What about TV horizontal deflection tubes as output? I need some schematic with ...

[slideman82]

Hi! This is my first post here! Well, has anybody listened to a power amp with 6DQ6, for example? Those TV tubes, I think they're pentodes, sound great, with lots of bass!!!! The most remarkable characteristic is that you can have much more output power than plate dissipation, so theirs performance is quite good. I have to repair an old national tube power amp with those 6DQ6 (it seems to be a Blackface Tremolo but different output) and it delivers 60W output! Some old Australian amps got those tubes as output, and there were 40W and 60W models.

Well, my point is to build a similar power amp, but using 6BQ6, that is similar to the one I mentioned but smaller, and I don't have any schematic with them. I've heard some people used to use 6BQ6 or 6DQ6 as audio output, I just want them for guitar output (nevermind THD).

Somebody throw me a line!

[Sock Puppet]

Here's a start:

http://www.freeinfosociety.com/electronics/schematics/audio/gibsonga78.pdf

look at the 78/79 series schematics, they use 6BQ5 in the output...

Weird though, that ga78 has phono inputs and a tremolo switch - far out!

S.

[bob p]

Weird though, that ga78 has phono inputs and a tremolo switch - far out!
if i had to guess, i'd say that the amp's designer was into "experimentation." :p

[slideman82]

Well, the 6BQ5 are quite different to the 6BQ6 I was writing about. The first ones are the same as the EL84 (mmm I think they differ a bit... because they're american?) and the others are for TV, although it could be used in audio. Thanks, anyway, for the help!

[Sock Puppet]

Another of my mistakes. This machine really does increase their throughput.

S.

[SlidePicker]

The 6BQ5 is just the American designation for the EL84, which was introduced as the EL84 by Phillips.

The 6BQ6 is a once-common TV horizontal output tube. Like most of the horizontal output tubes or "sweep tubes," it's a beam tetrode or beam power tube, the prototype for which was the 6L6. Main problem with it is that they're no longer made, but they're still readily available. Plus, it uses an anode cap that you have to avoid touching so you don't get shocked. Any schematic for an amp using a beam power tube or tetrode can be adapted to use it, with appropriate connections and the voltages adjusted to run it within its specs. I think you'll be happier with 6V6 or 6L6 types. If you have a bunch of these tubes around, they're fun to play with.

[slideman82]

Yeah, it could be funny! But, 6DQ6 has more bass response than 6L6, someone told me, and they are cheaper around here (about half an 6l6). The other point is you can get more power from these than the 6l6 with the same voltage, just give the control grid more negative voltage... I want to play with 6BQ6, 6AU5 and probably PL84 (I can find them really cheap too!).
Thanks!

[JJGross]

Here's something that might interest you.
http://www.dogstar.dantimax.dk/tubestuf/paraph.htm
Courtesy of the late great Fred Nachbaur.

It's a write up with schematics for a Paraphase amplifier using 6X8 tubes. Mostly used in old TVs, but also in old organs. The 6X8 goes extremely cheap these days because it's a hybrid triode-pentode tube and having both cathodes internally tied together doesn't make it easier to figure out what to do with them, but Fred came to the rescue and designed an amplifier using these tubes. Your average Lowery organ has something like 30 or 40 of these things in them.

I'm thinking about making one myself (I have a ton of 6X8 tubes doing nothing).

Cheers,
- JJ

[slideman82]

Thanks! That's what I'm talking about! What Mr. Nachbaur said is what I think! Do what you can deppending on what you have. Pretty good info.

[Jammin'John]

I sometimes run 6K6's in a tweed that I have........because I can ! :rolleyes:


JJ

[TD_Madden]

seems to be unaccessable...