Parts Salvage Question

[HJW]

I'm not sure if this is the right forum, so if not, the mods will move it I'm sure.

I bought 2 old consoles at a yard sale yesterday for next to nothing, and I'm wondering what parts it's common to salvage from them. One is a Motorola tuner/turntable and the other is an RCA turntable. Both have tubes.

As far as tubes, here are the labels. Top 2 are the Motorola, third is the RCA(click to zoom)








The Motorola 12AX7 will work in my guitar amp, and I assume the RCA 5AS4A will work as a drop in swap for my Sovtek 5U4G ? (I have not turned either unit on, and I'll have the tubes tested before I put them in my amp)

Besides alnico speakers, what other parts and components are commonly salvaged in these old amps ? Any of the tubes besides the 2 I mentioned ok for guitar amps ? The Motorola is an SK100M-T and the RCA is a Model PM 18.

I'll google the tube #'s myself, but if anyone see's anything at first glance, any info would be appreciated. I don't expect anyone to spend a lot of time looking them up.

The RCA is an older dual chassis point to point, and the Motorola has boards in it.

tia

[HJW]

Also, are the old RCA emblems in demand ? They look pretty cool.

[Prairie Dawg]

I'm not sure if this is the right forum, so if not, the mods will move it I'm sure.

I bought 2 old consoles at a yard sale yesterday for next to nothing, and I'm wondering what parts it's common to salvage from them. One is a Motorola tuner/turntable and the other is an RCA turntable. Both have tubes.

As far as tubes, here are the labels (click to zoom)








The Motorola 12AX7 will work in my guitar amp, and I assume the RCA 5AS4A will work as a drop in swap for my Sovtek 5U4G ? (I have not turned either unit on, and I'll have the tubes tested before I put them in my amp)

Besides alnico speakers, what other parts and components are commonly salvaged in these old amps ? Any of the tubes besides the 2 I mentioned ok for guitar amps ? The Motorola is an SK100M-T and the RCA is a Model PM 18.

I'll google the tube #'s myself, but if anyone see's anything at first glance, any info would be appreciated. I don't expect anyone to spend a lot of time looking them up.

The RCA is an older dual chassis point to point, and the Motorola has boards in it.

tia

What kind of outputs do they use? Will they power up?

If they're something that uses, say, a 6V6 or 6L6 in the output you might have some good iron to scrounge.

When you pull the chassis out, jury rig it just enough to measure the B+ and HV ac voltages at the rectifier tube socket and record them on a tag. Then if the iron's otherwise good save it for a project or to sell, but you can't do that unless you've got the specifications. Carefully cut the leads and tag them.

some of those old stereos and Hi Fi's have pretty good stuff on the chassis and I've scrounged plenty of it

[gmoon]

A pair of output transformers for a quad set of 6BQ5's looks like possible DIY gold to me... (6BQ5 == EL84.)

[HJW]

What kind of outputs do they use? Will they power up?

If they're something that uses, say, a 6V6 or 6L6 in the output you might have some good iron to scrounge.

When you pull the chassis out, jury rig it just enough to measure the B+ and HV ac voltages at the rectifier tube socket and record them on a tag. Then if the iron's otherwise good save it for a project or to sell, but you can't do that unless you've got the specifications. Carefully cut the leads and tag them.

some of those old stereos and Hi Fi's have pretty good stuff on the chassis and I've scrounged plenty of it

Thanks for the info. I'm new to all of this though. I know not to go poking around unless I want the Don King look, or worse, and I'm just now assembling some stuff I'll need to get my feet wet.

No 6L6 or 6V6's here though. You can click the thumbnails and see the tube #'s on those labels. I can post some more pics though.

[HJW]

A pair of output transformers for a quad set of 6BQ5's looks like possible DIY gold to me... (6BQ5 == EL84.)

I'm getting ready to pull the tubes. They are dusty. Thanks for the heads up on the 6BQ5's = EL84's.

Some pics on the way

[HJW]

Here are power amp pics (RCA). I haven't pulled the pre amp chassis yet. Again, click the thumbnails to zoom.











What are the metal cylinder shaped components ? I assume I don't need to be grabbing them ?

[HJW]

The RCA manual says it's 58 watts







On the tube under "Made in USA" it is marked 59-39. Is this a date code ?

[Enzo]

The whole machine uses 58 watts. Your audio power is not remotely that high.

The metal cans are electrolytic capacitors, probably multi-section ones at that. Most of the sections will be used as filter caps, and since this stuff is 50 years old, I would not think they would be of any use, any more than 50 year old tires would be of any use if found on an old car.

[Don Moose]

The one with the 35C5s and 35W4 has a series heater string, and may not have a power transformer - this can be a wildly unsafe thing to plug a guitar into unless you put a 1:1 isolation transformer between amp and wall.

- for an 'American' tube like a 12AX7 or a 6V6 - or a 34W4 - the digits before the letters are the heater voltage (most of the 12xx tubes will also to 6V heaters, thought). If you see numbers that aren't twelves or sixes, add them up to see how close you get to the local line voltage.

[HJW]

The whole machine uses 58 watts. Your audio power is not remotely that high.

Hi Enzo,
So how many rms watts will a pair of 6BQ5's do ?
Are you talking about the watts consumption marked, for example...................
"volts 115 AC - cycles 60 - watts 150" as marked on the label on the back of the Console ? I know that's a common mistake made thinking watts consumption is the RMS rating.

The metal cans are electrolytic capacitors, probably multi-section ones at that. Most of the sections will be used as filter caps, and since this stuff is 50 years old, I would not think they would be of any use, any more than 50 year old tires would be of any use if found on an old car.

Ok, noted. I'm wet behind the ears with this stuff, but I have learned filter caps need to be replaced after, what, 20 years ?

[HJW]

The one with the 35C5s and 35W4 has a series heater string, and may not have a power transformer - this can be a wildly unsafe thing to plug a guitar into unless you put a 1:1 isolation transformer between amp and wall.

Ok, thanks. Thats' why I asked But it can be done as you noted ? And I guess upgrade to a 3 prong power cord ?

- for an 'American' tube like a 12AX7 or a 6V6 - or a 34W4 - the digits before the letters are the heater voltage (most of the 12xx tubes will also to 6V heaters, thought). If you see numbers that aren't twelves or sixes, add them up to see how close you get to the local line voltage.

Thanks for that info. I'm still too new to this to understand it all, but I'll bookmark the thread for later on as I learn more.

The numbers I was inquiring about were the 59-39 under the stamp on the tube "Made In USA" Is that a date code ?

[HJW]

The one with the 35C5s and 35W4 has a series heater string, and may not have a power transformer - this can be a wildly unsafe thing to plug a guitar into unless you put a 1:1 isolation transformer between amp and wall.

Ok, I replied above and just realized you are talking about the Motorola with the 35C5s and 35W4. I'm not going to do anything with that one but pull some parts and speakers.

How about the RCA ? Can the phone jack already on the chassis be wired somehow as a guitar input ? The RCA is a gorgeous piece and I'd rather not just junk it. But if it can't be rigged somehow for guitar (practice applications), I'll just grab any decent parts and get rid of it.

[soundmasterg]

A 6BQ5/EL84 pair will give you about 15 watts, but they usually do these in stereo, so one 6BQ5 per side.

I've got an old all tube RCA console from 1964 that still works perfectly and its got a 6BQ5 pair in it also. It is plently loud....the speakers are probably efficient as most older good speakers seem to be. It sounds pretty good too, tho it is lacking in the bass and highs a bit as compared to modern solid state stuff. Whenever I get around to rebuilding it, I plan on upgrading quite a few things.

Greg

[olddawg]

OK...so this old beast has a stereo power amp with two open ended EL84 (6BQ5) amplifiers powered from a common power transformer. Here is what I would do. I would use the power transformer and reconfigure the two EL84s and a couple of 12AX7s to build an 18 watt Marshall clone or a VOX AC15. Probably a Lite IIb or such. You would have to buy or scrounge an appropriate output transformer since the two that are there are too small for a push/pull 18 watt amp. With a little luck and skill you can probably reuse the chassis. I would recommend using new ceramic tube sockets (although it's up to you), pots, jacks and components. Using a turrent or eyelet board would also be advisable. Still, you have the basis of a nice inexpensive little screamer here. Before you start check out what the B+ is. Keep in mind that it will be a little higher if you use an SS rectifier to free up heater current for another 12AX7.