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-   -   PS decoupling caps in Gainclone (http://www.diyaudio.com/forums/chip-amps/136359-ps-decoupling-caps-gainclone.html)

ClaveFremen 12th January 2009 01:12 AM

PS decoupling caps in Gainclone
 
Saturday I've finally built my first Gainclone (PCBs from chipamp.com)

http://img124.imageshack.us/img124/6...3333ro3.th.jpg

and Sunday was tweaking day... :D

I've started with Panasonic FC bypassed by Evox-Rifa MMk5:

Nice, snappy sound but definitively harsh highs, terrible sibilants :xeye: and lack of basses! (is correct 'sibilant' in English for letters like 's'?)

mmh... :whazzat:

Swapped MMKs with Evox-Rifa PHE246 (polypropilene) from the Zobel:

http://img301.imageshack.us/img301/3...3335jk5.th.jpg

better tonal balance... less harshness and sibilants but not enogh!

Swapped MMKs with Evox-Rifa PHE246 also in PS decoupling:

A little better but not much :rolleyes:

Pulled out bypass caps and swapped FCs with FMs:

A great improvement! Sibilants quite under control, just a hint of residual harshness. :cool:

BUT

The sound was a bit on the cold side, voices a bit thinner than what I like and sound it's a bit tiring.

Well I've some Nichicon Muse KZ laying around so I swapped FMs with KZ:

http://img83.imageshack.us/img83/234...3338qp2.th.jpg

That's it! :cool: less harshness and sibilants under control, voices are bolder, great basses!

http://img291.imageshack.us/img291/1...3341qr0.th.jpg

You could listen to music in total comfort!

In effect that's quite different from what I've read quite everywhere... :confused: has anyone had similar experiences?

mikesnowdon 12th January 2009 06:31 PM

Thanks for the interesting and informative post. ;)

Have you tried the Blackgates for local supply decoupling?

ClaveFremen 12th January 2009 06:42 PM

No, I didn't becase I don't have Blackgates in my parts bin...

And since they are out of production I prefer not to try ;)

mikesnowdon 12th January 2009 06:51 PM

They are still available from some suppliers but some values are very hard to get. I found 4 x BG STD 100uf 50v caps on eBay which I now have in my LM3886 based amp. It was a straight swap over the stock caps and made a really nice difference. I haven't tried the Nichicon's but I think from what I have read that they have a similar sound to the BG's. I think I will build a diy amp from scratch soon and Im quite keen on the chipamp.com kits. How does yours compare to other amps you have tried?

ClaveFremen 12th January 2009 07:52 PM

If you refer to other Gainclones or DIY ones: nope ;)

This is my first DIY project. :D

Until now only modded my Speakers, Amps (Marantz, NAD, HK) and CD Players.

And components selection always been a hard task with a lot of try and change... :smash:

Just removed bypasses of main PS capacitors: nice improvement (another bit of harshness gone...)

Now I'll try with some others bypass caps... it could be that MMKs are not that good (but in my SACD they were a nice improvement over Vishay MKT1826...)

Answering you question:

well, it maybe sounds a little better than my modded marantz receiver (in this moment it is still the pre) but I have to swap back speakers to the Marantz to say for sure!

huy5005 12th January 2009 09:24 PM

I would try with good 300VA power supply. I find that Panasonic FC is actually good with larger power supply ( > 300 VA). Of course, blackgate is better but too expensive for me. Just my 2 cents.

ClaveFremen 12th January 2009 10:01 PM

Quote:

Originally posted by huy5005
I would try with good 300VA power supply. I find that Panasonic FC is actually good with larger power supply ( > 300 VA). Of course, blackgate is better but too expensive for me. Just my 2 cents.
One or two 300VA?

The transformers that I've used are two 120VA R-Core = 240VA: quite similar, isn't it? :confused:

My knowledge of electronic is basic, so why a transformer with more power would make capacitors sound different?

Blackgate is too expensive also for me... ;)

ClaveFremen 12th January 2009 11:27 PM

Quote:

Originally posted by ClaveFremen
Now I'll try with some others bypass caps... it could be that MMKs are not that good (but in my SACD they were a nice improvement over Vishay MKT1826...)
I've tryed some Epcos Polyester caps and no harshness but sound was somewhat compressed less soundstage, less highs, less life! :xeye:

Part of the residual harshness was due to MMKs, they have more air but here they're not so good. :mad:

But in effect no bypass to Nichicon KG Gold Tune seems better: less harshness, more air, bigger and wider soundstage. :cool:

gainphile 12th January 2009 11:36 PM

Do they actually make different sound and did you control the test environment (eg. loudness level)?

I have yet to play around with my caps as I have been agnostic about all these changes. But now really interested if more can be gained.

ClaveFremen 13th January 2009 12:23 AM

Quote:

Originally posted by gainphile
Do they actually make different sound and did you control the test environment (eg. loudness level)?

I have yet to play around with my caps as I have been agnostic about all these changes. But now really interested if more can be gained.

The test enviroment was flat (pure direct mode) no tone controls and no loudness, using my Marantz receiver as pre.

I'm sure that transformers influence sound, I've buyed R-Cores for that. ;)

What puzzles me is why a different tranformer would change a capacitor's sound... a capacitor that is on LM3886 supplies and quite far from transformer... :confused:

I'm also sure that capacitors do change how a device would sound. I've heard it in every modification I've made to my Speakers, Amps and CD Players.

In effect I've had quite consistent results using Elna Silmics in signal path (replacing stock caps).

Also had good results replacing stock big caps (2200uf, 3300uf) before voltage regulators in all my Amps using Panasonic FCs or Elna Cerafines after or using Rubycon ZL on opamps supplies.

I've always thinked that Sony, for example, in my SACD Player wasted money using Silmics before and after regulators and on analog supplies and Nichicons Fine Gold on digital supplies...

Tryed to swap Nichicons with Oscon SCs there with bad results. :whazzat:

After my Gainclone experience I'm starting to think that audio caps has to be considered also in PSs. :scratch2:


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