Tube Amp - Capacitor Cross Reference?

[jpatti75]

By the way, here are some pictures of the unit, just to show you all what I’m dealing with (legs removed for transport). It’s a basic model, without an upgraded Drexel cabinet. I’m going to overhaul the cabinet (refinish, new speaker grill cloth) once I confirm I can get all the components functioning. I know it’s nothing necessarily special, but I like the styling and am always up for a new restoration project (my hobbies are all over the map). The tuner has a “Magic Eye” to help tune in a station...pretty cool feature. I don’t have a photo of the record changer, but it is a standard Voice of Music stereo model that Motorola used during this period. I believe it needs the full degreasing job they usually need to function. It’s as stiff as a dead carp right now.

 

[gadget73]

changers are usually well seized. Not terribly hard to service, just kind of messy and tedious. Does it have the gold shift lever setup or is it the regular rotating knob type controls?

 

[jpatti75]

It’s got the regular rotating knobs. I just watched a great video series on YouTube where a guy completely breaks down, cleans, and relubes these old VM changers. You’re right...looks tedious, but I don’t shy away from a good degreasing job. Something fulfilling about it when it’s done (assuming it works).

Part of me wants to upgrade the player to something newer that would also track a bit lighter, but I’m not sure of any limitations I might run into with the amp and or pre-amp in updating it a little.

 

[Tom Bavis]

The tuner may be HS-783, used in a number of Moto consoles. I'd offer a scan but my Sams files are 600 miles away at the moment. Fortunately, it's on Radiomuseum: https://www.radiomuseum.org/r/motorola_hk_42_ch_hs_783b.html

 

[gadget73]

not sure what that one tracks at, but its probably not awful. Original cart would be ceramic, so you'd need a phono preamp to use something with a mag cart. Not a big deal, it could sit between a different turntable and the original inputs. Did that with mine for similar reasons. I still run a record changer, just a slightly newer/better one.

 

[jpatti75]

The tuner may be HS-783, used in a number of Moto consoles. I'd offer a scan but my Sams files are 600 miles away at the moment. Fortunately, it's on Radiomuseum: https://www.radiomuseum.org/r/motorola_hk_42_ch_hs_783b.html

Thanks for sending the resource, Tom. There are two markings on the tuner chassis. There is one stamped on the body that says HS-1013A, and then on the side of the tuner there is a Motorola paper label that says HK-45-2. I’ll do some digging on the Radio Museum site.

 

[jpatti75]

Thanks for sending the resource, Tom. There are two markings on the tuner chassis. There is one stamped on the body that says HS-1013A, and then on the side of the tuner there is a Motorola paper label that says HK-45-2. I’ll do some digging on the Radio Museum site.

Here she is....https://www.radiomuseum.org/r/motorola_hk45hk_4_ch_hs_822hs82.html?language_id=2

 

[Tom Bavis]

HS-1013 tuner is covered in Sams folder 615-2B. But the one linked may be close enough.

 

[jpatti75]

Just waiting on parts now. I’ll let you all know how it goes. Thanks for all of the help!

 

[jpatti75]

not sure what that one tracks at, but its probably not awful. Original cart would be ceramic, so you'd need a phono preamp to use something with a mag cart. Not a big deal, it could sit between a different turntable and the original inputs. Did that with mine for similar reasons. I still run a record changer, just a slightly newer/better one.

While I’m waiting on amp/pre-amp parts, I’ve been thinking about the the record changer and the possibility of changing it out for something a little newer with a counterweight on the tone arm and anti-skate. While I haven’t made up my mind, if I do go that route, I just want to verify that no additional pre-amp would be required if I stuck with a model that has a ceramic cartridge?

Any recommendations on a “newer” player to consider are certainly appreciated. Doesn’t necessarily need to be a changer, but I am restricted on the dimensions to fit it in the cabinet so a more square base like the VM changers would be needed. Seems like there are a lot of Garrards out there that might fit the bill.

 

[gadget73]

right, ceramic would feed straight in, just the problem is they generally just don't sound as good or track as light as a mag cart does. The preamp doesn't have to be anything fancy. Mine is an old Radio Shack model that used to be everywhere for 20 bucks. Changer plugs into that, output from the RS preamp into the original phono inputs.

Smallest relatively high end turntable I can think of is something like a Technics SL5. Its a linear tracker basically the same dimensions as an LP sleeve. Dirt simple close and play operation, they sound good, and often just need a new belt for the arm drive mechanism. Not going to find that with a ceramic cart tho.

VM1200 series is probably what you have now, they're all effectively identical other than the color scheme. Zenith models had a better arm that tracked at 2 grams with a specific and actually quite good sounding ceramic cartridge. Garrard AT6 family is also small. My console has an AT6 with a Stanton DJ cart. Lots of models in that family, but the AT6, AT60, and SL65 are the top of the range. Others have lesser arms and/or lesser motors. Not sure the dimensions on the Dual 10xx series but that might be an option. Basically every record changer has the same mechanical problems with stuck grease and dead oil though.

 

[jpatti75]

You’re dead on, Gadget73. It’s a VM 1242. There is a Pfanstiehl cartridge available that tracks between 4-8 grams. The original cartridge was rated for 3-5 grams, but the one currently in the arm is toast. I was actually looking at a Garrard AT6 and a Dual 1019, and they both appear as though they would fit the space in the cabinet. (Not that it is a big deal, but I think the Garrards used the same wiring harness as my VM1242 to connect to the pre-amp to get power.) The Zenith MicroTouch models seem to be a little harder to come by, but it is good to hear your recommendation, as I have read other positive reviews on them. Funny, I recently saw an old TV ad from when the MicroTouch 2G came out, and they bounced the tone arm on the record to make their light tracking/no-scratch claim. Talk about cringeworthy if you love your vinyl!

I figured I wasn’t going to be able to escape a thorough degreasing job, no matter what I choose. Shucks!

Thanks, again!

 

[Dave451]

I can remember my mom and dad's Zenith console from the 60's with the "Cobra Arm" tone arm--snake head and all!

 

[jpatti75]

Ha! Those Cobramatics are pretty cool looking. My grandparents had a Zenith Allegro console, not nearly as cool looking a turntable (I believe it was a MicroTouch), but we would fire that thing up at Christmas time and it sounded great.

 

[gadget73]

The old Cobramatic was cool looking, but very different from a VM. I think Zenith quit making their own sometime in the late 50s. For a while they had a VM changer with a Cobra-looking arm with the eye dots though. By ~64 or so they were using the Microtouch setup. I have one of their BOTL consoles that I trash picked for someone that has that setup. Honestly sounds better than I would have expected given the low power amp and the dinky speakers. The tuner is excellent too, but I expect that from Zenith. They did know how to build a tuner.

 

[jpatti75]

Thanks to all of the great help here, I’m happy to report my re-cap job was a success today. No more transformer hum, all channels are working, and no static. Can’t thank you guys enough for the help. Next, I’m on to the record changer and cabinet refinish.

I do have one more question. The FM Stereo tuner has a single RCA out to the the pre-amp, but the input on the pre-amp has right and left inputs, as you would expect for stereo. I’m confused by the single RCA output on the tuner. Can I get a splitter cable like the one below to hook it up properly? The unit arrived with just a single RCA cable out to just one channel on the preamp. Currently, with the pre-amp in mono mode I can still balance right to left with monophonic sound, but when I set the pre-amp to stereo, only the channel I connect with the single RCA connection works, which makes sense.

RCA output on the tuner

Input diagram on the pre-amp:

Splitter cable? Or something else?

 

[gadget73]

That would feed to the external multiplexer. One in, two out. Usually has 2 or 3 tubes on it, a couple of cans, and a bit of magic to make it actually function. If this doesn't have one in the cabinet, there should be a selector position for "FM" and a second for FM MPX or FM Stereo. Just use the one that isn't stereo and it should give you mono FM from all speakers. The FM MPX output doesn't filter the 19khz pilot tone or provide the proper de-emphasis the mono connection does. That stuff would have been handled on the multiplexer.

 

[jpatti75]

Thanks, Gadget...the cable explanation makes total sense now that I think it through (I had it bass-akwards). The tuner has three settings, FM, AFC (FM), and AM. On the pre-amp’s balance dial, it is pull for Mono, push in for Stereo. When in Mono mode, all speakers fire like you said, when I put it in stereo (FM or AFC) the left channel (because that it what is connected to the tuner) fires, along with the third channel (woofer) ... nothing from the right. While I know I will get stereo from the record changer, I don’t get how Motorola could advertise this as an FM Stereophonic Tuner, but set-up as it is from the factory, it can only produce mono FM? Perhaps the original owners didn’t pop for the extra multiplexer feature?

I’m probably giving this way too much thought since I doubt I’ll be using this unit to play the radio often, and I can handle mono when I do. But, I am curious if there is an add-on multiplexer I might be able to use with the current set-up. (Yeah, OCD gets the best of me sometimes!)

I was fairly impressed with how everything was working, and the sound was pretty darn decent. I took a video I wanted to share with all of you, but I don’t use any of the permitted media sharing sites to post it to the forum. Sorry!

 

[cademan]

You are not supposed to use that FM stereo output jack connected to the preamp. It goes to an outboard multiplex adapter which was either pirated or the original owner didn't spring for one. My Motorola 3 channel is old enough that it didn't have FM stereo capabilities. It has a mono tuner but stereo turntable. When listening to the radio, I have to select mono on the preamp controls to have sound in all 3 channels.

The tuner should have regular left & right outputs somewhere on it that connect to the radio left & right inputs on the preamp. Using that FM stereo jack to the preamp, you should have no AM so there has to be some other connections. Can we see some good all around pics of the tuner?

With the original Motorola multiplex adapter, the FM stereo jack would go to the multiplexer and then the multiplexer would have a special plug which goes to that FM MON. (monitor) jack while having that jumper removed.

So in other words, and as it stands now, the tuner is mono but it should have other RCA jacks somewhere on it to plug into both the radio L & R inputs on the preamp???

 

[jpatti75]

Thanks, Cademan. Here are some pictures of the tuner. There is the one RCA jack that is marked FM stereo, and then there is that jumper port that has the jumper installed for Mono. No other RCA jacks that I can see? (EDIT- I do get AM with how the tuner and pre-amp are connected now.)

First, here it was it looks like from the front when fully assembled (chassis is a HK-45-2): https://www.radiomuseum.org/r/motorola_hk45hk_4_ch_hs_822hs82.html?language_id=2

Pictures of mine...

Pre-amp