Looking for dual power triodes.

[Shoog]

Can anyone suggest any dual power triodes which are suitable for use in audio (other than the 6080 family which I have already used).

Thanks

Shoog

 

[andyjevans]

You may include the 6528 with the 6080, but it's a bigger beast. Going the other way there's the 6BX7 which sounds pretty nice in outputs at lower power. I'm sure you know about all the dissimilar triodes like 6EM7, which only have one beefy section.

 

[powertriode]

Why not try something a little different like a Cossor 220B/240B.
😱

 

[billr]

if you get Valve Amplifiers 3rd edition, there is a pushpull amp using 6528s in there.

wonderful design, and expertly engineered

 

[ErikdeBest]

Although Morgan Jones is all in favour of Push Pull amplifiers, he used the 6528 to build his scrapbox challenge: a SE design.

Erik

 

[Shoog]

The 6528 looks interesting - but no more linear than the 6080's. I also don't really need any extra power. Also the input capacitance and medium Mu present problems for my prefered interstage transformer phase splitting.

The 220B and 240B look funky and interesting.

Shoog

 

[billr]

you're right on the valves, the pp design was using the 13e1s

 

[Mikael Abdellah]

Is the 6AS7G normally included in the 6080-family? Otherwise that might be a suggestion.

 

[Shoog]

How about the 5998. Looks slightly more linear than the 6080 and also has higher mu so should be easier to drag a bit more power out of it. Otherwise its very similar.

Shoog

 

[anatech]

Hi Shoog,
There is always the 6N7. A small class B push pull tube. It will operate with zero grid bias (says the manual).

The 6AS7G is lumped in with the 6080 family. Rather tightly I might add.

-Chris

 

[jlsem]

http://frank.pocnet.net/sheets/127/7/7236.pdf

 

[andyjevans]

http://frank.pocnet.net/sheets/127/7/7236.pdf

Lovely valve, but good luck finding them.

 

[Tubelab_com]

The 6080, 6AS7, 5998, and a few others that I can't remember are variations on the same tube. The previously mentioned 6528, and its relatives (6336A) are higher power series regulator tubes.

The 6BL7 and its brother the 6BX7 are vertical output tubes with identical triode sections. These are useful for small audio amplifiers. These sound pretty good.

The 6N7 (and its loctal brother the 7N7) are "class B" dual triodes. These were often used in transformer coupled driver circuits. I have boxes full of these, so I have experimented a little. Most of these came in metal envelopes, but glass tubes exist, and I have some. The data sheet makes no sense. Plate dissipation is rated at 5.5 watts per section in class B mode, but only 1.0 watt in class A mode. I wired both sections in parallel, and used them in a SE amp. I could get over 2 WPC in class A without any plate glow. I didn't have time to listen, or take any performance data.

Going lower in power is the 9 pin "computer triodes" (7044, 5687, 6463, etc) as well as the dual triodes characterized for vertical output use (12BH7, and the often critisized 12AU7) can be used for small (1 WPC) audio amps.

I have seen some funny looking dual triodes made for RF amplifier use, although I can't remember any numbers now. There are some dual pentodes that can be triode wired, although many have their screens tied together.

 

[jayme]

The 6N7 (and its loctal brother the 7N7) are "class B" dual triodes.

I thought the 7N7 was a loctal 6SN7?

 

[Tubelab_com]

I thought the 7N7 was a loctal 6SN7?

Aparently you are correct. That is what I get trying to remember facts from a long time ago, on a Monday morning. While looking this stuff up, I found a similar tube, the 6A6.

 

[Graeme]

The QQE3/12 or 6360 is a dual RF tetrode which provides a fabulous triode when elements are paralleled. Telefunken data sheet via Franks is excellent......whilst you end up with only a single triode....the linearity is perhaps unsurpassed. A pair should provide 6 or 7 watts. One long-term project of mine is PP triodes, but with cathode-feedback a la Quad II. Have wound the transformers. Hopefully your quest will be sufficient prompt for me to start the chassis-bashing.

(The bigger brother QQV06/40 is certainly no mean triode either)

Graeme

 

[jlsem]

Here are a pair but with common cathodes:

http://frank.pocnet.net/sheets/049/3/3C33.pdf

http://frank.pocnet.net/sheets/081/r/RK34.pdf

Lovely valve, but good luck finding them.

I particularly like the sound of this tube, but I believe from its appearance that it is a multi-grid tube internally connected as a triode.

John

 

[Shoog]

All very interesting suggestions.
I like the look of 6BX7, fairly linear and heavy duty. Unfortunately the combined plate dissapation is a bit low at 12W.

Overall so far I think its would have to be the 5998.

Keep them coming.

Shoog

 

[Geek]

This is a little extreme, but...

I know a fella who paralleled 1/2 dozen 12AU7's and is happy with his watt ( 😀 ). Maybe a few of 6SN7 or 6CG/FQ7?

 

[Tubes4e4]

Hi Graeme,

The QQE3/12 or 6360 is a dual RF tetrode which provides a fabulous triode when elements are paralleled. Telefunken data sheet via Franks is excellent......whilst you end up with only a single triode....the linearity is perhaps unsurpassed.

"fabulous triode" ... "linearity ...unsurpassed" ... sounds interesting, indeed 🙂

But I cannot find any triode-strapped plate curves for this tube to have a look myself. Mind to share them?

Thank you,

Tom