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Sorry,... I lied.... It's a Motorola

ttamd

ttamd

Active Member
The console I bought isn't a Magnavox, It's a Motorola SK100M-1. I know, none of you probably don't know it by that number. But, I have the amp section removed now. The numbers painted on the chasis say;

HS-1136A
1(the motorola logo)63

It's got 35C5 power amp tubes, and three output transformers (the lable show them as "to left channel speaker, to bass channel speaker, to right channel speaker"). Any idea of what I've got?
 
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A shock hazard.

The 35C5 output tubes mean it has no power transformer (the heaters are run in series, directly off the power line). At best, there's a 40-year capacitor separating the chassis from the 120V powerline - as Dirty Harry said, "Do you feel lucky?" Before you plug it in, get an isolation transformer, and it will be safe to run and connect a source. But there's still dangerous voltage inside...

About 2 W/channel, maybe a bit more to the center channel Some of the Motos used a single ended output for each channel, driven out of phase, with a push-pull transformer in series for the bass center channel. 2 output tubes, 3 channels.
 
hey ! you look alot like Linda Rondstadt :stupid:

pretty sure Tom's right . . no power transformer, so more chance of zapping yourself . . . I have a few fo these types of amps waiting for love in my basement . . . did the console have decent speakers ? All the Motorolas I've seen have Jensen speakers - good stuff . . .

in any case, it could be a fun first step into Toob Land :thmbsp:

just wait - in a couple years, you'll have tube consoles stacked like cord wood in your basement (not that I know anyone like that. . .)
 
There's a large black cylinder with a sticker on the top that has the number 154, on the side it has
Motorola
23K647850 F
40 MFD 150 VDC
50 MFD 150 VDC
100 MFD 150 VDC
1013 6252 FP
85 degrees C

I don't see a transformer between the AC cord and anything. The only transformers that I see are the outputs. Is this an OK amp for a noobie to start with?
 
The speakers are "Golden Voice". I thought the furniture part of it was interesting. Its only as tall as a coffee table, with a sliding door over the turntable area, and a space to stand records up through the top of the table. (I think I need to invest in a camera.)
 
IF you take tom's advice and buy a isolation transformer, then yes . . . it's a good place to start. Any tube amp, or SS amp for that matter, has the potential to zap you, and worse, make you dead. If your safe, I think any tube amp is a good place to start.

the pisser is tube stuff is cool, and most of it is about 50 years old. Like a classic car, anything this old will need some TLC. the advantage of your amp is it is a VERY simple circuit, and you can use it to wrap your head around tube circuits in general - pretty soon, you'll be upgrading to SE EL84 amps and PP 6V6 monoblocks if you really dig, you can find these goodies free :smoke:. Trace the circuit; figure out what every component does.

or do what I did:

by a few consoles, fumble around, find a nice, working magnavox 6bq5 amp, recap and have fun listening . . .THEN do the homework :D
 
Thanks to both of you, and don't worry, I'll play it safe. No power until I get the isolation transformer.
 
Motorolas seem to like hot chassis. I had an old Moto tv set, it would zap me pretty bad if I was foolish enough to touch the metal cabinet. Never fooled with it, I was just a dumb kid and it had a picture. Had I known more I probably could have fixed the thing, but at 13 it wasn't on my priority list to refurbish the free tv set.

Those 35c5 tubes aren't real powerhouses either, I think Tom is probably right on this, 2-3 watts per channel. Lots of tabletop radios used a 35c5 output tube, if that gives you any indication of the power level we're talking here. Its a fairly rugged little bugger but its not going to shake the paint off the walls either. In all honesty, you might be best leaving the amp in the original console, probably it would sound best in that environment.
 
Tom Bavis said:
A schematic is online at http://techpreservation.dyndns.org/schematics/Motorola.htm
Click to expand...
Tom,
I took a look at the site you suggested, but they don't show the HS-1136a ( I tried looking for other variations on the chasis number with the same result). I've looked at the HS-1135, but can't seem to get to the HS-1137. The HS-1135 looks close, but it doesn't have the bass channel, and doesn't show a rectifier that is on the HS-1136a. I downloaded and installed the Universal Schematic Locator software, but it doesn't find the HS-1136a either.
I seem to have a model that isn't documented very well. Of course it probably doesn't help that its over 40 years old and may not have been very popular.
 
Thank you Tom, that appears to be the exact circuit. I have aquired a 2 amp power conditioner that has a 120:120 isolation transformer incorporated in it. I'm also going to mount the chasis to a wood base that should be close to how it was mounted in the console.

Thanks to all the others that replied.

Matt
 
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