old console radio as guitar amp

[ghola]

I just bought 3 old console radios. I have not plugged them in. I would like to try running a guitar thru them, either as a practice amp or direct out (one of them has 2 1/4inch jacks labeled "stereo out", one on each side) They are a Philco 51-1733, Motorola 7F-11, and Bradford SL-480(8?). Bradford has output jacks. Motorola says "35 watts". Would phono pre amps in each be enuf for guitar? Im not looking for high volume, or pristine sound.

[SHiFTY]

You can certainly do this, I have and it can give cool tone! However make sure you don't destroy a nice old radio. BTW the 35W is the power input, it is most likely to be 5-10 watts output.

What you want is a microphone or turntable (phonogram) input, that will probably give enough amplification. A mono unit would be fine, stereo amps will probably leave one channel unused, and could be better used for hi-fi. Post some pics of the amplifier units and we can give you more advice on what to do. You might need to change some of the caps and so on, especially if you get a loud humming noise.

One thing to make sure is that the unit has a power transformer. If it does not, I would not recommend using it, as the chassis and your guitar might end up at mains voltage.

But yeah, you could eventually use the parts to build yourself something like an AX84... www.ax84.com

And also some of those old consoles had great sounding speakers in them!

[Sherman]

As shifty said you will need a preamp to boost the guitar signal if the only input to the amp was a tuner.

I've converted a couple of old tube record players to guitar amps by just putting in a 1/4" inch jack input into the phono section. It works great. The speakers in one of the consoles were shot (as was the case itself) but in the other the speakers were in fine condition and I used them in the new case I built. Very cool tone.

Also, I built a modified AX84 amp (I used the input section and tone stack from the 'Extreme' model on the same website with the EL84 output section of the AX84. Definitely a fun project and lots of control over tone and distortion and plenty loud through a 4x12 cab.

[ghola]

Try this link to see pics:

http://photos.yahoo.com/timington

Should I use a variac to power these up?

Would a simple 1/4" to phono input cable splice do the trick?

[tubelab.com]

My first guitar amp was an old Magnavox HiFi (mono) set. This was in about 1965. My parents upgraded to stereo and I inherited the Magnavox. At first I tried just splicing the guitar cord up to the wires that connected the turntable to the amp. (Hey I was 13 years old). I got sound, but not very loud. It took me about a year (forever to an impatient kid) but I got this ham radio guy to help me build a preamp. Now I could rock. I beat this old amp for about 3 years and all I could blow up was speakers. It was pretty easy to find another old dead HiFi to steal the speaker out of. I finally convinced my parents to buy me a real amp and the Magnavox went in the trash.

From the pictures The Motorola looks like it may have two 6V6 tubes in it. If this is the case try this one first. 6V6's work great for guitar. It also has a big power transformer. This is also a plus.

You can try to make an adapter cable like you describe, but you might not have enough gain. Most old consoles had a ceramic phono cartridge that put out far more signal that a guitar does. If your console has a magnetic cartridge then you will have too much gain.

If you fall short on gain, you will need to build a guitar preamp. Schematics for these can be found on the web in tube, solid state, or op-amp flavors.

[SHiFTY]

The Bradford is a stereo unit - ELL80 is a double power tube. You could use this to make yourself a little hi-fi amp. Actually you might just be able to plug in a CD player.

I like the look of the motorola. Rip the thing out and build yourself a guitar amp on the chassis. Make sure you keep the speaker and speaker transformers.

They all look new enough to power up gradually, IMHO. If they hum loudly or don't go, then turn them off!

[ghola]

Well, I powered them up. Bradford works fine except for FM Stereo- there is no sound on this setting. Philco makes almost no sound, but lites up. Motorola just hums, turntable seems to want to go, but is locked in place. I unplugged these 2 fairly quickly. Oh well, what can I expect for 40 bucks? At least one works. I dont have a tube tester so I cant check tubes, except visually.

[karma]

tubes and caps

nice find i love to rebuild stuff like that. my saba radio was like that now it works as good as any solid state radio i have.


cheers

[ghola]

Thanks guys for your suggestions. I am not a tech, however. Is this Moto rebuild a complicated/ expensive project? Is it a feasible one to bring somewhere for labor? I live in central Maine, Waterville area, and dont know any places that could do this. Since I wouldnt need the tuner section, I suppose I could just pull out chassis in order to have serviced.