GU-50 PP

[maton00]

I want to built the same amplifier as misko1985 but I have OPT Raa 3k with CF. Ub will be around 450V I suppose, what is the right current for gu-50 in this case? Maybe I try also triode connection. Thanks.

With triode connection will do 25W at 425-450V with a 5K OPT less than that the class B loadline would be very steep, but said that I have tested the GU50 in triode mode up to 560V with the same OPT for short and it didnt break a sweat....... but Im sure it wont last for long my supply sagged 80V at full blast......GU50 may be good for 30W in triode but more than that will be begging for troubles

 

[zintolo]

In pentode with 3k3 Raa load, 450 V on plates, 270 V on g2, 15 V on g3 and around -35 V on g1 (bias around 60 mA) you should get around 5 Wrms in class A, 40 Wrms in class AB1 and 90 Wrms in class AB2.

Best way to use them, looking at experts' design on this forum, around 850 V on plates, 270 V on g2, 15 V on g3, local feedback anode-to-g1 and 10k Raa load. This way a pair of them gives around 100 Wrms.

 

[zdenoeddie]

I have already tried, and with Ub=550V, Ug2=285V, Raa=3k, Ik0=50mA, I've got 25W (8R load). Driver is the same as in 1st post, for 285V regulator I used 6s19p+6z1p+Str150/30 own regulator.

 

[zdenoeddie]

Update: With Hammond 1650HA - 6k6 OPT, I've got 10W more on output. So it seems, that using 10k OPT (as Wavebourn wrote somewhere) is reasonable.

 

[Svytoslav]

70 watt

up to 40 W works in Class A

BEST!!!!