6AQ6 & 6C4 tube substitutes or elecrically the same tube

[gary o]

6AQ6 & 6C4 tube equivilants...Anyone know ?

Or diffent tube that is electrically the same ??

I think I read somewhere that the 6AQ6 is same as 6V6 & eqiv to a 6P1P

And the 6C4 is one half of a 12AU7 ??? Is that so ?...

Im just thinking of making a little pre with those tubes in ...but havent got those actual tubes but I have so so many other tubes Im hoping iv got something similar

Thanks

 

[pH]

Do you mean 6AQ5? That one is the equivalent to a 6V6 in a wee package.

Don't know about the 6C4 being half of a 12AU7. Some Gibson amps and old tube Echoplexes use them.

You might find some info here: http://www.nj7p.org/Tube.php

 

[bcarso]

According to RCA (ancient manual) the 6C4 has the same characteristic curves as half of an AU7A. It has slightly higher max plate dissipation.

 

[emrr]

You must be trying to make a Collins 6Q-1, or Altec 1512B. Those tubes are as cheap or cheaper than any of the options; why not just use them? 6AQ6 are frequently under $1.

 

[gary o]

Thanks fellas yeah not a 6AQ5 as in La2A & as you said thats like a 6V6 so it be unlikely for the 6AQ6 to be same as a 6V6 I spose

thanks for the info guys.

 

[ProfPep]

6C4 - by coincidence I found this the other day whilst looking for some ECC82's. I don't think it's been out of the box since 1944. If you have a good home for it, PM me and I'll test it.

For those who've read William Gibson: <Finn voice> "What d'you know punk, I got valves older than you...."

 

[BYacey]

6C4 is typically used as an RF oscillator, don't know how it compares to a '12AU7 or 12AT7 for audio applications.

 

[emrr]

6C4 is used in a lot of audio preamplifiers.

 

[BYacey]

[quote author="emrr"]6C4 is used in a lot of audio preamplifiers.[/quote]
That's interesting. I've seen them in radio applications quite a bit, but then I haven't worked on a large variety of audio preamps.

 

[bcarso]

My Tube Substitution Handbook, Sams Photofact series, 10th Ed., 1967, lists the following as similar to the 6AQ6: 6AT6, 6AV6, 6BK6, 6BT6.

 

[PRR]

> I think I read somewhere that the 6AQ6...

Be vague, or be informed.

> You might find some info here: http://www.nj7p.org/Tube.php

Yes, NJ7P's listings are better than "I think I read somewhere...."

Another source is Frank's scans of original datasheets.

If you are unsure what to Search for in Frank's, post here. Nobody has ever compiled a back-link database as good as the minds of people who read tube data books tooo many times.

6AQ6 is roughly half a low-performance 12AT7 plus two diodes, the standard AM radio detector amplifier stage. 6AV6 was far more popular. Neither is a go-to tube in non-radio audio, but they are handy when you need an odd number of small hi-gain stages (ignore the diodes), and were used as side-chain in some speech limiters.

> 6C4 is typically used as an RF oscillator

Two units in one bottle and socket leak to each other, and frequency dependent. In radio we often can't cascade two stages in one bottle; in audio we often can. (Even one tube in one bottle leaks: at AM band we don't use triodes we use tubes with a screen grid, but oscillators can stand P-G coupling.)

After proving that radio is single-unit per bottle and usually screen grid, I must admit that VHF FM bands can use dual/twin-triodes 12AT7 6BQ7 6ES8 in the front-end, though the very best tended to single units (or cascode, which is a variant screen-grid with the cost of an added cathode).

Much audio is cost-driven (I hear moans from the commercial designers here) so you "always!" use dual-tubes to save a buck. 6C4 is however modestly common as the grunt phase-splitter stage between a cascade of hi-gain tubes and the grids of power tubes, especially when you arrive at an odd number of small units. It probably gets used when a dual hi-gain tube needs a third stage to buffer its output. 6C4 is an adequate transformer driver if you swing that way (and just need one).

 

[gary o]

Wow great info guys ...love it thanks !
You got it doug I knew if you read this post youd find me out yeah Iv had Collins 6Q1 schematic here for a while omly just read that you drew it...Thnks have been thinking its only 2 tubes & a few solder blobs away & then I can listen to it.

Profpep that looks great Il drop you a PM thanks

Cheers everyone

 

[My3gger]

> I think I read somewhere that the 6AQ6...

Be vague, or be informed.

> You might find some info here: http://www.nj7p.org/Tube.php

Yes, NJ7P's listings are better than "I think I read somewhere...."

Another source is Frank's scans of original datasheets.

If you are unsure what to Search for in Frank's, post here. Nobody has ever compiled a back-link database as good as the minds of people who read tube data books tooo many times.

6AQ6 is roughly half a low-performance 12AT7 plus two diodes, the standard AM radio detector amplifier stage. 6AV6 was far more popular. Neither is a go-to tube in non-radio audio, but they are handy when you need an odd number of small hi-gain stages (ignore the diodes), and were used as side-chain in some speech limiters.

> 6C4 is typically used as an RF oscillator

Two units in one bottle and socket leak to each other, and frequency dependent. In radio we often can't cascade two stages in one bottle; in audio we often can. (Even one tube in one bottle leaks: at AM band we don't use triodes we use tubes with a screen grid, but oscillators can stand P-G coupling.)

After proving that radio is single-unit per bottle and usually screen grid, I must admit that VHF FM bands can use dual/twin-triodes 12AT7 6BQ7 6ES8 in the front-end, though the very best tended to single units (or cascode, which is a variant screen-grid with the cost of an added cathode).

Much audio is cost-driven (I hear moans from the commercial designers here) so you "always!" use dual-tubes to save a buck. 6C4 is however modestly common as the grunt phase-splitter stage between a cascade of hi-gain tubes and the grids of power tubes, especially when you arrive at an odd number of small units. It probably gets used when a dual hi-gain tube needs a third stage to buffer its output. 6C4 is an adequate transformer driver if you swing that way (and just need one).

Hey, i compared operating conditions and plate curves for triode sections of 6AQ6 to 6SL7, 12AX7 and 12AT7. 12AT7 is closest if i look at Mu only. But typical operating conditions or plate curves 12AT7 don't look that similar to 6AQ6. It seems to have much more current, lower Rp and higher transconductance at very similar biasing to 6AQ6. Plate curves tell me that 12AT7 has several times more current than 6AQ6 at the same Ua and Ug. I didn't go far to find closest replacement from very known tubes because i might be doing something wrong. So far the closest equivalents seem 6SL7 and 12AX7 as next. What do you guys think? Someone else said it is close to half of 12AX7, here i find it should be closer to 12AT7 which looks like different tube to me.

 

[emrr]

I've always thought it looked like the Frankenstein of a 12AT7 and a 12AX7 on paper.  I haven't found anything that's really an equivalent.  I have bought them new as cheaply as $0.5, love that part. 

 

[PRR]

> 12AT7 has several times more current than 6AQ6 at the same

You are correct. Higher purveyance. In other words, 12AT7 is four times fatter (bigger cathode) than 6AQ6.

As it is nearly the same heater Power (per unit; assuming diode cathodes are small), this is quite odd.

 

[rock soderstrom]

Old thread but I am on this topic at the moment. A really close equivalent for the triode section of the 6AQ6 is a 5751. Gain, plate resistance, transconductance and plate current a really similar.

http://www.drtube.com/datasheets/5751-ge1952.pdf
http://www.tubebooks.org/tubedata/hb-3/receiving_tubes_part_1/6AQ6.PDF

Maybe this useful for someone else in the future...