What did everybody use for replacement filter caps and to what effect?

[MusicFox]

I thought I'd start a specific thread to help us all find out all in one place what people did replacing the 30 20 20 20 quad cap in the tubers and what values were altered to what effect. What lessons learned and any regrettable decisions that were changed back to stock perhaps. I hope I'm within reason here. I have done much searching but it is awkward and all spread out in different threads.

[EdBass]

Some other posters as well as myself have had good luck with these;

http://store.triodestore.com/sdslabcapboa.html

Type "SDS Board" in the search engine and you'll get a bunch of feedback as early as 2002, but basically it eliminates any voltage issues (and then some), tightens up the bottom end and gives you a little more headroom.
They also work with tube or SS rectifiers.

[Soundmasterg]

The SDS cap board is a good approach. It works and sounds fine and is reasonably priced. It also fits right into the amp.

I've just used individual caps of either stock values or larger cap values on the first two sections in the amp depending on what was wanted. Usually that means series connected caps for the first two stages at double the final value....so if I want a 110uf cap in the first stage for tighter bass, then series connecting will require two 220uf caps and two 220k 1w resistors in series with each cap. 350v caps work fine and give you essentially a 700v cap for a given stage when wired in series.

The first two stages in the amp need a higher voltage rating, and sometimes the third one does also. I series connect the first two stages with 350v caps of whatever value, then I use a 500v cap for the third stage. I usually leave the preamp and phase inverter cap sections the same as stock because if you change it, it will affect the sound, since those stages are RC coupled. Changing value on the first two cap stages will result in a feel change, as if you go to larger caps, it makes the bass quicker to respond. The main thing however is getting a higher voltage rating to withstand the higher wall voltage these days.

Places like www.tubesandmore.com have most of the caps and resistors you'll ever need.

Greg

[djc]

that's what I used on my tube rectified 200s.  sounds great.  use it predominatley for bass, occasionally guitar. love it.  I think it sounds original, the only other Sunn tube amp I've used was a 6550 powered sonaro head all stock.  they sound similar but mine gets growli-er at high volumes.

[MusicFox]

Thanks all. So far so good. Its now the "RC coupled" filter caps of the 3rd and 4th filter that I want to know more about. Any insight? I was told too much capacitance at 3rd and 4th filters can cause bassiness and possibly oscillation. I'm guessing that a increase to 40 on one of the two (Which One?) will not change much as the SDS boards are 60 60 60 60 and such higher numbers anyway and people here are saying they work good.

I do have access to a new 40 40 40 Can Cap supposedly rated at 550 volt (I haven't seen it yet) and I was thinking of going the Variac route to power the amp at all times at 110 line volt anyway keeping the B+ at 1969 levels. Gigs and everything. A Variac is about as much as a set of tubes. I could still use a discreet 20uf for the last (or third) filter if I use the can. We'll see If the Can has a 600 volt surge rating first.

[Soundmasterg]

Thanks all. So far so good. Its now the "RC coupled" filter caps of the 3rd and 4th filter that I want to know more about. Any insight? I was told too much capacitance at 3rd and 4th filters can cause bassiness and possibly oscillation. I'm guessing that a increase to 40 on one of the two (Which One?) will not change much as the SDS boards are 60 60 60 60 and such higher numbers anyway and people here are saying they work good.

I do have access to a new 40 40 40 Can Cap supposedly rated at 550 volt (I haven't seen it yet) and I was thinking of going the Variac route to power the amp at all times at 110 line volt anyway keeping the B+ at 1969 levels. Gigs and everything. A Variac is about as much as a set of tubes. I could still use a discreet 20uf for the last (or third) filter if I use the can. We'll see If the Can has a 600 volt surge rating first.

Since everyone hears differently, it is almost something you have to try yourself to see what you like. Personally I am fine with the stock values on the flast two sections. If you go too high in value, then yes, you can end up with oscillations. They are usually do to grounding problems and insufficient decoupling in the amp. (running more than one gain stage per filter cap) Keep in mind that if you use a variac that the bias will change, and you need to make sure that you bias the amp at that 110v setting, and ALWAYS use the amp at that setting, unless you re-bias it. Personally I'd just find whatever values of caps that I like in the amp and use it that way.

Greg

[Isaac]

Some other posters as well as myself have had good luck with these;

http://store.triodestore.com/sdslabcapboa.html

Yup. Put one of those in my 200s, and couldn't be happier.