Collection of mods for Beresford TC-7520 [Archive]

leo

16-06-2009, 20:41

Ok, thought I'd try and gather various mods etc for Stans TC-7520 dac and add them on here, if we could keep this as a mod thread only and keep the discussions on the other threads just so it makes things easier to find

We'll start with the basics first, if I've done anything wrong or if its not clear just let us know, the idea here is to make things easy:)
Other mods will be added later but for now

Heres a pic of the riser board containing the op-amps

http://i273.photobucket.com/albums/jj220/kingbusoms/5.jpg

Below with the THS4032 fitted for the fixed output and AD826 for the HA/variable
For the THS4032 I used this browndog adaptor I converted to allow room with the 100nf ceramic fitted http://theartofsound.net/forum/showthread.php?t=2507

http://i273.photobucket.com/albums/jj220/kingbusoms/4.jpg

Below with the LM4562 fitted for the fixed output, Stan recommded removing MLC5 / MLC6 ceramics if using this particular op-amp, I compared with and without and must agree I preferred it without those caps, you can easily compare ,either by cutting one side of the caps leg or carefully taking out the riser board and desoldering the caps altogether (watch out for the hot melt glue and double sided sticky pad;) )
I've also not yet tested other op-amps with the caps removed, be careful with high bandwidth types

http://i273.photobucket.com/albums/jj220/kingbusoms/2.jpg

Below with the metal can LM4562HA for the fixed output

http://i273.photobucket.com/albums/jj220/kingbusoms/1.jpg

Op-amps I've tried so far in the fixed out which seem to behave

OPA2132
OPA2107
AD826
LM4562
LM4562HA metal can
Various NE5532
THS4032 + 100nf bypass, I got best results soldering this cap directly onto the THS4032 pins rather than the socket pins, so far its behaving

Only types I've tried so far for the variable out are OPA2107,AD826 and LM4562, all these worked, I personally like AD826 so far but its only early days

Most op-amps can be found here http://uk.farnell.com/ and also Ebay

Latest update 04/07/09

Swapping PCM1716 to WM8716

Warning, this is a fiddly job, not recommended if your not comfortable working with SMD, a mistake can result in a Knackered dac!
My advice is wait for Stans SE version

I used precision side cutters to cut the legs, I then removed each remaining leg on the pads with desolder wick
As can be seen I managed to lift pad for pin12, luckily it wasn't connected to anything
The board was cleaned with pcb cleaning fluid to remove caked on flux etc

http://i273.photobucket.com/albums/jj220/kingbusoms/pcm1716.jpg

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

http://i273.photobucket.com/albums/jj220/kingbusoms/WM8716.jpg

This mod made quite a noticeable difference to the sound, straight away I found it was smoother yet crisp in the highs
Left to warm up dynamics increase nicely

Added 05/09/99
Results may vary with this mod depending on op-amp, system used etc
Stans mod to the Caiman, details here http://theartofsound.net/forum/showthread.php?t=3740 also added a few pics and notes here for easy finding

If original 100pf ceramics are still inplace these need to be removed and replaced with resistor (Stan found 36k to be best so far, I'd have to agree) and 100nf ceramic cap soldered in series
Mod seems to work best with NA version of LM4562

http://i273.photobucket.com/albums/jj220/kingbusoms/DSCF3900.jpg

Fit as below

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

Update 23/12/09

Onboard 5v reg for dac and receiver changed to a diy discrete (this particular one in below pic is designed by John Swenson) I built it on vero/matrix
Other possible replacements are what Stan uses, Mouser Part No: 580-7805SR-C Manufacturer Part No: 7805SR-C, theres also a 12v version which can be used for supplying the Caimans audioboard , you need to swap the main external psu though to one of Stans 15v Caiman upgrades to give the needed voltage drop for the regulator

Alternative type regs are avaialble from Paul Hynes, Audiocom, Hi-fi upgrades etc, I hope to try a few of these others and do a mini shoot out, I'll add updates

Signal capacitors on audioboard replaced with a set from Stan, some details here post 72 http://theartofsound.net/forum/showthread.php?t=4580&page=8

I was quite pleased with these mods, both go well togther and help squeeze some more out of this unit

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

Limks to useful posts updated 24/06/2010

Stans mod to change the default input selection http://theartofsound.net/forum/showthread.php?p=131177
Stans mod to increase gain http://theartofsound.net/forum/showpost.php?p=126497&postcount=449
Stans mod to shorten track from audioboard http://theartofsound.net/forum/showthread.php?t=4580&page=49

Values and locations for those wanting to cap roll on the main pcb around regulation, dac and receiver IC , Elna SilmicII seems to be the favourite choice from those who's tried them http://theartofsound.net/forum/showpost.php?p=126600&postcount=457 http://theartofsound.net/forum/showpost.php?p=130716&postcount=1586

List of part numbers for the caps , Thanks Fran (fmzip)

Nichicon Muse Caps
UES1C470MPM

Elna Caps
RFS-25v221 2pcs
RFS-16V101 1pc
RFS-16V100 8pcs

Wima Cap
MKS20-.068/63/10

MartinT's diy external psu http://theartofsound.net/forum/showthread.php?t=6110
Stans idea using a linear CB radio psu http://theartofsound.net/forum/showthread.php?t=5893&highlight=psu

Murata regs tried and recommended by Stan, thanks to fmzip for link
http://parts.digikey.com/1/parts/1591591-regulator-switch-5vdc-0-5a-sip-7805sr-c.html

http://search.digikey.com/scripts/DkSearch/dksus.dll?vendor=0&keywords=7812sr-c

Dexa regulators tried and recommended by MartinT, thanks to Martin for link
http://www.newclassd.com/index.php?page=34

Updates 04/07/2010

Stans mod for bypassing output stage op-amps
http://theartofsound.net/forum/showthread.php?p=134411#post134411

StanleyB

16-06-2009, 21:04

DaveK

16-06-2009, 21:16

Hi Leo,
Speaking personally (and I'm sure for many others also) I think this post is absolutely brilliant. There are almost as many upgrade options for the 7520 as there are owners or op-amps so drawing all the threads/options together in one place is great. I hope it permits a concensus of opinion to develop as to which are the optimum upgrades to go for. I know some members much prefer to form their own opinions about such things, :smoking: but I'm also sure that others, like me, don't want to interfere in the bowels of their expensive 7520s any more than absolutely necessary, not having the knowledge or skill to recognise or correct any balls-up that they may commit. :steam:
Just great !!

leo

16-06-2009, 22:44

Thanks Dave! we can start off with the easy bits and probably go for the weird and wonderful mods later:lol:

TBH I reckon just the simple op-amp changes is enough anyway for most

StanleyB

17-06-2009, 09:02

Anyone with a set of those cans know how hard it is to get decent bass out of them.
If you are looking to improve that situation, then the THS4032 makes an ideal partner for the K701.

Stan

Codifus

17-06-2009, 16:13

This write up and included pictures are fantastic. I feel much more confident when it comes time to install my LM4562

Thank you much, Dave!

ReachtheSky

17-06-2009, 22:35

Leo I may be wrong, but regarding your pic of the riser board containing the op-amps, I was of the impression that the left op-amp was for fixed & variable output and the right op-amp for head-amp only?
Granville

StanleyB

17-06-2009, 23:10

I was of the impression that the left op-amp was for fixed & variable output and the right op-amp for head-amp only?
Granville
Good call.

STan

leo

18-06-2009, 00:41

trailer

18-06-2009, 08:15

Great post Leo.

Adrian B

22-06-2009, 22:18

There looks from the pictures of the pcb to be a host of possibilities for changing caps and resistors to one's favourite boutique brands (I like Kiwame Rs myself which seem to remove a bit of digital glare, plus Elna Silmic or Cerafine caps). Of course, with this killer DAC there may be no glare to remove!

Adrian

Gazjam

24-06-2009, 11:56

Great Post Leo :)

Good to have the mods all in one place.

I'm running the 4032 for Line Out and the 4562 for HPA.
I didn't know about the MLC5 and 6 Mod...interesting!

I prefer the 4032 to the 4562 for the Line output....I wonder if theres any milage in removing the MLC caps when using a 4032??

Any thoughts anyone or has anyone tried it?

*Fitting plugin Op amps is easy enough..I dont fancy having to resolder the caps back in again!!

Thanks.:)

StanleyB

24-06-2009, 13:13

I have been trying out some mods on the line output and the HP output. The line output one is quite interesting. Remove MLC5/MLC6 and add a 4.7nF cap across the resistors.
This mod was in response to my tests against the DAC1 latest version.

http://www.beresford.me/images/mods/HFMOD.jpg

Shanedudddy2

25-06-2009, 02:36

What difference does adding the 4.7nF capacitors make, may i ask?

StanleyB

25-06-2009, 19:41

Try something like some polypropylene types instead of the ceramics. What it does I leave to you to notice:eyebrows:.

Stan

lovejoy

27-06-2009, 08:17

Hi Stan,
Have just tried a couple of 47nf Polyprops as per your mods above, and with them in place I'm getting a rather loud hissing with the music playing in the background. Removed MLC8/9 as well, just in case that had anything to do with it, but still the same. Have removed the new caps for now and everything is OK again.

lovejoy

27-06-2009, 08:19

Oops.. Just realised my mistake... 47nf, not 4.7nf... :mental:

scrufftyguy

27-06-2009, 08:30

Hi everyone!

I'm considering ordering a TC-7520, what would people recommend as the best mod to carry out? At the moment I don't think I want to risk any soldering, so I guess that limits me to swapping the op-amps. I just ask as I need to order some coax cable and the seller also sells the LM4562NA. Should I chuck a couple of those in my basket at the same time, or is there another op-amp that's regarded as the better option?

I've had a scan through this thread but as a complete novice I thought I'd best ask out-right!

Thanks. :)

Ade

StanleyB

27-06-2009, 12:55

Oops.. Just realised my mistake... 47nf, not 4.7nf... :mental:
Abort the 4.7nF operation. I'll pull the picture soon. I sussed out that I have a different mod under the PCB that is not visible on top, which is causing the hiss.
The MLC5/6 is however still valid. Far smoother piano and guitar decays.

Stan

StanleyB

27-06-2009, 13:05

I just ask as I need to order some coax cable and the seller also sells the LM4562NA. Should I chuck a couple of those in my basket at the same time, or is there another op-amp that's regarded as the better option?
Have a look at my own coax cable before experimenting with anything else.

My only approved source for the LM4562NA is:
http://myworld.ebay.co.uk/yp53/
The seller has a TC-7520 and checks his stock of LM4562NA for best performance in each batch he gets. A few people have bought this IC from Hong Kong and the likes and they turned out to be noisy, fakes, or faulty. So be careful with your source.

Stan

scrufftyguy

27-06-2009, 13:15

Thanks for the advice Stan!

Would you consider the LM4562NA a worthy purchase, or would you say I should hang back and listen to the DAC straight out the box, and then decide on things? Or maybe invest in a different Op-amp? The seller I was thinking about is Mark Grant http://markgrantcables.co.uk/shop/index.php?main_page=product_info&cPath=48_31&products_id=111 who I've bought from before and is regarded by many as a very good seller.

Ade :)

StanleyB

27-06-2009, 13:31

I myself use a set of NE5532FE most of the time, and they are rare to the extreme.

Performance tuning should only be considered as an option if you are bored and know what you are doing. Otherwise the stock chips are good enough to blow away the majority of competing DACs. The opamp rolling issue is one that ideally suits those that are prepared to try different chips with different types of music. It is not a must. Not everyone would hear a difference with their system set up. The opamp rolling goes hand in hand with the rest of your gear.

STan

scrufftyguy

27-06-2009, 13:36

Thanks again for your input Stan, maybe I would be best just letting the DAC burn in and get used to the sound with the stock chips, then decide if I should change things around, or not.

I'm glad I've found this forum as I know that I can get some good advice if ever I do decide to make any changes.

Ade :)

Gazjam

27-06-2009, 14:13

I've bought loads of stuff from Mark Grant, great service.

Buy with confidence - I actually bought my 4562s from there. Replaced the one for the line out though with a 4032 which I found to be more my liking.

scrufftyguy

27-06-2009, 14:22

I've bought quite a few bits from Mark aswell, and rate him very highly too, i'll have to think about whether I jump in and buy some new op-amps straight away though.

Ade

lovejoy

27-06-2009, 22:51

Abort the 4.7nF operation. I'll pull the picture soon. I sussed out that I have a different mod under the PCB that is not visible on top, which is causing the hiss.
The MLC5/6 is however still valid. Far smoother piano and guitar decays.

Stan

Understood, thanks Stan.

I'd recommend anyone to do the MLC5/6 mod, especially if you listen to a lot of classical or acoustic music. I'd never really 'got' classical music, now it seems like the door has been opened for me.

leo

04-07-2009, 14:38

Updates will be added to the first post as to keep everything together, its worth checking every so often;)

Gazjam

04-07-2009, 16:31

Understood, thanks Stan.

I'd recommend anyone to do the MLC5/6 mod, especially if you listen to a lot of classical or acoustic music. I'd never really 'got' classical music, now it seems like the door has been opened for me.

But NOT with he Tirna 4032 Op Amps...?

Can anyone confirm?

leo

04-07-2009, 20:19

Not sure, will have to check it on scope.
I'm currently using AD827 without those caps and its ok, this ones pretty fast too

Gazjam

05-07-2009, 00:23

Not sure, will have to check it on scope.
I'm currently using AD827 without those caps and its ok, this ones pretty fast too

Hey thanks Leo, would appreciate that very much. :)

Thanks,
Gary.

leo

05-07-2009, 23:10

THS4032 is a little touchy in the highs with the caps removed, probably worth leaving them in

Gazjam

06-07-2009, 08:12

Thanks for the effort Leo, the caps stay in!

Cheers,
Gary.

*Now I've a wee niggle at the back of my head as to whether the 4562 with caps removed will sound better than the Tirna 4032!

I'll fit the 4562 and listen to that for a few days, see how I like it compared to the 4032.
I fitted new speaker cable recently which has opened up the sound considerably, so mabye its time to re-assess both opamps?

With the Caps removal mod, whats the general consensus of how much of a jump in quality there is over the "stock" 4562 fitting?
I listen to mainly rock/AOR but with a lot of classical/Movie scores too, and what I tend to enjoy a lot is realistic tone and timbre...that feeling of "being there", if you knbow what I mean?

Is THIS what the mod brings to the table? I heard it was worth doing for more realistic decay on instruments etc and someone got into classical more because of it?

Sounds good to me, will need to re-assess the 4032 v 4562 sound though.

Thanks.

Gazjam

07-07-2009, 19:00

OK,
had the 4562's in for a wee while now, liking the sound.

Different to the 4032's, higher up elements of the music (vocals, piano's, drum thwacks etc..) seem better seperated, but sound a bit flatter somehow, which makes for a more "exciting" listen, but I found it a bit fatiguing after hour or so.

I remember thats why I went to the 4032's in the first place.

Soundstage was good, but the trebles a bit up front and one dimensional if I was honest when compared to the more even handed approach the 4032 has.
Its good, but not as cohesive or 3D as the 4032's treble.

To me its the treble's "zing", those little details you hear that make the music more involving, more uhm..musical? :)

I took both the Caps off as per the Mod.

The trace of forwardness or flatness in the treble has now gone.
Leo called it right earlier, the OpAmps got more room to breath, it sounds more relaxed yet more detailed at the same time? I think because there's more air and naturalness to the treble the little things like reverb and decay are more apparent, and this makes for me a more musically involving listen.

I answered my own question...

To me, the 4562's with caps removal Mod sounds better than the 4032 Amps.
More involving, not fatiguing or digital sounding (which in my system it was a WEE bit guilty of) at all.

It sounds more pacey, more rythmic and more involving.
Instruments sound more realistic.

Perhaps the 4032 has a slightly more cohesive soundstage - but not by much, but it wasn't as involving (which is what counts really) as the setup I have now.

Highly recommended for those running 4562 amps in their line out. :)

sponge

07-07-2009, 19:32

Guys, Can we just clear this one thing - When talking about the 4562 - Do we mean the 4562NA (plastic enclosure) or the 4562HA (metal can) ?

Personally, I am running with the 4562NA in the Line-out socket and with the MLC5/6 caps removed.

If I've missed something - I'll hold my hand up - It happens... Often.

Ken

StanleyB

07-07-2009, 20:18

I have tried both opamps in the Caiman, and both perform fine with that mod.

Stan

Covenant

07-07-2009, 21:31

I have tried both opamps in the Caiman, and both perform fine with that mod.

Stan

Caiman or Cayman Stan?

Gazjam

07-07-2009, 21:42

Cayman?
http://wiki.answers.com/Q/What_type_of_animal_is_a_cayman

hope so anyway, :-)

StanleyB

07-07-2009, 22:13

Nope. See http://www.flmnh.ufl.edu/cnhc/csp_ccro.htm

To quote an extract:
HABITAT:
Extremely adaptable species found in virtually all lowland wetland and riverine habitat types throughout its range. [] Can tolerate a reasonable degree of salinity. If environmental conditions become too harsh, they will burrow into mud and aestivate.

That more or less describes the DAC perfectly.

Leo has been playing about with a close proximation of it, which is why he isn't around that often these days I reckon.

Stan

Gazjam

07-07-2009, 23:06

a-Ha!

Need to change my spelling Stan. ;)

The Grand Wazoo

07-07-2009, 23:18

Stan,

Extremely adaptable species found in virtually all lowland wetland and riverine habitat types throughout its range. [] Can tolerate a reasonable degree of salinity.

So does it work underwater, then?

You have PM.

Cheers

StanleyB

08-07-2009, 05:20

Need to change my spelling Stan. ;)
Forgot to mention that you can abort. A solution hs been found.

STan

StanleyB

08-07-2009, 05:22

Stan,
So does it work underwater, then?
It has been making waves before even surfacing yet:).

Stan

Gazjam

08-07-2009, 05:48

Forgot to mention that you can abort. A solution hs been found.

STan

oh, ok then Stan.

Look fwd to seeing it!

StanleyB

08-07-2009, 07:17

Look fwd to seeing it!
You'll have to save up if you want to hear it as well:lol:. I reckon that with its limited production run and ground breaking performance it is going to become a collector's item.

STan

Gazjam

08-07-2009, 10:08

I bet it will be more than worth it though, based on how good the 7520 sounds:)

Gary.

Codifus

09-07-2009, 14:47

Hello all,

I'm relatively new here and I've had my TC-7520 (and upgraded PSU) for a couple of weeks now. With the original opamps in my system (I use the Line-out side only, no headphones) the 7520 sounded quite good. The midrange was slightly un-involving, but still enjoyable.

I did the LM4562NA upgrade with MLC5/MLC6 caps removed and after a week found the upgrade to be nearly perfect. The system now really sounded good.

Here's the thing though, as has been suggested in this thread and others, the LM4562NA upgrade with MLC5/MLC6 caps removed does reduce the bass a wee bit in the lower registers, 40 Hz to 30 Hz. My speakers have dual 8" woofers and a bass port, and I like my bass. The system still sounds very very good but I know that I had better bass. The original opamps had a stronger bottom end.

I swear if the LM4562 upgrade had the right bass I would be done with finding the right opamp. From 100 Hz upwards that LM4562NA upgrade with MLC5/MLC6 caps absolutely shines.

Now that MLC5/MLC6 caps are removed in my 7520, I'd like to find other opamps to try to get my bass back. I am soldering challenged and the idea of putting those caps back.....well, let's not go there:)

Would it be a good idea to start another thread dedicated to 7520 mods with the caps removed?

I wanted to try the tirna 4032 mod, but that chip specifies that it doesn't have unity gain and therefore is not best suited to audio.That information makes me reluctant to try it despite all the glowing praise. Also, it seems to be suggested that now that I have the ML5/ML6 mod, the tirna chip is now not recommended.

I wonder do the metal can LM4562s make up for the lacking bass perhaps? I'm a bit confused also, is the LME49720 the same as the LM4562NA with just the metal can difference?

Here's a listing on ebay I'd like to try if I could get the advice on how to proceed;

http://cgi.ebay.com/LME49720-LM4562-TO-99-Metal-Can-Op-Amp-Location-USA_W0QQitemZ110410503326QQcmdZViewItemQQptZLH_Def aultDomain_0?hash=item19b4fa949e&_trksid=p3286.c0.m14&_trkparms=65%3A12|66%3A2|39%3A1|72%3A1205|293%3A1| 294%3A50

Thanks

CD

StanleyB

09-07-2009, 16:22

The combination I use on one of my boards is THS4032 for line output and LM43562NA for headphones. It gives more low end grunt compared to using 2X of the LM4562NA.

Gazjam

09-07-2009, 17:10

*Edited for relevance*

I put the 4032's Op Amps in after using 4562's and I can conform the 4032's dont work really well with the ML5/6 caps removed - the treble is quite harsh and a bit fatiguing. Possibly unstable?
I believe this has been confirmed by another Forum member testing this configuration on a scope.

trailer

09-07-2009, 17:16

No disrespect lads but this isn't this meant to be a sticky for a DIY mod guide?

Gazjam

09-07-2009, 18:07

None taken.
Your right.

:)

leo

09-07-2009, 18:59

Its all the fun and its easy to forget yourself:lol: I guess I could add the tried and tested stuff to the first post just so things don't get too spread out again:)

Regarding the op-amps, THS4032 was a little ringy in the highs without ML5/6, you can see this on the scope, it'll be ok ish one minute and then go touchy

Quite a few other op-amps will work with these caps removed, its mainly the fast high bandwidth types you have to be careful with

I currently use metal can LM4562HA with ML5/6 removed, it sounds really refined with a classA amp, nice bass, tight but full.
With a classA/B it sounded more lean, gives the impression of less body
Sounds great with both amps but I understand why some maybe finding some slight lack of weight using LM4562
Best thing to do is compare a few types and see what matches best with your kit.

BTW, I found the metal can LM4562HA better than plastic LM4562NA, the improvement is only small though so if you don't like LM4562NA upgrading to LM4562HA isn't going to be worth doing imo

StanleyB

09-07-2009, 19:11

BTW, I found the metal can LM4562HA better than plastic LM4562NA, the improvement is only small though so if you don't like LM4562NA upgrading to LM4562HA isn't going to be worth doing imo
I share your opinion on this, but I only tested it in the Caiman prototype layout.

:doh:. I just realized, so did you.

STan

lingling1337

10-07-2009, 01:15

Forgot to mention that you can abort. A solution hs been found.

STan

What exactly do you mean by "abort"?

StanleyB

10-07-2009, 05:11

What exactly do you mean by "abort"?
It was a private message to Gazgam.

lingling1337

10-07-2009, 14:54

Alright then.

So has anyone been tinkering about with the 7520? Any experimental mods that they want to let us have our hands on?

leo

10-07-2009, 19:11

Alright then.

So has anyone been tinkering about with the 7520? Any experimental mods that they want to let us have our hands on?

Plenty of experimental mods, I think its wise to be cautious whats suggested on a public forum though , some idea's could be harder for the causual fiddler to perform on the dac.
I tend to post things I think is easiest for most folks to try

lingling1337

10-07-2009, 20:21

Plenty of experimental mods, I think its wise to be cautious whats suggested on a public forum though , some idea's could be harder for the causual fiddler to perform on the dac.
I tend to post things I think is easiest for most folks to try

Not sure if the condescending tone is intentional but I'd still like to hear what's brewing in the minds of our top mad DIY scientists.

StanleyB

10-07-2009, 20:39

Not sure if the condescending tone is intentional but I'd still like to hear what's brewing in the minds of our top mad DIY scientists.
What condescending tone and which mad scientists :confused:? With that kind of thinkng you aren't going to get any further on AoS. I thought you mentioned you didn't like me the more you knew me. Now you take offense to to straight forward logical advise. Did you land on the wrong forum by mistake?

Gazjam

10-07-2009, 22:14

Not sure if the condescending tone is intentional but I'd still like to hear what's brewing in the minds of our top mad DIY scientists.

I'm sure you would, but you think thats a nice way to ask someone to help you?
:)

Guys help out here because they want to, not because they have to.
Its a good bunch on here, but maybe its bad form after only 11 posts to come on here and try to be a cunny funt?
Play nice....

leo

10-07-2009, 23:45

Oh well, guess can't please everybody:doh:

lingling1337

11-07-2009, 01:19

What condescending tone and which mad scientists :confused:? With that kind of thinkng you aren't going to get any further on AoS. I thought you mentioned you didn't like me the more you knew me. Now you take offense to to straight forward logical advise. Did you land on the wrong forum by mistake?

Mad scientists=DIY innovators, or, since you feel the need to turn everything into a semantics game, those persons who modify the internal components of the Beresford TC-7520 digital to analogue converter.

Condescending tone=
I think its wise to be cautious whats suggested on a public forum though , some idea's could be harder for the causual fiddler to perform on the dac.
I felt that that statement was bit condescending because I felt that Leo was sort of talking down to me, as if I couldn't handle such information. However, if it would ease some of the bitterness towards me on this forum then I'll gladly rescind the statement.

leo

11-07-2009, 03:01

I felt that Leo was sort of talking down to me .

That wasn't intentional, I come on here to offer help

Gazjam

11-07-2009, 07:16

No bitterness on this forum I can assure you.

Just relax and enjoy yourself, nobodys got anything to prove here.

Peace. :)

lingling1337

11-07-2009, 16:16

That wasn't intentional, I come on here to offer help

No hard feelings, then.

Dougr33

11-07-2009, 20:26

Bless you Brits for your politeness.. not sure I could have mustered it in this case ;)

DaveK

11-07-2009, 21:00

Hi Doug,
We all recognise that this guy is a most untypical example of a citizen of the USA. I guess that he is a Bush supporter and hasn't yet got over his defeat. (no offence intended, just in case .....). :)
As we say in Yorkshire "Politeness costs nowt" !!. Surely enlightened self interest should make him aware that asking usually gets better results than demanding - maybe he has got a major inferiorority complex and this is his way of making his presence felt. If he hasn't, then he certainly should have with an attitude like that.
Nice to hear from you again BTW. :)
Dave.
PS note the change of Username.

StanleyB

11-07-2009, 21:09

PS note the change of Username.
You are now single:scratch:?

Stratmangler

11-07-2009, 21:16

You are now single:scratch:?

Nope - I just gave Dave a call, and his good lady answered.

Chris:)

DaveK

11-07-2009, 21:19

You are now single:scratch:?

Hi Stan,
Nope, (thank God !!) :). I just thought that, as my wife's idea of hi-fi is her iPod on her Bose Sound Dock, it was more appropriate to leave her off the membership list. Should have stated that fact on my 'new' member's welcome message.
Cheers,

StanleyB

11-07-2009, 21:30

Phewww. I was worried that it was the DAC that did it...

STan

DaveK

11-07-2009, 21:35

Hi Stan,
Nope, you can sleep easy in your bed tonight :lolsign:
Cheers,

Dougr33

12-07-2009, 02:39

Hey Dave.

How did those op amps work out?

Now that you've changed your name, and being a fat guy (me, not you), it is my fervant hope that you'll change that grotesque dancing chubster!

Peace!
Doug

DaveK

12-07-2009, 08:31

Hi again Doug,
To be honest I haven't yet swapped anything - still getting a feel for the un-mod'd version and I have also, at different times, installed new speaker cables and new phono and co-ax leads into and out of the 7520 - still looking for a better optical lead and possibly USB lead for same application. Once I've settled on these I'll try the op-amp swapping. I took the lid off yesterday and gently lifted one op-amp, without removing it completely - seems easy enough !
I have also been keeping a close eye on the 7520 Mod posts on here and trying to see if any concensus of opinion accrues but at the end of the day the swap I will go for is the one that I prefer. All the same, any concensus that might accrue will probably be my starting point.
Cheers,

StanleyB

12-07-2009, 09:15

still looking for a better optical lead
I do a set of those that are far superior than some of the ones out there that you pay five times or more for. If you can find better than mine for less than £50 I'll even offer you a refund on your return postage.

Stan

DaveK

12-07-2009, 10:29

I do a set of those that are far superior than some of the ones out there that you pay five times or more for. If you can find better than mine for less than £50 I'll even offer you a refund on your return postage.

Stan

Good Morning Stan,
Just as an 'aide memoire' I quote below our recent exchange of PMs on this subject (you must get lots every day - difficult to recall any particular one.)

Originally Posted by Dave&Sue
Hi Stan,
I seem to remember a forum member singing the praises of an optical lead that he purchased from you for his StanDAC but I cannot find any trace of it on eBay. I am in the market for 1, possibly 2, optical leads, 1m and 1.5m in length. Am I mistaken or can you supply?
Thanks for your help,
Dave.

Hi Dave, they are available from:
http://www.beresford.me/UK/interconnects_1.html

Stan

The reason that I didn't follow through immediately with an order was that I couldn't see any reference on your site to any different lengths or indeed any length at all, and then other things tended to push it to the back of my mind. Without inviting you to knock the competition I also contacted Mark Grant with a similar question and he has also apparently forgotten about me, (I'm beginning to get a complex about this :lolsign: ), as he also never responded to my follow up query, but how does your TRC-222 compare with Mark's?
I would be very happy to order a TRC-222 from you if: -
1) you can advise me about the length(s) available, with reasons/logic if only one length is offered (I'm keen to learn),
2) you can offer me the usual(?) AoS discount, and
3) my name goes on the list of loaners for the new Caiman PSU upgrade
(hope you are still smiling ;))
Being serious for a moment, the above 3 'conditions' are expressed in order of importance :).
Look forward to hearing from you in due course.
PS
In view of your lack of comment am I to take it that you don't offer a 'Stan' grade USB lead? If so, are you able to advise where I can get a 'quality' one from? Afterall, the hub of this mini-system is the 7520 and it makes sense to couple it with leads known to enable it to give of it's best.
Cheers,

StanleyB

12-07-2009, 11:32

Hi Dave, the TRC-222 is not an optical lead.
However, that aside, the other details of the lead are:
1. It comes in 1 meter length.
2. It is superior in technical construction, weight (amount of conducting material), and bandwidth to the £150 Siltech London, which is the only other high-end lead in the world that that I know of that uses bare PCOFC as the conducting material.
3. I sell them at cost plus whatever the taxman fleeces me for just selling them. My cables are not bread winners for me, so discounts are therefore not offered. I merely offer them in order to make it easier for customers who live in no-man's land to do a one-stop shopping for a high quality lead.

I heard that Mark does a range of very classy stuff at competitive prices. My suggestion would be for you to give him a shout again. He is reckoned to be a very busy man, so I am sure he has not overlooked you intentionally.

Stan

ZebuTheOxen

14-07-2009, 14:29

I can fully vouch for the Toslink XQ cable.

I took a peek at the core under a jewellers monocle, lots of invididual strands of optical fibre. :)
My £4-for-10-metres toslink cable has a solid plastic core, I dread to think what it was doing to the signal :lolsign:

It should be noted that 10mhz is the recommended optical bandwidth for maximum performance in the Toslink / SPDIF red book. These cables meet that standard (and very probably exceed it).

StanleyB

14-07-2009, 15:38

It should be noted that 10mhz is the recommended optical bandwidth for maximum performance in the Toslink / SPDIF red book. These cables meet that standard (and very probably exceed it).
That standard is for 2 channel, 16 bit, 44.1KHz equipment of yesteryear. My cable is for 24 bit/192KHz and will handle 7.1. Realistically I should be charging £50 for that lead if I compare it to what else is on the market.

STan

mantisory

18-07-2009, 12:29

Hey everyone,
So I did the first mod last night, substituting the opamp for the LM4562NA and removing C5/6. I am using a toslink that is pretty long ~25 feet or so.
Before I did the mod, there was always a little popping sound when the first sounds came on, but now it is there every time the song changes...any ideas?
In any case, I may try moving the computer closer and see if that has any effect.
regards,
byron

Beechwoods

18-07-2009, 12:38

Hi Byron - and welcome the Art of Sound! When you get the chance why don't you stop by and say a little about yourself and your system in the Welcome (http://theartofsound.net/forum/forumdisplay.php?f=15) forum!

lingling1337

18-07-2009, 13:46

DaveK

18-07-2009, 14:49

Try a shorter toslink.

Very constructive post - thanks a lot !! :mental:
Cheers,

lingling1337

18-07-2009, 14:59

Very constructive post - thanks a lot !! :mental:
Cheers,

I'm absolutely baffled by your ignorance to, or unwillingness to recognize, your hypocrisy here. I try to make a legitimate suggestion to alleviate that user's problem and you reply to me to make a sarcastic comment about how you don't think my post is constructive enough? Just astounding.

mantisory

18-07-2009, 15:05

DaveC, I wouldn't say your post is very contructive at all...pot calling kettle?

DaveK

18-07-2009, 15:08

I'm absolutely baffled by your ignorance to, or unwillingness to recognize, your hypocrisy here. I try to make a legitimate suggestion to alleviate that user's problem and you reply to me to make a sarcastic comment about how you don't think my post is constructive enough? Just astounding.

Chillax sunshine - if you can't take it you shouldn't give it :ner::ner::ner::ner:
Pot, kettle, black and glass houses spring to mind.
What else did you think mantisory meant when he posted: -

In any case, I may try moving the computer closer and see if that has any effect.
Cheers,

Marco

18-07-2009, 15:11

Hi Hugh,

Do you think there could be a clue here:

In any case, I may try moving the computer closer and see if that has any effect.

Maybe Byron needs to use a longer than normal Toslink cable, which isn't ideal? I think it was your somewhat curt reply (and stating of the obvious), rather than perhaps giving more thoughtful advice, that prompted Dave's response. I don't think you're doing it on purpose now (since you've been warned), but you do have a rather unfortunate way of expressing yourself sometimes.

Marco.

mantisory

18-07-2009, 15:15

ok...reset - I didn't mean to spark discord :)
Anyway, to clarify, I am using a long TOSLink cable right now, and I think perhaps this may be an issue..but the problem has really been amplified since I did this mod, although it already existed to some extent previous to that...I never noticed the problem with the 7510 however...
Regards,
Byron

mantisory

20-07-2009, 22:06

hmm..
so the popping did not goaway, and now there is also a loud hissing noise out of the right channel when there is no signal going to the DAC...I hope I didn't fry my tc7520!
b

StanleyB

20-07-2009, 22:14

Is the popping sound from playback via the PC, or is it also from a CD player?
If it is from the PC I remember someone mentioning that the volume level in the audio mixer panel in Windows should be set to something less than 100%.

The noise could be from a suspect opamp. If you rolled opamps, go back to the originals and see if the noise is still there, or if it has gone.

Stan

mantisory

20-07-2009, 22:50

problem solved...partly because one of the caps i clipped was resting underneath the PCB and (possibly) shorting something...partly because the TOSLink cable was really not making a good connection. Took it apart, cleaned it up, put it back and in a better spot, and all is well
regards,
byron

Covenant

25-07-2009, 16:14

There is a guy on ebay offering mods to the 7520. The op-amps are already well discussed but he also offers to upgrade the internal power supply.
I quote from an e-mail he sent:
'what i will do is replace the opamps and improve the internal power supply , i will decouple the capacitors, and reduce the noise floor ,if you want a power supply they are £50 extra but if you are happy with your own power supply the other mods will be a great start for you'
I would like to know if this has already been done by anyone, the benefits and any problems?

trailer

25-07-2009, 16:17

DaveK

25-07-2009, 17:14

Yep, same guy !!

Gazjam

25-07-2009, 17:41

Is there a bargepole big enough....?

*EDIT*
Seems a reasonable guy from his feedback, would be good to invite him on here for a Q n A on what he does.

If he's 100% behind his services he'll welcome it? :)

Covenant

25-07-2009, 18:31

Some feedback from Stan or Leo would be useful here. Personally I wouldn't go for any mod that Stan hasn't tried or commented on. I have already seen a comment unrelated to this from Stan which implied that a modification to one part would cause problems elsewhere. Its too easy to think "Oh that component only cost £x, I will replace with one that costs £Y"

leo

25-07-2009, 19:14

Be interesting to get him on here, ideally a few pics and notes along with prices for the work done would give us more to comment on

StanleyB

25-07-2009, 20:39

'what i will do is replace the opamps and improve the internal power supply , i will decouple the capacitors, and reduce the noise floor ,if you want a power supply they are £50 extra but if you are happy with your own power supply the other mods will be a great start for you'
Somehow I get the feeling this sounds like a catch...

Stan

aewright78

02-08-2009, 01:06

The LM4562HA opamps with MLC5/MLC6 removed is a killer combination for string instruments and pianos. Triangles etc are also very well preserved during their travel from digital content to the ear drums.

Stan, I finally purchased a 7520 and it has now been "broken in". There is certainly more detail from my system, but now I am noticing some high frequency harshness and an increased noise floor compared to my stand-alone cd player.

Which of the opamp modifications/setups would you recommend I try?

Thank you for your help!

Sincerely,

-Adam

MartinT

02-08-2009, 06:31

Stan, I'm interested in buying a TC-7510 since I need more S/PDIF inputs and don't need USB. Could you confirm whether the op-amp mods described here also apply to the 7510?

I'm currently using an old Assemblage DAC3.0, which still plays well but is old (non-oversampled) technology.

leo

02-08-2009, 11:15

The op-amp and dac changes can be done to both 7510 and 7520 (7510 may require the wire mod along with a few other bits and pieces).
They won't sound the same though

MartinT

02-08-2009, 15:20

They won't sound the same though

Oh, is there more difference than meets the eye between them?

StanleyB

03-08-2009, 08:35

Oh, is there more difference than meets the eye between them?
Yes. They are two different products, but with a 'family' resemblance.

Stan

Gazjam

23-08-2009, 18:27

DaveK

23-08-2009, 19:48

ATTN: DaveC.

Dave was kind enough to loan me a selection of opamps to try in my "Caimanised" 7520, finally got around to trying them out today.

They were:
OPA134PA
NE5332N (Different make from Stans originals)
4971ONA

My Dac has the MCL5 and 6 capacitor legs snipped on the output board as well as the Wolfsen Dac transplant.
I was running LM4562 op-amps in both line and headamp sockets.

Unfortunately it wasn't much of a test, as for some reason the OPA134PA and the 4971ONA both were very distorted and only coming out of one channel.

Now, I dont know if this is because I snipped the Caps on the oputput board or what, but I couldn't make any judgement about these Op-Amps in the Caiman spec Dac.

The standard 7520-fit NE5332 though.... in comparison to the LM4562's were just not in the same class.

Far more clarity, whallop, soundstage depth...you name it.

So sorry Dave, not much to report!
I'll get 'em in the mail tommorow!

Gary.

Hi Gary,
They were given to me FoC by a fellow AoS member who, I believe, had them left over from his op-amp rolling activities (on a standard 7520 I believe) which may be evidence in support of your findings. If the kind donor of the op-amps wants to contribute to this thread it may be helpful. My memory has retained the name of the donor (for a change :) ) but I'd rather not name him - seems ungrateful but I'm truly not, it's just that I've realised my statement above may be open to that (mis)interpretation.
Cheers,

Gazjam

23-08-2009, 20:41

It COULD just be dave that without the 5/ 6 caps in place on the output board those OpAmps just dont work properly.

Says Gary, showing his ignorance of all things electronic!

leo

29-08-2009, 07:56

Incase I missed something somewhere and just to remind that OPA134PA and 4971ONA are SINGLE op-amps not duals, you need to use two each of those in a browndog socket for stereo.

Example OPA134 mono, OPA2134 stereo

Gazjam

29-08-2009, 09:27

THAT explains why they were only working on one channel!
Thanks for that Leo.

Although there was some signal coming through the other speaker?
Was this signal leakage maybe, or something else?

DaveK

29-08-2009, 10:52

Hi Gaz,
Would that explain what the little PCB thingy was - a browndog adapter to enable two such op-amps to be fitted into one socket maybe?
If so, would you like me to send everything back to you?
Cheers?

leo

29-08-2009, 12:32

Yep, theres NFB resistors so if theres no op-amp you'll get a very low signal

If you like either of those op-amps just get the dual version, it saves faffing about with converter boards;)
Some op-amps aren't available in duals but those ones you have are

DaveK

29-08-2009, 13:02

leo

05-09-2009, 17:08

Stans bass mod added to the first post for easy finding

HighFidelityGuy

07-09-2009, 09:42

Stans bass mod added to the first post for easy finding

Thanks Leo. Was 36k decided upon as the best value for everyone or is it dependent on the system the DAC is used with?

Thanks.

leo

07-09-2009, 15:15

Thanks Leo. Was 36k decided upon as the best value for everyone or is it dependent on the system the DAC is used with?

Thanks.

After a few trials Stan liked 36k best, I tried it and have to agree 36k seems to be the sweet spot (after trying various other values and was using 42k before)
I've now tried it with three different amps, two different pairs of speakers and a pair of headphones, it seems to go well with them all where as the other higher and lower values was more system dependent

Of course if your bored try a few alternative values , if you can't be arsed just go for 36k, its easy to cut out altogther if you don't like it:)

HighFidelityGuy

07-09-2009, 15:39

Thanks Leo. It sounds like you and Stan have tested this fairly extensively. I might give this a go, it sounds interesting. I'm also going to try the 4562HA's I have spare. I'll try them independently first though.

It sounds like this mod boosts the bass output a bit but also helps tighten it up. I'm slightly concerned about the bass boost as I already have a big boost around 150Hz due to a room node which I tame with EQ. However I have a dip in bass above and below 150Hz. I was wondering if was possible for you to explain what frequencies this mod seems to accentuate to help me decide if this is worth trying?

Thanks.

StanleyB

07-09-2009, 17:16

I starts at about 100Hz.

Stan

Covenant

07-09-2009, 17:58

Puffin

07-09-2009, 19:16

All this talk of expensive op-amp swapping makes me wonder if anyone has tried a discrete op-amp. You wouldn't be able to fit the lid on the case, but it might make for intersting comparisons.

Covenant

07-09-2009, 19:35

The first one I mentioned is only about £4 its the second one thats about £56 when you get two mounted on an adapter. I dont think I would pay that but would love to hear a review from someone who could afford it.
Tell us more about discrete op-amps Puffin if you dont mind.

leo

07-09-2009, 19:43

I have just been reading about a few op-amps and wonder if anyone has tried them:
They are
AD823 AN and OPA 627BP. The latter is single channel so two are required on an adapter. They are also very expensive.

Not much help but anyway

I've tried OPA627BP a few times in the past (not in this dac though)
It has its fans but I found it to add lots of signature in every app I tried it in, sickly chocolatey signature , some people will like that , I certainly didn't

AD823 maybe worth trying in the Headphone section, its pretty well specced for driving cans , not tried it in this dac yet though

Puffin

07-09-2009, 19:47

Have a look at the thread on Diyaudio for the applications for the Diamante. Basically it does the same as an op-amp IC, but with separate semiconductors.

http://i73.photobucket.com/albums/i239/saxonsex/image001.jpg

http://www.diyaudio.com/forums/showthread.php?t=114632&highlight=Diamante

I bought some boards, but have yet to build them. Too many projects, too little time!

HighFidelityGuy

08-09-2009, 08:57

I starts at about 100Hz.

Stan

Thanks Stan,

If it mainly affects below 100Hz then I think I'll give it a try.

Gazjam

09-09-2009, 11:56

As a non headphone user, I could just add the Bass Mod to the 5/6 positions and not bother with modding the other one?

Thanks.

StanleyB

09-09-2009, 14:18

what other one Gaz?

Gazjam

09-09-2009, 14:39

Lol I meant do I have to "bass mod the mlc 8/9 if I don't listen to headphones?
( as the mlc 8/9 don't affect the line output?)

would I just need to mod the mlc5/6 slots?

Thanks.

leo

09-09-2009, 14:46

As a guess (could have wrong end of stick) I reckon he means if the R+C wants adding across same place in the headphone amp?

I've noticed a few asking if this mod affects headphone out, Stan will correct me if I'm wrong the first op-amp (line out/variable out) is upstream of the HA so any mods done to the first op-amp will also have effect on the HA out

StanleyB

09-09-2009, 15:25

The mod only discuses MLC5/6 so don't start modding MLC9 etc!

Gazjam

09-09-2009, 17:41

Thanks Stan and Leo, that answers my question. :)

God, whats wrong with my command of the English language recently??? :confused:

too much :cool:

Covenant

09-09-2009, 18:41

Its a well known side effect caused by your scottish habit of eating deep fried Mars Bars. ;)

DaveK

09-09-2009, 18:47

God, whats wrong with my command of the English language recently??? :confused:

too much :cool:
Hi Gaz,
I think, personally, that for someone for whom English is not their native language, you do very well - all you really need to concentrate on is the bloody accent now and you'd (almost) pass for an Englishman, same as Marco :lolsign:
Cheers,

Gazjam

09-09-2009, 20:59

You Shandy-drinking southerners dont know what your missing. (hic)

Alex_UK

09-09-2009, 21:19

Nah, it's the big 4-0 lol.

Gazjam

10-09-2009, 09:29

Tell me about it ;)

apmusson

13-09-2009, 07:47

Anyone with a set of those cans know how hard it is to get decent bass out of them.
If you are looking to improve that situation, then the THS4032 makes an ideal partner for the K701.

Stan

Hi Stan, I have recently bought a second-hand pair of AKG 701s. I have both a Caiman and 7520 (love both of them) and wondered if you had any experience / thoughts / recommendations on which combination of DAC/Mods/Opamps would suit the AKGs? I have not done any mods to either DAC yet apart from changing opamps.

Any help is much appreciated.

Thanks

Ade

Stratmangler

13-09-2009, 07:56

I think post #5 on this (http://theartofsound.net/forum/showthread.php?t=3058) thread answers your question.

Chris:)

apmusson

13-09-2009, 08:03

I think post #5 on this (http://theartofsound.net/forum/showthread.php?t=3058) thread answers your question.

Chris:)

Ha. :lolsign:

I was after more.

Are there any of the mods that are worth doing. Also, I noticed that several have said that the THS4032 on the Caiman was a bit fatiguing...

I'm happy to play around myself, but if anyone has had good experiences with their experiments using the 701s I'd love to hear about them.

Ade

mirh

18-09-2009, 09:07

Hello everybody!

This my first post here :)

I have 7520 with new PSU. I use it only with my headphone Denon AH-D2000.
There is said here that:
"LM4562 fitted for the fixed output, Stan recommended removing MLC5 / MLC6 ceramics if using this particular op-amp"

What if I use only headphones? Can I put LM4562 to headphone output (on right site) and remove those ceramics or this mod (LM4562 to fixed/variable output and removing ceramics) is only for using with speakers?

I'm not good in soldering so this mod for me will be rather permanent :(
Providing it is possible for headphones, is it good mod for my Denon which are known for a little bit boomy bas (a bit out of control)

ZebuTheOxen

18-09-2009, 19:45

If you are staying with the PCM1716 DAC, then I fully recommend cutting the MCL 5 / 6 and putting dual 4562NA opamps in.

I got the WM8716 DAC done by tirna, and have just polished off the 36k mod on the caps, bringing them back into the loop. I found it significantly lacking in bass with the MCL 5 / 6 caps cut.

If I'm honest, I preferred the 1716 with MCL 5 / 6 cut, and dual 4562NA.
The WM8716 is totally unforgiving when it comes to recording quality and mastering.

trailer

18-09-2009, 20:12

ZebuTheOxen

18-09-2009, 20:32

And Mikes cables amplifies this too.
Who is Mike? Fairly sure I don't have his cables...?

apmusson

21-09-2009, 06:56

Big thanks to Tom for his assistance with my AKG K701 question.

I performed the MLC5/6 mod and stuck a 4562 opamp into the headphone socket. This is a great combination with the 701s and really makes them sing. I have also experimented with different opamps in the lineout socket as I understand that this has an impact on the headphone sound too - have eventually settled on the THS4032 because it seemed to add a little extra to the low end grunt.

Very happy. Not intending to change this combo.

Ade

Hi Stan, I have recently bought a second-hand pair of AKG 701s. I have both a Caiman and 7520 (love both of them) and wondered if you had any experience / thoughts / recommendations on which combination of DAC/Mods/Opamps would suit the AKGs? I have not done any mods to either DAC yet apart from changing opamps.

Any help is much appreciated.

Thanks

Ade

Shanedudddy2

21-09-2009, 11:36

DaveK

21-09-2009, 12:24

Seems the audio quality at work through using 7520 to power my headphones sounds considerably worse than at home.
I assume its a power issue, since I work in middle of town in business district, before this I thought power conditioning was total bs :S
Has anyone had any success with battery mods? Or anyway to get it to adapt it to make use of a battery system?
Im up for a bit of a challenge :P
ta

Hi Shane,
I coupled mine upo temporarily to a small totally enclosed lead acid 12v battery 'liberated' from my burglar alarm system when it was last serviced (over 15 years old but giving a charge across the terminals of 13.4v but 12.4v at the 7520) and I could not determine any deterioration in sound quality, so I went back to the supplied PSU. If it helps, from Stan, the plug/jack is 1.3mm diam and centre positive.
Cheers,

HighFidelityGuy

21-09-2009, 12:40

Covenant

21-09-2009, 12:53

Yep I tried a battery and didnt think it made any difference

DaveK

21-09-2009, 13:45

I believe Mr Beresford tried out battery power but found it didn't offer any benefits and caused more technical difficulties than were worth the effort. I'd suggest trying a budget mains conditioner like THIS (http://www.amazon.co.uk/Tacima-Conditioner-Frequency-Interference-Filter/dp/B000PS5700) and seeing if that made any difference.

Yep, I got one of these as a trial - I didn't think I had a problem with the mains but went on Alex_UK's recommendation - and I found it did improve things. This ain't gonna make much sense perhaps but the silence was silenter and the 'noises' were clearer- not a night and day improvement but noticeable nontheless.
For the asking price, £26 new or £20 S/H, it's worth a gamble IMHO.
Cheers,

HighFidelityGuy

21-09-2009, 14:10

I've got one too and I found it lowers the noise floor a little. Like you say, not a massive improvement but worth the money. On the down side I found it seemed to reduce the dynamics when used with my power amps, so I now just use it on low power kit like DAC, Blu-Ray etc. That seems to give a good compromise. It proved to me that mains conditioning can give benefits and has made me want to try more advanced products that claim to be more effective and have less of an impact on dynamics.

Alex_UK

21-09-2009, 20:23

As DaveK has mentioned, I was a complete non-believer, but tried the Tacima nonetheless (after reading an article in one of the mags - worth a gamble for the cost of a few CDs) As DaveK says, not night and day stuff (I didn't perceive I had a problem anyway) but the difference was noticeable (and being honest, sometimes I struggle to notice big changes in systems!) - I would definitely try one first, before modding to battery power - you might be surprised... if not, you'll get back most of what it cost 2nd hand. (I'd give you £20 for it, would use it in my AV system...) How about that - your upgrade is even underwritten! ;)

Codifus

22-09-2009, 20:06

What is the value of the original MLC5 and MLC6 caps? Mine are clipped on one end. Could I just add a 36K resistor in series?

Shanedudddy2

22-09-2009, 22:47

Think i`ll give it a go and see how it works with the mains conditioning, no harm i suppose if all else fails i got a surge protection extension lead right lol =P

leo

22-09-2009, 23:14

What is the value of the original MLC5 and MLC6 caps? Mine are clipped on one end. Could I just add a 36K resistor in series?

Going by memory I think the original ceramics was 100pf so it needs swapping for 100NF

Shanedudddy2

23-09-2009, 12:00

I live in Australia and checked the shipping, would be over half the cost, so dunno if I`ll bother, know of any similar products which work as well that i'd have better luck getting locally?
Thanks

Codifus

24-09-2009, 01:25

Going by memory I think the original ceramics was 100pf so it needs swapping for 100NF

I guess I'm stuck with the caps off, then. I am solder/circuit board challenged:)

Not a bad place to be, though. The OPA2132 in the line-out and NE5532 in the Headphone socket with MLC5/6 clipped is the most balanced I've had in my system.

CD

lemon

05-10-2009, 13:15

Hi, to all community of forum.
I have a couple of questions about 7520' mods.

a) If I replace the BB PCM1716 with the Wolfson 8716, the dac will be capable to play 192KHz sampling flac audio files?
b) the caiman is capable to this?

Sorry for my english...

leo

05-10-2009, 14:28

No, it'll do up to 24/96, the Wolfson chip is rated up to 192k but the input receiver supplying the dac in the Caiman accepts up to 96

lemon

05-10-2009, 15:06

Thanks for the info.

Is there any CS8414 equivalent to achieve 192KHz? Like CS8416, BB_PCM1796 or BB_DSD1792?

leo

05-10-2009, 16:06

Theres no pin compatible 192k receiver to the CS8414 (that I know of anyway)

lemon

14-10-2009, 20:07

Thanks for the info Leo...
Just I transfered the Wolfson DAC 8716 to my 7520!

Difficult job, but I am very happy for the result.

http://theartofsound.net/forum/attachment.php?attachmentid=674&stc=1&d=1255550769

PaulJ

07-11-2009, 21:50

My modifications to the TC-7510 and TC-7520.
I started with the opamp modification, removed the ceramic feedback capacitors, and so on.. It did improve the sound.

I read about experiments with better capacitors around the opamp. So, when there is a difference between capacitors then no capacitor should be even better. I removed the output capacitor. The output has then a DC voltage level of 5V. I checked the input circuit of my amplifier. It is directly coupled tube input. I took the risk and connected it directly to the output of the opamp. The sound improved a lot!

At the input of the opamp there is still a bad coupling capacitor! According the datasheet of the DAC, it is capable driving the amplifier directly! The only drawback is that you lose gain of 6dB, half the signal level. When that is no problem you can completely remove (skip) the opamp. That is always better then the best opamp!

If you want to play it safe then you only need one good capacitor at the output of the DAC. I have modified the output connectors and connected both, one in front of the capacitor, directly at the output of the DAC, and one after the capacitor. This way I can easily compare them. It is really a lot better without any capacitor!

Finally I replaced the PCM1716 with the WM8716.
http://img687.imageshack.us/img687/7742/p1120734.th.jpg (http://img687.imageshack.us/i/p1120734.jpg/)

lemon

09-11-2009, 12:49

Hmm, I think so that is something like this (http://theartofsound.net/forum/showt...=2352&page=143) (look at posts 1425, 1430 and 1432).

I have the same opinion, about this. :)

What are the characteristics of capacitors?

leo

09-11-2009, 14:47

Be very careful with DC offsets, an amp may have input coupling caps but normally this is after the vol pot, its not recommended to have DC on the carbon tracks

lemon

09-11-2009, 15:53

Codifus

09-11-2009, 17:19

Leo,
there is no DC offset in my solution.
Btw, I would appreciate if you explain me, what is happening here (http://theartofsound.net/forum/showpost.php?p=77809&postcount=1432)? - Related posts 1425, 1430

Lemon, you may wan to try your tests with only one opamp installed on the line-out side of the 7520. I noticed that with only one opamp, the system is louder and a bit clearer too.

CD

PaulJ

09-11-2009, 20:12

I have modified my TS-7510 and the TS-7520 of a friend of mine. I have used a 1 uF auricap (MKP) and a Audio Note copper foil capacitor (I think it’s like paper in oil, but then more expensive).
These should be one of the best coupling capacitors you can get, but the direct connection (without capacitor) at the output of the DAC is a lot better.

Before this experience, I never thought that you could hear a capacitor. It worries me a bit because there are still some other capacitors in the signal chain (loudspeaker filter).

It is important that you disconnect the opamp circuit in order to reduce the load of the DAC. The input resistance of the opamp circuit is about 4k7 (TS-7510) and that is already the limit of the DAC. I think the load of the DAC should be as low as possible (is high resistance) to minimize distortion.

My amplifier does not have a coupling capacitor. It has a potentiometer directly coupled to the gate of a Tube amplifier (only the first stage is a tube). So, the DC level at the DAC output ( 2.5V) is connected to the gate of the tube. The potentiometer is 100k and has no problem with the DC voltage. The only problem is that the gate cathode voltage is decreased by the input voltage. The same happens with a normal AC coupled input signal so I don’t think it will do any harm. This DC level is (in my case) dependent of the volume level of the potentiometer. So only when you play at maximum level, you have the full 2.5V at the input.

@lemon
Do you mean the phase shift between the two outputs? Normally there should be no phase shift at relative low frequencies. A filter causes a phase shift.

lemon

10-11-2009, 09:15

....@lemon
Do you mean the phase shift between the two outputs? Normally there should be no phase shift at relative low frequencies. A filter causes a phase shift.

Yes, exactly! There is a phase shift, which starts from 5KHz (little) and rises as the frequency increases (attached is 20).

I you compare the sinus btw 5KHz and 20KHz, it appears that the phase shift is for the fixed output (opamps)

http://theartofsound.net/forum/attachment.php?attachmentid=853&stc=1&d=1257529701

Covenant

22-12-2009, 16:05

Leo, when you have a spare few minutes could you please transfer the latest (appropriate) Caimen mods over to this thread?

leo

22-12-2009, 19:34

Leo, when you have a spare few minutes could you please transfer the latest (appropriate) Caimen mods over to this thread?

Which mods you mean mate? theres the cap changes posted by Stan (those grey ones on the audioboard) please remind me what else there is and I'll add em :)

Covenant

22-12-2009, 20:13

StanleyB

22-12-2009, 21:39

but you need to separate power regulation stuff which is only suitable for the Caiman (I think).
I have been playing about with the regulator upgrade from the Caiman on the TC-7520. The main issue is that the Murata regulators require some effort in order to get hold of them. Other than that, it works fantastic with the Caiman PSU.
We need help from someone who can order a batch of the Murata regulators, or we nee dto band together and do a group buy via Mouser in order to reduce their handling and shipping cost.

Covenant

22-12-2009, 21:51

Hmm interesting-so 7520 owners can take advantage of the Caiman power supply if the Murata's are fitted? I wonder if this might appeal to Tirna as they must know the 7520 well by now-I can think of a few people, including me, who would be happy to get them to do this work

leo

22-12-2009, 23:41

From here: http://theartofsound.net/forum/showthread.php?t=4580&page=5
onwards but you need to separate power regulation stuff which is only suitable for the Caiman (I think).
Sorry to give you some work Leo.

I've not tried the Murata regs yet, a few type regs I tried in the Caiman/7520 was discrete including some designed by John Swenson (schematics floating about on the net somewhere) , main reason I didn't post anything was because their not something you can buy off the shelf, I had to build them on matrix boards, their fiddly and a little time consuming doing them like this, a small laid out pcb would be much easier and quicker. building these things yourself is ok but its so easy to make a mistake and end up killing the dac chip or input receiver so I tend to be cautious recommending such mods to a commercial dac, soon as I get hold of some Murata's I'll compare them against the discretes and post results, pics etc. if they prove to perform the same or better than the discrete jobs it makes sense to go with the Murata's tbh rather than waste time and effort building your own

With the diy dacs I usually go mad with the mods etc but with the Caiman I try to keep things a little more simple so it would be easier for more folks to try:)

leo

22-12-2009, 23:49

Heres one of the discretes I tried

http://i273.photobucket.com/albums/jj220/kingbusoms/reg2.jpg

MartinT

23-12-2009, 07:38

Before I try the Murata regs can I just establish that I need the new Caiman PSU, not the original, since they require 15V to operate?

Stan - any chance that the new PSUs will be in soon?

StanleyB

23-12-2009, 07:52

Before I try the Murata regs can I just establish that I need the new Caiman PSU, not the original, since they require 15V to operate?

Stan - any chance that the new PSUs will be in soon?
Hi Martin, send me an email and I'll sort you out with a payment request.

Yes, you do need the Caiman PSU in order to get the Murata to work properly. My advise is to also do the audio PCB caps mod I mentioned in another thread. The two complement each other. Leo has been trying the caps mod with his discrete regulators as well. Best ask him what he thinks of it.
Feel free to pass by and listen to mine with the mods through my NS1000M and HD800, before you make the plunge. Bring your own DAC and some test tunes for reference.

MartinT

23-12-2009, 09:05

Thanks Stan. E-mail sent. I will go ahead and order the components since I am sure it will improve on an already outstanding product.

I'm not sure how many other users are using their Caimans for Sky HD (optical link) but I can tell you that the sound quality on some HD programming is quite superb (David Attenborough's Life is particularly impressive).

Alex_UK

23-12-2009, 12:29

I'm not sure how many other users are using their Caimans for Sky HD (optical link) but I can tell you that the sound quality on some HD programming is quite superb (David Attenborough's Life is particularly impressive).

Yes, I am Martin - stunning on some of the music programs on BBC HD, and MTV HD is pretty good, too. I gave up on surround years ago - crystal clear stereo is fine even with films I find.

Ali Tait

23-12-2009, 12:38

Even better with the huge soundstage of a good valve amp.

MartinT

23-12-2009, 14:07

Agreed, Alex, I have no time for surround sound.

leo

23-12-2009, 18:15

Another small update on first page

lemon

05-01-2010, 21:34

Happy New Year!

Leo, can you give us more info about changes on this area of PCB?

If I saw well, there is a capacitor missing beetwen tranzistors?

http://theartofsound.net/forum/attachment.php?attachmentid=1195&stc=1&d=1262726919...http://theartofsound.net/forum/attachment.php?attachmentid=1196&stc=1&d=1262726924

lemon

15-01-2010, 09:07

Anyone to give us the above information?

StanleyB

15-01-2010, 10:37

What is exactly the problem?

lemon

15-01-2010, 16:08

Hi Stan,

At the right side on the PCB of Leo a capacitor is missing.
http://theartofsound.net/forum/attachment.php?attachmentid=1195&stc=1&d=1262726919
The PCB of Leo

http://theartofsound.net/forum/attachment.php?attachmentid=1196&stc=1&d=1262726924
The same area of PCB on 7520

Is it a mod or something else?

StanleyB

15-01-2010, 16:30

Removing the cap with give a slightly warmer sound.

lemon

15-01-2010, 17:23

Thanks for the info, Stan.

Covenant

24-01-2010, 19:04

Its gone a bit quite lately. Any new op-amps you have tried? :scratch:

Gazjam

24-01-2010, 19:58

I had a play with different opamps again recently..

swapped back in the LM4562 to replace the 2132 I had been using?
This is with NO opamp in the headamp circuit mind..

The 4562 was "clearer" but didn't approach the level of foot tapping involvement of the 2132.

its just...better in my system.

That said, isolating the Dacs case from vibration made a BIGGER improvement than swapping over the opamps, so go figure?

Covenant

24-01-2010, 20:18

I forgot to mention I stuck a piece of aluminised tape to the underside of the 7520 cover. I couldn't tell you if its made any difference as I have done so many minor mods lately.

Gazjam

24-01-2010, 22:06

Ive dampened the inside upper case and the underside of the lower case, makes the Dac feel a lot more heavy and solid.
Also I've blu-taked it to a couple of the wee Tesco granite slabs, which are in turn blu-taked together.

So basically the combined weight of the granite is coupled to the heavier "dead" case of the Dac - which made a good difference in my equipment rack.

Kind of like putting the Dac components in a heavier better damped case maybe?

Marco

26-01-2010, 01:09

And Stan says such things wouldn't make a difference... ;)

Marco.

chrism

26-01-2010, 08:56

What you need is a lead-lined hardwood box suspended on special hi-tensile wires connected to the ceiling. Not sure if it will make it sound better but would be a talking point when you have the relatives round!

Regards

Chris

Gazjam

26-01-2010, 19:05

Or get some Mana....

but then peole WILL talk about you ;)

Covenant

29-01-2010, 12:53

Right I am going ahead with the regulator upgrade and will get Tirna to do the capacitor upgrade at the same time.
Could I have your opinion on the most suitable make (and if you dont mind the reference number)?
Thanks! :)

chrism

29-01-2010, 15:17

Hi Jerry,

I am a bit confused.

We are all waiting for the Murata super reg bulk order and I thought that you were asking Tirna about their requirements before any order was placed?

If they are not interested we can get on with it as there are at least 4 of us waiting to save on postage and it has been at least two weeks.

Could you please let Dave know what's happening so that he can sort it for the rest of us (very kind man).

Regards

Chris

StanleyB

29-01-2010, 15:54

Adrian at Audio Flair (http://www.audioflair.co.uk/) might be willing to do the mods as well.

Covenant

29-01-2010, 16:39

Hi Chris,
I spoke to Jimmy a few days ago to see if there was any more news about an idea he was thinking about. He hasn't progressed it so I am jumping in with the others on the Stan recommended regs mods. Jimmy is willing to do this mod and has said that he will do the capacitor upgrade whilst he has the case open for a very reasonable £10 (plus cost of capacitors).
Hence me wanting to order the capacitors based on what people recommended.
Sorry to have caused confusion, I think we are getting there!:cool:

ZebuTheOxen

22-02-2010, 18:56

Adrian at Audio Flair (http://www.audioflair.co.uk/) might be willing to do the mods as well.
Is this the same as the 7520 -> Caiman PSU upgrade discussed in the other thread?

StanleyB

23-02-2010, 08:44

I have had a word with Tirna Electronics and he'll be doing the regulator mods. After that he'll let me know that the mods are done and that the modded unit will accept the Caiman PSU.

mantisory

28-02-2010, 20:15

Hi there,
So a while back i did the remove the cap and replace the opamp mod...but i mistakenly removed one of the caps on the headphone side...now i would like to use the headphone amp and need to replace it...could anyone tell me the value of the cap highlighted in this pic?
Thanks in advance...
http://farm5.static.flickr.com/4056/4395332967_7017066724_o.jpg

StanleyB

28-02-2010, 22:04

It's 100pF

Dan Giovanni

01-03-2010, 21:49

I have had a word with Tirna Electronics and he'll be doing the regulator mods. After that he'll let me know that the mods are done and that the modded unit will accept the Caiman PSU.

Just a quick note: Jimmy at Tirna is nice guy and knows about electronics - IIRC he was a lecturer at Edinburgh University. He's done some work for me in the past which was of very high quality.

Gazjam

02-03-2010, 03:14

Not to mention Jimmy taught the guys who went on to form Wolfson...
Tis true..

Top quality, deal with confidence and a genuine nice bloke to boot.

Covenant

24-03-2010, 07:59

Jimmy offered to come to my house in Ormskirk to teach me how to solder and he lives in Scotland! :)

fmzip

14-06-2010, 14:19

Does anyone have the Elna Part numbers for the non-polarized caps that need to be replaced?

Searching high and low, I can't seem to find them.....

All I see is that they are polarized:

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

leo

14-06-2010, 14:54

fmzip

14-06-2010, 15:28

The grey coupling caps are Rubycon Nonpolar, as far as I can see they are now discontinued, somebody may have spares.
One of the members (MartinT) used these Nichicons as an alternative and reported good results http://www.hificollective.co.uk/components/nichicon_es.html

Awesome, thank you.

These are 4.7uf caps, correct? I am not home right now, I'd like to order them if someone can confirm please?

StanleyB

14-06-2010, 16:04

They are 47uF

fmzip

14-06-2010, 17:20

They are 47uF
Thank you sir.

As I live in the states Stan, do you ship abroad? I would like to order the Caiman PS since I have the Murata Powe regs in transit.

Looks like I have everything I need except for the part number on the Wima Cap mentioned in one of the many bookmarked threads I now have!

Does anyone know the particular Wima series called out here?

http://www.beresford.me/Downloads/Mod21pt2.pdf

I am assuming it's an FKP2 series:

http://www.wima.com/EN/WIMA_FKP_2.pdf

fmzip

16-06-2010, 12:39

Good Morning......

Can anyone help me out with this Wima Cap please? It's the last piece of the puzzle for me.

Thanks

HighFidelityGuy

16-06-2010, 12:47

Good Morning......

Can anyone help me out with this Wima Cap please? It's the last piece of the puzzle for me.

Thanks

Here ya go: LINK (http://gb.mouser.com/Search/ProductDetail.aspx?R=MKS20-.068/63/10virtualkey50520000virtualkey505-MKS2.068/63/10) :)

fmzip

16-06-2010, 12:50

Thank you for the fastest reply ever! :)

HighFidelityGuy

16-06-2010, 13:04

Thank you for the fastest reply ever! :)

I thought it was a 220PF?? No?

No probs.

If you're talking about the little red caps for the headphone stage that Stan said helped some high end headphones, then the ones I linked to should be correct. I had the link saved from when I did a group buy and I triple checked that I was ordering the right things back then. :)

fmzip

16-06-2010, 13:32

No probs.

If you're talking about the little red caps for the headphone stage that Stan said helped some high end headphones, then the ones I linked to should be correct. I had the link saved from when I did a group buy and I triple checked that I was ordering the right things back then. :)

Yes, you are correct! Thanks again

MartinT

16-06-2010, 18:09

As I live in the states Stan, do you ship abroad?

Fran - as you live much closer to Parts Connexion in Canada, I suggest you get the Nichicons from them. It was me who used them and they're very good.

fmzip

17-06-2010, 01:07

Fran - as you live much closer to Parts Connexion in Canada, I suggest you get the Nichicons from them. It was me who used them and they're very good.

Thanks for the tip Martin. I already have the Nichicon caps you suggested coming in as samples from another supplier :)

Step 1 has been completed!

Have to say, the Wolfson DAC makes a HUGE difference all on its own in my otherwise unmodified TC-7520!

StanleyB

21-06-2010, 09:12

There have been a lot of request for a mod to change the default input selection on the TC-7520 and Caiman. The following mod works on all my DACs. I used a Caiman PCB as reference, but the layout of the area is the same for the Caiman etc.

So let's start :).

First unscrew the USB PCB. It's two screws at the back of the case.

http://www.homehifi.co.uk/images/mods/IS/1.jpg

StanleyB

21-06-2010, 09:14

Next, look for C13 in the top righthand corner and just underneath the USB PCB.

http://www.homehifi.co.uk/images/mods/IS/2.jpg

StanleyB

21-06-2010, 09:14

Desolder C13.

http://www.homehifi.co.uk/images/mods/IS/3.jpg

StanleyB

21-06-2010, 09:16

Get hold of a 100nF ceramic cap of say 63V. It has to be a small cap!!! If it is bigger than the one in the picture, don't fit it.

http://www.homehifi.co.uk/images/mods/IS/4.jpg

StanleyB

21-06-2010, 09:19

If you want the TOSLINK input as default, fit the new cap in the position indicated. Press the cap down as far as you can, but make sure it does not touch anything other than the two soldering contact point at its end.

http://www.homehifi.co.uk/images/mods/IS/5.jpg

StanleyB

21-06-2010, 09:21

Confirm that it is not touching anything by using a small screwdriver or a needle. Run the needle along the bottom of the leads and the cap to make sure you are not getting any resistance from where the cap might be touching something.

http://www.homehifi.co.uk/images/mods/IS/6.jpg

StanleyB

21-06-2010, 09:22

If you want the Coax to be the default input instead, fit the cap as in the following picture.

http://www.homehifi.co.uk/images/mods/IS/7.jpg

StanleyB

21-06-2010, 09:25

Screw the USB PCB back in and hold it sideways to double check that the cap is not touching anything. By all means use some sort of insulation to keep the cap clear from anything else.
Sorry about the poor picture. The auto focus is focusing on the wrong part of the PCB. I shall try to retake that shot.

http://www.homehifi.co.uk/images/mods/IS/8.jpg

HighFidelityGuy

21-06-2010, 09:38

Awesome, thanks Stan! :cool:

fmzip

21-06-2010, 13:24

Awesome Stan....

I think I will pass on this one. I had a hard enough time swapping through hole capacitors!

leo

24-06-2010, 17:39

Just adding a few links to various posts which may be helpful, I'm adding the links to the first post (bottom of post) so their easy to find.

If theres anything I've missed you think is worth adding to the links let us know :)

fmzip

24-06-2010, 19:26

What about this one LEo or is this for just the Caiman?

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

leo

24-06-2010, 19:40

I'll add that one too thanks if I can find Stans post with the details , I think it maybe worth adding Caiman mods too :)

fmzip

24-06-2010, 19:59

Here is the link

http://theartofsound.net/forum/showthread.php?t=4580&page=49

leo

24-06-2010, 20:59

Here is the link

http://theartofsound.net/forum/showthread.php?t=4580&page=49

Thanks Fran, its now added ;)

fmzip

25-06-2010, 20:57

Thanks Fran, its now added ;)

Where are you adding these Leo? Link please? :)

MartinT

25-06-2010, 21:21

Go to the first post in this thread, Fran.

leo

25-06-2010, 21:35

Where are you adding these Leo? Link please? :)

Anybody wants anything else adding or changing etc , just let us know, the idea is to make things as easy as possible for folks if they fancy fiddling :)

fmzip

26-06-2010, 03:29

Definitely a very good post Leo. I think it may be a good idea to list the manufacturer part numbers for each mod. Took me some time to track down the Wima Cap, the Nichicon Muse Caps and the Elna's as well.

Nichicon Muse Caps

UES1C470MPM

Elna Caps

RFS-25v221 2pcs
RFS-16V101 1pc
RFS-16V100 8pcs

Wima Cap

MKS20-.068/63/10

leo

26-06-2010, 07:44

MartinT

26-06-2010, 10:53

Link for the alternative Dexa regulators which I am running:

http://www.newclassd.com/index.php?page=34

fmzip

26-06-2010, 12:32

And the links for the Murata Regulators, 7805SR-C & 7812SR-C:

http://parts.digikey.com/1/parts/1591591-regulator-switch-5vdc-0-5a-sip-7805sr-c.html
http://search.digikey.com/scripts/DkSearch/dksus.dll?vendor=0&keywords=7812sr-c

leo

26-06-2010, 15:29

Thanks guys, now updated :)

fmzip

30-06-2010, 15:01

I've been fiddling with my 7520, upgraded all the caps, DAC, power regs etc. Unfortunately I ran into a snag, if I press any coax input, all the leds go on. If I press the USB switch, all the LEDS go off.

Does anyone have a schematic for this unit ? I sent an email to Stan, waiting on a reply.

Any help would be greatly appreciated.

Thanks,

Fran

HighFidelityGuy

30-06-2010, 15:25

Are you still using the original 12V power supply? If so you either need to contact Stan to buy a Caiman 15V PSU or possibly source a linear one your self like some of us have done.

I suspect you're still using the 12V supply as I accidentaly used my 12V supply recently and ran into the same problem. I thought I'd knackered my DAC but it just wasn't getting enough juice to make the 12V reg work properly. The 12V Murata reg needs at least 13V to work peoperly.

I hope that helps. :)

fmzip

30-06-2010, 15:40

I have a 18V supply running at 15.65 volts. It worked perfectly for a few minutes, then I started tinkering. :( I touched up all my ugly solder joints with my new Weller iron and now I have the problem.

Really stumped here without a schematic. I am hoping it is my ribbon cable that connects the two boards together, one basically broke completely apart. Not sure if this is the problem or is now the problem as I've been handling the boards over and over looking for the issue. I will be removing both cables and soldering wire point to point, keeping my fingers crossed that this is the problem.

Being in the states, it's not simple to send it in for repair. Plus, I wouldn't want anyone to see my poor soldering skills ;)

MartinT

30-06-2010, 16:20

I was going to suggest that you look at the ribbon cables but you've got there first. It shouldn't be too difficult to replace them with individual solid core wires if need be.

fmzip

30-06-2010, 17:46

Would stranded 24 gauge be OK?

MartinT

30-06-2010, 21:47

Would stranded 24 gauge be OK?

Hmm, the Americans remain ever imperial in their measurements! I don't know what that is but would be tempted to get hold of some solid core as it is so much easier to solder to a PCB.

fmzip

01-07-2010, 00:16

HighFidelityGuy

01-07-2010, 13:08

24 "gauge" lol......

I still don't know my metric conversions yet! :)

Good news, switching problem is resolved!

Bad news, I have no audio out of the right channel. Swapped op amps, same issue. Pressing on EC7 and EC9 brings the audio back. Replacing with new caps into those two locations, same result. Replaced both Wima caps, same issue.

I cooked something, the DAC chip get very hot very fast. Schematics please, I am begging. :(

I'm so bummed out. Final steps, the very last mod, and now its dead.

I don't beleave stan has officially made any schematics available and I doubt he'd like people posting them unofficially.

If the DAC chip is getting hot during normal use then it sounds like you've shorted something. The first place I'd check would be TC2 and C2 just to the right of the DAC chip. As the new TC2 replacement is bigger than the one it replaced it can get very close to C2. Make sure they're not shorting on each other. Also make sure all the new polarised electrolytic caps are installed with the correct polarity. Look for the tiny + symbols on the PCB and make sure the verticle white stripe on the new caps is on the oposite side. If you manage to find a wiring fault then you may have cooked the DAC chip, so you may have the replace that as well.

Also make sure you have the power regs the right way round. The white sticker should be facing the rear of the chassis. Also make sure you don't have any blobs of solder kicking around the board. Those beggers get everywhere during de-soldering.

I hope that helps. :)

HighFidelityGuy

01-07-2010, 13:12

Another place to check is EC15 and EC16. They're under the opamp board. Make sure the bottom of the opamp board isn't shorting on the top of these caps. A little insulating tape will do the trick. It's a good idea to do this anyway although I beleave later revisions have shorter caps.

fmzip

01-07-2010, 13:39

Thanks for all the suggestions.

Stan did reply indicating that the schematics are proprietary which was disappointing but understandable. I was under the assumption that this information was available with all the modding going on. I probably should have asked this question before I started modifying it. It is quite interesting how some companies hold everything close to the vest and others do not. For example about a month ago I requested a schematic from Rotel, and they sent me one after I provided them my serial number. With most of the electronics on the market, there really is nothing secretive inside of them.

I spent about 7 hours checking everything out. The new regulators are installed correctly as it worked for a period of time. The polarity of the caps are also correct.

Interesting point regarding the tape. I removed that in order to try to get the cover back on. The cover has been off since the beginning as it will still not fit with the Nichicon Muse caps installed on the op amp board. I believe the caps you are referring to "TC2 " just to the right of the DAC chip may have hit the leads of the DAC. Or, my ribbon cable breaking may have caused the short elsewhere.....

I am going to order a Caiman from Stan and he said he would sell me a new board as well for my TC-7520. What I will likely do is start all over with the TC-7520 mods and leave the Caiman as is. This way I will never be at a loss for sound :)