• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Webcor Amplifier Speaker

Charlie C

Member
2004-12-12 12:25 am
NYC
I got this webcor amplifier speaker at a yark sale, Webcor Model MC 4903-1, it works, it has, 1ea. 12AX7, 2ea.6BQ5, and 5Y3GT. tubes; has 10" woofer, 5or 6" mid and tweater. with old wax caps between each speaker . It looks like it's from the 1940's. Could I make this work as a harmonica amp. from what I read these old amps make good harp amps, great tone. I would have to put a jack for a astatic jt40 mike high impedence. I'm new to tubes and electronics but am not new to electricity , I do hvac work. I was thinking of swapping the 12ax7 for a 12au7 and only using the woofer. any suggestions.


Thank Charlie.C.
 
First off, you'll probably want to replace the electrolytic caps (if you haven't already). That Webcor would probably make a great harp amp, with few if any changes to the circuit. There's a guy in Sacramento, Skip Simmons , who converts old PAs and whatnot to harp and guitar amps. He might be willing to offer some advice.

The weak link, I'd imagine, is the speaker. You might consider swapping the woofer for one of Ted Weber's harp speakers.

By the way, have a closer look at the tubes: you might have some nice ones. I've found some Webcor-branded Mullard EL84s in the past.
 
mholz said:
By the way, have a closer look at the tubes: you might have some nice ones. I've found some Webcor-branded Mullard EL84s in the past.

Ditto that.

This page is useful in deciphering the Philips codes.

The attached picture is a scan of some small codes... the delta means that they were made in Herleen, a B instead would indicate the Mullard plant at Blackburn.

dave
 

Attachments

  • 1c1-label.jpg
    1c1-label.jpg
    22.7 KB · Views: 108