Soldano hum

[Oddvar]

I have just finished my Soldano Slo.  Works great, apart from hum when I plug in the jack for the guitar.  When I wiggled the lead from the jack input, it was close to the chassis, up in the air, the hum was lower, but hi enough to be annoying.   There is a shielded wire going from the tip of the jack to V1/7.  The shield is connected to the ground on jack, bot not to the tube.
Also, when I touch the Normal volume, the hum increases. Anyone with a solution?

[shooter]

hum when I plug in

does it hum when you're not plugged in?
Have you ohmed the ground from input jack to where it should go?

[Oddvar]

It hums considerably more when plugged in, I haven't ohmed.

[Oddvar]

When I take out V1, the hum disappears...

[Oddvar]

And there is noise when I touch the normal pot, not the OD pot.

[shooter]

I drew pictures 
1 verify you have a ground
2 & 3 aren't needed since it's V1 or left

[Oddvar]

That is measuring 92k and 161k

[shooter]

measuring 92k

look at the schematic, left side 68k, with nothing plugged in, follow the wire left, through the input jack to ground, should = 0ohms, maybe 2.

[Oddvar]

It's 1.2 ohm

[shooter]

1.2 is good.
do a full set of DC voltage checks on ALL pins of V1 and post
also, I marked up the schematic more, cut out the switching circuit and route a temp wire like I have shown, help?

[shooter]

 
look at the wire inside the blue box, If you put that wire in, my guess is that shouldn't be there, unless maybe it's a Gig-a-hz amp 

[Oddvar]

This is the layout I have been using...

[Oddvar]

I will go through your amazing help here, I will use some time, schematics is a bit outside my knowledge...

[shooter]

   layouts are mostly useless to me except for finding the component I'm interested in from the schematic, we should get along well 

My guess is your switching circuit is inducing the hum since pulling V1 makes it go away.

[92Volts]

Are you using a shorting jack?

If not, hum when a cable is plugged in suggests noise comes from outside the amp, due to noisy environment (fluorescent lights can be bad), a poorly shielded cable, problem in the instrument, etc.

WITH a shorting jack, this doesn't tell us much, because the jack would ground out noise including any picked up in the amp when no cable is plugged in. If possible, disabling the shorting function of the jack would reveal whether the hum is brought in by the cable or simply allowed because the cable un-shorts the input.

[shooter]

Are you using a shorting jack?

covered in reply #8

[shooter]

Did they sell you a schematic?  If so, could you post it, I found variations on the one I have compared to your layout, when that happens my head locks up and I have to go paint 

[Oddvar]

This is the layout I used.

[Oddvar]

This is the schematic...

[Oddvar]

Another funny thing is that the noise seems to get slowly louder when the amp is on, close to oscillating.
I also tried to disconnect the Normal pot, but no change.

[shooter]

the noise seems to get slowly louder when the amp is on

that's with nothing plugged in?

try this, look at the layout I posted, selector switch, 4ohm, disconnect the blue wire I indicated.  any difference?
does the "near oscillation" sound like it wants to squeal?

also while you're at it, what voltage did you get for bias?

[Oddvar]

The bias is 54.1, and there was no difference when removing the lead you suggested.

[shooter]

Ok, getting creative, unsolder R2 from pin 7 V1B, unsolder R8 from pin 2 V2A.  Now solder the loose end of R2 (that was connected to pin 7) to pin 2 V2A, you might need to add a small wire to make it reach (make sure it doesn't touch anything, maybe slip some shrink wrap over, or tape, this is just a temp thing).  What this does if you look at the schematic, is to take the input and bypass a bunch of stuff and use it to drive V2A, eliminating V1 AND the gain pots, channel switching, and clean channel.

Tape off R8 for now so it can’t get bumped into something, double-check, then check again, ask questions if you’re not sure, once you’re happy, power up, there will be less gain, but hopefully no hum/osc/bothersome stuff.