Caiman Mods [Archive] - Page 3 - The Art of Sound Forum

NRG

05-06-2010, 23:18

I've only just caught up with the mods to the Caiman and I've gone in my own direction. The Murata regs look good but I can't justify the cost so I've made do with LT1086 and the Teddy 'Gyrator' made up onto strip board and squeezed into the available space. For the output caps I've not gone with the recommendations and stuck with what I like IE BlackGates. I was happy before the changes but I'm even happier now, the sound has swung more to where my TDA1541 sits, its grown some midrange fullness and importantly revealed a new level of detail retrieval.

The regs seem to have eliminated a HF noise observed on the 'scope and also reduced the switching noise by about 20db, I'm now very tempted to build a simple linear pretracking supply to see if it improves further....

StanleyB

06-06-2010, 06:59

NRG

06-06-2010, 10:47

I'm not sure there's a whole lot to share Stan!

I used the Teddy Gyrator cct and a LT1086-5 and a -12, they just squeezed under the lid. I added some small clip on heat sinks which made fitting even more fiddly. As the pinouts of the LT series are different to the standard 7805/10 I had to juggle the GND and OUT pins...not elegant but it worked. Some not so stellar pics below.

http://i94.photobucket.com/albums/l82/_NRG_/other/DSCF5060.jpg

http://i94.photobucket.com/albums/l82/_NRG_/other/DSCF5062.jpg

http://i94.photobucket.com/albums/l82/_NRG_/other/DSCF5063.jpg

http://i94.photobucket.com/albums/l82/_NRG_/other/DSCF5064.jpg

MartinT

06-06-2010, 11:23

Nicely done, Neal.

leo

06-06-2010, 13:00

Just to add another I knocked up a little adjustable shunt reg which I'm trying for the output stage
The one for the digital is an Audiocom super reg1

http://i273.photobucket.com/albums/jj220/kingbusoms/P1060334.jpg

StanleyB

06-06-2010, 17:00

I'm not sure there's a whole lot to share Stan!
I don't know what others think Neal, but I think that you have done a brilliant job there. Very much in the true spirit of 'more for less' as far as cost is concerned.

Ali Tait

06-06-2010, 18:01

Indeed,lovely job Neal.

chrism

10-06-2010, 15:02

Ok done the 12k resistor mod as well as the wire shortcut. The 12k resistor makes the bass seismic and a little too much for my room and speakers - sorry Stan.

I will leave it as is for a few weeks to settle down a bit but I think that the original resistors may need to go back in.

Regards

Recoil

11-06-2010, 23:56

I just can't find which Rubycon cap it is, i know it's bipolar, 16v and 47 uF.. Does anyone know the type?
And the Wima caps are MKP's?

Labarum

12-06-2010, 07:33

I just use the Caiman as Stan sent it to me, and I am very happy with it.

I do wonder what all you modders gain.

NRG

12-06-2010, 08:05

What do we gain? Better sound and a more enjoyable listening experience!

With the regulator change and cap mod I've found the tonal balance has moved to more like my TDA1541, which is a positive change for me. I'm using black gates so the tonal change isn't at all unexpected as I also use these with the 1541, however, what was unexpected was the level of detail retrieval that is now available, the Caimens separation and layering is so much better than before. I'm hearing new things on material that I thought I knew very well as if a mask has been lifted from the sound, TBH I didn't think this would have been possible as it was very good before hand....

Covenant

12-06-2010, 08:13

I just use the Caiman as Stan sent it to me, and I am very happy with it.

I do wonder what all you modders gain.

What you don't have you don't miss heh Brian?
I think the performance leap in comparison to the cost is substantial;well worth it to me.

Carson

12-06-2010, 08:27

I do wonder what all you modders gain.

Give it a try and see for yourself what all of the hype is about :eyebrows:

Gazjam

12-06-2010, 09:44

What you don't have you don't miss heh Brian?
I think the performance leap in comparison to the cost is substantial;well worth it to me.

+1 :)

The Vinyl Adventure

12-06-2010, 10:34

so tirna can do these extra resistor and signal path mods can they? ... hmm i wonder how my pre amp would be with the extra dynamic range... i suspect it would cope fine... my room on the other hand might not like more bass.... .... how is anyone else getting on with that set of mods?

The Vinyl Adventure

12-06-2010, 10:38

....
3. Minor Optional Upgrades free with any of above

These include changing a pair of resistor on the audio board to 10k or 12k Ohms. This upgrade is recomended by Stan Beresford to increase the gain and dynamic range of the fixed/variable amplifier outputs. thats pretty nice of him eh

The Vinyl Adventure

12-06-2010, 11:03

paid up and ready to go ... just gtta get it in the post... gonna take a punt on this 12k resistor and bits of wire mod... anything else i should ask for whilst its there do we think?

quadsugdenman

12-06-2010, 11:18

Hamish

I spoke with Jimmy yesterday and my Caiman goes off on Monday. ;)
He said the resistor upgrade is free because:

(1) Resistors are 'buttons' cost wise.
(2) They are easily changed while he is doing other mods.

I am holding off for the moment until I know what effect the original mods are going to have on the overall sound.
Your turn!!
Garry :lolsign:

The Vinyl Adventure

12-06-2010, 13:31

I've just gone for the lot... I'm fairly certain my pre amp isn't going to have a problem with the extra gain and dynamic range ...
I guess it will be a nice big jump in quality too and if I really don't like it ... Well it be a lesson learned that I shouldn't be so impetuous eh :)
just got back from the post office now... It will be with tirna by Tuesday :)
just gotta do without the usefulness of a caiman for a while now :(... What are tirnas tirnaround times like?

quadsugdenman

12-06-2010, 13:48

Dr Jim reckoned get it to him by Tuesday it could be back for the weekend depending upon his workload. He will be inundated soon so ye did right getting it to him pronto as the waiting times could get longer! ;)

The Vinyl Adventure

12-06-2010, 13:52

So I guess you will have yours back by next weekend and perhaps il have mine the following weekend... Interesting... By thy time I intend to have had the dynamik psu fitted inside my majik so I should be getting my self a tidy little set of upgrades :)

quadsugdenman

12-06-2010, 13:58

No I think yours could be back at the same time providing things have not got too busy during the week. As he explained the operation doesn't take too long it is just very 'fiddly' as he put it and he likes to test before and after the mods. So fingers cost you could be burnin in next weekend!!!

G

The Vinyl Adventure

12-06-2010, 14:06

Sweeetness! If that is the case il leave it running for a week in my office with constant music through it ... Then hopefuly if it's nicely burned in il be able to take it to the place I'm getting my majik 'dynamiked' and put it up against some monster "high end stuff" like the naim dac and klimax ds!! That should be good fun :)

just gotta try and get my hands on one of these more posh psu's now... Anyone fancy building me somthing? :)

Steve Toy

12-06-2010, 14:33

Anthony's yer man for a PSU upgrade.

Recoil

12-06-2010, 16:54

No one knows a part number for the Rubycon and Wima caps?

The Vinyl Adventure

12-06-2010, 17:06

I dunno which part it is that tirna have thousands of but if your trying to get the bits to do mods your self I'd give them a ring!

The Vinyl Adventure

12-06-2010, 17:16

Anthony's yer man for a PSU upgrade.

That was of course my first port of call... He's busy though int he

Recoil

12-06-2010, 18:45

I dunno which part it is that tirna have thousands of but if your trying to get the bits to do mods your self I'd give them a ring!

Since i live in Holland, i'm likely to get parts with such a low cost locally. I'm trying to look for photo's of the mod in which the Rubycons are visible in high-res, but without result.

Tirna asks 80 pound for just the parts.. I can buy the Murata's at 19 euro a piece, and the rubycons are (i guess) something like 1 euro a piece. That makes 45 euro against the 96 euro at Tirna.
If someone wants to look on his capacitors, then i'm a very happy guy.:)
(or a Farnell item number..)

Gazjam

13-06-2010, 12:22

HifidelityGuy (Dave) is your man for this....
He ordered the Rubicons and the Mutara's for the original Group buy on here.

Gazjam

13-06-2010, 12:30

Calling out to anyone who has the Wire/12K Resistor Mod done on their Dacs...?

I've upgraded mine to the Rubicon/Wilma/Mutara/Elna caps stage, and I love the clarity and micro-detail Im getting now...huge 3D soundstage too.

New mods always catch my eye though, and from what I've read the latest Wire/12K resistor mod adds to the bass and increases dynamic range....
Just the Dab for me in my system...although I would not want it at the expense of the clarity I now have with the Elna Slimic II's in place?

I'd really appreciate any comments from anyone who's had the latest mod done, with regard to the new mods effect on the overall sound of the Dac; particulalrly with regard to soundstaging and clarity.
Does increased dynamic range and bass = less openness in the soundstage with less clarity?
Always welcome more "thwack n thump" with my rock music :)....but still want to keep it sounding open and airy for classical! :)

I know Stan said he recommended the latest mod only for those using their Dac as a Pre into a Poweramp...but has anyone tried it with an integrated like mine?
I Just wonder how much of a problem it would be really...
(I have the spec sheet on my amp if any figures are required? ;))

Thanks!

Tony G

13-06-2010, 15:21

OK chaps, its embarrassing (to me) question time - my "mod your Caiman beyond recognition" project was delayed for a couple of months from reading about it and ordering parts to now.
Getting ready to "do the business" I dug out all the parts that have arrived piecemeal from various parts of the globe and find I have a couple that I cannot recall why I have them :doh:

Amongst the bits I bought a pair of THS4032 opamps and adaptors, that is fine, but I also have a pair of 220pf polystyrene caps that I cannot remember why I bought.
I have trawled back through the whole thread (over a couple of days) and did not find (might have missed it) any reference to them - might they have been suggested for bypassing these opamps ? if so which pins to connect ?

I would be most grateful of any pointers here.

@jasper - the Rubycon caps you want are 47uf 16v non-polar, sorry do not know a part no, alternatively Nichicon Muse non-polar of the same specification can substitute. Normal polarised 'lytics will not do.

leo

13-06-2010, 15:56

I remember one of the mods on the 7510 was to upgrade the cap across the fb resistor in the output stage (220pf Wima) not sure what its for in the 7520 or Caiman

StanleyB

13-06-2010, 16:52

but I also have a pair of 220pf polystyrene caps that I cannot remember why I bought.
Those are for MLC8 and MLC9 on the audio PCB. The are either side of the headphone opamp. I have tried values of between 100pF to 270pF.

Tony G

13-06-2010, 17:55

Thanks Leo and Stan for the prompt responses.
I was beginning to wonder if they belonged to another project.
Have added the info to my "mod notes".

fmzip

14-06-2010, 15:02

Nice :) .

I've just placed my Elna Silmic II & Nichicon caps order with Parts Connexion but the Muratas are out-of-stock everywhere I look.

Would anyone have the the actual Nichicon and Elna manufacturer PN's for the capacitors which they've used?

I thought I read that the caps need to be non polarized but the Elna's are not listed as such:

http://www.elna.co.jp/en/capacitor/alumi/catalog/pdf/rfs_e.pdf

Carson

14-06-2010, 17:21

The Rubycon's are the only non-polarized ones, the Elna's are standard polarized ones.

fmzip

14-06-2010, 17:24

The Rubycon's are the only non-polarized ones, the Elna's are standard polarized ones.

Thanks for the clarification. Been reading so many Caiman threads I am losing track as to which ones are what. Now I just need to find the Wima PN mentioned for the capacitor in this thread.......

Recoil

16-06-2010, 19:40

And i've found a discrete opamp that has to work in the Caiman due to the very generous supply voltage of 5-15v dc.. The Dexa-73728, available at Parts Connexion. Maybe this is a good alternative to the Burson equivalents..?!

fmzip

16-06-2010, 19:47

StanleyB

16-06-2010, 20:04

If funds allow, get THIS ONE (http://cgi.ebay.com/ebaymotors/MASTECH-DC-POWER-SUPPLY-LINEAR-VAR-0-30-VOLTS-0-6-AMP-_W0QQcmdZViewItemQQhashZitem2eac70428eQQitemZ20046 1533838QQptZMotorsQ5fAviationQ5fPartsQ5fGear). Set it to 15.6V~15.8V on the LCD display and double check the output voltage with a multimeter.
The noise figures are even better than a similar linear PSU that I use in the workshop.

Recoil

16-06-2010, 20:12

Would something like this work as a dedicated 15vdc linear power supply or can I make/find something better state side?

http://www.skycraftsurplus.com/dual-outputlinearpowersupply12-15vdc1amp.aspx

http://www.solahd.com/products/powersupplies/silverline.htm

It will work, but i think you won't notice any difference compared to the Caiman power supply.
If you want to try something that maybe is better than the standard supply, you may want to look at the following to make a powersupply (in correct order)
-A FUSE, properly rated
-a simple EMI-RFI filter (optional, while you're at it: add a zener diode to protect the circuit for powerspikes)
-a toroidal powersupply
-bridge rectifier
-buffer elco(s) (i don't believe in audio-class caps for powersupply buffers, but suit yourself)
-to stabilize the output voltage (and if you want to go hi-end): a 15 volt Murata or NewClassD regulator) (i think this step is pretty useless, as in the caiman has it's own regs for 12 and 5 volts..)

Notes:
-Do not supersize anything (especially the trafo and buffer elco's), it will have no effect other than a weight gain of your PS, a 10% oversize is enough for both)
-Please, please seek some help if you haven't done this before. You are working with potentially dangerous voltages, especially if you try to touch a loaded elco or take a live wire as ground etc..)
-I want to help you with the calculations once you've decided to build one yoursef
-ground properly
-add some additional components to make the PSU more sophisticated, like a switch, elco resistor etc..

fmzip

16-06-2010, 20:25

Thanks for the tips guys.

As I do not have the Caiman, I do not have the stock power supply. What I am doing is modding my TC-7520 unit with the Murata Power regs, caps, dac etc. Just had the Wolfson soldered in a few minutes ago! :) Once I get the regs, I will need a power supply...

I certainly don't mind building a power supply. All I would need is a list of parts and a simple schematic. I have a PCB assembly shop at my disposal to help with the assembly, testing etc. Can you help me with creating a parts list?

What I was really trying to do is weigh the costs of ordering/ delivering a Caiman PS to the states and seeing what I could do for the same amount of dollars versus time and effort....

Saw this one for around $45:

http://cgi.ebay.com/SOLA-REGULATED-POWER-SUPPLY-SLD-15-3030-15-/150379754449?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item230354f3d1

Maybe I will take Stan's advice and order the other. Would be nice to have a variable PS at my disposal for little projects as well :)
This 5 AMP one would work as well, correct?

http://cgi.ebay.com/Mastech-Variable-Linear-DC-Power-Supply-30V-5A-HY3005D-/380242611416?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item588839ccd8

fmzip

17-06-2010, 02:32

Stan, looks like the Mastech Power supplies you pointed out come in a 2 and 3 AMP model

http://www.kitsusa.net/phpstore/html/HY3002-MASTECH-single-variable-power-supply-0-30VDC0-2AMP-1232.html

Shouldn't 2 Amps is sufficient?

Or this one?

http://cgi.ebay.com/MASTECH-HY1803D-DC-POWER-SUPPLY-VARIABLE-0-18-V-0-3-/200458177273?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item2eac3d0af9

StanleyB

17-06-2010, 07:04

The 2 amps version is fine.

Covenant

17-06-2010, 19:10

I thought I should say a big thank you to Jimmy Dripps at Tirna Electronics for his great work on my 7520 fitting the Elna caps. Combined with a TeddyReg power supply it sounds superb.
Jimmy did the resistor mod and shortcut mod F.O.C-what a gent!

fmzip

18-06-2010, 00:19

How much is this power supply you are referring to and where did you get it?

AndrewR

22-06-2010, 09:20

Was it the BB 2132 you swapped from?
Been thinking of trying opamp swapping again soon once I've given the new mods a week or so to "heat up"

The OPA2132PA and AD826 are actually very similar sounding. I only had a slight preference for the 2132 - but may have been because I might not have run the AD826 in for long enough.

Just bought some of James' (Carson) mods for my TC-7520. Going for Silmics, Wolfson, Rubycon/Wima/MuRata. The MuRata's a bit of an unknown gamble for me, but I know I love the other components.

Very excited!

Andrew Randle

Gazjam

22-06-2010, 09:32

Hey Andrew,
I've got those fitted already to my Dac, think your going to be impressed. :)

Great Blog by the way...any events like the "hifi car boot sale " up near Scotland you know about? :)

StanleyB

22-06-2010, 09:47

The AD826 has a far better level of detail than the 2132 according to my ears.

The Vinyl Adventure

22-06-2010, 10:10

Got mine back from tirna today ...

quadsugdenman

22-06-2010, 11:29

Got mine back on Monday. What a great job Dr Jim did. I/He did not know that there is a slight difference in the case size between the Caiman+ and the standard Caiman. However Jimmy overcame the 1mm difference in case height and fitted all the new bits in with a bit of jiggery pokery.
It is already sounding so much better than before, and the beauty is it can only get better!!!! ;)
Well done Stan and Jimmy Dripps !! :cheers:

leo

22-06-2010, 13:24

The AD826 has a far better level of detail than the 2132 according to my ears.

I gave the OPA2132 a try and tried to live with it but in all honesty couldn't stand the thing, if I'm honest I even preferred the NE5532 over it.

AndrewR

22-06-2010, 14:49

I gave the OPA2132 a try and tried to live with it but in all honesty couldn't stand the thing, if I'm honest I even preferred the NE5532 over it.

For me the OPA2132 excels in all the 'musical cliches' and it has great bottom-end welly. I've tried many of the others, though not the THS yet.

I'm really looking forward to these Tirna mods. Every Wolfson DAC I've heard has sounded fabulous. Elna and Rubycon are quality-personified (So's BHC, but would probably be difficult to fit the case).

Andrew

MartinT

23-06-2010, 14:30

I'm slightly lost in the various threads - can someone please point me to where the original 12k resistor mod is described?

The Vinyl Adventure

23-06-2010, 14:32

page 45 this thread mate... stan, half way down ...

MartinT

23-06-2010, 14:40

Thanks, Hamish. Couldn't see the wood for the trees.

fmzip

23-06-2010, 14:41

I'm slightly lost in the various threads - can someone please point me to where the original 12k resistor mod is described?

http://theartofsound.net/forum/showpost.php?p=126497&postcount=449

I was looking at it last night and had it bookmarked.............

MartinT

23-06-2010, 14:46

Got it now, thanks Fran. Although I'm running the fixed outputs into a preamp I'm going to experiment with these values a little.

The Vinyl Adventure

23-06-2010, 14:47

id actually made a mental note of it being on 45 for when i spoke to jimmy at tirna ... turns out he was on top of it...
it doesnt seem to be causing my system any problems, that mod....
obviously with a change of speakers the same day as i got the upgrade to the caiman i now cant really say much about the quality of the upgrades apart from the fact that the caiman is now louder than it was .... no clipping or anything horrible like that for me ... which is nice... it sounds more dynamic and rich compared to the majik (that used to sound very similar to the stock caiman) but the reality of the situation its very difficult to make any realist conclusions on the sound quality with the added gain .... that all said ... its early days and i have probably only had about 3 hours of listening to it so far ... im gonna do a few more comparisons with the majik at some point ... and my mate greg said it was "obviously better than the majik" ... im just, as usual, a bit more hesitant to make early conclusions... ... ...

heres a question for you techy folks...
i find the caiman and the majik more similar than, say, the camin and the mf v-dac... is that likely down to the both using a wolfston chip?

NRG

23-06-2010, 15:10

Thought I'd post an update on my modded Caiman as its now been running for a few weeks.

The cap and regulator changes have certainly lifted the performance onto a higher level. Tonally the presentation has moved more to that of my DIY TDA1541 but the detail retrieval and layering is in a completely different ball park. The ability to easily distinguish between voices, pick out small details, inflections and detail in instruments is so much better than before it really is an eye opener. The sound is not so 'speaker bound as it was and now stretches further back, forward and up creating a larger picture with detailed presentation, material I though I knew well now has a new lease of life as I'm hearing stuff not heard before as well as being presented differently.

This is so good that the TDA has now been removed from the system! :)

Which interestingly caused me an issue. As soon as it was removed the sound deteriorated. Vocals became bright, hard and with 'grain'. I discovered that the Caiman does not like sitting on top of my rehoused and modded SqueezeBox.

I recall reports of the display radiating a lot of noise over on the SD forums so I placed a small cardboard box between the Caiman and SB where the TDA was sat and the sound improved. Putting the TDA back in and things where back to where they where....so I made a 'spiked' sub shelf that raises the Caiman higher still. Conclusion: placement certainly has an effect on sound.

Re the BB2132 mentioned earlier, I still can't get on with these. I find they thicken the presentation and bass becomes bloated and one note, the standard opamps still do it for me and seem to sound even better with the latest changes. Right off to listen to some more music!

:)

fmzip

24-06-2010, 14:41

I left mine for now so that I can do quick comparisons when I change opamps.

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

Stan, just to clarify, no trace cut is necessary here? This wiring in fact eliminates the need for a trace cut for all intended purposes?? Is this for the Caiman only?

MartinT

25-06-2010, 17:34

Regarding the resistor mod, the claim that I have read is that it increases volume and dynamic range. I've taken a look at mine and the standard resistor value is 8k2 with values of 10k or 12k being suggested. I can't tell for sure but I'm guessing it must be in the negative feedback loop since higher value = louder volume.

So who has tried which value, 10k or 12k? By how much is it louder? I question the claim for increased dynamic range since this is counterintuitive. DR is the difference between loudest and softest note so an increase in output voltage will give greater volume but the DR (within operating limits) will remain the same. Any observations?

fmzip

26-06-2010, 03:21

chrism

26-06-2010, 08:20

Yes I have done the 12k mod (about 3 weeks ago). I did not notice any difference in actual volume but did notice differences to the dynamic range. Individual sounds and notes spring out better than before and overall music has more weight. On the down side the bass is too pronounced but many may like this. I use floorstanders in a small room and again this will tend to increase the bass.

Well worth a try as it can easily be undone.

Just to add that my Caiman has:

Linear suppy set at 15.5v.
Murata regs.
Rubycon non polars to the opamp board.
AD826 opamp.
wire mod.
Used via variable out straight into a poweramp.

Regards

Chris

The Vinyl Adventure

26-06-2010, 09:56

Mine was definitely louder... It used to be basically the same volume as the majik ... It's now distinctly louder... It is sounding quite excelent today after aprox 60 hours of running the last 12+ of which have been with the cb power supply (if that makes any odds)
It does sound excelent... But as I said in the last post because of the increased level its proving very difficult to pin point what exactly is better.... I dot really care that much either ... All I know is I like very much how it sounds now... Sorry that's not a very diy thread comment is it :)

MartinT

26-06-2010, 10:51

Ok, I'm going to ease into this by replacing the 8k2 resistors with 10k. Will report back when done. Now to make a (very small) Maplin order...

Frizzup

27-06-2010, 00:41

Is it possible to add a 2nd optical input to my existing Caiman ?

I do not need the USB input so can I add the 2nd optical input receiver at the point on the PCB/Case ?

If yes what part do I need to order ?

Cheers
Frizzup:scratch:

MartinT

27-06-2010, 10:35

If you can't, there are plenty of optical<->co-ax converter modules available.

StanleyB

29-06-2010, 21:43

Is it possible to add a 2nd optical input to my existing Caiman ?
You can on the PCB, but it turns out that the Caiman USB socket entry hole was at some stage changed from its original location by a few millimeters. That's why I have a slightly different case for the Caiman+, which has the two TOSLINK sockets.
If you are handy with a file you can resize the USB hole so that it accepts an extra TOSLINk socket.

StanleyB

29-06-2010, 21:51

I have been experimenting with some PIC microcontroller software code to see if I could solve a frequently asked for feature. Namely a method that can detect which input on my DAC is active, and get the DAC to engage the corresponding input signal.

I managed to get the no frills version of the code working. At the moment the PIC resides in the PIC programmer whilst I figure out how to connect the switches and LEDs in the DAC to the PIC so that I don't have to rely on the switches and LEDs from the PIC programmer.

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

MartinT

30-06-2010, 07:42

Frizzup

30-06-2010, 09:08

You can on the PCB, but it turns out that the Caiman USB socket entry hole was at some stage changed from its original location by a few millimeters. That's why I have a slightly different case for the Caiman+, which has the two TOSLINK sockets.
If you are handy with a file you can resize the USB hole so that it accepts an extra TOSLINk socket.

Gidday Stanley,

That being the case what is the part I need to order that gives me the 2nd optical reciever. I'm handy with a file and also the soldering iron so the modification is no problem just need to know the manafacturer/part no please

Cheers
Frizzup

StanleyB

30-06-2010, 12:54

That being the case what is the part I need to order that gives me the 2nd optical reciever. I'm handy with a file and also the soldering iron so the modification is no problem just need to know the manafacturer/part no please

The one I use is a production line part. It is not sold by the manufacturer for general use. If you need one I'll see how much it will cost me to post it to AU. Best PM me your address.

StanleyB

30-06-2010, 12:58

Clever, Stan, but I've always preferred simple and have no problem with setting the input manually. A PIC controller is going to create a lot more internal noise, I'm guessing?

Now balanced outputs, that would be another thing :)
Why would a PIC be noisy:scratch:?

I'll leave a mod for balanced output to the wider community. I have already worked out that it would add at least £50 to the retail price (bigger case etc.), which would be a heavy price to pay for the 99% of DAC buyers who don't need it.

MartinT

30-06-2010, 14:49

Why would a PIC be noisy:scratch:?

Another clock running.

StanleyB

30-06-2010, 14:59

It doesn't have an external clock :).

MartinT

30-06-2010, 15:04

It doesn't have an external clock :).

Aha! My mistake then, carry on as normal :)

StanleyB

30-06-2010, 15:13

Maybe not. It's too complicated to mod the PCB and add the microcontroller. I guess I'll have to remain the only person with an auto search Caiman:ner: ...

HighFidelityGuy

02-07-2010, 11:53

Hi Chaps.

Quite a while ago I stumbled across THIS (http://www.audiodigit.com/index.php?section=81) inexpensive tube buffer and thought it would be interesting to try out. Then I noticed that aparently it can be used to replace the opamp output stage of CD players etc. So that got me wondering about whether I could use it like this in the Caiman. To make this work would I simply remove the opamp board from the Caiman and then wire the tube buffer basically as shown here:

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

I was thinking that this would give a nice short signal path from the DAC output straight into the tube buffer.

If that's correct, the bit I don't understand is that the tube buffer doesn't amplify the signal at all, so will I get a really low level output going to my power amps? :scratch:

Thanks.

Ali Tait

02-07-2010, 12:13

No,it says it outputs at 2v rms,which is standard line level.Should be fine.

tdog

02-07-2010, 12:26

And, do not forget Pass' FET buffer http://www.passdiy.com/pdf/B1%20Buffer%20Preamp.pdf which could be built into the box (probably very tightly)... Only Stanley can tell us if there is any gain in the opamp circuit/board. I'm guessing there is, especially after the "10k" mod, but for those with enough gain in their system they may want to try a buffer on the output of the output of the DAC.

HighFidelityGuy

02-07-2010, 13:52

From looking at the WM8716 datasheet, it has a maximum output of about 1V RMS but the Caiman has a maximum output of about 2.3V RMS I beleive. So there must be some gain being added by the opamps.

If I use the Caiman in it's standard state I have too much gain in my system. So I added an attenuator between my Caiman and power amps. This drops the signal by 10dB and allows me to have my volume dial around 12 o'clock at usual listening levels, so that's spot on.

So if the DAC chip has a maximum output of 1V RMS and this gets fed into a valve buffer that has no gain, then I'm guessing the maximun voltage my power amps will get is 1V RMS. So that may provide me with a similar level to my current attenuated Caiman.

Out of interest, does anyone know what 2.3V attenuated by 10dB is in volts? Knowing that would give me an idea of how likely this is to work.

Thanks.

MartinT

02-07-2010, 14:43

It's about 700mV.

tdog

02-07-2010, 15:07

or in other words, the 1V output is about -7dB down on the on the 2.3V output. Sounds like you have plenty of gain to try a buffered output...

Marco

02-07-2010, 15:14

Hi 'tdog',

Welcome to AOS! :)

Before going any further, could you do me a favour please and pop into the Welcome area and introduce yourself to our members, giving your real first name, basic geographic location, system details and music tastes?

This is the required procedure for all new members joining our community - cheers! :cool:

Marco.

ZZTop

15-07-2010, 19:02

Hello to all!

Stan sent me my Caiman 2 month ago to Buenos Aires. So I have allready the 15V PSU.
I didnt belive in burning in, but I realized that it really matters here.
Great sound.
I changed the 15V PSU for a car-battery, a clear improvement.
I have to charge it once a week and thats it.
As it never can be good enough.....
Is there a way to optimize the Caiman for 12V?

greetz
Uwe

Canetoad

19-08-2010, 07:01

Hi,

I've finally worked up the courage to open my Caiman and replace the opamps. I took out both LM4562NA and replaced them with AD826. I noticed that the output volume at the amp (NAD C-372) was a lot quieter than with the 4562s. I was wondering if this was normal. With the original opamps I had to use attenuators (10db) so I had some movement in the volume control on the amp. I had to remove them for the AD826s.

Is this a normal situation as it hasn't been mentioned anywhere in this thread?

Now listening to the new opamps. Seems the bass is more consistent than it was with the originals. Sometimes it just didn't sound right.

Cheers.

MartinT

19-08-2010, 07:17

I noticed that the output volume at the amp (NAD C-372) was a lot quieter than with the 4562s. I was wondering if this was normal.

No, the op-amp gain is determined by the feedback loop not the op-amp itself. You shouldn't notice such a gain difference. Are you sure the AD826 are actually running (inserted the right way)? You may be hearing the Caiman in passive mode otherwise. Try reinserting the LM4562 one at a time and testing both line and headphone outputs for gain changes.