radio conversion

[Suburbanite]

Hi, I'm thinking of converting this old radio to a guitar amp, mainly because I like the look of it, any one think it would be worth it? what kind of power would it have?

heres a schematic

http://www.valve-radio.co.uk/literature/litrobertsp4d.htm

heres the radio

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=220205612888&ssPageName=STRK:MEWA:IT&ih=012

[Enzo]

I am not sure if this is a good candidate for conversion. Seems a shame to tear up this neat old radio anyway. But really about all I see doing with it is using the box. This radio ran on batteries, so there is no power supply in it. You'd have to build one in. Very little of the circuit is audio, so youd have to add more circuitry. Is the power tube common today? It is low power, maybe that doesn't matter, I guess ther is nothing wrong with a amp putting out only a watt or two. it is a great looking thing.

[Suburbanite]

I suppose your right, It would be a shame but I might try and copy the box, I had thoughts of turning the tuning needle into a vu meter and all things aesthetic, I hadn't thought about the audio that much. I was looking around for something like this as a feet wetting project,

[Enzo]

I love the cover over the controls though.

[Suburbanite]

I know, was one of the first things that attracted me to it, I still like the Idea of all the stations on the dial with a vu meter on it, nice little light, tone controls peaking out just waiting to be used,

Still, I'm a better chippy than a sparky, so I should be able to copy the design, and then find another amp to put in the case, just need to find some blue leatherette for it

[Regis]

No offense but I agree with Enzo, that's a cool old radio worth restoring rather than gutting it (which you would have to do) to make a guitar amp. If it were just the empty cab you could put whatever you want in it.

Good Luck,

Regis

[Suburbanite]

I'll admit I agree, hope someone gets it and does restore it, shame I don't want a radio.

I'll still keep my eye out for a good project though

[Tubebass]

"Back in the day", as the kids have recently stopped saying, it was pretty common to modify a radio with an input and switch on the back panel. The switch just killed the audio from the detector circuit and fed audio from the new input into the radio's audio section. This allowed a turntable to be used with the radio's audio. Could work with guitar, though some external tone shaping might be needed to make things sound good.

[Paulinc]

I am going to try and convert a radio into an amp too. This my first post here, I'm a member of a bunch of different forums. I hope that it works out. I am actually picking up the radio tomorrow morning. Here is a picture, tell me what you think. Is it doable? I know I will be in and out of here looking for info and asking questions but I thought I would just jump right in.

[Paul P]

That looks more like an amp than a radio. I'd be surprised if you couldn't
convert it to your needs.

Paul P

[Steve Conner]

Yeah, that looks like an amp, maybe 20, 30 watts. The only thing I can see wrong is that a tube is missing, probably the rectifier. Maybe someone has already converted it for you. ;)

[Regis]

Yeah, looks like an old organ or pa amp, if it were a radio there would be a variable cap in there somewhere and a dial maybe. A schematic would help.

[Paulinc]

Well as it turns out, the iron I got my hands on is in fact an amp. The guy I got from on Craigslist didn't know anything about it. After some long searching I found out it is a 1950's Motorola HS 475 tube amp. I guess it came out of an old record player of some sort. Anyway, it has 2 6V6's and two 12AX7's in it right now, two of the tubes are missing as you can see, I found a schematic for it but forgot to bookmark the site so I am at a loss right now. I plugged it in and the tubes lit up so that is a good sign. I am going to be working with someone who has some experience with this sort of stuff, so I think this will be a fun summer project.

I just found the schematic-http://techpreservation.dyndns.org/schematics/56/56_Motorola_HS475_62.djvu