metal can 6v6's

[studioit]

Does anybody know the real story. Besides the fact that pin 1 is tied to the can. Are they the same / as robust as the glass ones? There 's all kinds of rumors - some say the're the same tube inside, some not . Some say don't use them in amps they get too hot etc. I have a few RCA's and have used them in a Blackfaced vibrochamp with great success- and sound. Anyone else have any experiences with them?

Ian

[Tom Phillips]

Ian,

There are metal 6L6s that have maximum ratings that are quite a bit lower than those of the glass 6L6GC. Maybe that’s where the rumors about the metal 6V6s originated.

We will do best to go with the documented facts from a reliable source. Let’s use the 1965 RCA receiving tube manual. According to the 6V6 / 6V6GTA data page the metal and glass tubes are identically rated except for:
1) The pin one case connection that you already mentioned
and
2) Some slight differences in the direct interelectrode capacitances
Without going into a big debate about the effect of #2 I say just install and bias the metal version as you would a glass version and, if you like the sound then you have succeeded.
You have already used them “with great success”. So have I.

Most guitar amps that use 6V6s exceed the basic ratings of the tube anyway, but that’s another story.

Regards,
Tom

[stokes]

I have used the metal 6v6's and the only downside I found was that when biasing into class A territory I couldnt see the plates to be sure they werent redplating,otherwise they worked the same as the glass envelope.

[Rob Mercure]

Anyone else got an "ST" 6V6

Only a slight "hijack" of this thread ("no, I don't want to go to Havana, Montego Bay will do nicely") - one of the "rarest" tubes in my collection is an "ST" - "spherical tubular" or "coke bottle" 6V6 branded "Delco." While I've seen lotsa other bottles from the 30s-50s with the ST shape this is the first 6V6.

Rob

[blodviol]

I've used metal RCA 6L6's in my Fender 5C5 ProAmp, and they are the best sounding tubes i've tried in there. but they get freaking hot, so when the amp had been on for 30 minutes, it started to sound too soft. less crunch, less volume and more sag. I solved that by blowing a fan into the back.

They sounded better than the 6L6GA's i have in there now. less headroom, but just perfect overdrive. Tung-Sol 6SC7G's, of course...

Well, I guess that had nothing to do with the thread, as they are not 6V6's..

Tríste

[stokes]

Only a slight "hijack" of this thread ("no, I don't want to go to Havana, Montego Bay will do nicely") - one of the "rarest" tubes in my collection is an "ST" - "spherical tubular" or "coke bottle" 6V6 branded "Delco." While I've seen lotsa other bottles from the 30s-50s with the ST shape this is the first 6V6.

Rob

I've seen some French "Mazda" brand that had the coke bottle 6V6's. wiwitubes.com is a supplier in China that has pictures of them.

[Jammin'John]

Metal

I have a metal 6v6 that I stuck in a deluxe and the fuse blew !

JJ

[J Martin]

The metal 6V6 tubes don't seem to dissipate the heat as well as the glass version. I only use them in low powered low voltage amps and old radio gear. They make a great oscillator for sending code on the 40 or 80 meter ham bands.

[Diablo]

Only a slight "hijack" of this thread ("no, I don't want to go to Havana, Montego Bay will do nicely") - one of the "rarest" tubes in my collection is an "ST" - "spherical tubular" or "coke bottle" 6V6 branded "Delco." While I've seen lotsa other bottles from the 30s-50s with the ST shape this is the first 6V6.

Rob

I've got 5 "ST" 6V6 tubes in my collection. Two Zenith, RCA Radiotron, Raytheon, and a Super Silvertone. The two Zenith tubes match perfectly (mA draw) and are happily powering my Deluxe Reverb clone.

[Diablo]

Only a slight "hijack" of this thread ("no, I don't want to go to Havana, Montego Bay will do nicely") - one of the "rarest" tubes in my collection is an "ST" - "spherical tubular" or "coke bottle" 6V6 branded "Delco." While I've seen lotsa other bottles from the 30s-50s with the ST shape this is the first 6V6.

Rob

Here you go Rob, for your viewing pleasure.
More ST shaped 6V6G tubes.

http://s268.photobucket.com/albums/j...d/6V6%20Tubes/

[SlidePicker]

Be sure when you use either metal 6V6s or 6L6s that you're not putting them into an amp where some bozo's used Pin 1 on the socket as a tie point for the screen resistor. That erroneous practice puts plate voltage on the tube shell and can give an unsuspecting user a nasty jolt. It's no problem when glass tubes are used, but it's bad construction practice to assume that only glass tubes will be used. (And was specifically warned against in the 1952 Radiotron Designer's Handbook 4th Edition, so it's not news, but people still do it. I've bought commercial amps that were built that way.)

[Diablo]

Be sure when you use either metal 6V6s or 6L6s that you're not putting them into an amp where some bozo's used Pin 1 on the socket as a tie point for the screen resistor. That erroneous practice puts plate voltage on the tube shell and can give an unsuspecting user a nasty jolt. It's no problem when glass tubes are used, but it's bad construction practice to assume that only glass tubes will be used. (And was specifically warned against in the 1952 Radiotron Designer's Handbook 4th Edition, so it's not news, but people still do it. I've bought commercial amps that were built that way.)

Like a gazillion amps from Fender....BF Deluxe Reverb being one example, with pin 1 a tie point for the grid resistor and charged up with the bias voltage.

[pila]

I have a couple ST shaped 6V6s, and an ST shaped 6L6. That's gotta be very early versions of those tubes.

[Jammin'John]

Old

Yes,those are very old versions.
Don't run 'em too hot........they can't take it.

JJ

[boots]

I just came across a few NOS RCA/JAN metal 6V6's and popped one in my Champ clone. It sounds great, as good as the best of the GT glass versions, IMO. It seems to be perfectly happy with 410 volts on the plate too, whereas it seems you have to pick through 6V6's in general to find ones that don't mind high B+ voltages. Next amp I build will have lower B+ because I think everything is just better that way - but it's hard to beat the sound of a "Champ in pain"! But I am impressed with how rugged the metal 6V6 is. It just doesn't LOOK as cool as the glass bottle, though!
-Boots