[C38368]

Hopefully I don't ruffle any feathers here, since this isn't strictly about amps, but this seems to be where most of the tube-related stuff goes on.

My folks have got an old tube radio that dates back at least as far as 1951. Now, I don't know if the electronics on it are any good right now, but I've been able to identify at least two bad tubes.

Currently, I can confirm that there are at least the following tubes in it: Tung-Sol 6BA6 (four of these) and a Tung-Sol 6AU6 that I suspect replaced a 6BA6 at some point in the life of the radio. Additionally, there is a Sylvania 6S8GT and two more Tung-Sols (5Y3GT and 6V6GT). There may be one more tube that I can't get at, also.

Now I'm far from an expert here, but my understanding is that these are 6V tubes. Is that correct? And if so... where in the bloody hell can replacements be found?

Thanks in advance for any input, and sorry it ain't amp-related

 

[Absorbine_Sr]

You might want to do some digging through this site:

http://www.audiotubes.com/

Or email him if you don't see it straight away. It can be kind of hard to locate things on his site. I've had pretty good luck purchasing from him.

A_Sr.

 

[sacd lover]

Quote:

Originally Posted by C38368 Hopefully I don't ruffle any feathers here, since this isn't strictly about amps, but this seems to be where most of the tube-related stuff goes on. My folks have got an old tube radio that dates back at least as far as 1951. Now, I don't know if the electronics on it are any good right now, but I've been able to identify at least two bad tubes. Currently, I can confirm that there are at least the following tubes in it: Tung-Sol 6BA6 (four of these) and a Tung-Sol 6AU6 that I suspect replaced a 6BA6 at some point in the life of the radio. Additionally, there is a Sylvania 6S8GT and two more Tung-Sols (5Y3GT and 6V6GT). There may be one more tube that I can't get at, also. Now I'm far from an expert here, but my understanding is that these are 6V tubes. Is that correct? And if so... where in the bloody hell can replacements be found? Thanks in advance for any input, and sorry it ain't amp-related

The 6BA6 is a remote cutoff pentode and the 6AU6 is indeed a substitue. But the 6AU6 is not a preferred substitue .... meaning the tube can work in place of the 6BA6 .... but that there are better substitues. The 6AU6 is a sharp cutoff pentode. I would stick with all 6BA6's unless you think this one tube socket position in this circuit is specifically designed for the 6AU6. The 6S8GT is a triple diode - high mu triode. The 5Y3GT is a full wave rectifier. The 6V6GT is a beam power tube.

I did a little searching for you and I came up with the following from searching one tube site ..... my second search turned up even better prices.

6BAG/ EF93 - $5
6AU6/EF94 - $5
6S8GT - $2
5Y3GT - $11
6V6GT - $17

Note: the original 6V6 is a metal base tube. I would stick with the 6V6GT or 6V6G. The metal type tubes often have problems from corrosion etc... usually due to poor storage.

I recommend trying Radiodaze. They have all the tubes you mentioned and their overall prices were the best.

www.radiodaze.com

 

[C38368]

Thanks folks, I knew you'd come through with answers.

As for the 6AU6 tube, although I know nothing of the topology of the circuit, simply looking at where the tubes are laid out relative to everything else makes me suspect that this was a replacement. There is a socket that might be for something different on the circuit, but that's occupied by a 6BA6 also.

Once I get it working again (cross fingers!) I can worry about finding the best tubes for whatever socket

 

[john_jcb]

With a set that old I would look at the capacitors as well. There is also a good chance that the power cord insulation is brittle which could lead to exposed wires. The pots also will need to be cleaned in most cases.

 

[C38368]

Quote:

Originally Posted by john_jcb With a set that old I would look at the capacitors as well. There is also a good chance that the power cord insulation is brittle which could lead to exposed wires. The pots also will need to be cleaned in most cases.

Oh, I've taken a look and I'm quite certain that the tubes aren't my only worry!
But I think I'll have much better luck finding local folks who can repair and/or help repair the electronics; finding tubes locally is a much more difficult task

 

[Uncle Erik]

I've been restoring old radios for close to 10 years now, and you shouldn't have any trouble finding those tubes. I've been a longtime customer of Antique Electronic Supply:

http://www.tubesandmore.com

You should find what you need there.

Also, the radio sounds like a good one. Most don't have power transformers, but I believe yours does. It's probably one of the better models.

As for restoration, they're not too bad. No matter what, replace the filter capacitors (electrolytics). Those are often the first to go and they're take other components with them, if you're not lucky.

For a 1951 model, you'll probably find a mess of wax/paper caps and carbon comp resistors. If the caps haven't failed, they will sooner or later. And I've never found a carbon comp resistor that was in spec, even at room temperature. A lot of restorers ignore the resistors, but as a rule, I replace them all.

If you really want to make it nice, give it a fresh set of Orange Drops and metal film resistors. It's a little work, but the total cost should be under $25, not including tubes. It'll have point-to-point wiring and be relatively easy to work on. Give it a shot. With new components and a couple tubes, your parents can get a lot of use out of it. I've got a couple sets that have been played every day for years now- no tube failures or other problems.