Caiman passive output mod revealed [Archive] - Page 5

LittleTone

21-03-2011, 00:10

Hi Guys - Just a bit of final advice please.

Have been running a 7520 with a 4526 and ML5/6 removed into a pre-amp with a 33k input impedence.
Today I carried out Stans suggested initial passive mod
http://theartofsound.net/forum/showpost.php?p=136331&postcount=207

Well that was definately a step closer to audio nirvana; but I guess I now need to fit the capacitors.
I've read all 101 posts on this thread and have come to the conclusion that I should be considering a cap' with a value of 2.2uf. In fact Martin has been so impressed with the 2.2uf 200v Auricap that I'm thinking I'll try these.
I just looking for confirmation from the experts out there that even with a standard 7520 this is the way to go
Great site guys - keep up the good work

Regards
Tony

isj1202

21-03-2011, 00:43

Tony I would go a little bigger than 2.2uf say 3uf.

I use 3.9uf Claritycap ESA into 24k for a Linn Kairn. I prefered these to the 4uf Auricaps I tried, 250V version of Clatiycap also allow the case to close.

MartinT

21-03-2011, 06:40

The Claritycaps are good but I preferred the Auricaps. The value is not too important as long as your preamp has a decent input impedance of, say, 50k ohm or greater.

LittleTone

21-03-2011, 08:13

MartinT

21-03-2011, 09:59

You definitely want the 50k 775mV otherwise the input circuit will be saturated into distortion.

LittleTone

21-03-2011, 10:37

Hi Martin,
Thank you for your assistance; I'm getting there

Yes, OK I'll switch it over to the 50k impedence setting. I had wondered about this; considering the output from the DAC was probably quite high.Needs a bit more stick on the volume control control though.
The Cap' calculator would suggest a value of around 1.6 uf now. Do you think that would be OK.
Curious - As I have no caps' in place at the moment does that mean my optimal
low frequency response is infinity. The sound is better; vocals have really come alive; more detail and the difference between good and bad recordings seems more noticeble. but does sound less controlled, especially at the bottom end. Hence the caps I guess.
TIA
Tony

MartinT

21-03-2011, 12:13

As I have no caps' in place at the moment

Hi Tony, what do you mean by this? Are you still using the op-amp board output? If so, then the lo frequency cut-off will not be DC but it will be very low.

With coupling caps, as you have calculated 1.6uF upwards will be fine, making 2.2uF the obvious choice unless you have a size restriction with certain brands of cap.

P.S. there is no need for the subsonic filter unless your speakers have very limited power handling.

Reid Malenfant

21-03-2011, 12:30

I'd get some capacitors in the respective positions as soon as possible if i was you ;) If i'm right the output of the DAC is sitting at about 2.5V for zero volts output as it's only powered by a single 5V rail. This means you are putting 2.5V DC down the audio cables to your amplifier & it'll probably be dropping this accross the input resistor which will result in an increase in Johnson noise.

I think you are lucky that it's not a DC coupled amplifier & must have capacitors on the input or you'd experience some serious problems :doh:

MartinT

21-03-2011, 12:50

Eek, I was hoping that Tony is not doing that!

LittleTone

21-03-2011, 13:28

Wired it like this post by Stan

http://theartofsound.net/forum/showpost.php?p=136331&postcount=207

Regards
Tony

MartinT

21-03-2011, 14:35

Ah, ok that's fine :)

nickbojko

13-06-2011, 19:02

i have been reading this post since beginning,stay with 47uf caps(nichicon zk's) very nuetral,bypass with polystyrene .06 to .1,better than any polypropelene.you can pick them up on the net surplus.I've been using them since the 80's,also use small values on power supply electrolitics,silver mica or polyester-pass.try listening comparisons.polypropelene's are good but the prices have sky rocketed.

Marco

13-06-2011, 19:59

Hi Nick,

Welcome to AoS :)

Could you please pop into the Welcome area and introduce yourself to our community?

This is required by all new members, so use the existing threads there as a guidline to see what info is required (system details and music tastes).

Cheers! :cool:

Marco.

nickbojko

13-06-2011, 23:10

has anybody though of buying another one and running them as mono pair?

MartinT

14-06-2011, 05:31

Not really, but do explain what you would expect to hear?

nickbojko

14-06-2011, 15:37

no cross talk between channels,everything is separated,power supplies,etc.getting back to caps-conrad-johnson has been using polystyrene coupling caps since the late 70's.

MartinT

14-06-2011, 18:49

I still like the sound quality I'm getting from 2.2uF AuriCaps. I like dual-mono construction in general, but doubling up on Caimans is probably egging the pudding too far and there may be better ways to do things.

Reid Malenfant

14-06-2011, 19:00

I can see problems straight away. You only have a single 75 ohm coaxial cable or Toslink. Splitting that into two without buggering up the 75 ohm impedance would be a game in itself :eyebrows: Likewise with the Toslink me thinks.

Of course after that the problems just keep mounting up. What you need to do is make seperate PSUs for the left & right output ICs or Gator if fitted. Would save a shed load of hassle at the end of the day ;) However still not the easiest if you don't know precisely what you are doing :eyebrows:

StanleyB

14-06-2011, 19:04

I like dual-mono construction in general, but doubling up on Caimans is probably egging the pudding too far and there may be better ways to do things.
Very much so. But I am getting fed up of the ever increasing pile of abandoned expensive prototypes. I need a breakthrough.. Maybe pure DC (i.e. no caps in the signal path ) might be the solution to those caps.

MartinT

14-06-2011, 19:09

...which leads to fully balanced design with XLR outputs, yay!

Please? :)

Reid Malenfant

14-06-2011, 19:16

...which leads to fully balanced design with XLR outputs, yay!

Please? :)
How about using two DAC chips in differential mode to do this? Surely a better idea than converting single ended to balanced :scratch:

MartinT

14-06-2011, 19:22

Yes, was thinking that, cancels out the distortions rather nicely too.

Reid Malenfant

14-06-2011, 19:23

Indeed :)

StanleyB

14-06-2011, 20:22

Balanced leaves me hot and cold... I don't even own a balanced amp. I am not running a studio set up after all.

Reid Malenfant

14-06-2011, 20:31

<snip> Balanced leaves me hot and cold... I don't even own a balanced amp.
:lolsign: You don't know what you are missing Stan, get up to date :spank:

I much prefer a balanced system & i'm sure Martin will totally agree :) The difference between balanced & single ended isn't subtle, it's quite noticeable ;)

MartinT

14-06-2011, 20:36

Agreed! Stan, balanced is not just for studios. It inherently has lower noise floor and better noise rejection but the thing I find is that balanced connection always sounds more dynamic and tighter in the bass, too - especially when the whole system is connected that way.

nickbojko

14-06-2011, 20:58

Try the em8740,balanced out and you can tap the + signal from each channel for single ended.

nickbojko

14-06-2011, 21:00

I ment the wm8740.

StanleyB

14-06-2011, 21:04

All well and true for a more expensive system, but the average punter is more into a T-amp, Grado SR80, and some bookshelf speakers. For him/her a balanced DAC is a waste of money. What that person is looking for is something with high satisfaction level at no more than £99.99 to £149.99. There isn't much out there that currently satisfies those buyers and their budget. The TC-7510 sold by the lorry full each year because it mainly catered for those kind of users. But few DACs in that price range have shown up lately with the same giant killer instinct. High tech designs with prices starting at £299.99 are now the norm rather than the exception. They can afford to be XLR.
But the budget conscious have been cast aside and left to take a punt on unknown quantities found on eBay. In the mean time only the expensive high- end solutions to each problem are being served up by many newcomers to the DAC market. It's economic overload for the financially hard pressed. We need a new revolution that will take us back to financial reality and serve us up with cuisine at take away prices.
The TC-7510 was one of those DACs that set a new trend with its features, performance and price. Even a two or more year old version can still sell on eBay for more than 80% of its original purchase prise. How many DACs can boast of the same value holding ability, let alone a budget DAC? If it had been balanced I doubt it would have been so cheap, and so popular at its price point. Maybe that explains why there was never a MK7 version :eyebrows:.

MartinT

14-06-2011, 21:09

You did ask for ideas! The budget market is very much me-too. Surely you've built up a following on the forums with the taste for a little more performance? Maybe it's just me.

StanleyB

14-06-2011, 21:30

I can only speak for myself, but what I call budget can be a difficult feat to repeat by even the Chinese DAC builders :eyebrows:. As I was playing with the prototype of the Caiman RC I put it aside and asked myself why I spent two years improving on the Caiman, instead of improving on the technology? I happen to read a review of a recent DAC that mentioned it introduced the technology of upsampling to 384KHz. It struck me that the TC-7510 was oversampling at 352.8KHz and 384KHz all those years ago, but little was ever made of it by me as far as marketing was concerned. There was only a brief mention in the product write up.
I suspect that my next budget DAC will be an equally impressive giant killer, and give me a bit more time to come up with something more spectacular for the well healed.

nickbojko

14-06-2011, 23:07

tdog

15-06-2011, 01:33

Just a note, I have both balanced systems (have worked with them for years) and non-balanced. After lots of experimenting, I do not believe that balanced is any panacea or that it has any inherent sound quality advantage. What it can do is to provide common mode noise rejection, and if implemented properly it can provide immunity to ground/earth current fluctuations (which unbalanced can overcome with good grounding practice). This may be useful for you in a specific case (I've seen this once domestically with high RFI problems), and it is useful for professional applications where cable runs of many 10s of meters are common. Balanced is of course mostly required for professional microphones as they have noise problems from long cable runs - that's a whole other story.

However, this comes at a cost of typically double the component count (which means double the distortion and noise generating bits), and added complexity. Balanced does give you an extra 6dB of gain (that's quite a bit), which can give the illusion of sounding better. Depending on how it is implemented (ICs etc), a balanced audio circuit can sound worse than its unbalanced counterpart due to poor implementation and added component count. I have experienced this with some balanced input power amps, which were essentially unbalanced but ran the balanced input through extra op-amps and sounded worse through the balanced input.

Stan is right, for typical home listening, unbalanced is fine and provides a more cost effective solution. With properly controlled listening tests, and well designed equipment, I've never heard a significant difference. Don't forget that such audio design gurus as Nelson Pass (and Scott Wurcer etc) have produced many unbalanced designs when they could have produces balanced versions if they thought it sounded better (yeah, OK, NP used balanced too with the later Zen-like designs, but for the extra gain...).

MartinT

15-06-2011, 05:51

However, this comes at a cost of typically double the component count (which means double the distortion and noise generating bits), and added complexity. Balanced does give you an extra 6dB of gain (that's quite a bit), which can give the illusion of sounding better. Depending on how it is implemented (ICs etc), a balanced audio circuit can sound worse than its unbalanced counterpart due to poor implementation and added component count. I have experienced this with some balanced input power amps, which were essentially unbalanced but ran the balanced input through extra op-amps and sounded worse through the balanced input.

I wasn't arguing for pseudo-balanced designs. I only use components with fully balanced internal design, where balanced connections are the natural continuity between components. There is no additional component count in this case, it's the natural way of connecting them up together.

MartinT

15-06-2011, 05:54

stan has done an excellent job regading the mod,work with what you have,upgrad to the best parts you can afford and improving the power supply is the heart of any audio gear.sad to say cost constrants to build in a certan price range limits some part quality.

Been there, done that :)

There's not really a lot more I can do to my Caiman. And lest anyone thinks I'm criticising Stan, nothing could be further from the truth. I applaud his great designs, his openness and willingness to be present on a forum to answer so many questions from the likes of us. He is a model to other manufacturers as to how to generate a large and loyal following.

Labarum

15-06-2011, 08:09

I just use my Caiman (and Gator board) as Stan sent them to me.

I can't be doing will all this fussing.

Any significant improvements would come in the speaker area, and that can get expensive.

Peter Galbavy

15-06-2011, 08:56

Note that I am very happy with my Caiman now that I have an updated Gator board from Stan and I don't think I have any need for XLRs.

That said I do remember reading that my Rotel Class-D amp, which uses standard ICE Class-D modules, is actually a balanced design but there is a simple phono to balanced board on the inputs and people have converted these back to a balanced input. Let me go google...

Ah, here is a discussion: http://www.avsforum.com/avs-vb/showthread.php?t=1109794&page=3 with a pointer to the original work on a French language forum: http://www.homecinema-fr.com/forum/viewtopic.php?f=1056&t=29914113

kininigin

23-07-2011, 10:13

I have had my caiman a few weeks now and im enjoying it very much but would like to try this passive mod.

When i had the 7520 i also had the gator board fitted which again was very good.I don't have the money to get the gator board for the caiman atm so for now can someone reccomend some caps to try.

My croft amp has an input impedance of 100 kΩ

HighFidelityGuy

23-07-2011, 11:05

With an amp input impedance of 100K you have a lot of options. Firstly I would recommend that you browse back through this thread and find the diagram that shows how to insert the caps into the opamp board sockets. Basically you remove the opamp board and insert the cap legs into the left hand socket. Doing the mod this way makes it easily reversible.

Next I would recommend that you familiarise your self with the cap value calculators HERE (http://www.v-cap.com/coupling-capacitor-calculator.php). Looking at the calculator on the right, you need to enter your input impedance in ohms (100000) and then decide how low you want your bass to go. I'd recommend that the highest value you enter in the Hz box is 10Hz. You can go all the way down below 1Hz if you like but there's not much point. There's more info on all that earlier in the thread. So if you put in 100000 ohms and 10Hz you get a cap value of 0.16uF. That means you need to look for caps that are 0.16 or higher. However there's not much point going above 22uF as that will give you a bass roll-off frequency of 0.72Hz. Don't worry if you can't find the exact value of cap recommended by the calculator. A close value will be fine.

Now that you know the cap value you need to decide the cap type. You mainly want to concentrate on non-polar caps, sometimes called bi-polar. Electrolytic caps are the worst type for this application but they're the smallest and cheapest and some do sound pretty darn good. There aren't many non-polar electrolytic's. Seen as you are able to use low value caps I'd recommend you look at film caps like polypropylene, polyester, teflon etc. They all sound a bit different. The only downsides are that they're bigger and more expensive. Teflon's are some of the most expensive but arguably the best. Some people like oil impregnated caps. These can be good but pricey. You would not believe how expensive some teflon and oil caps get. I'm talking £1000+ for some crazy ones. :eek:

On the subject of voltage ratings; anything from about 6V upwards is fine. Some film caps have ratings over 1000V which is also fine. Just remember that the bigger the cap, the bigger the cap leads. Leads above about 0.8-1mm probably won't fit in the sockets.

The choice of caps is mainly down to the price you want to pay and whether you want to be able to replace the cover or not.

THESE (http://www.hificollective.co.uk/components/nichicon_es.html) are some of the best electrolytic caps and are a great entry point to see if you like the passive sound. THESE (http://www.hificollective.co.uk/components/obbligato_gold.html) film caps are highly regarded and are good value.

ClarityCap's (http://www.hificollective.co.uk/components/claritycap.html) are also good value, as are the Mundorf Supreme (http://www.hificollective.co.uk/components/mcap_supreme.html). Elna electrolytic's don't seem to work well in this application, so avoid them.

Another tip is to avoid branded caps from foreign countries on eBay. There are lots of fakes around.

Happy cap rolling. :cool:

kininigin

23-07-2011, 20:25

Ali Tait

24-07-2011, 07:26

Good advice from Dave there. I'd add a vote for ClarityCaps, they are great for the money.

HighFidelityGuy

24-07-2011, 13:44

Wow,cheers dave,that's exactly the type of info needed.I have now had a browse through the thread and now have a better understanding,please don't test me though :lol:.

I tried the calculator but it doesn't seem to want to calculate,so i'll go with the calculation you did at 10Hz for now.

I don't think i'll be spending £1000+ on crazy caps,I've spent a little over that on my whole system :lol:

I might leave it a week or two,as the caiman has just finished burning in fully so want to get used to the stock sound before i go changing things around.

No probs. :)

If your Caiman is brand new then I definitely recommend that you let it run in for at least 200 hours before you start trying mods. The Caiman takes an unusually long time to run in and the sound quality can fluctuate quite a bit during the run in period. :)

kininigin

24-07-2011, 20:03

Good advice from Dave there. I'd add a vote for ClarityCaps, they are great for the money.

I had been leaning towards them or the mundorf's as they are not wallet busting and appear small enough to close the lid on.

No probs. :)

If your Caiman is brand new then I definitely recommend that you let it run in for at least 200 hours before you start trying mods. The Caiman takes an unusually long time to run in and the sound quality can fluctuate quite a bit during the run in period. :)

Well,it's second hand and the guy i bought it off used the usb input but assured me it was well run-in on the coaxial input but clearly it wasn't(unless he meant input 2).It's been sounding good the last week or so.

Probaly will leave it a couple more weeks,but knowing how good the gator board was in my last dac,it's tempting just to do it straight away.

kininigin

26-07-2011, 11:21

well my impatience got the better of me and i ordered some claritycap's from the SA range with values of 0.47uF,630V.

They turned up today,so i decided to fit them but the lead out wires seem to be too big and i didn't want to force too much.

I take it others have used these caps,so how did you fit them?

Alex_UK

26-07-2011, 11:22

I tried one pair (nit these though) that were a little too big, so just filed them down a little with a flat needle file - worked for me.

HighFidelityGuy

26-07-2011, 11:30

Or you could scrape the leads with a stanley knife or solder thinner wire to the end.
Make sure you insulate the leads too so they don't short on anything. :)

kininigin

26-07-2011, 11:31

I tried one pair (nit these though) that were a little too big, so just filed them down a little with a flat needle file - worked for me.

Makes sense,not sure i have a file about the house though.

So let the search begin.

Or you could scrape the leads with a stanley knife or solder thinner wire to the end.
Make sure you insulate the leads too so they don't short on anything. :)

I do have a solder iron,what sort of wire would be suitable?

Alex_UK

26-07-2011, 11:41

Makes sense,not sure i have a file about the house

If you've got a Missus, nick one of her nail files or emery boards! ;) Any bit of old abrasive paper will work, but take a bit longer. Last resort, go outside and rub them on a brick or concrete paving slab - anything abrasive will do, and you're not too worried about a perfect finish for this... :)

kininigin

26-07-2011, 12:05

So decided to scrape the wire with some wire cutters i've got.

Started to push it in to see if i'd scraped enough,was a little tight still so pulled it out along with the black plastic housing which has now split in half :doh: :(

Not sure what to do now :scratch:

kininigin

26-07-2011, 12:40

I've some how managed to fit the caps in.

I taped the black plastic housing back together with insulation tape,then using the wire cutters cut the lead out wires in half,so they now go in easily,especially with a bit of give in my bodged up repairs :lol:

Giving the caps a run-in now,sounds good allready.

(And i want to replace caps in my active monitors :lolsign:)

Alex_UK

26-07-2011, 12:47

kininigin

26-07-2011, 13:04

Phew - that was close! Glad it is working out - the caps will probably need some run in time, but probably not the 200 hours the Caiman did originally!

Darren, perhaps you'd be advised to reconsider your other project?! ;)

Must admit they sound very good atm,so if they get better,bonus.

Listening to some cinematic orchrestra and the first thing to hit me was the wider more defined soundstage.Everthing now sounds unforced and alot more anologue like,and all this for a tenner,amazing.

Well i'll reconsider alex for abit,then probaly carry on and if i bugger things up,i've got an excuse to buy some new speakers :eyebrows:

d00gz

25-08-2011, 23:07

Ive just completed the Passive mod on a Caiman with Murata Regs and Elna caps. The Muratas did not work well with the Gator board I installed (the usual high pitched noise that many users get) So, I removed the board and experimented with various sizes of caps slotted into the 5 hole connector. I am playing my Caiman into a 25kohm passive ladder stepped attenuator preamp.

I purchased a selection of cheap caps from Maplin to try with a view to purchasing good ones once I'd found the optimum capacitance. I tried 2.2uf but found it a bit fuzzy and distorted, no decent soundstage. I then tried 3.3uf which sounded considerably better. 10uf sounded pretty darn good with soundstage returning, clarity and a sound that reminded me of the gator board. 47uf started to thin the sound a bit. So, in conclusion, For my system, with a 25k preamp, 10uf polarised caps seem to sound the best for a passive mod. I will give it a few days, and when Ive finally decided Ill purchase a pair of higher quality caps to install. Hope this might help someone who is considering the passive mod.

MartinT

27-08-2011, 22:45

The capacitor type seems to be more critical than the actual value. What type did you settle on?

d00gz

28-08-2011, 22:06

Thanks, that is a good point about the type of capacitor. I have been switching between cheap maplins 10uf polarised, 4.7uf polarised and maplins "audio quality"47uf nonpolarised cap. After a few days listening, The 47uf non polarised cap appears to give the cleanest sound, but does reduce the bass kick a little. I think the clean sound may be due to the quality of the cap rather than its value. Ive decided to order a range of decent quality electrolytics probably nichon muse from hificollective. They are still less than 50p each. I will listen to them for a week or two before settling on a more expensive pair.

MartinT

28-08-2011, 22:13

Good plan, Doug. If you can stand it, read back over this complete thread as several of us have published our findings on a range of different capacitor types.

LittleTone

20-09-2011, 11:49

Hi Chaps,

Currently using 10uf Nichicon FG capacitors in the passive mod on a standard 7520. Amplifier impedance is 47Kohms

Came across this info regarding the Rega Dac.

'All the capacitors associated with the analogue signal path are Nichicon FG bypassed with MMK polyester capacitors'

Question is: Can one of you clever guys advise best bypass value and a good alternative to the MMK as I cant find them anywhwere.

Regards
Tony

MartinT

20-09-2011, 12:04

As a rule of thumb 1/100 is a good bypass value, so 100nF to bypass 10uF. For best sound quality go for polypropylene (but tend to be big) or film.

LittleTone

20-09-2011, 12:17

Thanks Martin,

Got some 2.2 Muse ES coming; what would the value be for them ?

probably unable to get them in the same holes so is just just solder them to the legs of FG's observing polarity.

Tony

MartinT

20-09-2011, 12:21

That'll work fine, Tony. Most polys and films don't have polarity to worry about.

HighFidelityGuy

20-09-2011, 15:35

If you want to try MMK's then you can get them HERE (http://uk.rs-online.com/web/p/plastic-film/2979970/) in the value that Martin recommended. They come in a pack of ten. :cool:

LittleTone

20-09-2011, 18:16

Thanks a lot,

Have ordered some.

Would you please tell me what 0.22uf would be in nanofarods ?

Local TV repair shop gave me two of these. Can you recognise them and are they worth trying.

Tony

Reid Malenfant

20-09-2011, 18:19

.Would you please tell me what 0.22uf would be in nanofarods ?

220 nanofarads or 220nf ;)

The pic you have there is of a 2.2uf or microfarad capacitor, which would be the same as 2200nf.

LittleTone

20-09-2011, 18:28

Thanks for helping out the novice; learning all the time but still need a bit of reassurance.
So to bypass a 2.2uf Cap; I should try a 22nf ?
Regarding the cap in the pic; I've been trying to identify it on the net and find any spec about it. Is it a film cap. Is it likely to be better than a modern lytic.

Do you think it's safe to try. I don't want to any damage to the DAC or Amp.

Tony

Reid Malenfant

20-09-2011, 18:31

Sorry Tony i haven't been keeping up with what you are planning to do. Looks like you have either a polyester or polypropylene capacitor there, yes, as you point out it's a film capacitor ;)

If you are planning on doing the passive output mod on the caiman then yes they'll be fine & sound much better than 99.9% of electrolytics :)

Frankly i don't think you need to bypass it, if you were going to though i'd suggest a really high quality capacitor like a polystyrene or silvered mica. You are more likely to find polystyrene at 22nf or 2n2 (2.2nf) though.

MartinT

20-09-2011, 18:35

Local TV repair shop gave me two of these. Can you recognise them and are they worth trying.

Tony, since they are 2.2uF in value I suggest you try them on their own - they look like good polys. Unless you have a preamp with a low impedance input, you should be ok for bass and they might sound good, you never know.

LittleTone

20-09-2011, 18:54

At the moment I,m running the passive mod with 10uf Nichicon FG,s. These were the best I could find quickly at Maplins. In an article I read today the new Rega DAC is using Nichicon FG bypassed with MMK,s. I thought if it's good enough for the Rega I'd try the same.
I also ordered some Nichicon Muse ES which an article suggested they worked well with Sonicap 0.22uf bypass. Hence that enquiry.
The caps in the pic were given to me by my local TV repair man. I just wasn't sure about them. Although they look unused I feel they probably quite old and was concerned about damaging Amp/DAC

Thanks to all that have helped me out
Tony

PS amp is 47Kohm. DAC is Standard 7520

MartinT

20-09-2011, 19:14

It's very unlikely that that type of cap would go leaky and cause damage. 2.2uF into 47k would be fine.

Reid Malenfant

20-09-2011, 19:17

It's very unlikely that that type of cap would go leaky and cause damage. 2.2uF into 47k would be fine.
Seconded, there is nothing to leak as no electrolyte :)

You may get a bit of phase shift in the extreme lower bass, but you'll still get a full 20Hz - 20KHz response.

MartinT

20-09-2011, 21:36

I'm waiting for the new Caiman case project so that I can use larger values than the Ansar 2.2uF caps I'm currently using.

LittleTone

24-09-2011, 18:24

For those who may be interested and like me; are spending a fortune trying loads of different caps (the postage is a killer); my Auricaps (2.2uf/200V for 47K load) arrived today. They REALLY ARE GOOD; and they haven't run in yet. At last some caps that gave me the same buzz as installing a Gator PCB with my previous amp.

*****Highly recommended*****.

Thanks to AoS members for their contributions.

Tony

:)

MartinT

24-09-2011, 18:29

my Auricaps (2.2uf/200V for 47K load) arrived today. They REALLY ARE GOOD;

Nice one, Tony. I'm still running mine. They get better over about a week of use, too.

LittleTone

24-09-2011, 18:47

Hi Martin,

Well I think it was down to you. THANK YOU very much.

Regards
Tony

Maestro

01-02-2012, 02:16

Hi
Hello! I just bought a Caiman G and would like to know if I can use this capacitor in the upgrade revealed by StanB in the begining of this post, the one in the fixed output - sorry to come up with such an old subject - and also, can I use these in tha variable output, with the same values?
Voilà the capacitor (ignore the photo, the right values are in the title, wich is 10uF/630V ). I hope this is not a ridiculous question, my knowledge in electronics are almost zero... Thanks a lot to everybody!

Maestro

01-02-2012, 02:19

I forgot to post the link

http://www.audiophonics.fr/condensateur-mundorf-mcap-630v-10uf-p-988.html
and also this one
http://www.audiophonics.fr/condensateur-audyn-cap-mkpqs-1000uf-630vdc-p-3564.html
Thank you.

HighFidelityGuy

01-02-2012, 09:49

Hi Francisco. You need to check if your Caiman has the Gator board fitted. I'm guessing it might have seen as there's a G on the end of the name. If it has a Gator board fitted then you don't need to do the capacitor mod. The Gator board was designed to replace the original output board and provide a similar improvement to the capacitor mod while making sure the Caiman is still compatible with any amp. The capacitor mod only worked well with some amps. If you are in any doubt then I would recommend that you get in touch with Stan Beresford (http://www.beresford.me/mainsite/contact.html) before you make any changes. :)

Maestro

01-02-2012, 10:19

Hi Highfidelityguy
Thanks! Well, this is the last version with the gator board, so I don't want to make this upgrade. That's good news! Now, I know that Mr Stanley choosed a very nice opamp, but I want to change it against a better one. I thought about the burson opamps, but they are not compatible. A very nice and competent seller in France explained me that and sait that Audio GD has discrete opamps with a similary circuitry. (I think you know them...). Audio gd has 3 different ones, and more affordable. For those who want neutrality, the answer is the "Earth". Now the question: how the hell do I know if I connect it the right way? Do I make some damage in my gator board if I place the opamp in the wrong way? Thanks again. Hope my english is not so bad, it has a lot of mistakes.
http://www.audiophonics.fr/audiogd-opaearth-aop-simple-composants-discrets-p-5309.html
http://www.audio-gd.com/Pro/diy/OPA/OPAEN.htm

HighFidelityGuy

01-02-2012, 10:54

Hi, before you do anything with opamps you need to understand more about the Gator board. The Gator board uses a discreet transistor output for the line level outputs. The opamp is only for the headphone output. So if you are mainly going to use the line outputs then changing the opamp is pointless.

If you want to try different opamps for the headphone output then you need to be very careful that you install them the correct way round. Also, many discreet opamp replacements like those by Burson etc are physically much bigger than standard opamps and are unlikely to fit inside the case. Another thing to remember is that not all opamps work well in every DAC. Again, I would recommend that you talk to Stan as he will know which opamps work well in his DAC.

For future reference, this diagram shows the correct numbering of an 8 pin DIL socket like those used with standard opamps:

http://upload.wikimedia.org/wikipedia/commons/thumb/b/b3/Pin_numbering_01_Pengo.svg/200px-Pin_numbering_01_Pengo.svg.png

Most opamps will either have a notch cut out at one end between pin 1 and pin 8 or a white dot next to pin 1. The opamp socket will have a notch at one end also. Make sure that the notch or white dot on the opamp is at the same end as the notch in the socket. Also ensure that all the pins drop into the holes. Sometimes a pin can get bent the wrong way.

You also need to be careful of static electricity. If you don't have an anti-static wrist band, then at the very least make sure that you regularly touch some bare metal that's grounded to discharge yourself. If you don't then you can easily damage the opamp or the DAC with your static.

Obviously you also need to unplug your DAC before you start changing anything.

Personally I don't think you need to change the opamp as the one Stan fits is very good for most headphones. You are likely to get better improvements by upgrading the power supply to a good quality linear model.

Please don't do anything unless you are 100% sure you know what your doing as several people have damaged their Caiman's by doing things wrong. As I've already said, if you are in any doubt, ask Stan. :)

Maestro

01-02-2012, 11:15

Hey, thanks again. You are helping me a lot.
Well, may be I don't need to change the opamp, but I know, (I'm sure), that a good power supply is more than welcome, and it seems to me that it should be my next upgrade. I also learned with your reply, that the op amp only affects the phones output:doh:! Nevertheless, for me that's the weekest point of the caiman. I was expecting a big improovement over the micro dac (udac) from nuforce... but I must say that I compared both with an ultimate ears, very good, but limited. By the way, if someone has a tip about what good phones to the caiman, please be free to refer it.
I like this: amt ERGO that costs about 300 euros, for me it is so good as the big stax. YES!! I mean it. If possible something in the 200 area...
I was tempted by this:
http://www.audiophonics.fr/alimentation-stabilisee-lineaire-12v-25a-tamp-vdac-p-5767.html
http://www.audiophonics.fr/alimentation-stabilisee-lineaire-15v-25a-m2tec-young-p-6335.html
Stalley also advised me about this: (and I respect his opinions, eyes closed)
but it is more expensive:
www.markgrantcables.co.uk
I see you have an upgraded PS, wich is....
Thanks again for you very detailed replys, I hope I will make such a good contribution in this forum. I've allready learned usefull and interesting things.

HighFidelityGuy

01-02-2012, 11:47

No problem. :)
I can't really help you with headphones as I don't use them much. On the subject of power supplies, I made my own based around a Teddy Pardo SuperTeddyReg (http://www.teddypardo.com/DIY/SuperTeddyReg.html). There are some threads about building power supplies that you could read. If you'd prefer to buy something already built then Teddy sells full power supplies but they're not cheap. I would also recommend Paul Hynes (http://www.paulhynesdesign.com/). He sells some awesome supplies which some people believe are the absolute best. They're also not cheap but he does do a wide range. They're mostly not listed on his website so you'd need to email him.

If they're all a bit too expensive then you can get cheaper linear supplies. I'd probably ask Stan what he recommends. You just need to make sure that you avoid any that are SMPS (switched mode power supplies). Linear is what you need. Preferably with 1A (1000ma) output or above at 15V. Don't use any higher voltage than this as this will damage the DAC unless you do extra modifications inside the DAC. :)

If you're looking at getting the ultimate power supply setup then I would talk to Paul Hynes about sending your Caiman to him for him to upgrade. Ask him to upgrade voltage regulators (to his design), input reservoir cap (to a higher voltage film cap) and supply one of his power supplies set to an appropriate voltage for his regulators. This really won't be cheap though. ;)

I should also mention that if your Caiman is quite new then you really need to run it for at least 100 hours of music playing time before you pass judgement on it's sound quality. Stan's DACs always take a long time to run in and can change quite a lot over this time. So you may find that the sound improves. :)

Ali Tait

01-02-2012, 12:02

Here's a good power supply at a sane price -

http://www.mains-cables-r-us.co.uk/power-supplies/384-mains-cables-r-us-dc-power-supply.html

I use a similar one on my Squeezebox Touch, and it was a very worthwhile upgrade. The chap that builds these is a friend and a member of this forum.

HighFidelityGuy

01-02-2012, 12:07

I've just had a quick look on the RS website and they have this linear regulated supply that can be set to between 5V and 24V with a 2A output: LINK (http://radiospares-fr.rs-online.com/web/p/products/3979842/?searchTerm=8937000090&relevancy-data=636F3D3126696E3D4931384E525353746F636B4E756D6 265724D504E266C753D656E266D6D3D6D61746368616C6C267 06D3D5E5C647B367D247C5E5C647B377D247C5E5C647B31307 D2426706F3D313426736E3D592673743D52535F53544F434B5 F4E554D424552267573743D383933373030303039302677633 D4E4F4E4526)
You would probably need to make a suitable cable to go between it's output and your Caiman. Stan might do that for you. I think the picture on the website is wrong. If you look at the datasheet it shows spring clip terminals for the output.
The only problem is it's currently out of stock. According to the UK website it's back in stock in stock next week. I think you will struggle to find a linear regulated supply with a suitably high output current for less than €80. :)

Maestro

01-02-2012, 13:39

Hi guys!
Well, I read carefully what you sent to the post, and after some consideration and also, (but not only...), from the point of view of good sense and reasonable price, I decided that the
http://theartofsound.net/forum/showthread.php?p=256313#post256313
is the "GO!" for me. It is in the same perspective of StanB advice, (the grant PSU), but I found that this one has a litle extra care of a dedicated DIY, if you know what I mean... It is not the most affordable, but still is reasonable for me. (I also like the looks!, and it counts for me). So I think that I will ask for one in a week or two.

I am someone who likes to decide, but I allways accept other points of view and I can change my decisions if someone opens my eyes.

Now that my decision seems to be taken, (is this correct??), I wonder what other meanfull upgrades can I do inside the litle box of the Caiman - allways at a fair price, of course. Tirna?
Thanks again, for both of you, (It includes Ali Tait. Hi Ali!)

Then I can go on with the choice of an amplifier...
UUFFF!!

HighFidelityGuy

01-02-2012, 14:42

That's a very nice PSU and I'm sure it will produce a worthwhile improvement.
If you decide you want to take things even further then I'd look at improving the DAC's internal power supply. The following things are possible:

1. Upgrade the voltage regulators.
2. Swap the reservoir capacitor to a higher voltage film type of around 10uF to 22uF.
3. Swap the protection diode on the power input for a wire link.
4. Swap the resistor behind the 5V regulator for a wire link

Upgrading the regulators will ensure that the DAC circuits get the cleanest possible DC supply. This mod provides the biggest improvement.

The original reservoir capacitor is a large value (10,000uF I think) 16V electrolytic model. As the standard input voltage is 15V, this capacitor is being run close to it's voltage limit. So a higher voltage capacitor is safer. Also, high quality linear supplies work better when feeding a smaller film capacitor. So something like a polyester film 10uF 25V+ model would be better. You will need to ensure that the lead spacing on the new capacitor is the same as the holes in the PCB. Also make sure that it's low enough to fit in the case.

Swapping the protection diode that's in series with the power input (before the reservoir cap) for a wire link will allow a little more voltage through to the voltage regulators. This will ensure that they are working at peak efficiency. Don't do this until you have upgraded the reservoir capacitor! Also, if you do this you need to be 100% sure that your power supply is the correct polarity otherwise you will kill the DAC. The MCrU power supply will be correct but be careful if you try other supplies later.

Swapping the resistor behind the 5V regulator for a wire link allows a little more voltage to the 5V regulator. Personally I don't think this is worth doing with most regulators as it will just make it run hotter.

Probably the best regulators are those made by Paul Hynes. You will need to ask him which he recommends for the Caiman. The only other regulators I recommend for the Caiman are NewClassD (http://www.hificollective.co.uk/components/nclassd_reg.html). These may be available from a supplier in France. You need a +12V model and a +5V model. You need to be 100% sure that these are fitted the correct way round!

Tirna may be able to do these mods for you but I wouldn't recommend that you use the Murata regulators that they are fitting. They have caused several people problems.

The other mods relate to the small capacitors around the DAC chip. I would say that these change the sound but don't necessarily improve the sound. So I would leave these until last, as you may not need them if you find you are happy with the sound you get.

You don't need any mods relating to opamps or opamp board capacitors as all of them were replaced by the Gator board. I would recommend you just stick to the power related mods for now. They provide the greatest improvements.

If you don't have any soldering experience then I would recommend that you get somebody else to do the work for you, as some of the mods are quite tricky, especially the regulator swap. Also be careful if you're reading through the forum for info as lots of things have changed as new versions of the Caiman have come out. If you are unsure how to do something then I recommend that you ask in the general Caiman Mods (http://theartofsound.net/forum/showthread.php?t=4580&highlight=caiman+mods&page=60) thread where I'm sure someone will be able to help. :)

EDIT: I forgot to mension about price:

The regulators will probably cost around €30-40 each plus postage, the new film reservoir capacitor should only cost about €3 or less, although you may have to buy a bag of 10 depending on the supplier. The wire for the links should only be cheap. Look for some copper or silver wire around 1mm diameter.

Maestro

01-02-2012, 16:05

Great!
I can do this, with someone checking things before I turn on, after each upgrade. I'm very used to soldering and I will use the OTA cable from 47Labs. It allways gave me incredibly results. I will post one or two clear photos, after making each upgrade and before feeding the caiman board. I saw the regulators, and I think it will be a very nice upgrade. I will buy the PSU first. It is the most important upgrade, (I think), and with the new PSU, future upgrades will make bigger differences. The Caiman PSU is good, but is obviously a compromisse to keep prices really down, but for the price it couldn't be better! Great great help! Thanks. I will post photos in a good french forum, when time comes.

Just check this out:
http://classdaudio.com/amplifier-kits-1/250w-x2-500w-x1-amp-large-power-supply-transformer.html

Do you know this? I bet this is better than Hipex modules. I'm tempted to buy one. I allready asked prices with vat, ship fees, etc.

Maestro

01-02-2012, 20:00

Hi HighFidelityGuy
I finaly decided that I will do the upgrade myself. It's not complicated and I don't have to send the dac away and wait weeks.

Fulci

04-02-2012, 15:31

Hello everyone!

I'm about to make the passive mod for my Caiman, I will try the Clarity Cap ESA first but have a few questions regarding this:

1. My Audiolab 8000A has an input impedance of 20k, so I should be using somewhere around 4uf. I'll try the 3.9uf, no problem here, right, or should I try another value first. If a brand doesn't have the 3.9uf, should I use a lower (3.3uf) or a higher (4.7uf) one?

2. Is there any difference in SQ between 250v or 630v? Can I use the smaller one?

3. What is the largest capacitor that can fit inside the case, or what are the dimensions free for placing a cap of this dimension? Can I use something like an AUDYNCAP MKP PLUS which is 35x63mm or an AMPOHM FP-CA-AU 4.7uf with 30x70?

4. Can I use some other cap 0.1uf in parallel and will I find any improvement?

5. Has anyone used any Mundorf here, like the MCAP MKP or the MCAP SUPREME, or is this just hype and marketing?

Thank you all in advanced for your help!

MartinT

04-02-2012, 17:56

1. use the higher value - 4u7

2. use the lower voltage - 250V as they will be smaller

3/4. I can't say as I'm not at home to measure at the moment

4. it's unlikely that a bypass for such good caps will alter the sound, but it's worth trying

5. no but the 2u2 Auricaps I tried were excellent

Fulci

04-02-2012, 18:14

Thank you Martin for your kind reply!

Unfortunately, the cheapest I can find for the Auricaps is £28 a piece, so this is too expensive. The ClarityCap ESA cost £4 and the Mundorf M-Cap cost under £3, so I will start off with a cheaper one and later move on to a better one, after going through all the other recommended mods.

The Auricaps 2u2 are 20x22mm, do you recall if there was much free space available after installing them?

Ali Tait

04-02-2012, 18:31

The clarity caps are very good.

keiths

04-02-2012, 19:01

I'm using ClarityCap ESA 250v 4.7uF which are 23mm diameter. These fit OK (I fitted them at the extreme right hand side and extended the leads). I think you would find it difficult to fit anything much bigger and still get the lid back on.

I think the ClarityCaps are excellent, by the way.

Fulci

04-02-2012, 23:00

Ok thank you all!

I will try the Clarity Caps ESA first. Maybe try the Mundorf MCaps later to see if there is much difference. Has anyone tried these?

MartinT

05-02-2012, 12:19

ClarityCaps are good and I enjoyed them, but I did sense a small but worthwhile improvement with the AuriCaps.

Fulci

09-02-2012, 15:19

HEEELLLPPP!

Damn thing! How did you get to stick the wire of the ClarityCaps ESA inside the tiny holes in PIN3B?

Canetoad

09-02-2012, 15:55

Solder some thinner wire to each end and plug that in. That's what I did. Cat 5 wire works OK. :)

MartinT

09-02-2012, 16:30

I unsoldered the multi-pin connector and drilled out the PCB holes :eek:

RoboCopper

09-02-2012, 16:41

I unsoldered the multi-pin connector and drilled out the PCB holes :eek:

for testing purposes I would suggest method what Canetoad sugested.

Once you find ideal caps, you can solder them as MartinT sugested.

HighFidelityGuy

09-02-2012, 17:05

Or you could just scrape the wires a bit thinner with a knife. That's what I did for the bigger caps I tried.

Fulci

09-02-2012, 17:26

Just f*cked this up! The optical does not work, and coaxial only works in one side. I think I broke one of the wires of the cap, or it's because one the pins became lose.

If it ain't broke, don't fix it! Darn!!! I'll heat up the old iron again!

Fulci

09-02-2012, 17:28

Ok optical works, just forgot to plug the cable! Got to get my head straight!

RoboCopper

09-02-2012, 17:29

Are you only doing passive mod?
For passive mod you should not use soldering iron.

Or if you doing recap upgrade with Elna Silmics....be very careful.

I have damaged my old 7520 by my inexperience with soldering iron :(

I am still sad when I think about it.

Fulci

09-02-2012, 17:40

Just to solder the cat5 to the caps wire.

RoboCopper

09-02-2012, 17:44

then, everything should work, both on coax and optical.

cat5 wire is a little thinner (I used them) so maybe you are not having proper connection inside those tiny sockets?
try to wiggle them a bit when everything is off of course.
(ok I admit, I had similar problem and wiggle them when volume on my preamp was at 7 o'clock).

Fulci

09-02-2012, 17:58

All is well now! All is welll.... for now...

It was just some bad contact. Can't move the Caiman around, or it'l stop working.

Sounds nice, not that much of a difference, just a bit more definition and air, can't wait to see when it's burnt in.

How long should it take?

I should've scraped the tip off a bit with a knife... why are all the simplest options the last to be thought of?

Listening to some Dark Side of the Moon a bit! Perfect testing album. Next will be Yes' Close to Edge! Best Bass line ever!!!

Fulci

09-02-2012, 18:02

I used a pair of twisted CAT5 for each cap wire. It was too thin and loose with just one. Should've taken a picture for the album... Tomorrow, maybe! For now will just enjoy music!

Which, by the way, didn't remember the last time I had a shiver while listening to this album... Or maybe I'm cold... goose bumps! THANK YOU STAN!!! THANK YOU ALL!!!!

Fulci

09-02-2012, 18:08

Don't want to be anoying, but I'm so excited now!

What was a just slightly musical machine, with just a little toe tapping PRaT became a full head banging and air drumming experience! Wow!

But it does distort a little... maybe it's where the magic is coming...

StanleyB

09-02-2012, 18:39

The caps need some burning in, after which the distortion will disappear.

Covenant

09-02-2012, 20:41

Listening to some Dark Side of the Moon a bit! Perfect testing album. Next will be Yes' Close to Edge! Best Bass line ever!!![/QUOTE]

I have always said they have good taste over in Portugal.:)

Fulci

09-02-2012, 21:01

LOL! No, not really, they don't... Just us, who tend to Hi-Fi forums.

Just discovered something new. Have you ever noticed the raindrops by the 10th minute in the "Close to the Edge" track. This is life changing! Better than having a child...

Magma's Ehmehntehtt-re was marvelous, all those crashes and cymbals and rides were incredibly more defined, you can hear the hi-hats open. The voices were not so great though, all the mid-tones were not that great I guess but the bass and rithm got much better. I will wait a little longer until the caps get fully burnt in. Also my amp needs a recap, maybe it'll help later.

I also discovered that there is another guy singing in the back in the first song of Yezda Urfa's Boris (incredible prog, if anyone cares). Damn, the guy really can't sing, now it ruined for me!

Finally, also got to listen to Charles Mingus' "Moanin" from the live version in Times Square '93.... WOW!!! I just got up and dance untill I couldn't catch my breath! Which was just a minute, actually... Got to get in shape! But this is really really groovy!

Usernametaken

25-03-2013, 04:06

Now that the dust has settled a little I have had time to rethink the mod wiring.
The latest suggestion for trying out the mod requires only two pieces of wires. That means that you can try the mod out before deciding if you want to invest in two expensive caps.
Remove the line output opamp.
Solder two pieces of wires to the outer pins on the connector on the left side of the PCB (looking at the DAC from the front).
Push the bare ends of the left wire into pin 1 of the empty IC socket.
Push the bare ends of the rightt wire into pin 7 of the empty IC socket.

http://www.homehifi.co.uk/images/mods/caiman/f1.jpg

This way of doing it allows you to also add some improvements to the headphone section. The muting circuit is also fully functional, and there is a bit of HF filtering to remove some of any HF noise.

If you add the 68nF caps mod ( reddish caps in the picture) by replacing the 100nF ones (blue or yellow on the original PCB), the headphone amp performance will be almost indistinguishable from the original layout. With the THS4032, and some non-polarised caps I am trying out, my HD800 and D7000 have not pulled away significantly from my K701 and HD650 in terms of musicality, detail, and clarity. So for headphone users this alternative way of adding the mod is well worth a go.

So this is my first foray into modding any gear so obviously I'm a bit wary of breaking something.
I played around with electronics in the past (HV, Tesla coils and solid state tesla coils) but I am more of a "paint by numbers" kind of guy due to my lack of understanding of electronic circuitry.
In other words, I can wield and iron, identify components, can follow a simple circuit diagram and love looking at pictures.
I want to do this mod to my Caiman but am having trouble struggling through this thread to find out exactly how to do it.
Stan's post above had all the info but the all important pictures are gone, is there an idiots how to anywhere with pretty illustrations?
Also, is there a "roadmap" of mods? I'm interested in trying out different op amps if this mod is successful.
Sorry for the very new newb posts.

Jim

MartinT

25-03-2013, 07:09

Not directly answering your question (because I never did the above mod, only the original recommended passive output mod), the photo below is one I took some time ago showing the two passive coupling caps (green) inserted directly into the socket vacated by removing the op-amp board.

http://farm9.staticflickr.com/8070/8223563594_fd1895c57d_b.jpg

Usernametaken

25-03-2013, 08:11

NRG

25-03-2013, 08:42

Usernametaken

25-03-2013, 08:54

Oh wow, it's easier than I thought. No cutting cables or routing wires.
Pull the board and insert the caps.
Thank you :)

StanleyB

25-03-2013, 09:07

I have had a lot of requests about the mods section that used to be on my website. I hope to have it back up in April so that there is a reference location for anyone wishing to try out any of the mods.

Usernametaken

25-03-2013, 12:41

Usernametaken

25-03-2013, 12:43

Yes, you will lose the headphones (obviously!), check to polarity of the caps if using 'lytics, see page 12 post 117. You may need to check to input impedance of your amp so as to select a decent sized cap that wont cause a LF roll-off

Apparently my input impedance is:
Input impedance (R and C) 22 kohms+ 100 pF

And what caps should I be looking at for my rather varied listening tastes.
Portishead, Cash, Classical, unplugged sets etc?

NRG

25-03-2013, 13:25

With a 22K input impedance I would personally not go any lower than a 2.2uF cap...that gives a 3Hz roll off point, listening tests would confirm if Bass was OK. Any larger sized cap would be OK, it will limit you to 'lytics though and IME I found PolyProps better sounding, the 'lytics all having some coloration or sound of their own...

MartinT

25-03-2013, 13:28

I agree with Neal, polypropylenes sound best but can be large and you may struggle to get the lid back on. On the other hand, 10uF bipolar Nichicon MUSE electrolytics sounded pretty good when I tried them.

Usernametaken

25-03-2013, 14:30

On the other hand, 10uF bipolar Nichicon MUSE electrolytics sounded pretty good when I tried them.

10uf/25V?

MartinT

25-03-2013, 14:34

Plenty!

Usernametaken

25-03-2013, 15:27

Plenty!

Thank you guys, very much.
Does the voltage of the caps matter so much, and is 2.2uf - 10uf a good range to look at?
Already have a set of Nichicon on the way but now I'm looking at other caps.
If it's a simple swap and change until I get the sound I'm after, I might just grab some other bits and pieces to test.
I can see this quickly becoming a slippery slope...

MartinT

25-03-2013, 20:53

No, voltage in this kind of coupling application is only at most the initial voltage differential when connecting up (say, the voltage rail at 16V) and quickly becomes tiny.

Usernametaken

26-03-2013, 15:34

Plenty!

Well....
I now have some Nichicon Muse FGs in 10V and some Elna Cerafines in 16V on the way to have a play with as well.
All 47uF as I honestly don't want to go playing with the capacitance until I know why it's a specific number and what changing it does :)

MartinT

26-03-2013, 15:50

As I remember, the Nichicon MUSE sounded best but Rubicons were also good. I never tried Elna Cerafine bipolars but if you look at my photo you will see that I replaced all the polar electrolytics with Elna Cerafine II caps and this made quite a difference to sound quality for a small outlay.

NRG

26-03-2013, 17:00

Well....
I now have some Nichicon Muse FGs in 10V and some Elna Cerafines in 16V on the way to have a play with as well.
All 47uF as I honestly don't want to go playing with the capacitance until I know why it's a specific number and what changing it does :)

The capacitor forms a high pass filter with the input impedance of the following amp stage. go too small and the roll off may affect bass subjectively, 47uF is more than enough!

http://www.ekswai.com/en_highpass.htm

Usernametaken

27-03-2013, 12:24

So I stole some 47uF caps from the opamp board because I just couldn't wait.
I'm new to audio lingo so please bear with me.
I'm noticing some sibilance in certain vocals and also female vocals appear a bit dull or lacklustre. I'm also getting some pops when switching between tracks, but this could be my source. It's also a lot brighter than before.
What I have noticed is that the instruments seem a lot more separated and defined, I guess this is what is referred to as sound stage.
The bass is also a lot more defined but seems to be lacking the depth that it was before, I'm unsure if this is actually due to less bass or due to it being a lot brighter.
I'm looking forward to my other caps arriving, I do like how it sounds bar a few small issues.
I take it I'm not the first person to run kit with the case removed. :)

Usernametaken

27-03-2013, 12:50

I'm also finding the vocals slightly lacking a presence, not sure if this is just the caps or I'm listening for things that don't please me :(

MartinT

27-03-2013, 13:10

Give each cap set a few days to settle, Jim. They take time to open up. However, your observations about bass tightening up and perhaps appearing less powerful match mine. I don't remember midrange (vocals) lacking presence, though. That sounds like new or poor caps, I think.

Usernametaken

27-03-2013, 14:55

I'm definitely suspecting the caps are strangling the vocals somewhat and pushing them to the back of the stage slightly.
I'm also finding the sibilance quite a distraction.
My caps are on the slow boat from China so I have no doubt the current caps will have plenty of time to settle in. :)
Thanks very much for your help by the way, it's been much appreciated.

Alex_UK

27-03-2013, 15:02

Just noticed your location - I was going to offer to pop some well burnt in ones in the post but I suspect that would be futile! Oh well!

Usernametaken

27-03-2013, 15:32

Just noticed your location - I was going to offer to pop some well burnt in ones in the post but I suspect that would be futile! Oh well!

Depends, if they are a set of Black Gates, I'll happily camp by my post box in anticipation.
I can't believe how much a set of FK 47uF are worth, are they actually worth it?
Funnily enough, post from the UK only takes about 5 days to arrive.

Puffin

27-03-2013, 17:10

Yes, you will lose the headphones (obviously!), check to polarity of the caps if using 'lytics, see page 12 post 117. You may need to check to input impedance of your amp so as to select a decent sized cap that wont cause a LF roll-off

As you have mentioned the loss of the h/p facility on the Caiman, I think it might be worth saying that in relation to the 7510 the "wire" mod takes the h/p facility out. I suspect it may also take the variable output out (but I have not tested this).

I am currently downsizing my system and going to an h/p system. I had never tried the h/p output on the 7510 and thought I would give it a go. Plugged in......Nothing. Just as thought I removed the "wire" mod and bingo....Sound! If Stan is re-instating his mods page - might put back the 7510 mods and those that don't know, will then see what the wire mod was:)

I did the passive mod to the 7510 (which is a different beast to the Caiman) and used the variable sockets by cutting the links to the board and wiring direct. I assumed that when I re-connected them that I had made a mistake as I got no sound. However the "wire" mod may have been the culprit. Must give it a try.

Usernametaken

29-03-2013, 15:03

Has anyone found that there's a popping sound between tracks with this mod?
Only seems to be when queuing up a new track.

MartinT

29-03-2013, 15:33

I think you only get that noise if you bypass the muting relays. I don't get it any more since going with the Gator upgrade.

Usernametaken

30-03-2013, 14:45

is the Gator board still available? I can't seem to find one anywhere.

MartinT

30-03-2013, 15:07

Try asking StanleyB directly?

Usernametaken

31-03-2013, 11:59

I'll send him a PM :)

Alex_UK

31-03-2013, 20:43

10th April - see here (http://theartofsound.net/forum/showthread.php?p=425455)

Usernametaken

01-04-2013, 00:06

Awesome, thank you :)

Usernametaken

01-04-2013, 10:27

I'm on the list!
Now just to wait for my caps to arrive and be burnt in so I can figure out which ones I like the sound of the best.
I have a number of other hobbies and it's extremely rare to get this level of support for a product, let alone having a manufacturer not just OKing, but actively participating in the modification of their products.
Stan, absolutely brilliant service mate, I am extremely happy that I decided to get myself a Caiman.
Outstanding.

Usernametaken

09-04-2013, 10:46

Nichicon caps arrived and I'm now burning them in.
Noticing the same sibilance that had started to fade slightly on the old caps, I suspect burning these in will have the same effect.
Really liking the Nichicons for a first listen. Warmer than the caps I nicked from the opamp board and more defined. Looks like my bass is a bit louder as well.

MartinT

09-04-2013, 15:35

Yes, of all the electrolytics I liked the Nichicons best for coupling and Elna Cerafine II best for replacing all the PCB caps.

Usernametaken

17-04-2013, 08:25

So my Caiman board arrived less than a week after I ordered it!
Is it OK to replace the four 50v/47uF caps on the "output" half of the board with 10V/10uF Nichicons?
There are also four of the same type around the headphone opamp bit as I don't use the headphone out, I see no reason to replace these.
Incidentally, using the 10uF caps in the passive mod instead of the 47uF removed all popping between tracks and a nasty pop I had from new on system power on.

HighFidelityGuy

17-04-2013, 09:32

Do you mean Gator board? If so I don't think there will be a lot of point from a sound quality point of view. I know Stan tried a lot of different cap makes and values on the Gator and settled on the ones that gave the best all round performance.

I'm not sure if 10V caps will be up to the job as well. You'd have to ask Stan or measure how much DC is across them somehow. On the subject of popping, that shouldn't happen if you still have the output muting relays in place. However it could be that your amp is particularly sensitive to very low frequencies. So by using a high cap value in the passive mod you may have been allowing single digit frequencies to reach the amp. Which is usually not a problem. The 10uF caps may have attenuated these enough to remove the problem.

You may find that the Gator board doesn't have this problem. If that's the case then I'd leave the stock caps in place. If you still get the pops then I would just try replacing the pair of caps that are after the output stage. I think the other pair are before this and will probably just be to prevent the output transistors from seeing the slight DC offset on the DAC chip output. The caps around the headphone opamp won't affect the line output. :)

Usernametaken

17-04-2013, 11:06

Sorry, yes. Gator board.

LittleTone

08-05-2013, 12:57

Hi Chaps

Anyone interested in these http://sdrv.ms/10aVqQe
A pair of Auricap 2.2uF 200V Capacitors; used for the passive mod in a Beresford 7520 DAC.
£30.00 inc postage

Tony

Usernametaken

11-05-2013, 14:14

Am I correct in thinking I have lost a bit of bass since installing the Gator?

Alex_UK

11-05-2013, 14:32

How many hours has it been playing for? If it is only new, then quite possibly - IME (and others) around 200 hours and it will be fully burnt in. I didn't believe in burn in until I bought a Caiman and then the Gator (and some caps with the passive mod.)

MartinT

11-05-2013, 14:51

The Gator gave me the drive I was missing and certainly didn't lack bass when I moved over to it (from Auricaps in passive coupling mode).

Usernametaken

13-05-2013, 23:56

Ah, it maybe has 50 hours on it, that might explain it then.

Edgar

30-04-2017, 10:02

Thread necromancy! - I've just got the Beresford 7520 and I've done the 5 minute passive output mod. I have some 3.3uf Nichicon FWs in there (had them lying around), but also have some Nichicon MUSE 47ufs coming.

I have a query:

I like the sound of the pre-amp on my Sansui AU-317 so I don't want to go straight into the Sansui power amp from the Beresford. However, the variable output on the Beresford gives me better fine control of the volume on the AU-317.

Now that I've done the passive mod, is it 'OK' to use the variable output from the Beresford into the pre-amp of the Sansui (AUX) or am I degrading the signal? Should I still be using the line output into the Sansui?

(The problem with using the line output is that the level is a bit high for the Sansui and I can't put the Sansui volume above about notch 3 - plus the Sansui has an annoying notched volume which can bee too loud or too quiet!)

Thanks all.