6DQ5 specs for audio

[rsumperl]

Greetings everyone,
Does anyone have specs for the 6DQ5 in P-P audio service? Load resistance, bias, plate & screen voltage? I've searched the Internet and haven't found anything.

Thanks,
Ray

[Bandersnatch]

hey-Hey!!!,
You're going to have to do some load line drawing. For pentode mode. pick your g2 voltage and B+ and see what fits in under the dissipation line. For triode mode, it is just a matter of picking a load 3-4x the plate resistance and an OP under the limits.
cheers,
Douglas

[davorin]

6DQ5 is very close with 7867 and less close with 6EX6, 6CB5A and 6CD6GA, but can work in any amplifier with any of those tubes (small bias correction).
Also seem very useful in G2-drive amplifier.

[wrenchone]

Interesting - the specs of the 6BQ5 and 7867 do look pretty close. I had my eye on the 6BQ5 for screen driven duty, but I may try it elsewhere. On a similar note, one of our members has coaxed decent push-pull performance out of the 6BQ6, an unabashed sweep tube. Georce (Tubelab) has also thrahsed some amazing amounts of power out of a pair of 6BQ6 as well, though that was a "test to extinction" situation.

[davorin]

6DQ5 is a big brother of 6BQ6, about 2-3 times bigger and stronger! But yes, the same principle can use to drive 6DQ5, 7867 and other big similar tubes. 4 tubes 6DQ5 can give 200W in normal Push-Pull class AB1 with less than 4% distortion, and same output tubes work last 3 years every day 4-5 hours. (drive at g1: Ua=600V, Ug2=150Vstab.,Ug1=-45V, Ra-a=3800ohms, Ia-min=2x30mA, Ug1eff.~2x40Veff.)

[Geek]

Originally Posted by davorin

6DQ5 is a big brother of 6BQ6, about 2-3 times bigger and stronger! But yes, the same principle can use to drive 6DQ5, 7867 and other big similar tubes. 4 tubes 6DQ5 can give 200W in normal Push-Pull class AB1 with less than 4% distortion, and same output tubes work last 3 years every day 4-5 hours. (drive at g1: Ua=600V, Ug2=150Vstab.,Ug1=-45V, Ra-a=3800ohms, Ia-min=2x30mA, Ug1eff.~2x40Veff.)

Ooooo, golden info. Thanks!

Cheers!

[tubelab.com]

Here is some interesting info:

I was hanging out at Stans (ESRC) swap tables during a rain shower at the Dayton hamfest. I spent that time looking at tubes. If I spot a big box with a number that I don't know, or vaguely remember from my past, I will open the box and check out the tube. I have "discovered" a few winners that way.

I remember the 6DQ5 from the dawn of the color TV era as being a big sweep tube that was never very popular. I found several in Stans collection, looked at them, and then put them back when I found that they were $10 each. I prefer cheap tubes for obvious reasons.

Maybe 5 minutes later a guy walked up and asked for 6DQ5's. He said that he was using them in an OTL audio amplifier. He wanted a particular RCA to match the ones that he already had.

I added that number to my shopping list and managed to find a few used $1 6DQ5's that didn't look too bad. I have collected about 6 since then.

Investigating the specs reveals a very high peak cathode current rating for a 1950's vintage tube, 1 AMP. This is why they work in OTL's and they will probably make a good P-P output tube. I'll hook mine up eventually.

[davorin]

I did not try this schematic.

[Geek]

Originally Posted by davorin

I did not try this schematic.

I'd try that.... but with a less wimpy 250V reg screen and 400-500V anode


I've used this tube in some kick butt power supplies before I got my Lambda ... pretty unperturbable tube

Cheers!

[matviychuk]

Originally Posted by davorin

I did not try this schematic.

Where could i get a larger version of this image? i can't read it? Some one can help me please?