Not sure it'll make as much difference Gary,yours has the Murarta regs on does it not?
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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
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.Quote:
Originally Posted by Ali Tait
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?
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.
Yeah..Quote:
Originally Posted by Ali Tait
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...
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.
Thanks Stan.Quote:
Originally Posted by StanleyB
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.
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.Quote:
Originally Posted by OLED
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
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.
Yep, SuperTeddy reg, 100VA tranny, HexFred bridge rectifier, 22,000uF Mundorf smoothing cap etc.Quote:
Originally Posted by Gazjam
Here's a not very good photo of it before I'd finished bolting it all together:
http://i2.photobucket.com/albums/y48...n_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.
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?
No probs. :)Quote:
Originally Posted by Gazjam
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. 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..Quote:
Originally Posted by HighFidelityGuy
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.
Sounds good Rob!
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:
Quote:
Originally Posted by Gazjam
http://i73.photobucket.com/albums/i2...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.
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.Quote:
Originally Posted by Ali Tait
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.
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
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:
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.
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 :)
Ahh yes I think you're right,I'd forgotten that.Maybe something from the Lampizator site then?
This might be good-
http://www.diyhifisupply.com/node/408
Maybe something like this if valves are too expensiveQuote:
Originally Posted by Ali Tait
http://www.lampizator.eu/LAMPIZATOR/...ishizator.html
Could also try something based around the Pass B1
You could try it with the AN dac too :eyebrows: if its any better than the supplied AN circuit is the main questionQuote:
Originally Posted by Ali Tait
Aye,that's the question!
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.
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.Quote:
Originally Posted by HighFidelityGuy
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
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.
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.Quote:
Originally Posted by HighFidelityGuy
Isn't it just there to protect from incorrect polarity? If you are careful with polarity why not replace it with a wire link?Quote:
Originally Posted by MartinT
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 :) They aren't that fast anyway, there is much faster & softer recovery diodes out there for switching applications.Quote:
Originally Posted by MartinT
If it's voltage drop someone is worried about fit a schottky barrier ;)
Quote:
Originally Posted by MartinT
Quote:
Originally Posted by Clive
Quote:
Originally Posted by chrism
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:Quote:
Originally Posted by Reid Malenfant
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?Quote:
Originally Posted by Reid Malenfant
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.Quote:
Originally Posted by HighFidelityGuy
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?Quote:
Originally Posted by Reid Malenfant
While we're on the subject, what type of diodes/bridge rectifier would you recommend for use in a SuperTeddy reg based supply?
Thanks. :)
150mA :).Quote:
Originally Posted by Reid Malenfant
Thanks Stan. :)Quote:
Originally Posted by StanleyB