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1959 Motorola Console, Gauge Wire?

consolrepair

consolrepair

Member
Question for all you vintage tube enthusiasts out there. I have an old 1959 Motorola Console, Model SK32W, with 180 Watts amp. The wires inside are frail and old. I feel they may be contributing to a degradation in quality. I don’t know what gauge they are but they are super thin, so like higher that a 16-guage, maybe 20 gauge or higher. Would my amp and speakers benefit at all by installing 16-gauge wire? Would it blow anything out. I can find out any answers to / answer any questions you have.

Specs:
This model has Qty(1) 15" PM speaker, Qty(2) 8" dual-cone PM speakers and Qty(2) 5.25" PM speakers. Uses Record Changer VM24RC or VM29RC (This has been swapped out with a MicroTouch 2G Record Player). Has separate bass channel that drives the 15" speaker.

Further Notes:
The Motorola Model SK32W is an AC operated 17 Tube AM/FM Console Receiver with a three channel stereo Phono Amplifier and 4 Speed Automatic Record Changer. Uses AM/FM tuner/pre-amp chassis HS-776 and power amp/power supply chassis HS-775. Cabinet is Walnut. AM band tuning range: 540-1600KHz, FM band tuning range: 88 -108MHz.

Amp is HS-775C, 12AA59.

More info: https://www.radiomuseum.org/r/motorola_sk32wsk_32_ch_hs_775_hs.html#a
 
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FYI, 180 watt is not the speaker power but rather the wall current draw. Even the radio museum has it wrong with 80 watts.

Do you have pics of your amp? Two EL84's per channel are good for about 10 - 12 watts per channel. Their bigger amp (don't know the model number off hand) which uses six 6V6GT tubes is only 30 watts.

You can read all about power output tubes and what they put out by looking up the tube data sheets.

The wires are most likely okay as that is what the engineers used and should be fine aside from the outer insulation cracking or breaking up.

Tube amps produce low current so the wire gauge doesn't have to be very thick.
 
Here are pics of the amp:
 

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In general it doesn't really matter, as long as it's not super thin.
I mostly use 16 AWG, sometimes 14, but that's because it's standard size (well, here at least).
Bonus is that nowadays you can get these sizes in nice old vintage looking cloth wire (retro look)

The only thing that it does, is raising the series resistance a teeny bit.
But nothing to be to worried about, unless you run tens of feet of wire.

Beautiful piece of furniture btw!
 
Fair guess 180w is the power consumption. Looks like one of their 3 channel / 4x 6bq5 amps. Probably ~3w L and R and ~12w for the center channel. Might be some other distribution of power but I doubt total is more than about 20w.

The original is probably not thicker than 16awg. Agree its not particularly critical. Use wire that is long enough, I've found that too-short wires really screw up the sound.
 
Very fortuitous this thread came along.

I am planning ("planning" means I'm not accomplishing anything as of right now) a PP 7591 build, and I want to actually buy a set of spools of 600V rated wire for this and future builds, repairs, etc.

I make my own "Vintage" (colorful fabric / heavy gauge) line cords, but I am not interested in vintage look/fabric for internal wiring.

Keep in mind that it has to be "compatible" (as easy to use as possible) with the little holes/slots in 9 pin (noval) socket terminals.

Does that last requirement force me down to 18 or 20 awg?

Comments on Teflon, Silicone, or other insulation? (Assuming all are rated at 600V)

Specific recommendations of products?
 
I've used 18 awg 600v wire from lamp ballasts and its borderline too large. Works on octal, not so great on 9 pins. 20awg is probably what you want.

PVC is the usual, it melts. Teflon doesn't melt but I understand it can be difficult to strip cleanly. Never used it so no experience. Silicone is like test leads. Also can be a little tricky to strip and it tends to be thick but its not too prone to melting. I have used some of that, but the last silicone wire I used was I think 3kv rated for some plate leads on something. It was a scrap salvaged out of a gas heater with a spark igniter. Worked great and it looked nice but really thick insulation. Gross overkill for 500v, but size-wise it fit nicely and the price was right.
 
22 gauge is fine except for long heater supply runs with big power tubes. Good for 7 amps (but one foot run of it would drop 0.24V on a round trip...). I use 24 and 22 gauge even for heaters, but wouldn't make a long daisy chain - voltage would be too low at far end.
 
Thanks for all the replies, I really do appreciate it. Another question, off-topic. I replaced the original turntable with a Microtouch 2G. I BELIEVE it is a MM cartridge, although I'm not sure. I'm going off what the guy who repaired it and installed the needle said, and he said this turntable would have a lower volume output than the original turntable. I assume that is because the original had a ceramic cartridge and this one doesn't. Or vice versa. I'm not sure. All I know is the guy who repaired it said, the needle / turntable had a lower output.

Is there a way I can find out what kind of cartridge is in this and what I need to do to compensate to get the proper sound? I was looking at getting this: (DJ Pre II) to boost the volume, and put it in between the turntable and the preamp inside. But I'm not 100% sure if that's the right way to handle it. Is this something I should get, can anyone provide proper insight on what to do?
 
verify what its got, you're talking the difference from about a half volt vs 5mv or so for a mag cart. if it actually is a mag cart, any phono preamp will get the job done. I have that setup in my own console.
 
Hey don't know how to tell if it's MM, do you? Here is a photo:
 

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consolrepair said:
I replaced the original turntable with a Microtouch 2G. I BELIEVE it is a MM cartridge, although I'm not sure. I'm going off what the guy who repaired it and installed the needle said,

Is there a way I can find out what kind of cartridge is in this
Click to expand...

@consolrepair

With regards to determining if your cart is MM or not I would suggest contacting the guy who installed he should be able to shine some line on the subject

If not there is a dedicated "Turntables" sub forum here at AK where you could create a new thread specific to what you're asking.

https://www.audiokarma.org/forums/index.php?forums/turntables.28/
 
pretty sure thats an original ceramic Microtouch cart. Its a good ceramic, but way too hot to feed into a mag phono stage. Needs to work into a high impedance input though, prob 1-2M.
 
So, I found my answer. The cartridge is a ceramic with a slightly lower output voltage to the original, 0.25v compared to .3v. So I guess not a big difference. One of the other things I was looking at doing, that someone had mentioned, was replacing the "high-end" speaker. It doesn't really get a lot of the high-end as more modern speakers seem to. I was looking to replace the smaller one, which is a 5.25 speaker. The low-end is covered. But I wondered if I could replace that one with a 5.25 KEF Uni-Q driver out of a KEF R300. I can get them for $200 each. Would that work?
 
seems awful expensive given what this is. I sure wouldn't put $400 worth of speakers in a console. If you really want to extend the top end, honestly just adding a small tweeter to the mix might be all it takes. I have a pair of Vifa dome tweeters in a console that do a really nice job and they're around 20 bucks each. A simple crossover wired off the existing L and R speakers to keep the tweeter from trying to go too low would be all you need. Those can be had for not all that much money. Only trick is you'll probably need to make a hole for it in the speaker baffle.

Are the caps in this thing any good? If the stuff in the crossover isn't right or the L&R amp channels are not performing properly it won't do much on the top end. Same issue with bad parts in the preamp around the tone controls.
 
$20 bucks each is also good if you think that will improve the sound. Where can I find said tweeters? I replaced the caps a while ago. I forget to what, but they are brand new as of a year ago. Honestly the thing sounds beastly. It’s an awesome machine. But, like I said, it’s missing a little bit of clarity on the top end. That, and hearing the motor from the turntable are probably the two biggest things hindering the performance.
 
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