Anybody know tube radios?

Discussion in 'Amp Tech Center' started by timfred, Nov 9, 2019 at 1:09 AM.

  1. timfred

    timfred TDPRI Member

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    So I picked up this late 50's RCA 6-RF-9 at an estate sale for the princely sum of $27:

    [​IMG]

    Mahogany cab, AM/FM/Phono, 8" speaker, 5Y3, 6AV6, and an original black plate RCA 6V6 (plus a bunch of radio tubes and stuff). I recapped it, replaced the 6AV6 with a 12AX7, reworked the amp circuit (more like a 5F2), swapped out the RCA phono jack for a 1/4" jack, and now I have an AM/FM/Guitar amp. I added an SS rectifier to bring up the B+ voltage. Sounds great now, and I have a Weber speaker on the way so it should sound even better soon. AM/FM reception is OK, I'll try to align it at some point.

    So one thing I didn't change yet is the AC power setup. 2-wire, no fuse, LC filters on both legs with the "C"s being "death caps" to chassis. Plus, one leg of the AC is connected to a wire and antenna terminal on the back of the chassis and the power cord is used as a radio antenna.

    Does anybody have suggestions on what to do with the power? I assume the LC filters are to cut any RF from the mains supply. How important are they?

    If I add a grounded power cord, any issues with the antenna setup? (which seems super unsafe anyway to have exposed AC on the back of the chassis right by the guitar input jack).

    What about the heater wiring, which uses the chassis as one leg of the AC? OK to ground the chassis?

    Thanks in advance!
     
  2. Dacious

    Dacious Poster Extraordinaire

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    No problem. SF Champs have one leg earthed through chassis, I've had two and dead quiet.

    Ditto earth lead to chassis bolt. Remove death cap. It's worth adding a tag strip and fuse holder if you can jam one in. A 3AG fuse neatly attaches to a 3 hole tag.
     
    timfred likes this.
  3. Tonetele

    Tonetele Poster Extraordinaire

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    We had an old Philips radio that had those original parts in it.
    My Mum bought it off a guy who needed a lady friend for the night. She got it for 10 pounds .
    We didn't even have a black and white TV til I was eleven years old ( 1967).
    That's where i heard Roy Orbison, Dusty Springfield, Elvis, then the Beatles and Rolling Stones.

    Now you can brag you have really true vintage amp. Cool!:)
     
    timfred likes this.
  4. stevemc

    stevemc Tele-Holic

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    i have 3 old table radios.one each from the 40's 50's and 60's.the oldest is really cool.have seen it on ebay sold for $500.i'll keep them though.i have enough amps though i get the appeal of conversion.
     
  5. printer2

    printer2 Poster Extraordinaire

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    I converted an old radio cabinet but did not keep much other than the wood and I rearranged the baffle area.

    [​IMG]

    Here is the schematic of the RCA set for anyone interested.

    http://www.nostalgiaair.org/pagesbymodel/897/M0014897.pdf

    The antenna is hooked up to the line through the cap to keep the 110V 60 Hz out of the input. If it were me I use an external FM rabbit ears if I wanted to use it. I would not have the capacitor on the line if you are using it for guitar. Otherwise ground the chassis with a three prong cord.
     
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  6. timfred

    timfred TDPRI Member

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    Thanks all. I cleaned up the AC power section today: grounded cord, deleted the caps and antenna connection, added a fuse. Didn't notice any difference in radio or amp performance, except FM, which now needs an antenna to get any station at all.

    Jammed with a buddy and it held its own against his early 60s Gibson GA-5.
     
  7. Milspec

    Milspec Friend of Leo's

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    I only restore the Trans-Oceanics....got nothing for the kind of readios you are working with. The beauty of the Trans-Oceanics is that most of the trouble lies in the AC power section, but you can run them off batteries and bypass most of it that way.
     
    bender66 likes this.
  8. Tonetele

    Tonetele Poster Extraordinaire

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    Bill May of Maton guitars, probably the best Australian guitars ( Tommy Emmanuel's personal favourites) started making amps back in the late forties.
    Some discernung musicians, James Black, a great multi - instrumentalist plays an old Maton amp and a Fernandez Lawsuit Telecaster given to him by that firm when he was working in Japan. He's toured and played with many bands and is the keyboard and/or guitarist you hear, but never hear about. His old Bill May amp is about thirty watts ( RMS) and tweed like an old Fender. Sounds great.
     
  9. tubelectron

    tubelectron Tele-Holic

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    Yes, me... ;)

    In the past I had a little European-made collection of what you call "Cathedral" or "Tombstone" radios from the 30s : Minerva, Grammont, Gody, Pathé, Malony, Ergos, Ducretet, Record... Today I still keep my 1957 Blaupunkt Milano :

    [​IMG]

    And I recently restored a 1959 Blaupunkt Riviera for a friend :

    [​IMG]

    -tbln
     
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  10. bender66

    bender66 Poster Extraordinaire Silver Supporter

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    Picked up 4 tube radios this Spring, 1 a big upright and another a Trans Oceanic. They're all in great working shape too.
    20190609_140154.jpg
     
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  11. printer2

    printer2 Poster Extraordinaire

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    Just as information, the above amp I built did not have a viable grill cloth. I went to the dollar store and got a place mat that had a weave pattern and antiqued it with some dye, the original color is the light colored splotches. I have used these place mats for a number of amps.
     
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  12. Milspec

    Milspec Friend of Leo's

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    Excellent finds. Here outside of Omaha I can pull stations from Canada and Mexico on my Trans-Oceanic with the factory antenna. Not bad for 1949.
     
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  13. drail

    drail Tele-Meister

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    Years ago( 40 years) I bought some land from a old gent that worked on tube radios and tvs, I remember going in his shop and seeing all these tube radios and tvs that he was working on. Later getting into guitars and amps I thought that he could have worked on tube amps also, he did give my dad a old tube radio. Great memories from another era.
     
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