Marshall 2203 REEEEEEEEEEE-work

[harddriver]

So you are getting correct mv/ma readings on all four 1 ohm 2 watt resistors now?

[PLX]

So you are getting correct mv/ma readings on all four 1 ohm 2 watt resistors now?

Yeah, when I stopped using the variac and just plugged into the wall outlet @ 124 VAC, my bias adjust pot maxxed out at 38.5mA - which was exactly 70% plate dissipation.

[harddriver]

If you are going to consistently run the amp at 80-90ACV on the variac then you would have to compensate the B+ voltage drop in the bias circuit by reducing one of those two resistors(15K or 47K) just prior to the bias pot so at 90 ACV the bias can be set hotter due to the lower B+ voltage.

My 68 Ed spec B+ is around 300- 350( I would have to check my last bias notes from last year) or so at 90ACV but since i always run it at 75-85 ACV all the time I did drop the 47K resistor to give me more negative bias so I can run the tube at higher current draw with that 350 DCV B+. So I do rebias the amp into the normal ranges while being at 350DCV B+ due to running the variac at 85-90ACV.

[harddriver]

So you are getting correct mv/ma readings on all four 1 ohm 2 watt resistors now?

Yeah, when I stopped using the variac and just plugged into the wall outlet @ 124 VAC, my bias adjust pot maxxed out at 38.5mA - which was exactly 70% plate dissipation.

So all fours 1 ohm resistors are reading just fine on wall voltage then! That's fantastic news!

Is the variac of good quality like a STACO or Ohmite or is it a cheap o made in CCP one? Maybe the variac was doing some weird shit?

So it looks like the rebuild was highly successful then!

Does it sound like you remember or better??????

[PLX]

So all fours 1 ohm resistors are reading just fine on wall voltage then! That's fantastic news!

Is the variac of good quality like a STACO or Ohmite or is it a cheap o made in CCP one? Maybe the variac was doing some weird shit?

So it looks like the rebuild was highly successful then!

Does it sound like you remember or better??????

It's this one..



Tenma 10A
Weighs a ton.

It sounds like I jumped into a time machine, went back to 1977, punched Ed in the nose and took his amp.

[harddriver]

So all fours 1 ohm resistors are reading just fine on wall voltage then! That's fantastic news!

Is the variac of good quality like a STACO or Ohmite or is it a cheap o made in CCP one? Maybe the variac was doing some weird shit?

So it looks like the rebuild was highly successful then!

Does it sound like you remember or better??????

It's this one..



Tenma 10A
Weighs a ton.

It sounds like I jumped into a time machine, went back to 1977, punched Ed in the nose and took his amp.

So it's a vintage USA made TENMA then? I have a STACO USA 10amp for my amp work and the vintage Ohmites for my ED amp setup. You can buy use STACO's on ebay from labs and schools for next to nothing, just a thought for you.

Ed has a sore nose then that's awesome PLX, nothing better than hearing what you like out of your amp!!! It makes it all the toil worth while....

[PLX]

So it's a vintage USA made TENMA then? I have a STACO USA 10amp for my amp work and the vintage Ohmites for my ED amp setup. You can buy use STACO's on ebay from labs and schools for next to nothing, just a thought for you.

Ed has a sore nose then that's awesome PLX, nothing better than hearing what you like out of your amp!!! It makes it all the toil worth while....

Yeah, I bought this thing from an electronics supply house in Houston 27 years ago.

[harddriver]

That's a good one..........made in USA!!!!!!!!!!!!!!!!!!!!!!!!!!

[PLX]

That's a good one..........made in USA!!!!!!!!!!!!!!!!!!!!!!!!!!

[PLX]

variac set @ 70VAC
Two EH 6CA7's in the outer sockets
8Ω tap into 16Ω 4x12 cab