Silvertone 1481 Harp modifications

The Silvertone amp is very easily modified because it uses point-to point wiring. Please be VERY careful when working with tube amps the voltages can KILL you. First thing to do is identify ALL capacitors and short them to ground for a few seconds making sure they are fully discharged.

Here is a list of the modifications that I use on my Silvertone 1481:

1) Add a 22 uf by-pass capacitor electrolyte on the first 2.2K cathode resistor ( this adds more bass. Be sure that the negative side of the cap is to ground)
2) Replace the second 2.2K resistor with an 1.5K resistor (This adds more gain - don’t do this to the first tube stage or you will get too much feedback)
3) Move the volume control from the first preamp tube stage to be last thing just before the output stage, just after the tone control (this allows creamy preamp tube distortion at any volume level)
4) Replace all .01 uf coupling capacitors with .02 uf capacitors (this allows more bass and midrange to pass from stage to stage)
5) Replace the 270 ohm resistor with a 240 ohm resistor rated at 10 watts. (this runs the output stage a little hotter, but is still in spec for a 6V6 output tube
6) Replace the original 7 inch alnico speaker with a 10 inch alnico speaker

With these changes the amp will be as good as any harp amp out there. It works great for guitar too unless you’re looking for a guitar amp that does not add distortion.

Good luck