Doing Things Wrong

Tube Amplifiers

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These are actually a couple of Amp-in-Case models, 1448 on the left, 1457 on the right. The cases had pretty much disintegrated, so I built new cabinets for them, a pretty neat design if I say so myself. I re-capped both and installed new Jensen speakers.

I modified the bigger one with about a dollar's worth of parts to be more like a Fender Champ. That gave it a lot more kick. Great tremolo. It has an 8" Jensen speaker on the other side, just like the original. Lastly, I added the attenuator. I also have a 1472 that I rebuilt. I love the old Danelectro stuff. But the one that sees the most use is my little Craftsman amp.

The smaller one could use this upgrade:

https://www.instructables.com/id/Isolation-transformer-upgrade-for-old-guitar-amps/

However, I seldom use it, and I installed a modern plug that can't be inserted wrong, so as long as the outlet is wired right, it is safe.

Single-ended tube amp - classic 60s small tube amp design. Salvaged from an old Sears Silvertone amp-in-case, re-capped and upgraded. 12AX7 preamp, 6V6GT power amp, 12AX7 tremolo, 6X4 rectifier. It doesn't get much simpler than this - all point-to-point wiring. The speaker is on the other side, a modern version of the original 6" Jensen. The tube windows are not just there because they look cool - tubes get HOT - too hot to touch, and need lots of cooling. Hence the big air gap along the side. I also installed an attenuator, so I can get that nice tube distortion without bothering the neighbors.

One issue with old amps like this is that they are often grounded very unsafely. If something goes wrong, 400 volts or more could go up your guitar cord. That kind of voltage can be lethal, in any case very painful. I didn't want to cut the cord on this antique, so I routed it inside the box, where everything is done correctly to make it safe. You can see the modern 3-wire power socket on the side. ( Above that is an auxiliary power outlet for pedals. ) If you want to play with these things, you should know what you are doing!

1448 Schematics

1457 Schematics

1472/1482 Schematics

Fender Champ Schematics


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Together with the guitar, this was the first of my modified Audiovox design to be completed. Solid poplar bodies, stained to look like walnut, with single bindings. Each pickguard used an entire sheet of material; only these two got the pearl treatment, the rest got much less expensive masonite pickguards.

Printed from luthierylabs.com