#1
Ok, calling all fellow electronics!

I've found a working 57' german tube radio. (Will post pics soon). And I will be trying to turn it into a practice tube amp (it would be easier to build one from scratch, but seeing as I'm a cheap bastard that has a free toy to tinker with, I'll just mod)

It's been some time since I've last worked with tube-based amplification circuitry, and radioelectronics never were my field of knowledge, plus it's been ****ing years since school, and I had no practice so... I'm pretty much as good as a begginer on this field

Anyone tried that? And if so, were there any problems with the input impedance? I've also been thinking of adding a DPDT, seeing as the whole thing is simply

radio reciever-->poweramp-->speakers
                ^
                 |
                 |
        Existing Line in (possible guitar input, I'll just add another one if anything occurs)


but it plays the radio AND the line in at the same time (what the **** was the point of that? Who wants to listen to their music alng with the radio?).

EDIT: For all of you waiting to see the hollowbody explorer I was building, good news! It's almost done! Pics and new thread coming next week!
Quote by bakk
Hi,
I have been pickin' up some Arabic radio signal things. Every time I turn up my Amp, this crazy Imam starts messing up my chords.



Proud owner of a 1987 Kramer Baretta I w/ spider Guitart.
#2
generally when people convert an old radio they just strip the entire preamp and replace it with a preamp from an amp that has the appropriate tone, so you could simply take a fender preamp and drop it in, there's really not alot to it.
or
you could do it the hard way and try to makeup some new circuitry around the amp you already have, using the existing tubes and whatnot. its not impossible, it just takes alot of work, really, adding an existing preamp to it is the better option, heck, you could even have multiple preamps, like have a marshall channel and a fender channel.
might be worth a shot...
#3
Quote by sempri_fi
generally when people convert an old radio they just strip the entire preamp and replace it with a preamp from an amp that has the appropriate tone, so you could simply take a fender preamp and drop it in, there's really not alot to it.
or
you could do it the hard way and try to makeup some new circuitry around the amp you already have, using the existing tubes and whatnot. its not impossible, it just takes alot of work, really, adding an existing preamp to it is the better option, heck, you could even have multiple preamps, like have a marshall channel and a fender channel.
might be worth a shot...


Hmm... that's some thinking you got me into. Guess I'll just try to find a way around it, seeing as It's gonna have to be a poor man's amp. A fender preamp would just cost me a whole heck of a lot. Maybe some cheapo no-name tube studio preamp... We'll se, we'll see... The funny thing in Poland is, that buying an existing no-name chepo preamp is a whole lot cheaper than constructing it yourself... But maybe... I'd be grateful, if you'd point me in a direction of some simple (the simpler the cheaper) fender-style preamp schematic.

EDIT:

Now that I think about it, I may be really shooting for a tinny low-fi sound...
Could be interesting. I dont really need another hi-quality amp. I've already got a JCM800, so...

Anyway, schematics would be nice.

EDIT 2:
Hmm... More thoughts:

Maybe I could use the stock preamp as another channel option. Like have a JCM800 style preamp, Bassman style preamp and the stock "lo-fi" style preamp... could be cool.
Quote by bakk
Hi,
I have been pickin' up some Arabic radio signal things. Every time I turn up my Amp, this crazy Imam starts messing up my chords.



Proud owner of a 1987 Kramer Baretta I w/ spider Guitart.
Last edited by binjajer at Jun 19, 2007,
#4
yea, i hear ya

here's a bassman schematic, it has 2 tubes in it if you dont count the phase inverter http://www.drtube.com/schematics/fender/bassman-5f6-a-schematic.gif
and here's a champ schematic, really simple, i tube pre, but it doesnt have a phase inverter http://www.drtube.com/schematics/fender/champ-5c1-schem.gif

you might be able to keep the phase inverter that you have on the amp already, that'd save you a tube and thus money...
#5
You must be reading my mind. Thanks, man. I'll post in a week or so and post some pics and sound clips.
Quote by bakk
Hi,
I have been pickin' up some Arabic radio signal things. Every time I turn up my Amp, this crazy Imam starts messing up my chords.



Proud owner of a 1987 Kramer Baretta I w/ spider Guitart.
#7
dont replace the preamp! i played a hollow body through a ghetto blaster and it was great!
Member #5 of the UG Luthier's club.
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Quote by carousel182
i im gonna have to agree with t heff
#8
Quote by t heff
dont replace the preamp! i played a hollow body through a ghetto blaster and it was great!


Well, I've read somewhere that Brian May used to play through an old radio...
We'll see, when I'll finally have the radio in my hands.
Quote by bakk
Hi,
I have been pickin' up some Arabic radio signal things. Every time I turn up my Amp, this crazy Imam starts messing up my chords.



Proud owner of a 1987 Kramer Baretta I w/ spider Guitart.