6AQ5 vs 6V6

[Stuff4bikes]

Is it just me or does a 6AQ5 seem louder in an identical SE circuit.....

I built a 5F2 with all RCA tubes including the 6v6 as my first real amp...sometime back....

I built an identical circuit with identical  transformers but with a 6AQ5.....and It seems much more vibrant/fuller volume......

I know the tubes are somewhat identical sans the envelopes but I feel there's a difference.....

[jordan86]

Interesting. Following this. I recently discovered the 6AQ5. Was curious how they might do in pulling off a cranked 10W amp with some sort of plexi/jtm preamp.

[sluckey]

Interesting. Following this. I recently discovered the 6AQ5. Was curious how they might do in pulling off a cranked 10W amp with some sort of plexi/jtm preamp.

My little smoky is idling at 11.9 watts! Sounds good cranked, but it's a pentode preamp pushing a Marshall 18W tone circuit. This was a simple experiment using all 7-pin pentodes. Your Plexi/JTM preamp idea would probably work very well too.

     http://sluckeyamps.com/smoky/smoky.pdf

[HotBluePlates]

Is it just me or does a 6AQ5 seem louder in an identical SE circuit.....

Funny that I have 6AQ5s sitting around "just in case" but have had an amp that used them.

*All* the old tube manuals said to refer to the 6AQ5 entry to get curves for the 6V6.  They're supposedly identical to 6V6, except for form-factor and basing.  Of course the mini-bottle means they will tend to run hotter.

... seem louder in an identical SE circuit.....
... a 6AQ5..... seems much more vibrant/fuller volume...

It's easy for individual tubes to be different.  What if your 6AQ5 has more Gm than your most-recent 6V6, and delivers more power with the same load/drive-signal?

It's possible to use a normal Gm tester to try to figure this out, while a lab-grade setup will tell you the difference for-sure with same applied voltages.  And a real power output test (though uncommon today) would tell for-sure if the individual 6AQ5 is stouter than the individual 6V6.

[Stuff4bikes]

I have quite a few 6v6 champs and princeton's to compare and I feel 6AQ5 has a bigger sound...

[kagliostro]

If I remember it correctly, 6AQ5, due to smaller phisical dimensions respect 6V6 tubes are rated for a max B+ of 250V, may be the difference in response is there when you put it in a circuit that is thinked for the bigger 6V6 (that is planned to use a higher B+ voltage respect the stated 250V)

At a high B+ the tube will last in a less time but may be it will exprime at best it's possibilities ?

Franco

p.s.: To push tubes at a higher B+ voltage is Good Practice in guitar amps 

[AmberB]

My RCA tube manual says that the 6AQ5 has a max plate voltage of 275 volts and the same for the screen grid.
The 6V6 is rated at a max plate voltage of 350 volts and a max screen voltage of 315 volts.
Apparently that it the operational difference between the tubes.
Obviously, we know that a 6V6 will operate above that voltage because Fender has been putting 400 volts plus on them since the late 1960s...
I know that Gibson used the 6AQ5 in some of their little amplifiers with pretty good results.

[kagliostro]

I know that Gibson used the 6AQ5 in some of their little amplifiers with pretty good results

If not why some time ago did I got a little stock of 6AQ5 & 6005W ? 

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My RCA tube manual says that the 6AQ5 has a max plate voltage of 275 volts and the same for the screen grid

May be, for sure you are correct, GE datasheet says 250V, but it is near the same thing

http://www.r-type.org/pdfs/6aq5-2.pdf

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For those who can be interested, here a misknown (to many peoples) russian version of the 6V6, the 6P1P tube, a mild way between 6AQ5 & 6V6, in fact it is a 9 pin tube (like el84)

http://oldradio.qrz.ru/tubes/russian/detail/6p1p_2.shtml

http://oldradio.qrz.ru/tubes/russian/short/6p1p.shtml

Franco

[PRR]

max plate voltage of 275 volts

Design Center or Design Max?

"Center" has a safety margin; often 10%. MAX is supposedly drop-dead (but never is).

[bmccowan]

I can think of no logical reason that 6AQ5 tubes would be louder than 6V6 tubes. But jeeze there are so many variables. You follow your first post with "sounds bigger." To me that points to those subjective variables. Lets say a particular tube in a particular circuit emphasizes the mids - it'll sound "bigger." I suppose one could measure with a decibel meter, but why bother. If it sounds louder to you; it is. If it does not; it isn't. BTW, I agree with the comment on Gibson's with 6AQ5s. Nice sound once you remove the "tone suck" T-filter. I have a Gibson (a GA-5 variant) and an Epiphone (EA-50T) with similar PP 6AQ5 circuits - they are fun amps for home playing and the Epiphone has a cool almost art deco look to the control panel.