The fun of after fire up trouble shooting

[Tone Junkie]

Just taking a break and thinking out loud any idea,s please jump in I just finished a new build fired here up sounds great basicaly a 2 channel with an extra gain stage. kind of differant this one starts as a 1987 bright channel marshal then goes to a 2 stage like the 2203 with differant cap values,  the second channel has an extra gain stage with just a 10k resister and no cap for a cathode. so it goes 1 gain stage then 2 then 3  followed by normal marshall tone stack all gain stages run of the same tone stack.
The funniy thing is channel 1 the bright channel is dead quiet switch to channel 2 quite noisy like an old 12ax7 tube a I won once that had a lot of hiss.
 Both channel one and channel two are off from V1 I have changed out the tube checked all my usual suspects . I always seem to miss a ground some where, I did try a new ground schem I used the one from merlins site so it should be perfect. could a bad cap some where cause hiss I guess I need to get my terminology right does anyone have a recording of say 60 cycle hum and other hiss problems so I know the differance when Im talking about them . Oh to clarify a few things elevated heaters, my switching is down on the power amp side with shielded cable used to run almost everything on the pre amp side of things, plus all the switching. Ive used the chopstick trick no change anywhere.
my next move will be to wire the second channel straight with out the switching and see if that clears it up. Thanks Bill     

[HotBluePlates]

So the 2nd channel has a stage with a 10k cathode resistor and no bypass cap? Is that the first stage of this channel?

If so, try tacking a 25uF cap across it, just as a test. If the hiss goes away, you might have to look at replace the cathode resistor and/or trying a different value and/or including a bypass cap.

[Tone Junkie]

Thank you my friend that was actually the 3rd stage I looked and didnt explain it well. It doesnt really change channels so much as add gain stages the first 2 are 2.7k and .68 on the cathode its the 3rd thats 10k when shifting between the 1st and second it shifts the volume out of the path of the 1st and puts it behind the 2nd hopfully in a little bit I can wire it straight without the switching and see if its still noisy. the 3rd stage actully doesnt add any more noise to the situation its all in the area around the second stage.
I just didnt know if like a bad cap could add that kind of noise even though there mostly sozo,s and a couple orange drops there are a couple that have been in other amps before. I was kind of stressed and needed to re group a bit. You guys have always been a great group to talk to, most of you guys have light years of experiance beyond me and I have learned a huge amount of things here expecially some good trouble shooting technics. One of the best being walk away and think about it for a bit.
Thanks guys

Sorry to much talk my soldering irons hot need to get buisy