[zygadr]

Apologies to post on this forum (especially Hugh)again for a non ASPEN amplifier question, but I know that I will get a straight answer from all the knowledgeables here

As per my previous thread on modifying a Kenwood KR-A4080 13 year old receiver, I have one question to ask, and I promise to leave you guys alone and by the Apen amp modules as intended ........it's all about money

My question is : this amp's signal path is simple and direct coupled with few components compared to many other types.So, ........is it worth changing all the decoupling and bypass caps that exist around the main components (primarily eletrolytics and ceramics around, but not in the signal path, of the T092 devices on board) or will this make little if any difference to the sound quality?

As there will be quite a lot of work, which I don't mind and I have numerous Black Gate STD,PK,etc. at my disposal, It would be nice to know if all the effort would be obvious in the sound quality department.

Your opininions are most welcome!

[AKSA]

Zig,

It's generally worth replacing all caps in the signal path, and all stability caps (the one I mentioned should be polystyrene, or silver mica). Caps which decouple power supplies are not as important, but can be replaced, particularly in the power supply, with high quality, Nichicon Muse/KG are good examples but there are others such as BG and Cerafine.

The BGs have a long break in period, which is infuriating, but after about 150 hours they do deliver the goods.

Hope this helps, gotta buy that Lifeforce!

Hugh

[zygadr]

Thanks for your response Hugh.I will soon be replacing all the ceramics in the actual amplifier circuit with polystyrene as you suggested. These however are mostly next to small electrolytics(a couple are 220uf 10v). If I understand correctly, these aren't exactly part of the power supply directly, but do carry some voltage through them and do power various parts of the amplification stages. So, they should be replaced if possible?

Yeah, I know about those black gates, they're a pain at first, but brother!........when they click in.......what a cap!!

[AKSA]

Zig,

If the ceramics are high value and bypassing electros, better to replace the electro and leave it unbypassed.  Otherwise, replace with a film cap, polyester or preferably, polypropylene.

Small value caps should be polystyrene, or very small, such as stability caps, silver mica.

Other signal caps should be polypropylene, or as in the case of RTX from Relcap, polyprop/polystyrene hybrids.

This selection works for me, YMMV of course, depending on how your ears have been branded....   

Cheers,

Hugh

[zygadr]

Hugh, that explains it thoroughly. The Kenwood is a mixed bag of values in the ceramics(smallish pf values - max is 10,000pf) electrolytics vary : 1.0mf, 10mf, 22mf, 47mf and three 220mf.
I guess it would be better to replace all these eletros with better quality ones as you suggest and leave out the ceramic bypasses where applicable?
Where there are just small value ceramics on their own,polystyrenes will be used.
Hope this is correct.

[AKSA]

Zig,

You got it!!   

Hugh

[zygadr]

Many thanks for your time and effort Hugh. Still saving up$$$$$