New, (to me) tube amps!

outlawmws

On the Run
Well, I’ve been busy. I’ve picked up 3 tube amps in the past 2-3 weeks. :banana:

One from Grumpy, a late 50’s Motorola Golden Voice console amp. 6V6’s as outputs, so it’s what? About 20 watts? Picked it up on a whim to play with, without any specific plans, just to twiddle with. :thmbsp:

Thinking if I can get a second, I can go stereo, but if not, maybe a mandolin amp? I’d need pickups, my mandy is acoustic… Been cleaning it up, trying to figure what all the wires go to, and found and ordered a schematic for it. Also picked up some aluminum knobs with flanges for the pots at a local electronics surplus house. Already looking better! :yes:

Front view:
 
The second is a Dynaco ST70 from CarlV. He’s local so I was able to visit and see his awesome Mac collection! Cool stuff! It’s a nice early one and hasn’t been messed up. I’ll need to do caps at least though. Sounds great, but nothing to drive it with but SS, so I went looking for a Preamp.

I wound up with another Motorola that is stereo, has a preamp, + amp and reverb unit. 4 EL87’s with 12ax7a’s in the preamp. I’m guessing this was also from a console, it has inputs for a radio and phono. And it also has a center Base driver, which I thought was sort of funny. Sort of an early HT concept. A center “sub” from the mid 60’s I’m guessing. Anyone have any thing resembling information on this one? The chassis looks to be gold iridite, but hard to tell exactly.

It’s been used some and had a small toggle installed to turn it on and off. It also has a couple of tube diagrams that are the size of large postage stamps.

I am inquiring about a Schematic for it now.

On a side note, I think I figured out Motorola’s date code on these amps.

Just below the chassis model no (i.e. HS-966a) which is ink stamped, is another number. Looks like this: 9M61. the M is the Motorola logo “M”.

I’m pretty sure that translates to the 9th month of 1961…

Top view:
 
Nothing specific to help, but in the 60's my dad had a tube stereo he cherished. It had the center bass driving a massive old 12" built into the corner, with two smaller wing speakers. Separate chassis for preamp and power amp. Didn't have the vibrasonic control and was a smaller chassis than yours but much larger transformers. I don't recall brand or anything else. It sure sounded better than the toy stereos I'd managed to concoct, when I was home alone I'd play my Beatles albums on it. He had worked for Motorola in the years just prior. I believe I still have the woofer. The amp was all built-in so he may have left it when we sold the house and moved. He was using a much smaller ss rig in the new place. I'd love to run across something similar to that old tri-amp, just for the memories.

It was great to read about another three-channel setup and see the pics! Thanks!
-Ed
 
heathkit tv said:
Oooooo, VIBRASONIC! WTF is that? Some sort of reverb?

Anthony

:yes: I believe so, the vibrasonic box had a pair of springs as far as I could see in the Epay pics. It wasn't in the box when shipped and I dont think it was removed along the way, that box was glued AND taped shut! dynamite pack job. :yes:

I have Emailed the seller and am awaiting his reply. I'm not really expecting an immeadiate reply since he could be traveling for the holidays. :scratch2:
 
The 6V6 amplifier would make for a choice guitar amp!!! Nice little collection.
 
Sure sounds like a reverb unit....the spring design is pretty much classic. I had on of those Pioneer jobs from the early 70's with the green rectangular dial on the faceplate. I could play the top of the unit like a bongo to get "interesting" sound effects!

Anthony
 
There is a Sam's on this... 490-10. Kind of hard to find because it is listed under Quasar, though it is labelled Motorola.
 
I bought a Motorola Console stereo with the same amplifier,(I think?) from a Estate sale.

The chassis appears to be the same. It was a left and right single-ended EL-84 with EL-84 PP in mono for the 3rd bass channel on one chassis.
12AX7 drivers.
It ran a big 15" inch Jensen "Designer Series", with the smallest magnet I've seen on a 15" woofer. It was in the center of the console, with little 8 inch wizzer cones on the sides (or front?). The little 8 inchers don't sound too ragged...."Golden Voice".. or something.
It had a pre-amp for phono, with a input for tape, 12AX7 with 12AT7 I think.

I noticed a line cord attached to the woofer output transformer when I bought it. The woofer had a open voice coil, so I wouldn't doubt it the OPT is fried as well.
Dunno how worthwhile the little single-ended output transformers would be.

That damn power supply transformer is a monster. Between that, and a reasonable strong quad of Motorola "Golden Voice" EL-84's(Philips?), I guess I got my 20 bucks worth.
 
I have one too but have never used it. My guess is that you won't get much if anything under 100Hz out of the SE OPTs, but the mids on full range drivers ought to be very good.
The drivers Jensen built for console manufacturers had such little alnico slugs it is hard to imagine the size of the voice coils. I just put them on the curb when I get any. I bet they don't last long when hooked up to some kids' amp, but just maybe someone gets them that has low powered gear. I just can't consign old drivers to the landfill myself.
 
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