6G6B Bassman, airbrake, blown OT, tears

[vibratoking]

What!!??

[rdjones]

[img:298:327]http://ep.yimg.com/ca/I/yhst-8476489043 ... 562327.gif[/img]

[Toppscore]

"As I see it, I have the following options:
A. Buy a new, high-quality replacement OT (Mercury magnetics or whatever the cool kids are into these days).
B. Find a Bassman OT from '64 or thereabouts (do these ever even appear on the market? What sort of prices would I be looking at?)
C. Get it rewound. (Is it possible? How much does it cost? Is there even a point in doing it? Who does that sort of thing here in Europe?)
D. Bury the amp and deny that it ever existed."

Get a Mercury Magnetics to play now.
Keep an eye out in the future for an OT
that will better match your vintage amp. Toppscore

[mr_hankey]

(...)

[Firestorm]

Interesting about the component changes. I always thought that was one of Fender's weirdest tone stacks: the 1M resistor kills almost all the bass, so going to 220k puts some of it back. The 470pF bumps up the mids a little. Seems like using unmatched mix resistors was done to adjust the relative loudness of the two channels. As to the filter caps: I wonder if 600V caps were going out of supply. Are the remaining filters 600V or something lower?

[ToneMerc]

[img:400:346]http://i.imgur.com/sFKNKzl.jpg[/img] That black stain conducts quite well. It's a Tung Sol 5881, by the way.


I compared the amp to the schematic while I was going through it. There are a few differences in the bass channel from the schematic. The solder joints appear untouched, so I'm quite sure it was done back at the factory. What effects would those changes have?
[img731]http://i.imgur.com/YaFHDcB.png[/img]
Another difference is that it came with 2x 70uF filter caps in series before the standby switch (with 2x 220k resistors).

Hmmm, those values looks like it was modded for guitar, including padding the bass channel. In the two I built last year, I changed the slope to 43K and to 330 and 390pf treble caps verses the factory 250pf. if you want to make the bass channel even more guitar friendly, gently remove he .002 from the V2b plate.

TM

[rdjones]

I compared the amp to the schematic while I was going through it. There are a few differences in the bass channel from the schematic. The solder joints appear untouched, so I'm quite sure it was done back at the factory. What effects would those changes have?
[img731]http://i.imgur.com/YaFHDcB.png[/img]
Another difference is that it came with 2x 70uF filter caps in series before the standby switch (with 2x 220k resistors).

Hmmm, those values looks like it was modded for guitar, including padding the bass channel. In the two I built last year, I changed the slope to 43K and to 330 and 390pf treble caps verses the factory 250pf. if you want to make the bass channel even more guitar friendly, gently remove he .002 from the V2b plate.

TM

This seems like a late transitional version right before the emergence of the Blackface.
The tonestack values look like a move toward the Blackface values.
The series main filters are a Blackface trait.

It probably also has the strap handle, right ?

reddog

[mr_hankey]

(...)