does anyone have any experience with these two pentodes in a power amplifer? they seem to be very very similar on paper, wondering if the el95 was philips adaptation of a 6aq5 or the other way around. Is there a reason why these wouldnt be swappable in a circuit?
6aq5 vs el95
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6AQ5 is a small/cheap 6V6. 6.3V 0.45A heater, 12W plate dissipation. Surely not a Philips invention.
EL95 is new to me. At a glance, 0.2A heater and 6W plate means it is only half the brute that a 6AQ5 is. US-registered as 6DL5.
It's like putting a 215 CID (3.5L) engine in for a 427 CID (7L) engine. It won't go so good.
And Mu of 6V6/6AQ5 is ~~10, for EL95 it says 17. It will need very different bias.
So like the throttle lever comes out with different leverage; you will have to re-adjust the idle and WOT settings.
I am much too lazy to compare pin-outs, but I suggest you triple-check that.
> swappable in a circuit?
EL95 in a hole made for self-bias 6AQ5 would, by coincidence, bias-up to a tolerable DC current. The higher Mu would force less current for the same voltage and bias resistor, roughly half which suits that half-size cathode and plate. If you keep the load impedance the same, the power output is a quarter of the 6AQ5's mighty 4.5 Watts (half current times half voltage is quarter power). If you double the load impedance, you get about half of a 6AQ5's output. The sheet claims 3 Watts out (2/3rd of the 6AQ5 claim) but at an unusually high 12% THD-- heavily fudged.
EL95 is interesting where a 6V6/6AQ5 is overkill, assuming you can give it a hi-Z load or tolerate less than max-possible power. 6V6 has the advantage that you can get a replacement on Friday night, but I guess 6AQ5 is no easier to source than EL95. They run about the same price (~~$10) at the major bottle-stores.
EL95 is new to me. At a glance, 0.2A heater and 6W plate means it is only half the brute that a 6AQ5 is. US-registered as 6DL5.
It's like putting a 215 CID (3.5L) engine in for a 427 CID (7L) engine. It won't go so good.
And Mu of 6V6/6AQ5 is ~~10, for EL95 it says 17. It will need very different bias.
So like the throttle lever comes out with different leverage; you will have to re-adjust the idle and WOT settings.
I am much too lazy to compare pin-outs, but I suggest you triple-check that.
> swappable in a circuit?
EL95 in a hole made for self-bias 6AQ5 would, by coincidence, bias-up to a tolerable DC current. The higher Mu would force less current for the same voltage and bias resistor, roughly half which suits that half-size cathode and plate. If you keep the load impedance the same, the power output is a quarter of the 6AQ5's mighty 4.5 Watts (half current times half voltage is quarter power). If you double the load impedance, you get about half of a 6AQ5's output. The sheet claims 3 Watts out (2/3rd of the 6AQ5 claim) but at an unusually high 12% THD-- heavily fudged.
EL95 is interesting where a 6V6/6AQ5 is overkill, assuming you can give it a hi-Z load or tolerate less than max-possible power. 6V6 has the advantage that you can get a replacement on Friday night, but I guess 6AQ5 is no easier to source than EL95. They run about the same price (~~$10) at the major bottle-stores.
6AQ5 is EL-number EL90. Not EL95.
EL95 is a newer EL42. This is specifically aimed at car radio. In the US we used 6V6 and then 6AQ5 for this job. It could be that smaller cars/batteries in Europe favored a tube half the size of a US dinosaur. The EL42 is made to be the same height as your RF/IF/driver tubes.
EL42 may be seen as a small-bottle higher-gain EL2. EL2 is arguably a half-size EL1, which is similar to a US '42 or 6K6, and maybe 6F6 and (major tweak) 6V6. So the types are "related", but in the same way that all humans are related.
These tubes also offer a bit more sensitivity than 6V6 and kin. That's largely a matter of habit. The gain diff is not enough to change how many stations you get, or allow you to drop a whole tube.
Backing up: 6V6 is 6L6 technology in a smaller 6F6-like package. Many-many 6F6 rigs were re-designed as 6V6 rigs, because the 6V6 uses less heater and gives better gain. Taking the 6V6 as the improved 6F6, and 6AQ5 as the small 6V6, then the further improvement from 6AQ5 to EL95 must not have been seen by US designers as urgent. Certainly 6V6/6AQ5 and kin filled many-many roles well.
But if you need an entire 6V6/6AQ5, then you need two EL95 to do the work.
EL95 is a newer EL42. This is specifically aimed at car radio. In the US we used 6V6 and then 6AQ5 for this job. It could be that smaller cars/batteries in Europe favored a tube half the size of a US dinosaur. The EL42 is made to be the same height as your RF/IF/driver tubes.
EL42 may be seen as a small-bottle higher-gain EL2. EL2 is arguably a half-size EL1, which is similar to a US '42 or 6K6, and maybe 6F6 and (major tweak) 6V6. So the types are "related", but in the same way that all humans are related.
These tubes also offer a bit more sensitivity than 6V6 and kin. That's largely a matter of habit. The gain diff is not enough to change how many stations you get, or allow you to drop a whole tube.
Backing up: 6V6 is 6L6 technology in a smaller 6F6-like package. Many-many 6F6 rigs were re-designed as 6V6 rigs, because the 6V6 uses less heater and gives better gain. Taking the 6V6 as the improved 6F6, and 6AQ5 as the small 6V6, then the further improvement from 6AQ5 to EL95 must not have been seen by US designers as urgent. Certainly 6V6/6AQ5 and kin filled many-many roles well.
But if you need an entire 6V6/6AQ5, then you need two EL95 to do the work.
