Monday, October 12, 2015

Peavey weirdness now morphing into Blunt Instruments

UPDATE: I think I've found an appropriate name for the amps I build, I checked TESS and nobody's sitting on the trademark, so henceforth and forevermore, anything I build will be yclept a "Blunt Instrument". You heard it here first.

Last week as I considered the state my monster amp project was in I decided to plunge for power and output  transformers for the Super Bee.

There are two potential sources for this class of iron, and a possibility of a third. There is, of course, the ubiquitous offerings from Mercury Magnetics about which more anon, or the offerings from Mojotone which are manufactured by Heyboer. If Classic Tone made these transformers I would have shopped there but alas! they do not.

The net total was $117.42 for the Mojo 753 power transformer, and $109.70 for the Mojo 756 output transformer-which came with multiple taps by the way. Shipping was another $20 or so. Mercury would have run me $425 plus shipping so it was a no brainer.  I suppose I could have used a Twin Reverb power transformer which I have as well as a Twin Reverb output transformer and then had to come up with a 5v filament transformer to run a rectifier tube which would have saved some dough but would not be close to the original setup. This amp has to look and sound like something Fender built. If I wanted to hunt til I'm old and gray I could possibly have turned up an original p/n 7993 Triad power transformer and a 45268 output transformer but that is not a likely proposition. I could die waiting.

The transformers were installed with blue Loctite on the screws. I've seen too many get loosened up with age.

I've selected a new old stock Mullard GZ34  for rectifier duties and RCA black plate 6L6GCs for power section duties. I think Uncle Boris over at Sovtek can do the  rest. There is also a Dynaco socket mod for protecting the rectifier tube which I plan on incorporating- to power 4 6L6GCs is asking a lot of a 5AR4.

With the board built, all I have to do now is build a bias board and a cap board, install some controls and start stitching. The biggest unknown is fitment and speaker selection. That will come later.

On the top you can see my layout. This was possible only because a friend owns a high power tweed twin and I was able to lay out the components in the original way. By comparison there is a shot of a recently built tweed twin replica and the output transformer and cake pan are reversed.


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