Does anyone know what this rectifier is??

[Resonator Guy]

This rectifier is out of my 52/53 Carvin Model 20 amplifier. There are absolutely no markings left on it and I can't yet figure out what it is. It has a 6.3 volt filament and, after looking at pictures until my eyes tired out, I think it could be a 6X5GT but I am not sure. It is the only one I could find with the offset plates. I also suspect it is completely shorted out.
Any ideas as to what it is.

[olddawg]

This rectifier is out of my 52/53 Carvin Model 20 amplifier. There are absolutely no markings left on it and I can't yet figure out what it is. It has a 6.3 volt filament and, after looking at pictures until my eyes tired out, I think it could be a 6X5GT but I am not sure. It is the only one I could find with the offset plates. I also suspect it is completely shorted out.
Any ideas as to what it is.

[ATTACH=CONFIG]25456[/ATTACH][ATTACH=CONFIG]25457[/ATTACH]

Have you simply tried calling Carvin? They still exist in Escondido CA. They are usually very helpful and quite curious about their really old stuff. Maybe send them an email first. If it doesn't get you a long distance call charge I would just call. What have you got to lose?

[52 Bill]

The internal structure looks like a 6X5GT, but that's no guarantee. How is the socket wired? What are the current requirements of the circuit?

[Jazz P Bass]

Here is the datasheet of the 6X5.
http://frank.pocnet.net/sheets/127/6/6X5.pdf

[Tom Phillips]

Since you have already determined that the rectifier heater runs on 6.3V I agree with 52 Bill that tracing out the socket wiring and will most likely verify that the amp was wired for a 6X5. Have you tried the trick of fogging the glass with your breath and then rotating the tube under strong glancing light to see if the faint traces of the original making can be seen?

[Resonator Guy]

Olddawg, I sent Carvin an email but no response yet.
Bill, I will trace out the socket wiring today and post using J P bass' datasheet pic as reference.
Tom, I have tried that with a magnifying glass and bright light with no luck.
I figure I need a good rectifier in there to see if the PT is fried. Since it is dark and rainy here today, I shouldn't be outside working so I can make some progress here.

[Resonator Guy]

Okay, here is the way the tube is wired.
Pin 1 - nothing
Pin 2 - heater of 6V6
Pin 3 - Power transformer
Pin 4 - nothing
Pin 5 - Power transformer
Pin 6 - nothing
Pin 7 - heater of 6V6
Pin 8 - Filter cap

Don't ask for any readings, because that would mean I could plug it in with a good tube,

[Jazz P Bass]

Looks like a 6X5GT to me.
http://www.lovisolo.com/valvole/per-cuffia.jpg

[g1]

In a situation like this (oddball rectifier I don't have), just to test the PT etc., I just stick a couple of diode strings in the socket, power up with limiter lamp or variac.

[Resonator Guy]

I don't have any diode strings. I ordered a couple of 6X5GTs for 99 cents that will get here in a couple of weeks, unless the US Postal Service is shut down too. I figure that two of us, me and Jazz P, make a quorum and it is a 6X5GT.
When I tested the old rectifier, it showed shorts on both sides and when I pressed the test button, the base lit up like it had a bulb in it. Hope I didn't wreck my tester.

[52 Bill]

I don't have any diode strings.

So no strings attached. How about any basic 1N4007s?

I ordered a couple of 6X5GTs for 99 cents that will get here in a couple of weeks, unless the US Postal Service is shut down too.

I guess that will depend on how long the shutdown goes on.

I figure that two of us, me and Jazz P, make a quorum and it is a 6X5GT.

Okay, I'll jump on the bandwagon too.

Hope I didn't wreck my tester.

Probably not, they do have fuses and internal protection circuits.

Have you tried the amp without the rectifier tube installed? You won't have B+ voltages, but if the transformer is working, you will have AC voltages on the filaments and on the rectifier tube socket.

[km6xz]

It is most probably a 6X5GT as you assumed but you can often get some of the invisible marking to show up by rubbing it with a soft lead pencil. The markings were lightly etched so they might not be visible but they are still there.

[Resonator Guy]

[QUOTE=52 Bill;320258]So no strings attached. How about any basic 1N4007s?


No, I have nothing like that in my parts drawers.

I will try it without a rectifier. My wife says I have to do that in the garage so I won't stink up the whole house if the PT is bad.

[R.G.]

Two UF4007s and a power resistor make a good impersonator of most vacuum tube rectifiers. The nature of the tube is pretty well faked by varying the value of the resistor.

And the heater power is really, really low.

[Gingertube]

You can be reasonably confident about it being a 6X5 as the guys have said above. Apart from some specialist damper diodes (for TV set use) the 6X5 was about the ONLY 6.3V indirectly heated (seperate cathode) rectifier tube there was. I have a tube signal generator from that era and it certainly runs a 6X5. The next generation gear with 6.3V indirectly heated retifiers ran EZ80, EZ81, 6CA4 9 pin tubes.
The pin out is correct for 6X5 - have no fear about plugging one in to see what happens (assuming you don't have a shorted filter capacitor at least).
Cheers,
Ian