power supply are set at 13.8V. The Caiman needs 15V. But I realized that to set a linear power supply to an exact figure of 13.8V would mean that there had to be some sort of voltage preset in the case.
There are quite a few linear power supplies listed on eBay for CB radio, but Maplin also list a few and a new branch opened up about 10 minutes from my home a few months back:). So off I went and grabbed myself one of THESE (http://www.maplin.co.uk/Module.aspx?ModuleNo=231) I grabbed the 3A version, which is all that would be needed for this application.
A quick look inside the unit reveals two pots.
http://www.homehifi.co.uk/images/mods/linear/psu.jpg
The one on the left should be turned all the way clockwise in order to get it to output close to 15V.
http://www.homehifi.co.uk/images/mods/linear/pot.jpg
WARNING NOTICE: : If you intend to try this mod, but you are not experienced with electrical safety procedures, make sure that the power supply is unplugged from the mains before you remove any screws on the case. Do not plug the power supply into the mains whilst the top cover on the power supply is unscrewed and removed!! Just turn the pot in the direction shown and that should be close enough to 15V.
http://www.homehifi.co.uk/images/mods/linear/15V.jpg
I cut off the DC lead on an old TC-7510 power supply in order to make up the DC output lead from the modified CB radio power supply to the Caiman.
I tried out the linear power supply on the TC-7520 and Caiman, both in modded an unmodded state.
The bad news is that the Caiman power supply produced better results than the modded CB radio PSU when tried on an unmodified TC-7520 and Caiman.
The good news is that the modded CB radio PSU comes into its own with a Caiman fitted with the Murata regulators. A lower noise floor brought out some previous hidden detail in cymbals etc. There are more listening sessions to endure, but so far I am not disappointed with the £22 layout I made.
Thats excellent Stan and its also cheap! Never actually thought of using a CB psu, nice thing is its ready cased etc :)
The Maplins bench supplies are a good way of trying out a basic linear supply (I had the 5v one for quite a while set at various voltages). The trafo is quite noisey though and the regulator very basic. The linear PS I have now uses a Toroidial 90 Va traffo, full wave rectifier, 10,000uf smoothing cap and a two stage regulator. This is much quieter than the Map's one and really helps give the Caiman a very "analogue" type sound.
Sounds really good with and without the Murata upgrade.
Regards
Chris
Covenant
30-03-2010, 07:08
This is the one I have been building:
http://cgi.ebay.co.uk/Variable-DC-Power-Regulator-0-24V-up-to-5A-DIY-kit_W0QQitemZ280323854145QQcmdZViewItemQQptZLH_Def aultDomain_0?hash=item41449a8f41
But my advice is DONT DO IT! ;) By the time you add a decent toroidal transformer, case, switch, wire and other bits and pieces it costs in the region of £50. Stick with Stans suggestion.
Jerry,
can you provide us with some details about your PSU build? I just came along the same kit when I did some research for a DIY linear supply ... Would be interesting if you could share your experience in building it and listening to it.
-
Cherrs,
cz
StanleyB
30-03-2010, 10:42
I tested the power supply for noise on my scope, and at less than 10mV rms it is quieter than the 7812! The latter has between 30 to 70mV according to some datasheets.
Looking at the guts of the CBR PSU it should be quite an easy job to make improvements to its performance, which is already good enough for the job in hand. The internal PSU on the TC-7520 and Caiman does further regulation and noise filtering.
This is the one I have been building:
http://cgi.ebay.co.uk/Variable-DC-Power-Regulator-0-24V-up-to-5A-DIY-kit_W0QQitemZ280323854145QQcmdZViewItemQQptZLH_Def aultDomain_0?hash=item41449a8f41
But my advice is DONT DO IT! ;) By the time you add a decent toroidal transformer, case, switch, wire and other bits and pieces it costs in the region of £50. Stick with Stans suggestion.
I've seen that PCB somewhere before Jerry.... ;)
Looks good!
apmusson
30-03-2010, 13:47
Stan.
I want to use the cable off an old 7520 wallwart power supply. Is there an easy visual way to tell which wires is should be connected to the +ve and -ve terminals?
Thanks
Ade
Take a look at this little beauty!
1601
Regards
Chris
StanleyB
30-03-2010, 14:55
Is there an easy visual way to tell which wires is should be connected to the +ve and -ve terminals?
The lead with the grey stripes is +V.
apmusson
30-03-2010, 15:12
Thanks - as usual. Ade
The lead with the grey stripes is +V.
Covenant
30-03-2010, 15:21
Jerry,
can you provide us with some details about your PSU build? I just came along the same kit when I did some research for a DIY linear supply ... Would be interesting if you could share your experience in building it and listening to it.
-
Cherrs,
cz
Hi Paul,
I cant tell you what it sounds like 'cos I made a slight blunder and touched both probes of my multimeter together when I was adjusting it.:(
New regulator to be installed.
The instructions were none existant-it said 'assemble as diagram' but the diagram was very poor. Anyone above numptie stage should put it together in an hour. Took me about a week. It didn't tell you that the regulator should be bolted to the heatsink and separated by a mica washer and didn't mention heat compound.
Parts are all well known and the circuit board is a beefy 2mm thick.
... so I'm looking forward to reports after you installed new reg ,-)
Cheers,
cz
Covenant
05-05-2010, 07:51
Well my home made power supply has been running with my Murata regg'd 7520 (thanks to Puffin for the repair) and I have to say the results are stunning. Just to complicate matters I have also switched to the AD826 op-amps so I can't be certain the improvement is all down to the power supply.
The improvement is across the range-vocals, soundstage, dynamic range, its like having a new system.
If you have gone as far as fitting the Murata's then you NEED to get a decent 15v supply.
Jerry,
nice to hear. Do you run the PS kit you mention in the other PSU-Tread (http://theartofsound.net/forum/showpost.php?p=118254&postcount=25)? Any mods on the kit done? I ask as you mention it's a little bit noisy ...
Cheers,
cz
Covenant
05-05-2010, 19:39
I have to say that I cannot notice any noise but I am looking forward to seeing (and hearing) what the Teddyreg does.
I am looking forward to seeing (and hearing) what the Teddyreg does.
Note also that I built a PSU for the Caiman using the SuperTeddy reg. Sounds very good indeed.
PSU for Caiman with Pics (http://theartofsound.net/forum/showthread.php?t=6110)
The Vinyl Adventure
25-06-2010, 19:29
I did this...
Turned the thing to most clockwise... Reads 15.36v should I turn it down to 15.00
I think you're safe up to 16V, but don't blame me if it explodes! How does it sound?
The Vinyl Adventure
25-06-2010, 19:34
Dunno .. Not tried it yet..
Cheers for pointing me to this thread Martin ...
Any more firm comment on the voltage issue... I'm trying to avoid fire here ;)
"Today I 'arr been mostly turning things clockwise"
http://i73.photobucket.com/albums/i239/saxonsex/Jesse.jpg
The Vinyl Adventure
25-06-2010, 19:41
I know we have spoken on the phone before buddy.. But it would seem from that post we have actually met - it's that spot on... (maybe its just the overwhelming impression I give of not knowing anything... :) )
I just said to Hannah " check me out, I just did somthing with electrical stuff and it hasn't broken anything yet..."
She asked what I did... I said .. "well I turned a thing clockwise" .... :lolsign:
Leave it on max, you'll be fine. If you need a connector for it, cut off the DC cable from the cheapo Caiman PSU (the 12V one), strip the end and solder it into the PSU (positive to tip of the plug). You then have the other end to plug into the Caiman.
The Vinyl Adventure
25-06-2010, 20:10
Done... And it works ... Well, the blue lights are on... I'm watching the Tele at the mo...
I'm curious now to try the Maplin Linear PSU with my modded dac - I have the Mutaras and maybe Im not getting the best out of them with the PSU I currently have?
I'm using the Maplin adjustable one previously recommended for the 7510 Dac, which Im running at 15V.
Do we Reckon the fact that the new one is Linear will be a big enough improvement over the switcher I'm running now? (Which runs 15V dead on)?
Does the fact that I'm using a "foo" power cable (Krystal Kables Titan) with the PSU make a positive difference and hence I should keep what I've got?
Also....(cap in hand)...
Does anyone have a spare 7520 psu kicking around I could use for the plug?
I dont want to cut off the plug from my own Maplins variable switcher, as I could pass it on to someone who could use it.
If you have PM me, sure I'll have an I/C or even a few CDs for your trouble.
Thanks.
Gaz.
Gaz,
If you can wait a couple of weeks, I'm away from home at present, I have a spare 7520 PSU that you can have if no else has one available in the meantime.
Gaz,
If you can wait a couple of weeks, I'm away from home at present, I have a spare 7520 PSU that you can have if no else has one available in the meantime.
Hey, thanks for that! :)
much obliged..
Gary.
:cool:
Any thoughts on potential improvements on sound quality with Stans CBR Linear Vs my current Switcher (@15v with Foo mains lead)?
Go for it? :scratch:
ta.
StanleyB
03-07-2010, 20:29
You get a better signal to noise ratio, which brings out a bit more detail.
Does the Caiman use special power plugs or is it a version of the usual 5mm diameter DC plug?
It's a 2.1mm DC plug, if I remember correctly.
2.1mm inner pin? You can get these on fleabay in long and short versions for very little dosh. The X-10D uses the same type..
If you're ordering other bits from RS, this 2.1mm plug-n-lead is available -
2.1mm DC Adaptor Cable (294-7030)
You get a better signal to noise ratio, which brings out a bit more detail.
Thanks Stan!
Its a Go! :)
You get a better signal to noise ratio, which brings out a bit more detail.
Agreed, that's what I'm hearing with the linear supply.
StanleyB
04-07-2010, 20:54
It's a great idea to try linear if you are also going to try the passive output mod.
Stan, did I remember correctly you saying that 15-16V 3A would be fine for the linear power supply. If so I came across these, I've not seen regulation as good as this, 0.25 mV RMS ripple! http://www.acopian.com/store/9-(7).aspx model A15MT300 (15-15.5 V 3 A). For $215 it's a bit more than your CB power supply but 0.005% regulation :stalks::stalks:
Peter Galbavy
06-07-2010, 15:49
... plus $25 for 230V option. Ugly as hell but if it works. One question though is if it hums at all ?
Good question. I'm trying to see if there is a UK based distributer to get hold of a sample to see what they are like. Spec's though are amazing!
StanleyB
06-07-2010, 16:47
Stan, did I remember correctly you saying that 15-16V 3A would be fine for the linear power supply. If so I came across these, I've not seen regulation as good as this, 0.25 mV RMS ripple! http://www.acopian.com/store/9-(7).aspx model A15MT300 (15-15.5 V 3 A). For $215 it's a bit more than your CB power supply but 0.005% regulation :stalks::stalks:
Are you trying to crack a nut with a hammer:eek:? The Mastech HERE (http://cgi.ebay.com/MASTECH-VARIABLE-DC-POWER-SUPPLY-HY1803D-0-18-V-0-3A-/380243455653?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item588846aea5) is almost as good and a mere fraction of the price. If I could get hold of these in the UK or they did a 240V version I would get a few.
Are you trying to crack a nut with a hammer:eek:? The Mastech HERE (http://cgi.ebay.com/MASTECH-VARIABLE-DC-POWER-SUPPLY-HY1803D-0-18-V-0-3A-/380243455653?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item588846aea5) is almost as good and a mere fraction of the price. If I could get hold of these in the UK or they did a 240V version I would get a few.
http://www.mastechpowersupplies.com/variable-regulated-power-supply-hy1803d.html
220v/50hz for US$69.95
Frizzup
Ali Tait
06-07-2010, 19:38
220v is not enough for the UK.
In light of these linear power supply discussions could anyone confirm the following;
As an owner of one of the earliest Caimans that came with the old smps power supply, the two cost effective (non DIY) options open to me in the UK are;
1) Modded CB radio from Maplin - £22 (less energy efficient and only of benefit to an Murata modded Caiman.)
2) Order newer Caiman smps from Stan. Is that even possible, are peole finding the change worthwhile, and what is the UK delivered price?
Thanks
Hi Sean,
Welcome to AOS! Where are you from, mate? :)
Marco.
Thanks for the welcome
I'm in East London.
I just filled in my profile this minute.
Cheers, Sean. Enjoy AOS! :cool:
Marco.
Are you trying to crack a nut with a hammer:eek:? The Mastech HERE (http://cgi.ebay.com/MASTECH-VARIABLE-DC-POWER-SUPPLY-HY1803D-0-18-V-0-3A-/380243455653?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item588846aea5) is almost as good and a mere fraction of the price. If I could get hold of these in the UK or they did a 240V version I would get a few.
I there, I thought Hi-Fi was all about diminishing returns, so cracking your nuts with the biggest sledge hammer was the right way to go:lol::doh:
I just discovered a third option to add to my previous list;
3) "Maplin variable output dc transformer (L11BQ) and setting it to 15V" compliments of the audioupgrades modding page on the caiman where they said it "gives greater headroom for the regulators (modified version) plus improves the overall sound." Goes for about 30 pounds.
Any opinions? Should I post in another part of AOS perhaps?
I there, I thought Hi-Fi was all about diminishing returns, so cracking your nuts with the biggest sledge hammer was the right way to go:lol::doh:
Hi 'OLED',
Welcome to AOS! :)
Could you please pop into the Welcome area and introduce yourself to our community by supplying your first name, system details and music tastes, as this is a requirement for all new members joining AOS.
Cheers! :cool:
Marco.
Hi Marco,
Just put myself up on the welcome page for everyones delectation. Great fun site by the way, hours of mischief with a soldering iron now unfolding.:lol:
Cheers Andy
Could not resist the convenient and promising Maplins option I mentioned above and bought it today.
It may because the Caiman was straining running into a 3-way PLLXO and so my experience may not apply to most users, but the improvement was obvious. I can say that my cd player never sounded so real nor enjoyable before I changed from the tiny 12V SMPS to this 15V model.
Well worth it for my set-up.
This is the PSU I'm using with my Dac...
I'm running it at 15V with Mutara regs.
No doubt it might be better than the stock one..but how would it compare to the Mapin CD radio Linear supply I wonder?
Any experiences of them both?
I used the Maplins Bench supply with a 7510 and then Caiman and it worked very well with both. I found that using a better linear supply improves the sound further though. The Maplins Benchy is good and cheap but the traffo and regulator are clearly built on a budget with low cost components.
The smoothing caps could easily be swapped out though.
Regards
Chris
Cheers for that Chris..
so you reckon then the linear CD radio supply Stan suggests would be better than what im running just now?
Just wondering where the most benefit would come from - 15V switching supply or 15V linear...and would it be worth shelling out for?
Gaz.
I think a good linear supply beats switched mode in this application as the DAC chip appreciates a very clean, low noise DC rail. With the Murata reg that you have, a low noise supply just gets even more out of it.
As to which linear supply, that's a good question. Most of us only have the one to listen to so it's hard to compare.
My Maplins smps is hot, hot, hot! I thought smps was attractive for its energy efficiency but I have my doubts now. Perhaps this smps was built cheaply and so is overheating!?? My other 12V amp SMPS modules are cool as you like.
I think I'll go for the CB PSU Stan suggests since I just ordered the Caiman kits (regs, caps, opamps) from Tirny, which Stan claims will benefit more from the linear PSU.
Can anyone tell me how hot does the CB PSU get, if that is an indication of the energy efficiency? I would like to keep the electricity usage down where possible:)
The Maplins CB Linear also runs hot but it has a decent heat sink and the case is ventilated. Hums a bit as well but this does not affect the sound at all.
I really don't like switching supplies as they tend to set my power amp off humming as well. I can always hear a difference with my set up when a SWPS is plugged into the mains as well.
Well designed linear ones with a nice quality toro, good quality smoothing cap and two stage regs keep the floor noise down to the Muratas. I am looking at a multiple supply that will do away with the Muratas presently.
Regards
Chris
StanleyB
13-07-2010, 08:14
Let's not get carried away with the SMPS versus Linear PSU issue. The differences between the two when using the Murata regs is only noticeable on top notch amps, speakers, and headphones. Personally it does not make sense to me, since the Murata regulators are also based on the switching principle. In theory the Murata regs should give the same output noise results when used with a MSPS or Linear PSU. It doesn't however according to my scope. The Murata seems to have been designed for linear power supplies in my view.
I have designed a prototype regulator filter, and Leo kindly built a couple of samples for both of us to test. It's more filter than regulator, and is used in the place of the 12V regulator. It works on both SMPS and Linear, matches the Murata for noise filtering, and costs less than £1 in components. So that might be a far more economical method to consider once I have fine tuned the filter design.
Bloody hell. More upgrades.
:sofa:
Does anyone sell replacement screws for the case? I think the heads on mine are getting worn off.
:piano:
StanleyB
13-07-2010, 10:23
They are not upgrades ;). On AoS we try to find sensible low cost solutions to otherwise expensive alternatives, and then share the information with anyone interested who has a working soldering iron:ner:.
Actually, on reflection, you make a very valid point. Here I am dreaming up all sorts of mods etc. for people to try on my DACs. But that might give the impression about the product. One only has to look at my competitors who do not have a long list of mods to recommend. So maybe I should halt thinking up any more mods for the rest of the year or even longer. I can ask a small company to advertise mods etc. instead. Worth me thinking about, since business is slow right now and other means of income need to be looked at.
PM me your address and I'll see how many screws I can find for you next time I sweep the floor in my office :lol:.
No. Keep on with the mods Stan as I think it is a big selling point and hugely enjoyable. You can always periodically sell an updated model when the time is right encompassing the mods for those who prefer unmolested original kit.
A Linear PS is best (based on my dabblings) but at a high cost compared to the SMPS. I don't think one can be built for under £100.00 or so.
The latest one that I am trying to get up and running has multiple voltages i.e. 12v, 5v and 5v and is to power each critical bit of the Caiman without the need for internal voltage regs. I agree that the Murata switching regs are a great low cost soln but could be a bottleneck for further gains.
Will let you know how I go on.
Regards
Chris
Yes, seconded, please keep on with the new mods. I've learnt so much over the last couple of years owning a Beresford or two. (I even remember having to ask what "op-amp rolling" was at one time). Mind you, my soldering skills have not improved I hasten to add.
I bought the Caiman and the Tc-7520 because it was moddable! :)
I look forward to coming on here for some new ideas.
Please don't change you marketing strategy, keep the ideas coming! :)
I can handle the soldering, but of course desoldering is where things can get frustrating for a noob like me.
HELP while I'm here. I want to take off the front board to try the 12k resistor mod, but once the screws are off, the volume control holds the board in place. How do I take that off without damaging anything please?
HighFidelityGuy
15-07-2010, 18:14
I can handle the soldering, but of course desoldering is where things can get frustrating for a noob like me.
HELP while I'm here. I want to take off the front board to try the 12k resistor mod, but once the screws are off, the volume control holds the board in place. How do I take that off without damaging anything please?
Carefully pull the knob off the shaft of the volume control. Don't snigger. :lol:
Then once that's off there's a nut and washer to remove. Once they're off you should be able the lift the boards out. I doubt you'll just be able to get the front board out due to the length off the shaft. I find the best way is to lift both boards in the middle so the edges with the sockets and buttons come out last. Also be careful with the gold buttons as the have a habit of flying everywhere.
I hope that helps. :)
Thanks, I went ahead and forced it as you suggested. It was damn tight and only really came off by turning it all to way to the right and half screwing it off, pulling it off.
Thanks again.
Just been wondering. With the passive mod removing the op-amp board, this should lower the current requirements of the DAC. This might mean some form of CLC (capacitor - choke - capacitor) smoothing circuit could be feasible on each rail...
Any thoughts?
Andrew
A third order choke like that would be very effective at filtering out noise. However, it would exhibit high output impedance and would not respond very well to the current demands of the DAC. Better to go with an active stage such as the Murata or Dexa regs.
I've been thinking about linear supplies for the Caiman. Shouldn't the 10,000uF capacitor be replaced by something like a 10uF film cap if the linear supply uses a voltage regulator? Most regs do not like charging up such a big cap and the big cap will downgrade the supply performance in that it's the big cap that determines noise & impedance, not the voltage reg. If using a non-regulated supply then the big cap is fine.
If a 10,000uF is wanted for use with a reg it should be placed following the bridge rectifier and before the reg (more than 25V rating will be required, so not the same cap).
Good point, Clive. What's the biggest high quality cap we could get in there?
Good point, Clive. What's the biggest high quality cap we could get in there?
There's 28mm clearance. A 4.4uF ClarityCap SA is 30mm diameter. I find these dimensions are approx, often slightly overdone to be on the safe side.
The ClarityCaps are amongst the smallest but more searching is required as we don't need a 630V cap. If we can find 400V or 200V rating caps they should be smaller.
A Mundorf Mcap Supreme 3.9uF is also 30mm diameter. I wonder which would be better at high performance reservoir duties?
A Mundorf Mcap Supreme 3.9uF is also 30mm diameter. I wonder which would be better at high performance reservoir duties?
My nature is to be sceptical that the capacitor is very critical, I'd have thought any half decent polyprop would be fine. Whether 4uF is better or worse than 10uF could be more a important factor. Another approach could be 10uF elect bypassed with a good 1uF cap or even 0.1uF or 0.01uF - or indeed all three.
This seems very sensible with a very well controlled power supply. I'll chat with techs in our electronics workshop this afternoon to see what they think as well and report back. Have either of you tried it yet by the way?
This seems very sensible with a very well controlled power supply. I'll chat with techs in our electronics workshop this afternoon to see what they think as well and report back. Have either of you tried it yet by the way?
I've not tried it yet. Most recommendations for linear regs specify 10uF as the output cap, so this is the basis for my thinking. I doubt 10uF is that critical, so 5uF or 20uf should be ok too but it would be good to get an opinion on this. The 10,000uF I believe is only in there for switched mode supplies, though it would be fine with an unregulated standard (linear) supply too.
Just been trawling the www, came across these, might be just too big but....
http://www.audiocap.co.uk/sn335j250a-signalpath-33f-250v-polypropylene-tin-foil-audio-capacitor-with-5-tolerance-80-p.asp
A Solen 10uF / 400V is 26mm x 38mm. I wouldn't want one as a coupling cap but it would be fine in this PS position.
http://www.audioloudspeakers.co.uk/falcon_capacitors.shtml
There's a 250v 9.1uF Solen that is 23mm x 33mm, should be perfect.
Whilst getting started on a new linear power supply, it occurred to me that if you use a highly regulated low ripple power supply, do you need a capacitor across the input at all, effectively the power supply already has one across it's terminals?
HighFidelityGuy
27-07-2010, 13:07
Would THIS (http://www.diyhi-fi.co.uk/mundorf_mkp.shtml) Mundorf Mcap MKP 250V 15uF be suitable for this application?
I got sent a pair by accident when I ordered a higher value and was going to send them back but if they'd work for this then I may as well pay for them and keep them.
Whilst getting started on a new linear power supply, it occurred to me that if you use a highly regulated low ripple power supply, do you need a capacitor across the input at all, effectively the power supply already has one across it's terminals?
I removed the PS caps on my 7510 when I went linear with it and it made a remarkable improvement to the sound I was getting from it. Funnily enough I was thinking of doing the same with the Caiman now that I've settled happily on a linear supply with the passive output mod, so you've just spurred me into removing it this week.
Cheers
HighFidelityGuy
27-07-2010, 13:46
I removed the PS caps on my 7510 when I went linear with it and it made a remarkable improvement to the sound I was getting from it. Funnily enough I was thinking of doing the same with the Caiman now that I've settled happily on a linear supply with the passive output mod, so you've just spurred me into removing it this week.
Cheers
I'll be very interested to know what difference this makes Rich. Do let us know. :) What linear supply are you using? Cheers.
Ditto Rich, I think this could be the way to go forwards.
Cheers Andy
Rich, I guess you are running short leads from the power supply to the Caiman to avoid potential IR drop. It then comes down to a fast enough transient current supply to the DAC or audio stage (if still used). We are debating at the moment whether a good linear power supply can supply a transient current demand as quick as a good cap across the power supply. I think this is why Clive suggests still keeping a small polyprop cap in there.
Another noob question, if you do not mind, now that my Caiman mods kit has finally arrived from Tirna (post office messing me around again).
What is the best way to remove these LEDs from their fixtures. Should I force them cold or heat the glue first? What temp do you suggest if I heat them and for how long?
I am being careful since I would struggle to fix anything should I break it.
Thanks for any help.
Sean
HighFidelityGuy
27-07-2010, 17:45
Another noob question, if you do not mind, now that my Caiman mods kit has finally arrived from Tirna (post office messing me around again).
What is the best way to remove these LEDs from their fixtures. Should I force them cold or heat the glue first? What temp do you suggest if I heat them and for how long?
I am being careful since I would struggle to fix anything should I break it.
Thanks for any help.
Sean
The glue isn't very strong, so you should just be able to push them from the outside, then pull them free from the inside. I've not had any problems doing this on the numerous occasions I've dismantled mine.
Good luck. :)
Thanks, mission accomplished.
Hi guys,
The linear supply is a TeddyReg circuit supplying 15V. I bought a load of the bare boards from a group buy over on Pink Fish Media going back maybe 18 months to 2 years ago. The supply cable from the output of the board into the Caiman isn't that short - probably around 3ft long in fact, but as I recall, the addition of a 10uF tant (at C6 I think but now I'm really stretching the old grey cells) meant that keeping the leads short wasn't so critical.
The TeddyReg is supplied by a pretty chunky toroidal transformer which was salvaged from an old broken piece of kit and supplies 18-0, which is then passed through Schottky diodes into a low ESR 20,000uF cap. For something that was cobbled together I'm really pleased with how it works with the Caiman - and for anyone who has a linear supply and is suffering some sibilance, I can highly recommend the Schottky diodes over the standard types.
I had been thinking of putting a snubber across the 20,000uF cap, but I think I'll have a go at removing the 10,000uF in the Caiman first and then also try a small polyprop in there and see what difference there is with and without input cap.
HighFidelityGuy
28-07-2010, 14:45
I decided that seen as several of us were using SuperTeddy regs in our linear supplies that I'd email Teddy Pardo to ask what cap he would recommend using.
He said that he would recommend using a 10uF film or Tantalum cap. Unless you have the supply extremely close to the DAC (a few cm), then you could get away with as low as 0.1uF.
So under normal conditions a 10uF film or tant cap will be best.
I hope that helps. :)
I found a 63V 10uF poly film cap at work today, so I might try installing that this week.
I decided that seen as several of us were using SuperTeddy regs in our linear supplies that I'd email Teddy Pardo to ask what cap he would recommend using.
He said that he would recommend using a 10uF film or Tantalum cap. Unless you have the supply extremely close to the DAC (a few cm), then you could get away with as low as 0.1uF.
So under normal conditions a 10uF film or tant cap will be best.
I hope that helps. :)
I found a 63V 10uF poly film cap at work today, so I might try installing that this week.
Sounds like a general accord is being formed (MartinT on the moded Beresford thread) is also trying something very similar. Once I can find a descend box to put my power supply in I'll follow on with a film cap replacing the 10mF beast. Look forward to hearing your first thoughts on the effect.
Cheers Andy
I've just noticed the WIMA I was going to use is 22uF 16V, cutting it too fine as I set my SuperTeddy to 16V output. I shall have to buy something suitable so I'm scouting around and will resume in a few days' time.
HighFidelityGuy
28-07-2010, 23:55
I've got a hexfred diode on order to replace the standard one used on the power input, so I'm going to wait until that arrives before I try my 10uF film cap. Hopefully it should be arriving this week so I'll be able to try both out soon. I've already replaced the resistor behind the 5V reg with a wire link and swapped the regs for Murata's, so I don't think there's much else I could upgrade on the power side of things inside the Caiman.
I had been thinking of putting a snubber across the 20,000uF cap, but I think I'll have a go at removing the 10,000uF in the Caiman first and then also try a small polyprop in there and see what difference there is with and without input cap.
Hi Rich,
My linear supply is very similar to yours. I'm using a SupeTeddy, HexFred rectifier and 22,000uF low ESR smoothing cap. So I'm interested in this snubber cap that you mentioned. What improvement should this make to the supply and what rating and type of cap should be used?
Thanks. :)
So under normal conditions a 10uF film or tant cap will be best.
this week.
I've tried both and found the tant to be a lot more neutral sounding. I found the film cap tended to brighten the balance a bit too much to my ears. That may be different if you're using a SuperTeddyReg of course - I must try one of these some time.
My linear supply is very similar to yours. I'm using a SupeTeddy, HexFred rectifier and 22,000uF low ESR smoothing cap. So I'm interested in this snubber cap that you mentioned. What improvement should this make to the supply and what rating and type of cap should be used?
This idea came from my tweakings to my Marantz CD65 where I changed all of the PSU caps for large value Panasonic FM caps which improved things overall but dulled the treble and killed timing a bit, so I added 100nF X7R caps across them all - Result, timing was incredible and gave sweet, clean and non-digital sounding treble.
HighFidelityGuy
29-07-2010, 09:25
I've tried both and found the tant to be a lot more neutral sounding. I found the film cap tended to brighten the balance a bit too much to my ears. That may be different if you're using a SuperTeddyReg of course - I must try one of these some time.
This idea came from my tweakings to my Marantz CD65 where I changed all of the PSU caps for large value Panasonic FM caps which improved things overall but dulled the treble and killed timing a bit, so I added 100nF X7R caps across them all - Result, timing was incredible and gave sweet, clean and non-digital sounding treble.
Thanks.
Would THIS (http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=6844938)be a suitable tant cap?
Thanks for the info on the snubber cap. I don't think I'm suffering from those issues but I guess it's worth a try. I might look into this at a later date. Let us know if you try it.
Cheers. :)
I tried one of those out of a mixed bag of caps I got from Maplins and really never got on well with them, everything seemed rather muddy sounding in comparison to the standard tants I use:
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=5381938
Hopefully I'll have some free time to try the snubber this evening. I shall report back.
I've just noticed the WIMA I was going to use is 22uF 16V, cutting it too fine as I set my SuperTeddy to 16V output. I shall have to buy something suitable so I'm scouting around and will resume in a few days' time.
I was thinking of a Mundorf MKP (15uF 250V) http://www.diyhi-fi.co.uk/mundorf_mkp.shtml, it should fit in. Also, how are you planning to mount the Claritycaps? the 47uF are BIG:eek: or are you planning to run at a low frequency cut off at say 10 to 20 Hz and go for a smaller cap?
Cheers Andy
Oh no, they're 1uF in value so should give a low frequency cut-off of <2Hz with 100k input impedance. My speakers go deep, but not that deep :-)
Ah ha, I see your not quite into that gut wrenching C below bottom G regime, unlike Durham Cathedral Organ! In that case there is a lot of choice for good quality thin films.
Oh they can reproduce the shake of a 64' 16Hz pedal no worries. I sold my REL Studio II subwoofer because I didn't need it any more!
I removed the PS caps on my 7510 when I went linear with it and it made a remarkable improvement to the sound I was getting from it. Funnily enough I was thinking of doing the same with the Caiman now that I've settled happily on a linear supply with the passive output mod, so you've just spurred me into removing it this week.
Cheers
Lovejoy. Did you place any jumpers where the caps had been?
Guys, ready to go to a linear supply with my Caiman after hearing the difference one can make over at Ali Taits with his 7510.
Once the dust has settled on which supply, caps or other stuff needed to get the best pub of a linear....any chance of some diagrams or photos for us non soldery types??
Ta.
Ali Tait
02-08-2010, 13:36
Not sure it'll make as much difference Gary,yours has the Murarta regs on does it not?
I'm talking from general experience as I've not yet Wolfsoned my 7520. I have however done the passive mod.
Here's what I expect....
For passived Caimans the 12V (or 10V) reg powers some ICs but not the opamps any longer. So in some respects the quality of the 12V supply may be less crtical now. I expect the 10000 uF cap should be replaced with a 10uF film or tant. The linear supply for a passive output Caiman can probably be unregulated if well filtered or a simple reg supply using a 7815.
Sorry this isn't the simple non-diy info you wanted....we need to be sure what works best first.
For a Caiman with opamps I expect a higher quality linear super reg supply would be worth doing.
I have also been thinking along the same lines as Ali. I think that a good linear supply with 12v, 5v and 5v supplies may be best with the internal voltage regs removed.
The 12v and Wolfson 5v looks straight forward to wire up but not certain where else to feed a dedecated supply to.
Regards
Chris
Ali Tait
02-08-2010, 14:12
Yes sounds like a good idea,I have a spare 5v supply.Perhaps Stan could advise?
StanleyB
02-08-2010, 15:56
Yes sounds like a good idea,I have a spare 5v supply.Perhaps Stan could advise?
Feel free to experiment. I myself would always use a regulator as close as possible to the main circuitry. Less chance then of any RF etc. hooking onto the DC leads from PSU to chips. If using a split external PSU, don't forget the RF filters. A parasitic bead in each lead should do it in most cases.
Ali Tait
02-08-2010, 16:06
I have a 7510 with passive mod Stan,which I'm feeding with a regulated linear supply.I have another 5v one.Where would be the right place to connect it please?
StanleyB
02-08-2010, 16:17
Try connecting it to the output pin of the 5V regulator, after desoldering the 5V reg. But make sure it is 5V, not 4.5 or 5.5. Some chips have a very low tolerance factor.
Not sure it'll make as much difference Gary,yours has the Murarta regs on does it not?
Yeah..
mines has the Mutara's fitted Ali..
so we reckon it wont be as much of an improvment switching to a linear supply?
the difference with your 7510 was very obvious...
Ali Tait
02-08-2010, 19:22
Aye but mine doesn't have the regs.Still worth trying though,you may still get a improvement,though perhaps not as great as with the 7510.
Ali Tait
02-08-2010, 19:23
Try connecting it to the output pin of the 5V regulator, after desoldering the 5V reg. But make sure it is 5V, not 4.5 or 5.5. Some chips have a very low tolerance factor.
Thanks Stan.
If you have a passive output, do you need to supply 12 or 15 V at all, do you only require the 5 V for the DAC power rail?
It the PS caps are removed should jumpers be put in their place?
Having given it some thought, I would assume not.
Ali Tait
03-08-2010, 10:36
If you have a passive output, do you need to supply 12 or 15 V at all, do you only require the 5 V for the DAC power rail?
Well that was my thought,to try feeding the dac with it's own regulated supply.These are pretty good supplies I've got I think,low ripple.
Majority of dac and receiver chips I've tried tended to be quite sensitive to the quality of the supply just as much as the analogue sections, some are much more picky than others so its worth going for the best you can if going to the trouble of doing other various mods too imo
HighFidelityGuy
04-08-2010, 16:39
I'd agree with that.
I compared my linear supply to the original Caiman supply on my Caiman that has Murata regs and I could definitely hear an improvement using the linear supply. I could hear more subtle detail in the background and the noise floor seemed to be lowered. I guess the linear supply must have better signal to noise ratio.
The improvements were subtle though and I'm not entirely sure they were worth the money I spent but I think it's worth trying the Maplin CB radio supply Stan recommended. :)
Hey Dave,
your linear PSU for the Caiman, was it a diy job with Teddyregs etc?
ta.
Gaz.
HighFidelityGuy
04-08-2010, 18:20
Hey Dave,
your linear PSU for the Caiman, was it a diy job with Teddyregs etc?
ta.
Gaz.
Yep, SuperTeddy reg, 100VA tranny, HexFred bridge rectifier, 22,000uF Mundorf smoothing cap etc.
Here's a not very good photo of it before I'd finished bolting it all together:
http://i2.photobucket.com/albums/y48/DTM2000/Hi-Fi/Beresford%20DACs/Caiman_PSU_01-1.jpg
Thanks Dave!
I'll have a bash with the Maplins one..jeez, just checked their website, have you seen their returns policy!?
basically you cant return it unless its faulty...then you need to get it "checked" before a refund...hmnn.
Reckon the Maplins supply is good enough quality?
ta.
Ali Tait
05-08-2010, 07:39
Leo,I'm already feeding the dac with a regulated linear supply.Do you think there's any mileage in using another linear supply to feed 5v to the dac chip directly?
HighFidelityGuy
05-08-2010, 09:26
Thanks Dave!
I'll have a bash with the Maplins one..jeez, just checked their website, have you seen their returns policy!?
basically you cant return it unless its faulty...then you need to get it "checked" before a refund...hmnn.
Reckon the Maplins supply is good enough quality?
ta.
No probs. :)
That sounds a bit dodgy of Maplin. I would have thought that contravenes UK distance selling rules where you're entitled to return the item for a full refund (minus shipping) within 7 days of purchase. I thought that was law. :scratch: It's supposed to protect you against accidentally purchasing an unsuitable product due to you not being able to actually see the item in the flesh. I'd pull them up on this. :)
EDIT: Here's a link to the regulations LINK (http://www.oft.gov.uk/shared_oft/business_leaflets/general/oft698.pdf). You want section 3.22 onwards. Basically you have the right to return the item within 7 days of receiving it even if the item is fully working. :)
No probs. :)
That sounds a bit dodgy of Maplin. I would have thought that contravenes UK distance selling rules where you're entitled to return the item for a full refund (minus shipping) within 7 days of purchase. I thought that was law. :scratch: It's supposed to protect you against accidentally purchasing an unsuitable product due to you not being able to actually see the item in the flesh. I'd pull them up on this. :)
EDIT: Here's a link to the regulations LINK (http://www.oft.gov.uk/shared_oft/business_leaflets/general/oft698.pdf). You want section 3.22 onwards. Basically you have the right to return the item within 7 days of receiving it even if the item is fully working. :)
Thanks for that Dave, very interesting..
Theres a Maplin 10 mins away from me, but I think I'll order through their website :)
(From the Maplin Website..)
Unwanted Goods under Distance Selling Regulations:
"The Distance Selling Regulations give customers the right to change their mind and to cancel an order within seven working days. Reasonable care should be taken whilst the goods remain in your possession and goods must be adequately packaged when being returned back to Maplin. Customers whose transactions are covered by the Distance Selling Regulations, the seven day cooling off period is inclusive within our 28 day returns policy."
Their own "28 day return policy" dictates that once an item is "used" (i.e. plugged in or even the box opened) it cant be returned unless faulty.
The wording above is a bit ambigious have to say..."the seven day cooling off period is inclusive within our 28 day returns policy"..which I TAKE to mean that 28 days included the 7 day cooling off period, meaning an extra 21 days over and above it.
Sounds like someone clever has worded it to make it look as though their returns policy supercedes the Distance Selling regs?
You see any probs with this?
Ta.
I have one of these Maplin 3A supplies in the garage which I used with some Class D amps. I will have to give it a try with the B/F.
HighFidelityGuy
05-08-2010, 11:39
The seller can offer extra days above and beyond the 7 day cooling off period and these don't have to be as generous as those layed down in the distance selling regs but they do have to state what the returns policy is in writing. From what I understand the 7 day rule will always supercede the sellers own policy. As for the bit about it being used, I doubt they could prove this if you packed it up exactly as you received it and returned it within 7 days of receipt.
So in the end it seems that you have more rights by buying online than you do by buying in store. The only downside is that you'd have to pay for the return postage. Unless you can return it to your local store. :eyebrows:
Thanks for that Dave, very interesting..
Theres a Maplin 10 mins away from me, but I think I'll order through their website :)
(From the Maplin Website..)
Unwanted Goods under Distance Selling Regulations:
"The Distance Selling Regulations give customers the right to change their mind and to cancel an order within seven working days. Reasonable care should be taken whilst the goods remain in your possession and goods must be adequately packaged when being returned back to Maplin. Customers whose transactions are covered by the Distance Selling Regulations, the seven day cooling off period is inclusive within our 28 day returns policy."
Their own "28 day return policy" dictates that once an item is "used" (i.e. plugged in or even the box opened) it cant be returned unless faulty.
The wording above is a bit ambigious have to say..."the seven day cooling off period is inclusive within our 28 day returns policy"..which I TAKE to mean that 28 days included the 7 day cooling off period, meaning an extra 21 days over and above it.
Sounds like someone clever has worded it to make it look as though their returns policy supercedes the Distance Selling regs?
You see any probs with this?
Ta.
http://i73.photobucket.com/albums/i239/saxonsex/Holiday022.jpg
OK. Tried the Maplin tonight. The PS has previously been modded with a larger smoothing cap by-passed with a poly cap, that's all.
I have been using a Teddyregged supply made up with bits plundered from wrecks. The tranny is probably only about 15va. The Maplin tranny I would guess at about 80va.
I was a bit surprised at the presentation. Very solid and has brought the mid-range out. Bass seems more a part of the whole and treble very sweet. I find that if you can increase the volume and not get harshness, then something must be right. I like improvements that cost nothing (well, relatively speaking as a garage cast off)
I have been listening to the passive mod (the white caps are 4.7uf Sonicaps) I will do some listening over the weekend with the active mode.
Leo,I'm already feeding the dac with a regulated linear supply.Do you think there's any mileage in using another linear supply to feed 5v to the dac chip directly?
You use the 7510 don't you? I think the 5v reg in these isn't as close to the dac chip and receiver as they are in the 7520/Caiman.
Instead of running a separate 5v supply to dac which may add a few probs because of the lead lengths, longer grounding returns etc I'd keep your main linear supply if its good and try improving the onboard 5v regulation , you could try tightening things up and run it closer to the dac and receiver chip.
Ali Tait
06-08-2010, 23:18
Yes it's a 7510.Ok thanks,I'll have a look.Even as it is though,it's not as good as the AN dac,that is comfortably better,but then it should be,given the retail.
Well if you've now gone passive its a good enough time for you to try a valve output stage like the AN dac
Ali Tait
07-08-2010, 07:36
Aye,thats a thought too.Have you tried one with the Beresford?
I've not tried one with the Caiman yet Ali, if anybody has any idea's what we can try :eyebrows:
Ali Tait
07-08-2010, 13:56
Well I was thinking maybe that output stage that Nick came up with would be very good,not cheap though,you need a pair of Sowter pp output trannies,and a pair of I think it's 6n1p's,which are cheap enough,so the trannies would be the major expenditure-more than the cost of the dac I think!
Thinking about it though,if I was to do that,I may as well do it to the AN rather than the Beresford.
Ali Tait
07-08-2010, 13:58
Oops no,it's 6n6p not 6n1p.
I think Nicks circuit was for differential output dacs, I'm still wanting to try one with the Sabre, it does make sense to try something cheaper with the Bdac, something which doesn't scare everybody off price wise :)
Ali Tait
07-08-2010, 21:31
Ahh yes I think you're right,I'd forgotten that.Maybe something from the Lampizator site then?
Ali Tait
07-08-2010, 21:37
This might be good-
http://www.diyhifisupply.com/node/408
Ahh yes I think you're right,I'd forgotten that.Maybe something from the Lampizator site then?
Maybe something like this if valves are too expensive
http://www.lampizator.eu/LAMPIZATOR/FETISHIZATOR/fetishizator.html
Could also try something based around the Pass B1
This might be good-
http://www.diyhifisupply.com/node/408
You could try it with the AN dac too :eyebrows: if its any better than the supplied AN circuit is the main question
Ali Tait
07-08-2010, 23:16
Aye,that's the question!
HighFidelityGuy
10-08-2010, 11:00
Has anyone who's using their Caiman with a SuperTeddy based linear supply tried swapping the Caiman's reservoir cap for a 10uF film or tant cap yet? I'm interested to know if any different caps change the sound at all.
I've tried a basic poly cap and haven't noticed any change so far.
Has anyone who's using their Caiman with a SuperTeddy based linear supply tried swapping the Caiman's reservoir cap for a 10uF film or tant cap yet? I'm interested to know if any different caps change the sound at all.
Yes, I did it this morning. Swapped out the 10,000uF reservoir cap for 2 x 10uF metallised polyester film caps. I also took out the 22R resistor feeding the +5V Dexa reg, replacing it with a wire link.
The SuperTeddy is set for exactly 16V. So far so good, it sounds very crisp and detailed with no lack of bass punch at all. I'll let it properly run in and report back later. I've left the Rubycon coupling caps in place as they sound excellent and I didn't want to change too much at once.
http://www.mtc.me.uk/images/CaimanReservoirMod.jpg
HighFidelityGuy
10-08-2010, 14:55
Thanks Martin, I'll be interested to hear if you think it makes any change to the sound.
I've ordered a few other types/makes of caps (tant and film) to try out, so I'll post my findings.
I've mostly done the same mods as you although I'm using Murata regs and currently have some Jensen caps for the passive mod (I'm trying lots). I've also swapped the resistor behind the 5V reg for a wire link but I've also swapped the fuse for a wire link. My next mod will be to swap the diode of a hexfred to see if that makes a difference. I'm trying to get the cleanest power possible into the DAC so that I can forget about that side of things and concentrate on tuning the sound with the choice of passive output caps.
My next mod will be to swap the diode of a hexfred to see if that makes a difference.
Someone correct me if I'm wrong, but since that diode is permanently conducting in the forward direction and not switching, the speed of a hexfred diode will make no difference.
Someone correct me if I'm wrong, but since that diode is permanently conducting in the forward direction and not switching, the speed of a hexfred diode will make no difference.
Isn't it just there to protect from incorrect polarity? If you are careful with polarity why not replace it with a wire link?
If you take the diode out with a wire link remember to drop the voltage into the Caiman by around 0.5v if you are already feeding above 15.5v or so. The only way around this is to swap out the smoothing cap rated at 16v and any others in front of the voltage regs rated at 16v.
Regards
Chris
Reid Malenfant
10-08-2010, 18:59
Someone correct me if I'm wrong, but since that diode is permanently conducting in the forward direction and not switching, the speed of a hexfred diode will make no difference.
If that is indeed the case then you are absolutely spot on :) They aren't that fast anyway, there is much faster & softer recovery diodes out there for switching applications.
If it's voltage drop someone is worried about fit a schottky barrier ;)
HighFidelityGuy
10-08-2010, 19:10
Someone correct me if I'm wrong, but since that diode is permanently conducting in the forward direction and not switching, the speed of a hexfred diode will make no difference.
Isn't it just there to protect from incorrect polarity? If you are careful with polarity why not replace it with a wire link?
If you take the diode out with a wire link remember to drop the voltage into the Caiman by around 0.5v if you are already feeding above 15.5v or so. The only way around this is to swap out the smoothing cap rated at 16v and any others in front of the voltage regs rated at 16v.
Regards
Chris
If that is indeed the case then you are absolutely spot on :)
You are of course all correct. :) It was really just the lower forward voltage drop that I wanted, whilst keeping the protection. I guess it's highly unlikely that I'll accidentally reverse the polarity and seen as I've already removed the fuse it would seem a little hypocritical to keep the diode. So I guess I'll bypass it. That would fit in better with my mission to ensure minimum voltage drop and maximum current delivery anyway. :eyebrows:
They aren't that fast anyway, there is much faster & softer recovery diodes out there for switching applications.
If it's voltage drop someone is worried about fit a schottky barrier ;)
That's an interesting point Mark, I thought HexFred's were supposed to be almost as fast as a schottky but smoother and therefore better for audio applications. What do you recommend as being fast but smooth?
Cheers. :)
Reid Malenfant
10-08-2010, 19:17
That's an interesting point Mark, I thought HexFred's were supposed to be almost as fast as a schottky but smoother and therefore better for audio applications. What do you recommend as being fast but smooth?
Cheers. :)
As i say a schottky barrier ;) These are perfect for using as commutating diodes in class G & H power amplifiers as they switch very cleanly (far better than any epitaxial diode). They also have much less voltage drop when carrying a similar current (assuming the same current rating). They are majority carriers unlike any epitaxial diode which is a minority carrier. They don't store charge in the junction like epitaxials which needs to be removed to shut the thing down when reverse biased all of a sudden.
I'm not sure what the current draw is of the DAC you are using. Let me know or tell me the diode you are/have removed & i'll suggest a schottky replacement ;)
HighFidelityGuy
10-08-2010, 19:32
As i say a schottky barrier ;) These are perfect for using as commutating diodes in class G & H power amplifiers as they switch very cleanly (far better than any epitaxial diode). They also have much less voltage drop when carrying a similar current (assuming the same current rating). They are majority carriers unlike any epitaxial diode which is a minority carrier. They don't store charge in the junction like epitaxials which needs to be removed to shut the thing down when reverse biased all of a sudden.
I'm not sure what the current draw is of the DAC you are using. Let me know or tell me the diode you are/have removed & i'll suggest a schottky replacement ;)
Ah, I see. :doh: I'm not 100% sure on the Caiman's current consumption but I don't think it's more than 2.5A. So what would you recommend for that?
While we're on the subject, what type of diodes/bridge rectifier would you recommend for use in a SuperTeddy (http://www.teddypardo.com/Articles/SuperTeddyReg.html) reg based supply?
Thanks. :)
StanleyB
10-08-2010, 19:57
I'm not sure what the current draw is of the DAC you are using. Let me know or tell me the diode you are/have removed & i'll suggest a schottky replacement ;)
150mA :).
HighFidelityGuy
10-08-2010, 19:58
150mA :).
Thanks Stan. :)
Reid Malenfant
10-08-2010, 20:02
Ah, I see. :doh: I'm not 100% sure on the Caiman's current consumption but I don't think it's more than 2.5A. So what would you recommend for that?
While we're on the subject, what type of diodes/bridge rectifier would you recommend for use in a SuperTeddy (http://www.teddypardo.com/Articles/SuperTeddyReg.html) reg based supply?
Thanks. :)
2.5A i'd recommend a 1N5820 or 5821/5822, the only difference is breakdown voltage. The 1N5820 being 20V, 21 being 30V & 22 40V. As it's forward biased then toss a coin for it :lol:
I'm not sure what the SuperTeddy current output is & a brief look at the link gave no clues. Obviously current capacity & voltage breakdown are going to be important. Let me know what the main rectifier has to deal with & i'll be able to put you in the picture.
You can always overate the diodes, i always do & this results in less voltage drop as well as being overkill & effectively lasting probably longer than any other component :eyebrows:
As an example i wanted a load of schottkys that would be happy with a continuous current of 11Amps or so but at low voltage. I happened to find a load of 15V devices ( i needed 10V max) & each one was rated 100A. They'll last forever :lolsign:
Reid Malenfant
10-08-2010, 20:04
150mA :).
:lol: Ok then, a 1N5819 will suffice ;)
HighFidelityGuy
10-08-2010, 21:00
Awesome, thanks Mark.
The SupperTeddy has a maximum output current of 1A as standard I believe. 2A can be achieved with upgraded jfets. I'm using a 24V toroidal transformer. Does that help you to figure out what diodes would be best for this?
Thanks.
Reid Malenfant
10-08-2010, 21:23
Use the previously mentioned 1N5822 ;) 40V 3Amp..
These will handle 3A continuous DC (over 10Amp peak pulsed @ 50Hz) & have a maximum reverse voltage of 40V. However, they do have rather thick leads to the diode & i'm guessing that these help conduct heat to the circuit board to help dissipate heat. You could always upgrade to a higher current schottky such as the type mounted in a TO220 type transistor case & carefully bend the legs to fit.
It's what i'd do :eyebrows:
I'll be back tomorrow if you have any more questions, feel free, it's what its all about :)
Bests to you... 2433
Hi Mark, I'm feeding my SuperTeddy from a standard bridge rectifier (inline four pinout). Are there any fast switching low noise bridges in existence, do you know?
Not tried any of these myself yet http://www.partsconnexion.com/rectifier_bridge_hex.html
I'm currently trying some Cree Silicon Carbides (but as discrete) in another dac. Its quite surprising the effect you can get playing about with the rectifiers
For the Caiman I'm just going to try running the supply after the input DC diode just to see, for the STR I just use a rectifier made from UF4002
Thanks, Leo. Never seen a bridge rectifier with 5 legs before! I will check the pinout but may make up my own with four hexfred diodes.
Ali Tait
11-08-2010, 14:28
I was going to suggest making your own,it's easy to do.
Reid Malenfant
11-08-2010, 15:23
Hi Mark, I'm feeding my SuperTeddy from a standard bridge rectifier (inline four pinout). Are there any fast switching low noise bridges in existence, do you know?
Well i do now that Leo has linked to some :lol:
Offhand no i don't, but as Ali says they are easy enough to make & then you'll have a much wider choice of diode types to play with :)
HighFidelityGuy
11-08-2010, 15:23
Not tried any of these myself yet http://www.partsconnexion.com/rectifier_bridge_hex.html
I'm currently trying some Cree Silicon Carbides (but as discrete) in another dac. Its quite surprising the effect you can get playing about with the rectifiers
For the Caiman I'm just going to try running the supply after the input DC diode just to see, for the STR I just use a rectifier made from UF4002
That's what I use in my SupperTeddy supply. Specifically part number SEMI-68495 (http://www.partsconnexion.com/product4794.html). I chose that over the 22A one because I brefered the case style.
http://i2.photobucket.com/albums/y48/DTM2000/Hi-Fi/Beresford%20DACs/th_Caiman_PSU_01-1.jpg (http://s2.photobucket.com/albums/y48/DTM2000/Hi-Fi/Beresford%20DACs/?action=view¤t=Caiman_PSU_01-1.jpg)
Am I likely to gain any sort of improvement by swapping this to a bridge made out of 1N5822 schottky diodes?
EDIT: I just thought; the 1N5822 is 40V. I'm currently feeding my bridge with about 24V AC and getting about 38V DC out the other end. Are 1N5822 diodes still suitable for this application?
Thanks. :)
Is there anything limiting the type of 10 uF cap you can use to replace the Caiman resovoir cap with, i.e. not physical space (a problem) but dielectric strength? Is there a reason why Stan had a special 16V 10,000uF made or was it that it just had to be dielectrically strong enough to take the 15V power supply? I can't see a problem in using a polyprop cap with say 400 V dielectric strength in there but then I'm a physicist not an electronics engineer.;)
Cheers Andy
HighFidelityGuy
12-08-2010, 13:01
Is there anything limiting the type of 10 uF cap you can use to replace the Caiman resovoir cap with, i.e. not physical space (a problem) but dielectric strength? Is there a reason why Stan had a special 16V 10,000uF made or was it that it just had to be dielectrically strong enough to take the 15V power supply? I can't see a problem in using a polyprop cap with say 400 V dielectric strength in there but then I'm a physicist not an electronics engineer.;)
Cheers Andy
My guess would be that stan had the original resevoir cap made to match the original switching supplies that he sells. So I don't think those considerations will apply to using a linear supply in quite the same way.
Power supply design expert Teddy Pardo simply recommended a film or tant cap of suitable voltage rating, nothing more specific than that. So I don't think anything fancy is required. :)
Power supply design expert Teddy Pardo simply recommended a film or tant cap of suitable voltage rating, nothing more specific than that.
That's what I did - 2 x 10uF metallised polyester film fit perfectly in the gap vacated by the electrolytic and should offer much faster response. The reality is that it does sound very good indeed, having the edge in dynamics and fine detail.
Hi Martin,
Any reason why you put in two film caps?
Reid Malenfant
12-08-2010, 13:34
Am I likely to gain any sort of improvement by swapping this to a bridge made out of 1N5822 schottky diodes?
EDIT: I just thought; the 1N5822 is 40V. I'm currently feeding my bridge with about 24V AC and getting about 38V DC out the other end. Are 1N5822 diodes still suitable for this application?
Thanks. :)
I think you'd have to try schottkys & see if there is any difference yourself tbh. There won't be a lot between a fast rectifier & schottkys in theory, practise might be a different matter though ;)
I'll have a look about for some 60V rated versions, yes 38V is cutting it a little close :lol:
Any reason why you put in two film caps?
Because they fit and it gives me 20uF smoothing :)
Reid Malenfant
12-08-2010, 13:55
60V schottky diodes rated at 3Amp - SR360, 5Amp - SR560
A quick suggestion is to type schottky into ebay search (http://shop.ebay.co.uk/?_from=R40&_trksid=p3984.m570.l1313&_nkw=schottky&_sacat=See-All-Categories), there are loads of them :eyebrows:
HighFidelityGuy
12-08-2010, 14:06
60V schottky diodes rated at 3Amp - SR360, 5Amp - SR560
A quick suggestion is to type schottky into ebay search (http://shop.ebay.co.uk/?_from=R40&_trksid=p3984.m570.l1313&_nkw=schottky&_sacat=See-All-Categories), there are loads of them :eyebrows:
Awesome, thanks Mark.
I might look at swapping the bridge in my supply to these to see if it makes any difference. I'll probably not do it for a while though as I don't want to change too many things at the same time.
Cheers. :)
Because they fit and it gives me 20uF smoothing :)
Yep, very clear that one:)
squeezethatbuffalo
13-08-2010, 02:30
I think Nicks circuit was for differential output dacs, I'm still wanting to try one with the Sabre, it does make sense to try something cheaper with the Bdac, something which doesn't scare everybody off price wise :)
Hi Leo,
I really want to try out the same valve output stage. Unfortunately, I didn't grab the schematic while I can (audio-talk seems to be down). Do you think it's okay to send me a working link or a copy of it?
Thank you!
Edit: Oops, nevermind, the site's up again!
Hi Leo,
I really want to try out the same valve output stage. Unfortunately, I didn't grab the schematic while I can (audio-talk seems to be down). Do you think it's okay to send me a working link or a copy of it?
Thank you!
Edit: Oops, nevermind, the site's up again!
Here you go http://www.audio-talk.co.uk/phpBB2/viewtopic.php?t=2170
squeezethatbuffalo
15-08-2010, 17:16
Thank you leo!
Out of curiosity, how are things going with your Buffalo II? ;)
Thank you leo!
Out of curiosity, how are things going with your Buffalo II? ;)
So not to derail this thread :) http://theartofsound.net/forum/showthread.php?p=144315#post144315
UPGRADING THIS LINEAR SUPPLY...
..is my next project.
Any pointers as to what, how and where? :scratch: :)
I really noticed the improvement over the switching supply I had (Maplins variable set to 15v), so my eyes (ears?) were opened a bit as to how important a good supply was.
I'm sure this Maplin CB radio supply has some bog standard parts in it, any idea how it can be improved as a PSU for my Caiman?
Thanks.
Gaz.
If your up to it and if the raw DC supply has enough headroom you could maybe try disconnecting the stock regulation and fit something like a Super Teddy reg or similar . Going for a ready built unit as an upgrade is going to cost you a fair bit more tbh compared to upgrading what you already have
Thanks for that Leo..
I'd be looking to upgrade components within the Maplins psu rather than gettin something new.
The Teddyreg gets a lot of mentions here...an option for sure.
Need to do my homework on these supplies..at least know a wee bit about what I'm asking!
I know not a lot, not a big diy / soldering guy!
If your up to it and if the raw DC supply has enough headroom you could maybe try disconnecting the stock regulation and fit something like a Super Teddy reg or similar . Going for a ready built unit as an upgrade is going to cost you a fair bit more tbh compared to upgrading what you already have
Seconded for the TR or STR. I have a "ripple eater" between he Maplin and B/ford. I upgraded the smoothing caps in the Maplina and bypasssed them with some Poly caps.
Seconded for the TR or STR. I have a "ripple eater" between he Maplin and B/ford. I upgraded the smoothing caps in the Maplina and bypasssed them with some Poly caps.
You sound like the man I want to speak to Rob!
ok to PM, get more info about this?
Ta. :)
Gary.
You sound like the man I want to speak to Rob!
ok to PM, get more info about this?
Ta. :)
Gary.
Can I stop you? :eyebrows:
Ali Tait
24-09-2010, 14:03
Gary,I can do any mods you want doing to the PS mate.
Theres a choice of regs you can try Gaz , Super Teddy regs, Audiocoms , Paul Hynes, ALW super regs etc so plenty to choose from.
Gary,I can do any mods you want doing to the PS mate.
There's only one way to settle this.........:sofa:
Ali Tait
24-09-2010, 16:13
Haha! No,I meant I could do the mods you suggest!
Thanks for the pointers guys, and Cheers Ali for the offer.
Duh duh, dee dee dee duh,
Who you gonna call.....?
ALI TAIT!
Rob, you have PM, cheers.
mike1210
14-12-2010, 00:29
Has anyone tried one of these
http://www.fidelityaudio.co.uk/beresford_psu.shtml
not cheap I know
Stratmangler
14-12-2010, 00:34
Has anyone tried one of these
http://www.fidelityaudio.co.uk/beresford_psu.shtml
not cheap I know
You won the lottery ? :lolsign:
twelvebears
14-12-2010, 04:56
You won the lottery ? :lolsign:
Yeah that was my reaction when I saw it....
Interestingly this is the chap who first started selling Beresford 'tweaks' on ebay I believe, and while by all accounts he's a very decent chap and everything, I can't help but think that the price of his stuff is now a bit 'ambitious' given some of the alternatives.
I mean if you were in the market for a headphone amp, would you rather spend £350 for this guy's 'cheap' model or the same money on Alex Nikitin's top-end SE version?
StanleyB
14-12-2010, 08:10
The things some bottom feeders will do just so that they can have a parasitic relationship with the Caiman :rolleyes:.
Reid Malenfant
14-12-2010, 11:26
Has anyone tried one of these
http://www.fidelityaudio.co.uk/beresford_psu.shtml
not cheap I know
Something doesn't add up there :scratch:
50VA transformer with a 15V regulated output at 5 Amps :scratch:
:lolsign:
Something tells me a 100VA transformer would be needed in reality :rolleyes:
StanleyB
14-12-2010, 11:47
It has mystical powers, for which one is expected to pay a mythical price ;).
Any progress on modding the Maplins linear supply? Is this PSU still worthwhile upgrade for a Murata regs, Gator board Caiman, on a decent system?
P.S.
The things some bottom feeders will do just so that they can have a parasitic relationship with the Caiman :rolleyes:.
Obvously not endorsed, yet is advertised as a "Beresford Dac Ultra PSU", giving the impression it is a Beresford product. Is that legal? Should someone say something?
amdismal
13-04-2011, 18:44
I'm a little perplexed at the moment. I recently got a linear PSU for my Caiman, to see if it would make any difference. I adjusted it for 15V, plugged it in - and the Caiman didn't work properly - all the input lights turned on. I quickly turned it off.
I then checked the Caiman PSU, and saw that it was giving out 12V, not 15V. Odd.
Were there two versions of the Caiman?
The earliest Caimans, one of which I purchased, came with a tiny PSU that was 12V. I upgraded this by purchasing the newer, larger 15V SMPS, which has "Beresford Caiman" printed on the front.
So no, I believe there is only one Caiman, but two PSUs sold in its history.
The earliest Caimans, one of which I purchased, came with a tiny PSU that was 12V. I upgraded this by purchasing the newer, larger 15V SMPS, which has "Beresford Caiman" printed on the front.
So no, I believe there is only one Caiman, but two PSUs sold in its history.
I think that is correct - initial Caimans were sold with the 12v PSU, but an upgrade to the 15v one was offered on here and presumably on Stan's site to early adopters who wanted to upgrade, and all further Caimans were then supplied with the 15v PSU. So I don't believe your problem is directly related to 15v - maybe something else is awry? (Polarity?)
StanleyB
14-04-2011, 07:13
I'm a little perplexed at the moment. I recently got a linear PSU for my Caiman, to see if it would make any difference. I adjusted it for 15V, plugged it in - and the Caiman didn't work properly - all the input lights turned on. I quickly turned it off.
I then checked the Caiman PSU, and saw that it was giving out 12V, not 15V.
Is the DAC working fine with the 12V power supply?
I'm a little perplexed at the moment. I recently got a linear PSU for my Caiman, to see if it would make any difference. I adjusted it for 15V, plugged it in - and the Caiman didn't work properly - all the input lights turned on. I quickly turned it off.
Sometimes the Caiman powers up with all lights showing. Could you select an input by clicking one of the source buttons? Does it then work? If so, it's fine :)
All the lights come up on mine on power-up, but there sure ain't anyone home :lol::eek:
StanleyB
14-04-2011, 10:51
If you are using a power supply that is not one of mine you might find that all the lights come on whne you first power the DAC up. You have to press one of the input selector buttons before the DAC gives you any sound. In some cases you might have to press several of the buttons, before pressing the actual one that you have a signal connected to.
amdismal
14-04-2011, 11:11
Thanks guys, I will try all these things! It works perfectly with the 12V PSU it came with. I have checked the polarity, so presumably am in the 'can't do any damage' zone, so will leave it a bit longer and randomly press buttons.
Stan - why does it have this behaviour with non-Beresford PSUs? Is there something about the power delivery that is unique to your PSUs? I would have thought that power is power, just that some has lower ripple.
And what voltage should I feed it for best results? While the PSU is adjustable, it's a soldering job and I don't have all the right resistors (I had to wire loads together in series and parallel to get the right resistance for 12V!), so it's a bit of a palaver to try blind testing, to say the least!
And what voltage should I feed it for best results? While the PSU is adjustable, it's a soldering job and I don't have all the right resistors (I had to wire loads together in series and parallel to get the right resistance for 12V!), so it's a bit of a palaver to try blind testing, to say the least!
It doesn't need to be that difficult honestly.
From Stans original post:
http://theartofsound.net/forum/showpost.php?p=112542&postcount=1
I have one of these and have found it a good improvement over standard, especially if you have upgraded the internal regualtors in the Dac to Muratas's.
I dont know my a*rse from my elbow when it comes to soldering :), but Stans instructions here are very easy to follow.
You can do better than the Maplin supply of course, but I would think it would need to be a serious DIY job, or pay £££ for something like a Teddy pardo supply.
Mutara's.
Did you mean Muratas? LOL!
Did you mean Muratas? LOL!
uhm..... yeah. :)
glad someone spotted the deliberate mistake?
HighFidelityGuy
14-04-2011, 12:33
The LED's on my Caiman go a bit funny sometimes after reconnecting it to the PSU. Pressing a few buttons like Stan suggested always sorts it out. It's nothing to worry about. I nearly crapped myself the first time it happenend as I thought I'd junked it doing a mod. :lol:
amdismal
14-04-2011, 16:24
It doesn't need to be that difficult honestly.
Well the PSU I have is the one I have. I should put a pot on it so I can vary it easily, but haven't got round to it.
However, it still does the Xmas light thing, even if I press lots of buttons for a minute or so - and that's at 12V. Why does it do this, anyone?
I'm a bit miffed that I seem to have a 12V Beresford PSU for my 15V Beresford device, but it works as is. I shall put the PSU back into the storage, I think...
HighFidelityGuy
14-04-2011, 16:51
The Caiman isn't a 15V device as such, it works with 12V and early Caiman's were shipped with 12V transformers. The 15V Caiman supply is an upgrade. The Caiman only requires a 15V supply if the 12V regulator has been upgraded to a Murata version as they have a dropout voltage of about 13V.
I would suggest that you try a different 15V linear supply as your current one may be faulty or may not like charging the large reservoir capacitor in the Caiman. The best results with a linear supply seem to come when the cable length between supply and Caiman are kept as short as possible and the Caiman's reservoir cap is replaced with a smaller film version. There's info about this earlier in this thread or one of the other linear supply threads. :)
StanleyB
14-04-2011, 17:02
I'm a bit miffed that I seem to have a 12V Beresford PSU for my 15V Beresford device, but it works as is.
The Caiman PSu was developed as part of a further upgrade, starting at the original TC-7520 that some of us modified with a WM8716 DAC chip. Things progressed from there with a modified TC-7520 called the TC-7520SE, and later renamed to Caiman. A few months after that people started experimenting with power supplies and I brought out my own modded PSU for the Caiman, which was sold with the Caiman as a package and at an additional cost.
I am not sure why you are miffed. It was well publicised on AoS that there was going to be a Caiman PSU, and that anyone with the Caiman DAC and TC-7520 PSU could upgrade to the Caiman PSU at cost plus shipping and VAT. I even put the Caiman PSU on my site as an upgrade.
So if you want a Caiman PSU as an upgrade it is still available to AoS members at the stipulated cost.
Well the PSU I have is the one I have. I should put a pot on it so I can vary it easily, but haven't got round to it.
However, it still does the Xmas light thing, even if I press lots of buttons for a minute or so - and that's at 12V. Why does it do this, anyone?
I'm a bit miffed that I seem to have a 12V Beresford PSU for my 15V Beresford device, but it works as is. I shall put the PSU back into the storage, I think...
Hey fellah just trying to help ... :)
StanleyB
15-04-2011, 06:39
If you got a bench type power supply with an LCD display, you can set the PSU to 16V (16.2V works for me, but that's pushing it) and hear a slight improvement over the 15V power supply. This combo works best with the Murata modded DAC in my selection.
Interesting Stan. The LCD bench supplies in Maplins seem to be SMPS based. This looks versatile with 5MV ripple and noise;
http://www.maplin.co.uk/triple-power-supply-5925
StanleyB
15-04-2011, 07:24
I don't like the Maplin one. I tried it, but took it back. It's switched mode and worse sounding than the Caiman PSU.
I have a spere lab specced linear one up for sale if anyone is interested in trying one with Caiman and can pick it up. Weights 5Kg. I should put it in the classified I reckon.
Just tried linear with this set-up.
Caiman+Muratas+gator
Large, costly, made with my blood, sweat, and tears, speakers.
CD player and a movie.
Tonight changed the 15V SMPS for a linear supply (at 16V as Stan suggested). Swapping between supplies takes seconds so comparisons were easy.
First CD; No difference on the two tracks tried, but then I never liked this CD.
Second CD; Changing between supplies was surprising for me. Going back to the SMPS was immediately unpleasant in comparison. I thought my DIY speakers were the problem, but everything is realistic (or "smooth") now. For example, the strings were getting lost under the layers of performers, but now each layer is present and easy to follow. I had to brace myself on some dynamic parts before, but now the sound is so realistic, i.e. free of distortion, that I can relax fully. This was most obvious in an action movie I use for testing.
Other CDs; Same positive experience.
More detail, more realism, more pleasant. I'm happy, and surprised at the difference to be honest.
StanleyB
16-04-2011, 05:36
I recommended the use of a laboratory power supply before, and I am pleased that you can hear the reasons why ;).
Just tried linear with this set-up.
Caiman+Muratas+gator
Large, costly, made with my blood, sweat, and tears, speakers.
CD player and a movie.
Tonight changed the 15V SMPS for a linear supply (at 16V as Stan suggested). Swapping between supplies takes seconds so comparisons were easy.
First CD; No difference on the two tracks tried, but then I never liked this CD.
Second CD; Changing between supplies was surprising for me. Going back to the SMPS was immediately unpleasant in comparison. I thought my DIY speakers were the problem, but everything is realistic (or "smooth") now. For example, the strings were getting lost under the layers of performers, but now each layer is present and easy to follow. I had to brace myself on some dynamic parts before, but now the sound is so realistic, i.e. free of distortion, that I can relax fully. This was most obvious in an action movie I use for testing.
Other CDs; Same positive experience.
More detail, more realism, more pleasant. I'm happy, and surprised at the difference to be honest.
Which linear supply was it?
I run the Maplins CBRadio one Stan recommended and found similar.
Thats only at 15V though...
http://cgi.ebay.co.uk/Bench-Power-Supply-0-30-VDC-0-3A-Variable-1A-5VDC-/320681379601?pt=UK_BOI_Electrical_Test_Measurement _Equipment_ET&hash=item4aaa198711#ht_3457wt_907
http://www.circuitspecialists.eu/fixed-dual-output-bench-power-supply-csi-3003x5-p-163.html
Apparently, the Muarta regs only get their preferred 15V from at least a 15.6V supply, due to 0.6 diode in the Caiman blocking that bit of current.
read this with interest as I've built several psu's for the sb3 ..... so my two penny worth ....
mod the linears by swapping out the noisy rectifier diodes and replace with schottkies ..say 30 dq10's for a 3amp psu ....
caps ..no one has twigged that 10 parallel 100uf will make 1000uf ...and once you cosider that many smaller caps will sound superior to one large cap ....to do with the esr [?] of larg and small caps think ..
my linear for the sb3 started with 5000uf ....but no has in excess of 20000uf of pannasonic fc's [ 20 x 1000uf ]
this combined with a 100va torroidal ....
you don't get more bass or treble ...its actually in the delicacy and fine points of the music that are brought to life . This is over the stock linear ..... the smps just seem to inject noise into the unt ..so I'm assuming the same happens with the caiman and the 7510 ?
Reid Malenfant
27-04-2011, 19:13
Good point about the schottky diodes Pete ;)
I certainly wouldn't go so far as to say that lots of caps will be superior to one big one just because of lower ESR, you need to take into account the circuit inductance & resistance due to all the extra tracks/connections which would be needed to connect 20 capacitors (in your case) in parallel. Done right it can improve things though under certain circumstances :)
Throwing capacitance at it will reduce the ripple voltage on the capacitors & because any regulator only has a certain amount of ripple rejection it will result in lower ripple on the output which is a good thing :cool:
Nothing like an OTT transformer either ;)
read this with interest as I've built several psu's for the sb3 ..... so my two penny worth ....
mod the linears by swapping out the noisy rectifier diodes and replace with schottkies ..say 30 dq10's for a 3amp psu ....
caps ..no one has twigged that 10 parallel 100uf will make 1000uf ...and once you cosider that many smaller caps will sound superior to one large cap ....to do with the esr [?] of larg and small caps think ..
my linear for the sb3 started with 5000uf ....but no has in excess of 20000uf of pannasonic fc's [ 20 x 1000uf ]
this combined with a 100va torroidal ....
you don't get more bass or treble ...its actually in the delicacy and fine points of the music that are brought to life . This is over the stock linear ..... the smps just seem to inject noise into the unt ..so I'm assuming the same happens with the caiman and the 7510 ?
Hey Pete, good to see you on AOS.
Bringing this thread full circle somewhat, I've Stans recommended Maplin linear CB Radio PSU and found it was a nice step up over the stock switched unit.
Of course it can be upgraded..and many of the guys on here would be interested in doing that I'd imagine?
Any thoughts Pete what could be done specifically with this supply? Start of with teh general advice given above or....?
maybe an Idoit's guide (for me at least!)..we all like to get most bang for our buck round these parts... :)
thanks.
Good point about the schottky diodes Pete ;)
I certainly wouldn't go so far as to say that lots of caps will be superior to one big one just because of lower ESR, you need to take into account the circuit inductance & resistance due to all the extra tracks/connections which would be needed to connect 20 capacitors (in your case) in parallel. Done right it can improve things though under certain circumstances :)
Throwing capacitance at it will reduce the ripple voltage on the capacitors & because any regulator only has a certain amount of ripple rejection it will result in lower ripple on the output which is a good thing :cool:
Nothing like an OTT transformer either ;)
the multiple cap thing was from research carried out in the 80's documented i the short lived mag called common ground ....and I believe was published under grahmn nalty's name ...but Ill check ...
jon a more practical side I've used this technique endlessly ....as it works , its clearly audible .... one of the reasons is its easier to keep a small cap charged ..they are faster to react to any demand placed upon the charge ...so it should be evident that sharper leading edges on the musical notes is one of the more obvious benefits ...
I'll look up the article and provide a precis at some stage ...unless anyone else has the document .
Hey Pete, good to see you on AOS.
Bringing this thread full circle somewhat, I've Stans recommended Maplin linear CB Radio PSU and found it was a nice step up over the stock switched unit.
Of course it can be upgraded..and many of the guys on here would be interested in doing that I'd imagine?
Any thoughts Pete what could be done specifically with this supply? Start of with teh general advice given above or....?
maybe an Idoit's guide (for me at least!)..we all like to get most bang for our buck round these parts... :)
thanks.
would need to see the curcuit ..
but try 11dq10's inplace of the rectifier doides as a jumping off point
Being a complete and utter numpty when it comes to wires n' things I don't usually tinker with electrical stuff but having read Stan's idiot proof instructions on this thread I decided to have a go with this upgrade.
I bought the psu described from Maplin's today, removed the cover and did as Stan says inside the unit. With heart in mouth I cut the dc cable from the Caiman psu for connection to the new one. Had a real fright though when I stripped it and saw the cable wasn't the twin run I was expecting. After much deliberation with my dark side I figured out the connection and, at arms length, switched on.
Wow....what a transformation! I use the Caiman with a Duet (bought a new psu for this today also) and am staggered by the improvement. More clarity, better separation, better imaging, overall much cleaner sound. This is now by far my best source, I'm very happy!!
Thanks Stan.
StanleyB
14-05-2011, 17:24
This is now by far my best source, I'm very happy!!.
And no doubt very proud of your first attempt at modifying an electrical product you only just bought ;). All that fun from me at no extra cost:).
And no doubt very proud of your first attempt at modifying an electrical product you only just bought ;). All that fun from me at no extra cost:).
Ha ha, have a drink on me:cool:
I don't think I'll be rushing off to buy a soldering iron though:lolsign:
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