Dumble #040 - guess what ? no trim pot - what values??

[bluesfendermanblues]

Hey you'all
There's a lot of rave about the #124 amp, which was photo doc'ed in great detail, but what about the #040 that doesn't even have a pre OD trim pot.

Any opinions on this construction and what pre OD values did HAD use?

http://personalpages.manchester.ac.uk/s ... 20%230040/

[Bob-I]

With these pics you should be able to read the color codes. I'd do it but I'm colorblind.

Also search for "Understanding the OD entrance". There was a good thread on this a year or so ago.

[butwhatif]

The trim is fixed at 33k to ground from what i can make of it--

[ic-racer]

I think this is the thread. Way back on page 37: https://tubeamparchive.com/viewtopic.php?t=400

I think the schematic (except for the OD entrance) would be similar to the "70s Schematic" http://www.schematicheaven.com/dumble.htm

[oldmacman]

Use the 100k trimmer and 220k resistor. It sounds much better.

Ben

[Structo]

Interesting.
I wonder what year this amp was built?

Notice how the bypass R/C layout is different from the later ones.
Good shots of V1 and V2 lead dress.
Thanks!

[img:640:480]http://personalpages.manchester.ac.uk/s ... ges/19.jpg[/img]

[butwhatif]

here's a closeup of the od in/out, only one resistor behind the cap that can't be identified-- also the od cat's and pr's have been modded for more gain-
hard to say who did it--

[Structo]

Is that pic from #40?
It doesn't look like this board from #40

[img:640:480]http://personalpages.manchester.ac.uk/s ... ges/12.jpg[/img]

[butwhatif]

of course not, but from the same batch i believe

[bluesfendermanblues]

It is supposed to be #040

check the link and click the #040 folder

http://personalpages.manchester.ac.uk/s ... ey/dumble/