Wednesday, August 26, 2009

In The Beginning...

In the beginning, my wife's Aunt Norma's Motorola AM/FM tube radio sat on the floor waiting for me to decide what I should do with it. Aunt Norma figured that if anyone had use for an old radio with tubes in it, that it would be me. I did pull the back from it a few weeks ago just to check out what type of tubes operated the unit. She had told my wife that one tube didn't work.

I found the usual array of radio/television type tubes, which I am not familiar with because they are never applied in musical instrument amplifiers. I've buttoned the radio back up or I would name them off here. There was one nice Motorola 12AX7 which I've identified as a Mullard. I pulled it and tried it in one of my amps and it does have a sweet sound for a tube that's been at it for 50 years. By the way, the Motorola label completely disappeared after that short test run. Glad the paint stuck on there long enough to tell me that it was a 12AX7. I wouldn't of had the knowledge to identify it and tell it from its close cousins. I did recognize the rectifier as being common in smallish guitar amps--EZ80 or maybe it was EZ90, one of those.

The radio is a table top model, but with nothing indicating which model. At some point I may delve into the electronics and spark something up, but what I decided to do yesterday was check out the two speakers hanging on either side of the radio. Each speaker box could detach from the unit and be spread out about 10 feet from the radio. I figured from the get go that they possibly would make decent harp amp speakers with a little alternate wiring.

First, though, I wanted to try and identify what I had. Removing the back of one of the little cabinets revealed a 6" alnico speaker with "Golden Voice" stamped on it, with code numbers on the side. Through the marvels of the internet, I discovered that I had two 1962 Oxford alnico speakers and that convinced me to continue my little experiment. I checked the Ohms and got a reading of 6.9 ohms at the terminals and since I would be using an amp that prefers an 8 Ohm load, I decided to wire them up for half of that--figuring that lower would be better with a tube amp. After wiring the speakers together with a spare 15' speaker cab cable on which I kept one 1/4" plug attached to plug into the amp, I found that the Ohms read 5.4 at the end of the plug--so the load may just not be as low as I figured since the length of the wires came into play.

Bottom line is that I plugged these dudes into my Voice of Music 8 watt amp, wailed away, and got some really nice rawkus tones going. I had a bit of fun sticking the speakers around me in different positions and playing with the acoustics they provided. Of course, these will seldom have a use outside of my house, but within these walls, they be cranking. Anyway--


Brad Knapp said...

Sounds like a fun project!

Ricky Bush said...

Yeah, Brad, these speakers honk!