tune 'em up - old russian radios

[ksl]

hey!
i know, my granny has an old radio like this http://home.onego.ru/~vitalybr/SETS/oct_l.htm

is it possible to use its amplifier and get a good sound from the amp

[Morse]

Hi KSL;

Uhhh, why would you want to trash a beautiful old radio like that for it's amp? It's even got shortwave on it for heaven's sake!! In all honesty, if it were mine, I'd do any required repair and cosmetic work on the radio, then enjoy it for many many years to come. Modern radios (in my honest opinion) are no where near as good in terms of reception quality as the old timers until you get into the really pricey ones (probably has something to do with building the entire radio on a single chip....). Also, they are hideously ugly with their plastic exteriors. Wood looks so very much better!!

If you're looking for a low cost DIY amp, I'd look to piece together something like a 6BQ5/12AX7 SET mated to a set of small, efficient DIY fullrange speakers like the Fostex FE103 (don't know about availability on Fostex's there, but I bet you can find some good fullrangers there that are 'out of fashion' now).

Just my 2 pence worth, but it seems a real shame to gut an old beauty like that!!
Morse

[James D.]

Here is an excellent site with good info on soviet era tubes that are superb for audio:

Klaus english audio site

I'm sure the russian part of the site has more info... if your russian is good - mine's non-existent...

Soviet military components are very popular for building valve amps as they are generally very good value.

Please don't destroy the beautiful radio you have - scratch build your amp - it's more satisfying that way too...

ciao

James

[ksl]

nice link james!!!!!!!!!
i don't want to trash the wooden box, it's just too gorgeous, but the budget is small THE WOODEN BOX STAYS... what's happening inside............ that's the question at the moment

[7N7]

Originally posted by ksl
nice link james!!!!!!!!!
i don't want to trash the wooden box, it's just too gorgeous, but the budget is small THE WOODEN BOX STAYS... what's happening inside............ that's the question at the moment

I'm sure that we are all agreed; that beautiful - indeed magnificent - radio should stay exactly as it is.

Most of us just "breadboard" our prototypes. You could do the same very cheaply.

We then comfort ourselves by saying " Well, it's just temporary"

I am sure you understand......

Looking at the specification, I imagine that the output transformer would probably be unlikely to be of suitable quality for proper music reproduction; since AM radio was bandwidth- limited and the upper frequency was 4.5kHz, there was little point in manufacturers installing de luxe transformers that would not be needed. I daresay that there have been exceptions, but it seems unlikely.

Best of luck

7N7

[Colt45]

according to the schema, the output tube is 6P6S (AKA 6V6) in PP

[bournville]

KSL,

I agree with all the comments urging you not to make fundamental changes to this attractive old radio. Apart from anything else, I'm not sure how you could use the existing parts in it to produce anything more powerful - following the schematic the set is already using the RF amplifier as an AF pre-amp when the radio is switched to gram mode - is gain a problem?