Bypass cap question

puretube · Post by **puretube** » Tue Dec 14, 2004 10:54 am

On the '68 100 watt SuperLead board, what is the value of the electrolytic bypass cap on the cathode of the first stage of valve 2 (pin 3)? Most amps I see have a .68uF cap here.

Post by **VelvetGeorge** » Tue Dec 14, 2004 2:22 pm

.68uf is correct.

George

Billy Batz · Post by **Billy Batz** » Tue Dec 14, 2004 2:24 pm

The only other common (not that common though) Marshall value I know of there is 330uF. Thats the supposed value in the EVH Holy Grail amp. Ive always had the stage 2 Ck on a switch to take it in and out. I mostly used .68 but I tried the 330u and its a interesting sound in its own right. Its inspired me to use an on/off/on minitoggle in my newest 100W project to switch between no bypass and those 2 values though Ive read posts were people do things like put a 5 way rotary switch in there and go through more values. Usually .68uF wouldnt be an e-cap.

puretube · Post by **puretube** » Tue Dec 14, 2004 3:55 pm

Thanks for the help.

The picture I saw was George's '68 100-watt SuperLead board. I will have to try out the 330uF on one of mine.

puretube · Post by **puretube** » Sat Jan 15, 2005 12:21 am

Just an update............

I tried the 330uF cap and I am very pleased with the tone. The cap has brought a little more focus to the midrange (but not making it over pronounced). The amp still has a great open growl, but I feel that it now sits better in the mix of a full group. Its similar to adding light compression to the channel at the mixing desk, but I get it onstage (without relying on monitors).

For reference sake, this is a split cathode design with the channels bridged (50-watt).