Og peavey 5150 stock screen resistors?

  • Thread starter Thread starter dannykookoocookjr
  • Start date Start date
Nigel said:
Sounds like you’ve got some weird tubes too. That amp wants 6L6GC’s, and the low screen resistor value is part of the charm in that it drives them much harder as most circuits today are 470 ohm whereas stock is 100 ohm, or around 1/5th the value. That’s why they’re biased cold, to keep from cooking them.

King Edward preferred JJ 12AX7’s in all slots too. I did this in a friend’s 5150 II that was stock save JJ 6L6GC’s and it was perfect. Shuguangs work well too but Sylvanias were the OG and the true secret sauce behind “Block Letter” toanz.

What are you trying to get out of the amp?
Click to expand...

They’re biased cold because peavey had reliability issues after their good stock of sylvanias ran out. He has 1K screens like most of us which now lets you bias the amp to get it out of crossover distortion which they come with stock from the factory.

The only other mod they need is the bias modification to adjust the bias and that’s it. Select choices of preamp tubes is all that’s needed to get them to sound great.

I hate JJ anything. I loaded mine with either EH, 9th gen, or sovtek.
 
glpg80 said:
They’re biased cold because peavey had reliability issues after their good stock of sylvanias ran out. He has 1K screens like most of us which now lets you bias the amp to get it out of crossover distortion which they come with stock from the factory.

The only other mod they need is the bias modification to adjust the bias and that’s it. Select choices of preamp tubes is all that’s needed to get them to sound great.

I hate JJ anything. I loaded mine with either EH, 9th gen, or sovtek.
Click to expand...
Do you mean to say Ed's amp had 1K's, or OP's? I agree x-over distortion is undesirable, but disagree on JJ's as they produce a tone in 5150's I prefer greatly to Sovteks.
 
Nigel said:
Do you mean to say Ed's amp had 1K's, or OP's? I agree x-over distortion is undesirable, but disagree on JJ's as they produce a tone in 5150's I prefer greatly to Sovteks.
Click to expand...
The OPs. Please read the thread in full :)

It’s subjective. I hate the top end of JJs. They’re all a sonic mess and sound like a wool blanket is over the cabinet. Doesn’t matter the volume.

The only JJ I can tolerate is a JJECC803. The rest I throw in the trash.
 
I’d like a bit more pick definition some more organic overdrive.i like he the hot rodded jam sounds the best.im also just in a fanatic stage of modding which I kinda feel like i could regret it because im not very experienced and not exactly sure what i want.just kinda bobble head around.i can’t afford anything else so im trying to make do with what i got.ive got a bunch of pedals that help me kinda quench my thirst.i think ultimately i just want the peavey to kind out do the standard ones.i would really like to find the actual pcb layout of the mk sig 5150.ive found the combo with the two power tubes and have been studying it thinking the preamp would be the same.i think having the pcb layout will help me understand the schematic/diagram better.if anyone could help me find that I’d be stoked.!?
 
Nigel said:
Do you mean to say Ed's amp had 1K's, or OP's? I agree x-over distortion is undesirable, but disagree on JJ's as they produce a tone in 5150's I prefer greatly to Sovteks.
Click to expand...
I’ve got 3 ruby 12ax7 ag**not the plus I keep going back and forth between the spax7 and the rubys
 
Nigel said:
Sounds like you’ve got some weird tubes too. That amp wants 6L6GC’s, and the low screen resistor value is part of the charm in that it drives them much harder as most circuits today are 470 ohm whereas stock is 100 ohm, or around 1/5th the value. That’s why they’re biased cold, to keep from cooking them.

King Edward preferred JJ 12AX7’s in all slots too. I did this in a friend’s 5150 II that was stock save JJ 6L6GC’s and it was perfect. Shuguangs work well too but Sylvanias were the OG and the true secret sauce behind “Block Letter” toanz.

What are you trying to get out of the amp?
Click to expand...
id like to get more of a pushed jcm with the 5150 resonance
 
Ha
psychodave said:
Easiest way is to replace the NFB resistor with a 100k pot (drill a hole in the back of the amp) . Of course I’d put at least a 27k resistor in series so the lowest negative feedback the amp would see would be 27k.
Click to expand...
ve you done this with the 5150 if so do you remember what the letter/# it was under on the pub
 
Nigel said:
Sounds like you’ve got some weird tubes too. That amp wants 6L6GC’s, and the low screen resistor value is part of the charm in that it drives them much harder as most circuits today are 470 ohm whereas stock is 100 ohm, or around 1/5th the value. That’s why they’re biased cold, to keep from cooking them.

King Edward preferred JJ 12AX7’s in all slots too. I did this in a friend’s 5150 II that was stock save JJ 6L6GC’s and it was perfect. Shuguangs work well too but Sylvanias were the OG and the true secret sauce behind “Block Letter” toanz.

What are you trying to get out of the amp?
Click to expand...
I put some Tungsol 6L6GC-STR's in mine along with the Tungsol 12ax7 in the first spot and JJ's in the rest and it made it sound huge..mine already had what looked like a Bias mod in it..I sold it like the dumb ass I am.
 
This is why I don’t feel comfortable buying a 5150 used. No idea what someone has decided to do to it, who doesn’t know what they’re doing and has sub par soldering skills. I wonder how many got circulated in the used market, un-disclosed after the hype of doing mods a couple of years ago. An amp, that stock, defined a generational sound in rock and metal suddenly needed to be improved….🤷‍♂️
 
You must log in or register to reply here.
Back
Top