Radio conversion to guitar Amp (help?)

[Mor Paul]

So, my grandfather's house was recently sold. As he was a dabbler in all sorts of stuff when he was alive, there was a lot of electronics in his shed.
Not too much of it was of any use for me, but there were 2 radios. Since one looks 50's ish, my mom wants it kept together.  The other one, however, is fair game. From what I found online, it is 1975 or earlier I think.
Since I needed an guitar amp, I thought it could be converted. And ideas of what to do? (fingers crossed for just throwing a 1/4" jack in there")

Here's a schematic. Links to a larger version.

 

[line6man]

i dont see any schematic...

its been a while since i have done electronics work (i used to make my own stompboxes before i converted fully to line6 gear).
but i think the first thing to do is to find where the input of the power amp is, and then you could try to feed your guitar to that and see what happens.

is this a solid state radio, or is it vacuum tube based?

but may i ask:
why would you want to use an old radio as a guitar amp??? ??? ???
i can almost guarantee that your guitar will sound like shit thru an old radio, LOL

 

[Mor Paul]

To have an amp Also to dabble.
Save some money.

(I reuploaded the image. Something went funny and messed up earlier. I previewed before I posted and it was fine.  :tard

 

[line6man]

ok, first of,

preceed at your own risk....
if something goes terribly wrong, i dont want to be liable for it.
this is all just suggestions...

try this:

pick up a cheap little dollar store radio or something to give you an audio output.
theres the chance that you could fry your guitar pickups if you mess up (or if i messed up by reccomending something)
so its best to use something you dont care about.

feed the output into the volume pot.
i dont know which side is the input and which is the output, so try them both.
KEEP THE VOLUME LOW on the radio you are plugging in to simulate the guitar.
if you hit the output side, its going to be full blast...
once you know which side is the input (the one where the volume pot functions properly) and you know it works ok, disconnect the radio part of the radio so that its just a power amp.
that **should** be it...


edit:
i marked off the 2 terminals to play with so you would know where to look, but i cant upload the file.
i emailed the file to you instead.

its the green and blue terminals.

edit:
it looks like the power switch is attached to the volume pot...
so be careful not to mess with that.

 

[Mor Paul]

mariogamer99@gmail.com

Don't worry, I've got 2 parents who are experienced with electronics.

 

[OzziePete]

Max,
I will gladly avoid any sort of suggestions to change this or that, as I am not an expert at any of this (and can barely read a schematic).

But one of the few things I have learned about adapting a standard hi fi or consumer type of amplifier to guitar use, is the problems of the pickups being one type of impedance and the usual electronics used for radios, stereo hi fis etc. are another. So usually the first thing that has to be addressed is the signal input - and changed over to match the guitar's type of impedance (I think guitar pickups have a high impedance, whereas the usual radio, hi fis, etc. are low impedance).

I had some friends who thought it great to use a hi fi stereo in the 70s when we were all starting out playing guitar, and everyone I knew that went that way instead of buying a small practice guitar amp, blew their parents' hi fi amp! From what I can also remember, my friends had very clean guitar sounds but when they pushed for volume, the type of distortion they got was not at all pleasant.

Just my 2c worth....

 

[Mor Paul]

I'm sure this has been asked before, but what's a loud, clean, cheap amp? (good, too)

 

[jackthehack]

Define "cheap"?

 

[Mor Paul]

Probably ~350 and below.

 

[DocNrock]

PM CB B4 you shock the s... out of yourself!

 

[Mor Paul]

I'm starting to think this probably won't be worth it. I can buy an amp with my birthday money in december, but will have to wait for the rest of the rig.

 

[line6man]

Max,
I will gladly avoid any sort of suggestions to change this or that, as I am not an expert at any of this (and can barely read a schematic).

But one of the few things I have learned about adapting a standard hi fi or consumer type of amplifier to guitar use, is the problems of the pickups being one type of impedance and the usual electronics used for radios, stereo hi fis etc. are another. So usually the first thing that has to be addressed is the signal input - and changed over to match the guitar's type of impedance (I think guitar pickups have a high impedance, whereas the usual radio, hi fis, etc. are low impedance).

I had some friends who thought it great to use a hi fi stereo in the 70s when we were all starting out playing guitar, and everyone I knew that went that way instead of buying a small practice guitar amp, blew their parents' hi fi amp! From what I can also remember, my friends had very clean guitar sounds but when they pushed for volume, the type of distortion they got was not at all pleasant.

Just my 2c worth....

yep, you gotta take that into account too.

"PM CB B4 you shock the s... out of yourself!"
where is that point?
either way, i agree... tubes run at very high voltage.

 

[line6man]

I'm sure this has been asked before, but what's a loud, clean, cheap amp? (good, too)

buy a line6 amp!
they make the best in the world (modeling gear) in my book. and thats why i am a diehard user.
you could get a spider 3 for a decent price, although if it were me buying a cheap amp, i would look for a used flextone 2 combo.
with a flex 2 you get alot of better feautures IMO.
MIDI I/O, effects loop, AIR direct outs, better control over effects. etc...

 

[jackthehack]

Forget that solid state junk; if you're building a "Micawber" and have $350 for budget, start looking for a usd Fender Blues Jr, tube amp

 

[jimh]

Forget that solid state junk; if you're building a "Micawber" and have $350 for budget, start looking for a usd Fender Blues Jr, tube amp

+1.  Definitely

 

[Mor Paul]

Thanks Jack and Jim. I actually emailed someone about one yesterday afternoon, but it was sold.

 

[jackthehack]

Just saw this on Musiciansfriend.com; I imagine they are trying to blow out remaining inventory before the Blackheart 15 watt heads/combo arrive; circuit design is very similar to the Fender Blues Jr. Hope you have the money to order it now, as at the blowout 1/2 regular price of $149 they should disappear pretty quick. Think these come with a real cheap set of Chinese tubes, but still sound decent and you can always upgrade the tubes later to something nicer for around $50-55

http://guitars.musiciansfriend.com/product/Crate-V-Series-V18112-18W-1x12-Tube-Guitar-Combo-Amp?sku=487051

 

[stubhead]

"Roadworthy construction, modern features and genuine value are causing legendary players and novices alike to develop a thermionic love-Jones for the Crate V-Series tube amplifiers."

A thermionic love-Jones? Shouldn't "love" be capitalized? :dontknow:


(Which "legendary" players?)

 

[DocNrock]

I think CB put on another thread to forget using radios for amps; bad for the shock factor.

 

[Patrick from Davis]

CB did note that about the particular radio in question in that thread.  The tube based set up for building a cheap amp is a record player due to the similarity in design.  I would suggest rebuilding the tube based radios for the knowledge and you can probably get more on eBay for a nice tube radio that works.  There is quite an underground for that.  But as noted before, anything with a tube has the potential (hah!) to shock you out of the living world.  It is not a point that is arguable, it should be just taken as fact and that is that.  You can safely play with it, but you need to get some education about what to do to work safely.  My suggestion would be to ask CB nicely.  He knows more than the rest of us combined about tube amps.  Good luck
Patrick