Doing Things Wrong

Silvertone 1457 Guitar & Amp (3/5)

The attenuator circuit for both the 1457 and 1472 amps

The LPad is the first stage and does most of the work, the fixed second stage can be switched in for even more quiet. The 50 watt LPad should be sufficient for at least a 20 watt amp. The capacitors suppress audible pops from the switches.

For the circuit above, the 1457 amp is nominally 5 watts at 4 ohms, while the 1472 is 10 watts at 8 ohms. The idea is to bleed off power while maintaining a constant impedance to the amp. This lets you get nice natural tube distortion without the neighbors calling the police. For these small amps, heat dissipation is not a problem.

Each circuit has two options for the fixed second stage, one for 12db and one for 20db - choose one. The values of the fixed resistors depend on the impedance of the speaker. For simplicity, just omit the second stage, it is not necessary, I was just experimenting.

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The glue is all dry, time to flatten out the blank. I clamped a piece of scrap wood at the edge of the bench for a stop, and laid the blank up to it on some padding. This will stop it from shooting off when the belt sander hits it. I sorted through all the vacuum cleaner parts I have collected over the years, and finally made an adapter to hook the sander to the little shopvac under the bench. Then I put on a new 80-grit belt, and went at it.

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