Power tubes with metal bottles.

[Resident 217]

Years ago I tried a couple of metal jacketed 6L6's in a deluxe reverb.
I thought at the time they sounded awful and werre not versatile as the tone was...hard.
so I dscrapped the idea. They were cheap.
These days however tastes has changed in the music world with
contemporary metal and pop music .

Anyone tried it lately in a Marshall or? to see if there was anything worth capturing there.
with digital effects and EQ on tap in the recording world there may be some audio sound morsels to munch upon
not to mention I thionk those tubes are still really cheap.

Anyone ever seen any EL34's made of metal?

Might be good for contemporary metal...pun intended.

Could paair them up with someof those solid state preamp tube replacement plugs the had out years ago
..ha ha !

 

[Jon Snell]

A 6L6 is a 6L6, or a 6L6. Nice valves, when biased properly. Class Ab2 is best for power.
6L6 was metal case and 6L6G was a glass bottle.
(The British and Europeans called tubes a valve because we dropped its first name; Thermionic.
A tube is the UK is or rather was, the thing that produced a picture in your old fashioned TV set because it is essentially a Light Tube and yes we dropped the first name of that as well.)

 

[Matthews Guitars]

Some amps have the B+ voltage tied to a pin on the octal socket which is the outer metal case on some metal cased tubes, so this combination makes for a deadly situation. Touching the tube while the amp is running would result in a nasty shock or be fatal.

So....be sure that this isn't going to be a problem for you if you decide to do that. Check for voltage on the case, or ensure that the tubes can't be touched while the amp is running. (Leave the back cover on.)

 

[StingRay85]

The only metal tubes that still have some value are the Telefunken VF14 and EF12 preamp tubes. 6L6 is maybe worth 5 euro in Europe, have a couple of those but they look too boring to use, especially compared to those big old beautiful 6L6G tubes

 

[Jon Snell]

Some amps have the B+ voltage tied to a pin on the octal socket which is the outer metal case on some metal cased tubes, so this combination makes for a deadly situation. Touching the tube while the amp is running would result in a nasty shock or be fatal.

So....be sure that this isn't going to be a problem for you if you decide to do that. Check for voltage on the case, or ensure that the tubes can't be touched while the amp is running. (Leave the back cover on.)

The sheild is connected to pin1. Pin1 is connected to either the cathode pin8 or ground. If your chassis is not earthed or ground, maybe it will be an issue.
Otherwise, quite safe if correctly wired.
As it should be.

 

[Resident 217]

I wonder if thy'd sound fdifferent if you mess with the bottles profile. Like put some small dints in them and miss shaped them but not lose the vacumn.
I do think the different material does sound dirferent as does size.
Glass is technicallly a fluid whereas steel is not.
The RCA fat bottle 6ca7's sound much diffeeeeeeeeeerent thaaaaaan EL 34's for exmaple.
Kinda like 6v6's but a little bigger...just like the sound. EL84's sound like we would expect them to when compared to larger diameter tubes.

So size does matter.

Has anyone tryed making tunbes from other material? Ridgid ceramic, silocone rubber or Carbon graphite or what ever?
Not an easy experiment by no means.

I know that rubber tube dampeners do change the sound.

 

[Gutch220]

When calculating bias, do you guys use 27w or 30w for the output of a 6L6GC? I've heard both, each from very reputable people.

 

[mickeydg5]

Years ago I tried a couple of metal jacketed 6L6's in a deluxe reverb.
I thought at the time they sounded awful and werre not versatile as the tone was...hard.
so I dscrapped the idea. They were cheap.
These days however tastes has changed in the music world with
contemporary metal and pop music .

Anyone tried it lately in a Marshall or? to see if there was anything worth capturing there.
with digital effects and EQ on tap in the recording world there may be some audio sound morsels to munch upon
not to mention I thionk those tubes are still really cheap.

Anyone ever seen any EL34's made of metal?

Might be good for contemporary metal...pun intended.

Could paair them up with someof those solid state preamp tube replacement plugs the had out years ago
..ha ha !

Dude, metal tubes are the oldest and while still good are lower in electronic ratings.
No, there are no metal EL34 types.
More modern equipment and modern higher wattage amplifiers have higher voltages applied so old metal tubes should not be used.
I hope that makes sense to you.

 

[alpha al]

Some amps have the B+ voltage tied to a pin on the octal socket which is the outer metal case on some metal cased tubes, so this combination makes for a deadly situation. Touching the tube while the amp is running would result in a nasty shock or be fatal.

So....be sure that this isn't going to be a problem for you if you decide to do that. Check for voltage on the case, or ensure that the tubes can't be touched while the amp is running. (Leave the back cover on.)

Most metal tubes have pin one connected to the case. That is for shielding when the tube is used in RF applications.

Pin one is also connected to the metal base on American made 6550's. I don't know if Russian and Chinese 6550's do that or not.

It can be dangerous if pin one is used as a tie point. Some amps use pin one for the screen resistor. Fender does not.

 

[Matthews Guitars]

The yutz who had "modified" the '69 plexi I bought a few years ago had tied B+ to pin 1 and this made the metal base of the 6550s electrically hot! Nice way to keep people from stealing your power tubes! That was the amp I gutted out completely and rebuilt as close to original spec as possible.....including welding up a metric crapton of extra holes that had been added to it!

 

[Pete Farrington]

The RCA fat bottle 6ca7's sound much diffeeeeeeeeeerent thaaaaaan EL 34's for exmaple.

My understanding is that North American made 6CA7 is a beam pentode, whose design has been engineered so that its characteristics match those of the suppressor grid pentode EL34.

 

[TassieViking]

Glass is technicallly a fluid whereas steel is not

I'm confused by this, glass and metal melt at very high temperature to become a fluid.
So does a lot of things, plastic, bodies, lots of things melt and then some turn to ash.
Some things are a fluid until they cool down enough then they turn solid, thank goodness the snaps stays liquid in the freezer.

Sooo....where do the lead crystal wine glasses end up in this equation ?

 

[printer]

Sooo....where do the lead crystal wine glasses end up in this equation ?

They don't solder worth a damn.