adding bias pot and test points to pignose 40(HELP)

[SoulofSound]

i have a pignose 40, I bought a 10k fender bias pot and was going to put it in series with the 56k resistor thats in the amp.. While I was at it I was going to add test points for biasing..

Question 1- Is the 10k pot going to be fine with the 56k resistor? or do i need a lower value?

Question2-Banana clips=2 power and 1 ground...
Is this right, the test points wire from pin 8 of each power tube to the(+)banana clips .. then from each (+) to the (-)banana clip with 1 ohm 1% resistors.. Then ground to chassis from (-) banana clip.. Correct??

i was also trying to get more bottom end and a little more clean sound out of the volume..

heres what i have done.

Ok, i swapped C17 for a .1uf cap, swapped C14 with a .047uf, removed C9 but put it back with an brown drop .047uf cap, and R11 to a 1.5K resistor.

this only gave me a little more low end on the distortion side..

I also had to re-arrange my pre-amp tubes from V1-TungSol 12ax7, V2-RCA 12av7, V3-Mullard 12ax7,

TO

V1-RCA 12av7, V2-Mullard 12ax7 and V3-TungSol 12ax7. Just to get it to sound ok with distortion/overdrive..

I have a TungSol 12at7 on the way but its been lost in the mail. so this is what i have for now.

[MWJB]

The 10K bias pot isn't going to make a great deal of difference in your amp...might be just enough, but I would be inclined to use a 50K pot, wired as a variable resistor in series with 39K or 47K to ground.

Set negative voltage to -60vdc @ pin 5 before installing tube & fine tuning in mA.

"Question2-Banana clips=2 power and 1 ground...
Is this right, the test points wire from pin 8 of each power tube to the(+)banana clips .. then from each (+) to the (-)banana clip with 1 ohm 1% resistors.. Then ground to chassis from (-) banana clip.. Correct??" In principle yes, don't have the amp to look at so can't see how easy this is to implement (e.g. are pin 8s grounded directly via a PCB trace?).

Have you tried the amp wit & without C21?

Try a larger value at R19, will make the amp less waspy/middy, smoother & rounder, try 56K & 100K.

Lower mu tubes are likely to reduce low end, rather than increase it but will help if you're looking for less distortion. I'd start by trying 12AT7/5751 in V3, subbing V1 for a low mu tube is reducing gain at 2 series stages in 1 go, so subbing V2 &/or V3 should give a more subtle change?

[SoulofSound]

i had a heck of a time finding the 10k bias pot and seemed to be the only one.. can i use a regular linear taper 25k to 50k pot??

Or am I looking for one of those lil plastic style 20k 20 crement pots?

[SoulofSound]

Well i put everything back original except c14.. I also have c9 removed.. i lifted one end of r34 and c21 to try that also.. It seems c21 and r34 do nothing when cut. I also tried adding a 1/4w 68k in series with the R19 resistor then a 22k in series but it seems to add to my shrill effect.

My problem is with the mods is that they take away my cleans and add shrill n mudd to my overdive/distortion even with a pedal.... So going back to the original got me a lil closer but having to run the 12av7 in v1 is the only thing giving me any cleans..

Thinking I need to add the bias pot to the amp before i go any further.. I dont understand why the mods intended to add low end are actually adding gain, breakup,mudd and highs?

[MWJB]

"i had a heck of a time finding the 10k bias pot and seemed to be the only one.. can i use a regular linear taper 25k to 50k pot?? Or am I looking for one of those lil plastic style 20k 20 crement pots?" Yes a regular linear pot will work, as will a cermet pot...whatever is the most practical to install.

[SoulofSound]

Here is a schematic