I have a silvertone valve radio that I would like to convert to an amp head.
I would like to reuse some of the parts, such as the tubes. They still function and are a 12AT6 (Hit Ray), 12BA6 (Westinghouse), 12BE6 (Zenith), 50C5 (Brand not distinguishable), and a 35W4A (Sylvania).
Would I use the 50C5 and 35W4A as the power amp? And the 12AT6, 12BA6, and 12BE6 as the preamp? Also should I reuse the old resistors/capacitors if they still work without problems? Or should I get new? What size transformer do I need?
How would I find out what impedence of speaker/cab I could use? Would it be the same as the speaker in the radio? (If it even has it marked :? )
What would the wattage of the amp be? I don't imagine it would be all that much.
I'm not gonna make it something with lots of switches. Just on on'off switch, Volume and if i'm very lazy just on overall tone control (No Treble, Mid,or Bass Knobs).
Would it be worth the time of building (what I would assume would be) a small amp?
Does anyone know of any good sites that have amp schematics?
Sorry for all the questions, but I would like to know. :mrgreen:
Check out the radio on a collector's site. Most tube radios now have some collector's value, some have a lot. Many radios have a phono input in the back already, no mods needed, just a plug adapter from the Radio Shack. They aren't often good for converting, most of the circuitry's for RF and IF amplification, tuning, and frequency conversion. That stuff doesn't lend itself straightforwardly to audio use. The audio section will be a clean, low gain amp that often expects to see a line level input, so unless you use a preamp your volume will be low and you won't have any distortion available. Fun to tinker with, but for the most part not a substitute for a guitar amp.
"A cheerful heart is good medicine."
Oh yeah, for sites with info on amp building & schematics, plus help:
http://music-electronics-forum.com/
I think you'll find it VASTLY easier as a first project to build a new, purpose-built guitar amp from scratch (or even better, from a kit!) than to try to convert a radio into an amp. And you'll save a nice old radio from being torn up. (I love those things.)
"A cheerful heart is good medicine."
Long ago and far away as a child I had a record player with radio combo. The radio had a phono input as Ric described to amplify the 45 RPM record player input.
If your radio has such an input this would be the best case.
Scrounging parts out of the radio to build your own amp would be a huge learning experience if you wanted to learn electronics but otherwise a frustrating waste of time.
Where is Heathkit when you need them???
Unimogbert
(indeterminate, er, intermediate fingerstyle acoustic)
There are a bunch of folks offering guitar amp kits now, and several are linked on the AX84 site.
"A cheerful heart is good medicine."
I agree with Ricochet. I'd sell that radio to a collector and use the money to do an ax84 kit. I think you would be better off in the long run. :)
Every once in a while, I've thought about doing an ax84 amp, someday I will.
