Valve amp capacitor advice sought

**James G** · 06-05-2009, 13:36

Hey guys, I'm hoping to get some advice these caps in my amp (TRV-35SE). I'm not sure about the application so I have included a photo. They are the copper colored Vitamin Q caps. Just an uneducated guess is that they are cathode bypass caps? Sorry but I have't been able to find any schematics for you to look at.

I noticed that on the images (last page) in the amp's owner manual they are different caps (white plastic).
http://www.triode.co.jp/en/contents/...s/TRV-35SE.pdf

From what I could find on the net the VitaminQ caps are mostly described as warm, smooth, nostalgic, etc. What I'm looking for in sound is more like open, detailed, clear, etc. Something that will let ALL of the sound of my tube choice show through. Then I will see about getting some quality NOS tubes, maybe something like the ones Marco got in his Ultimate ECC83 thread.

Would changing these caps to a different type such as a Mundorf Supreme or the like help get me closer to what I'm looking for, or am I barking up the wrong tree? Any suggestions much appreciated.

**jonners** · 06-05-2009, 15:47

James -

I would think they are more likely to be coupling caps. They seem too small to be for cathode bypass.

**Mike** · 06-05-2009, 16:13

Originally Posted by jgarner71

What I'm looking for in sound is more like open, detailed, clear, etc. Something that will let ALL of the sound of my tube choice show through.

I'd be tempted to suggest polypropylene caps, something like the Soniqs SAX type from WD should do the trick!

http://wduk.worldomain.net/acatalog/...apacitors.html

Cheers...

**alb** · 06-05-2009, 17:18

Interesting that an amp named TRV-35SE, should turn out to a push pull. Anyway it looks well made with decent components.
They probably are coupling caps and it looks as though you have enough space in there to experiment.
Another suggestion would be Dynamicaps.

**James G** · 06-05-2009, 17:25

Thanks guys for the info.

Mike, from the description they certainly sound like what I'm looking for. In changing the cap type, should I keep with the exact same values?

I found this link from a Japanese audio site and the guy has the same amp as I do with Vitamin Qs loaded, but his are .1uF. Now I'm even more confused.

http://community.phileweb.com/mypage...20081208/8861/

**James G** · 06-05-2009, 17:37

Originally Posted by alb

Interesting that an amp named TRV-35SE, should turn out to a push pull. Anyway it looks well made with decent components.
They probably are coupling caps and it looks as though you have enough space in there to experiment.
Another suggestion would be Dynamicaps.

Heh, I know what you mean.

I think the SE is for Special Edition. It was originally released as TRV-34SE and only 500 made as like a 25th anniversary commemoration. But then he got such good feedback that he decided to keep going with it and just changed the name a bit to differentiate the anniversary ones. If I understand correctly. Well, something like that.

Hmm, the Dynamicaps are described as lush, smooth and warm. I don't doubt they are excellent though.

I'm having a terrible insomnia night. Too much coffee today.

Gotta get some rest. I'll check back tomorrow evening.

**Mike** · 06-05-2009, 17:49

Originally Posted by jgarner71

In changing the cap type, should I keep with the exact same values?

I found this link from a Japanese audio site and the guy has the same amp as I do with Vitamin Qs loaded, but his are .1uF. Now I'm even more confused.

I would stick to the values as fitted, it could be that this guy has other mods or has been altering values to suite his own taste.

I seem to remember Sprague VitaminQ caps being popular with guitarists for that 'vintage Gibson' sound, so they are possibly quite 'flavoured'.

**alb** · 06-05-2009, 17:50

I found this link from a Japanese audio site and the guy has the same amp as I do with Vitamin Qs loaded, but his are .1uF. Now I'm even more confused.

0.1uf either way is unlikely to make any difference. Just make sure they match or exceed the originals with regard to voltage.

**Ali Tait** · 06-05-2009, 23:12

Another option would be teflon SCR's.You can get these from hificollective.Not cheap but very good indeed IMHO.Give just the sound you are looking for.Another contender would be Audionote coppers.Another excellent cap.

**James G** · 07-05-2009, 15:03

Well for the price and seeing as how this is my first experience with these kinds of caps, those Soniqs SAX are looking like they might be the ones.

I'm thinking of moving up from .22uF to .47uF to stiffen up the bass. The amp is a bit on the bass shy side. Any thoughts? Big mistake?

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