Good radio tube:6AQ5/6005

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It is a very old type of tube,at that years,it ever have a good performance and using at some transmitter and transceivers.Such The Drake TR-3 and TR-4 transceivers and the 2-A, 2-B receivers use the 6AQ5 tube as do the Collins KWM-1 transceiver and the 51J-3, 51J-4, 75A-2, 75A-3 and 75A-4 receivers. The Collins KW-1 transmitter uses four 6AQ5 tubes.
The 6AQ5 tube is also used in the Hammarlund HQ-100, HQ-145, HQ-160 and HQ-180 receivers and in the Swan 260, 270 and 270B transceivers. National, Hallicrafters, Racal, Eddystone and many other manufacturers also used the 6AQ5 tube.

At an accidentally chance,I got some this tube from USA.

Next,I will make a parallel single-ended amp,the base shell had already done,please see the attached picture.

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These tube are from RCA,Sylvania, Hytron, GE etc...

[Colt45]

Cool.. 6AQ5 is basically a 6V6, derated a little bit because the tiny bottle.

6005 is the SQ version.

Russian outfits used to make 6P1P.. same idea again, but 9pin mini instead of 7 pin..

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Originally posted by Colt45
Cool.. 6AQ5 is basically a 6V6, derated a little bit because the tiny bottle.

6005 is the SQ version.

Russian outfits used to make 6P1P.. same idea again, but 9pin mini instead of 7 pin..

I know this 6p1p type,but i don't know what is the performance.

[Kenneth Zhu]

Also China-made 6P1. Miniatured 6V6, but the safe operating point with the highest output is 250v a-g and 250v 2nd g, only one of the operating modes of 6V6.

[ianc13]

TDSL has sheets for the 6AQ5, see:

http://tdsl.duncanamps.com/show.php?des=6AQ5

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Picture of Mini-Fairy.

[Poindexter]

I have implemented with this device a bit in triode. They meet their specs, test very tight, are as linear as a 6V6, very nice. Best I found were Sylvania green-print 6005.

They all have huge cylindrical plates that look way kewl, and are hideously microphonic. Now, I was using them low and hot (80v, 22mA) as a linestage tube, and maybe they don't have as much friskiness at 20v on the grid as they do with 1v, but i was eventually forced to find another device for my application.

I still have a bunch of nicely tested and sorted ones, and a, ahem, pretty good 6V6 power amp circuit, so maybe I'll try them out there someday.

My experience, draw your own conclusions, and so on.

Aloha,

Poinz

[Kenneth Zhu]

6AQ5 or its millitary equivalent 6005 works perfectly under triode connection, as the linearity is almost as good as trioded 6V6.

But the output is too thrifty-1W, almost. Some people have tested the PP triode of 6AQ5, and the results are inspiring. "Very smooth and sweet", as they say.

I don't like such low B+ voltage operation. The reason is simple: the ordinary tubes are designed to work under high voltage, and only under high voltage can they have the expected linearity. If not being specially designed, such as ECC99, working under low voltage conditions that are not recommended in the mannul may lead to serious distortion.

But guys like this kind of "soft distortion", calling it "tube sound".

Hehe...