NOS AB CC drift and tweed amps

[Jim50hertz]

I'm building  a 5G9 Tremolux and my NOS Allen Bradley carbon comps are all drifty.  No surprises there.

Higher values are drifting upwards to up to 15% from tolerance.

Sure the values in vintage amps have and will drift upwards anyway but my question is, in a low wattage tweed amp like the Tremolux will it make a significant difference?

Should I attempt to get resistors which are closer to tolerance or just go ahead and build?

 

[Jim50hertz]

Schematic for reference.

 

[sahib]

Considering that no two same model vintage amp sounded the same this will be of no exception.

Go ahead and build it and tell us the mojo.

 

[Jim50hertz]

This does seem to be the consensus from the chats I've had.  Thanks Cemal

My transformers are in the post and the board is laid out.

Some chassis drilling work then building over the holidays. 

Cabinet is probably 3 to 4 weeks off.  I have my eye on a P12Q for this build, I'll also try a Celestion Alnico blue I have that I just don't like in my 5E3 but love in my lower powered 5F1 variant

I'm quite excited about the tremolux, should be fun

Nice new amp to usher 2015 in...  8)

 

[pH]

The tweed tremolux is a fantastic amp, one of my favorites that I've built (and I've built plenty!). I'm using an old P10R in mine, although it also sounds great through several other speakers. 15% off spec for your resistors should be ok, just check your voltages to make sure they're close and adjust to taste.

Have fun,
Paul

 

[emrr]

Parallel appropriate high value metal film to compensate if needed.  The carbon will still be doing most of the work. 

 

[Jim50hertz]

Thanks Paul, I'll build with what I have and tweak from there.  I'd love to know more about your build, the Tremolux is a little off the 'clone tweed' beaten track. 

Doug, the idea of paralleling metal films did not occur to me, thanks for the suggestion.  I'll build up the amp, check voltages and take it from there.

 

[pH]

My mistake Jim, I built the earlier 5E9 cathode bias version.  Wasn't the 5G9 a brown era amp? I've heard great things about them too, I'd imagine it would have a bit more oomph for playing live whereas mine is about on par with a tweed deluxe in terms of power and sponginess. My build was kludged together in a salvaged PP 6V6 mono amp, a real ghetto beauty!

 

[Jim50hertz]

My mistake Jim, I built the earlier 5E9 cathode bias version.  Wasn't the 5G9 a brown era amp? I've heard great things about them too, I'd imagine it would have a bit more oomph for playing live whereas mine is about on par with a tweed deluxe in terms of power and sponginess. My build was kludged together in a salvaged PP 6V6 mono amp, a real ghetto beauty!

Let's have some pics then Paul! I love ghetto builds

Yeah the 5G9 is a later circuit (57-59).  Kinda rare, bigger cab, LTPPI bias wiggle trem.  Bigger and louder than 5E3/5E9 with one less gain stage.  Less squish but still with a tweed voicing.  Some have described it as a baby bassman.  Looking forward to hearing it!