Old radio to a tube amp

[vendettav]

I know I know, there's been tons of these threads I guess.

I recently came up with this radio from 50s. HUGE ASS radio and I'm guessing it's a tube radio. made in USSR, Baltika brand. I guess.

The thing is, it's quite hard for me to get to it, so if it's not worth it I might as well save the effort.

So do you think I can get it to work? As a tube amp? Reference, links, advices and thoughts would be awesome!

[reverberation66]

sure you can get it to work as a tube amp.  How difficult this will be would be based on the design and condition, without knowing either of these things it's hard to say what would be involved.  might take a lot of work, might not...does it have phono inputs?

[teemuk]

I know I know, there's been tons of these threads I guess.

Yes, there have.

You should try searching and reading them, you know.

In summary: With a good chance there are various reasons why it's more worthwhile to renovate yourself a nice vintage radio and use other means to build a guitar amp.

Such reasons include, for example:
- About 90% of the circuitry is for tuning purposes, entirely useless for generic audio and is basically something to toss away completely
- Proper safety standards are not likely met (e.g. power transformer typically missing)
- The audio circuitry is often subpar and very low power. Adequate for tabletop radio, leaving a lot to desire for musical instrument amp
- Circuit architecture wise there may be very strange design choices, which may be very dumbfounding and poor for an amplifier that is likely meant to be overdriven. e.g. Expect to find numerous "odd" tubes and very non-guitar-ampish feedback and biasing schemes.
- The old chassis is most likely way harder to work on and to populate with all neccessary parts than an entirely new "empty" chassis or a chassis cannibalised from a dedicated guitar amp.

[maartendh]

I agree with teemuk, it will be a lot of work. You can use the trannies, the power tube and probably some pre-amp tube and start building a simple SE amp on a new frame. Or you can do what we did back in the early sixties; just plug your guitar into the pick up input channel (usually there was one) and rock away.  Speakers of these old radios were not hifi by our standards, but then again they were very suitable as (low wattage) guitar speakers as they can deal very well with the extremities of an amplified guitar signal.

Have fun,
Maarten

[jbgron]

There's a guy close to me who specializes in converting old radios into usable tube amps.  I've never actually heard one but they look cool.

http://www.valvechild.com/Guitar_Amps.html

[Canucker]

"huge ass" is always the problem...if its something small you can always use it for the casing of a head that will have people drooling madly over it. Why did everything look so cool back in the day and now its all ugly and boring? I guess everything now is flat and boring for the sake of packing for shipping.

[greaser_au]

Please, do not wreck for parts - these old things are rare & getting rarer.   Repair/renovate  (if you have the skills) and sell to a collector.  Use the proceeds to buy parts to build with.

david

[Paul Marossy]

Please, do not wreck for parts - these old things are rare & getting rarer.   Repair/renovate  (if you have the skills) and sell to a collector.  Use the proceeds to buy parts to build with.

david

+1

[amptramp]

My daughter's favourite guitar amp is a 1938 Universal Radio 6103-E Minerva which was built with a 1/4" phono jack.  Just plug and play.  It has a 6C5 driving push-pull 6F6's and man, that 11 watt output is LOUD from the 12" electrodynamic speaker.  Everyone who has played it has marvelled at how good it is.  It uses a push-pull driver transformer capacitively coupled to keep DC off the primary.  When the phono plug is inserted, a set of contacts opens the screen circuit to the RF, mixer and IF stages so there is no radio noise.  It was originally sold by Eatons, a now-defunct Canadian department store.

[PRR]

The thing you need to know: does it have a Power Transformer?

Transformerless tube radios were common in the USA and I have seen it in European designs.

Playing guitar without a power transformer is the same as sticking your finger in the wall-outlet. It's OK on dry wood floor, potentially lethal on concrete or near a pipe or radiator.

*With power transformer*, snip the lead to the top of the Volume pot, add jack there. You will probably want a clean booster in front. This is easily un-done.

If the radio has NO value, you can re-assign the IF stage to be a first audio stage.

[PRR]

> I'm guessing it's a tube radio. made in USSR, Baltika brand.

"Baltika" brand radios were made 1950-1954, and also 1990s. The '90s job is a commercial communications rig weighing 200+ pounds.

The 1950s jobs are all the same chassis, in two different case sizes, and probably variant trim.

These ARE transformer power. Nominally safe to touch the chassis. (Of course insulation breaks-down with age.)

Baltika 52, Baltika 6b8, Baltika M-254, Baltika {Балтика}: 500x360x280mm / 19.7x14.2x11 inch

Baltika RZ-1 (PZ-1), Baltika: 560x360x280mm / 22x14.2x11 inch

Valves / Tubes 7: 6A7 6k3 6h6s 6J8 6e5s 6p6s 5z4s  

6p6s is near-enough a 6V6. (Think "Champ".)

6J8 is not a diode-triode, as in US radios. It is a 6SJ7-like pentode. It just may have enough gain to work e-guitar without a booster.

Feeding-in is too-too-easy. NO hack-work. There is a 2-pin connector, probably on the back. On my data it is called "3B". (Not "A3", not ""BHEWHLp"", pardon my Cyrillic.) Turn the band-selector knob all the way to the 6th position, it inputs from 3B. This is probably a "phono" input, but of a type that will work with e-guitar.