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RCA Vintage Tube Mixer - 4 X 1 Mic preamps

Discussion in 'Preamps / Channel Strips' started by audiokid, Apr 13, 2013.

  1. audiokid

    audiokid Staff

    Look at this gem!


  2. Audiofreek

    Audiofreek Active Member

    I've got an old RCA lathe recording amplifier that looks similar to that,except it has a playback amp in it as well.I'm having it worked over to get it functioning again,as all of the oil filled caps have dried out.
  3. audiokid

    audiokid Staff

    Cool, whats the history on it?
  4. Audiofreek

    Audiofreek Active Member

    I bought it off of ebay a few years ago,non functioning.It powers up,but no audio passes.It's an RCA MI-1109a,very early piece with the large VU meter,and plywood side panels.Can't find a shematic for it. I had Mike's Tech-on-call looking at it,but without a schematic,he found it difficult to trace down the issue/s, so he is going to drop it off at Electron Sound and Percussion Monday.I'll post some pics after I get it back, see if anyone here might know anything about it.I think I might just end up flogging it off to someone with more Vintage RCA tech expertise,so that they can revive it.I'm not interested in shipping it back and forth across the continent to have it repaired.You can drop in there Monday afternoon to have a look, if you're interested.I think I paid a little over $200.00 bucks for it.It looks to use the same transformers and the 6sj7 metal tubes on the input section.
  5. audiokid

    audiokid Staff

    Ya, I did some searching for you and just found "your inquires" on it. Try The Lab
  6. pan60

    pan60 Active Member

  7. Kurt Foster

    Kurt Foster Distinguished Member

    oohhhuuu! kurt likes this.

    they should have painted it a hammertone grey though. the fire engine red is a bit much ....

    there's a bunch of this kind of stuff on eblo ... i mean ebay ... search vintage mixers.

  8. Audiofreek

    Audiofreek Active Member

    Yeah,80 grand for that side car??
    My RCA has the old brown rinkle finish I think,it's beeen a long time since I've seen it,maybe it is grey or black.
  9. Kurt Foster

    Kurt Foster Distinguished Member

    it's down to $69 G's but it's "Beatles" .... (well not really. '72 is post Beatles but it is EMI) yeah he's out of his mind. it will never sell for that much. he's probably trolling for the best possible offer / price he can get. still it's cool.

  10. Audiofreek

    Audiofreek Active Member

    (Dead Link Removed)

    Here's a $20,000.00 project for ya.
  11. audiokid

    audiokid Staff

    hehe, fun to look at but I'll stick with this Neos, and insert some of this LA-2A :) or that fire engine red RCA gem sure is tempting.
  12. audiokid

    audiokid Staff

    I'm thinking of putting a bid in on this. Its got one output . How does this work exactly. Man would I love to have that!

  13. JohnTodd

    JohnTodd Well-Known Member

    I'll stick to Cubase and my plugins, they are the b--- PUT THAT DOWN!!!

    < / Johntodd runs away for his life, dodging an intense battery of gunfire ! >

  14. Kurt Foster

    Kurt Foster Distinguished Member

    ya gots to use whuts ya gots to use .... diddlydoo

    this was (Dead Link Removed)


    more modern .. STEREO but still tubes... good for what Chis is doing.
  15. DonnyThompson

    DonnyThompson Distinguished Member

    LOL... I see we've now reached the gear "p o r n" posts. It was inevitable. LOL

    Some nice pictures though, to be sure.

    Personally I can't see that API selling for 70 large, but anything is possible I suppose, especially if you could target rich collectors - like Neil Young or other analog purists with deep pockets.

    Maybe I'll pull out my Wollensak 2 track R to R with the "cat's eye" VU meter and take some pics. ;)
  16. mberry593

    mberry593 Active Member

    That "API/RCA/Melcor is a RCA BC-100. All BC-100s were custom designs. They did use Melcor opamps with RCA stickers on them. We had one in Control room F at NBC, Washington. It was not well received mainly because it used a fairly awkward pin mix-minus matrix located in back of the operator. That was promptly replaced with an API push button matrix.

    The biggest problem with this was that back in those days ( early 1970s ) we had to take the main output of the console (summed to mono), pad it down to mic level, and send it through a terrible RCA BA-44 because we needed to have +40 (yes, +40 that's not a typo) to feed the output channel switching system.

    The BC-100 didn't last long. It was soon replaced with a beautiful Neve, our third Neve.
  17. Audiofreek

    Audiofreek Active Member

    Here's my project: P1010071.jpg P1010073.jpg anyone ever see one of these before?
    Top left knob is for mic gain, lower left is amplifier volume ,next is a bridge /match switch, fuse ,record/Playback switch.the two 1/4" jacks in the corner are monitor outs.
    The back has a balanced input to T1,there are two more input transformers conected to jacks on the side panel.
    The balanced output comes from that wopper in the middle.No numbers on the outside of any of the input trannies,the OP transformer has a few letters and numbers on the bottom.
  18. Audiofreek

    Audiofreek Active Member

    Here's another ebay special that I picked up. P1010002.jpg P1010003.jpg

    I've got ten of these two channel discrete transistor preamplifiers with UTC 0-16 Iput transformers,their own rack and power supply.
    power supply crapped out,I never got them working.
    Made by WI,or IW(not sure which)Audio,Model AA-613.
    Anyone ever seen these before?
  19. mberry593

    mberry593 Active Member

    I believe those are Ward amps. This is not Ward-Beck.....different company. WMAL used them at their Greentree road plant. I don't know anything about them but here is a lead:

    Call Dave Sproul at WMAL in Washington and ask if he still has any manuals for them. He is a very nice person & I am sure he will help you if he can. Use my name if it helps.

    Good luck!
  20. Audiofreek

    Audiofreek Active Member

    Thanks,I appreciate the help,perhaps they can become somthing other than a 40lb door stop.

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