This is a Gm100 Se Running in class A2. Got a many watts with hight Ht
Diy Amplifier ??????????????????????????
Diy Amplifier ??????????????????????????
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Could you please tell, what is the turns ratio of the output transformer for GM100 ?
What is plate voltage and grid-cathode voltage? This tube is similar in application to 833 tube, but even a bit more user friendly (allows more negative grid voltage that 833 at the same plate current). Internal plate resistance is around 3...4 kOhm. It has nice cylinder-like grid and plate geometry.
What is plate voltage and grid-cathode voltage? This tube is similar in application to 833 tube, but even a bit more user friendly (allows more negative grid voltage that 833 at the same plate current). Internal plate resistance is around 3...4 kOhm. It has nice cylinder-like grid and plate geometry.
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Nice work, the OPT's look tiny in comparison to the OP valve, what is the OP power and what is your HT? Also how are you driving it?
Andy.
Andy.
�� Im still looking for someone that can test my fillament current sources �� Nice build, if you need it il send you the board design for a 20A capable regulator. For free.
Also Great build, im interested in how you chose to drive it.
Also Great build, im interested in how you chose to drive it.
I’m used ac for heating the filament. The filament transformer can supply 20 amp. Symmetry winding made the equal for each side and centertab can use as chathode and reduced the humm
El34 swing plate 70 vpk can drive the big one
Regard
I guess you operation mode could be similar to values (zero grid bias voltage) from this russian diy person (Mr Rezvoy)
Ua=1500V, Ia=260mA, Ra=7,8k (Ra=2Ri), Ug=0V, Uin peak=60В, Ig peak=100мА, Рout=50Вт
Such a trick with A2 operation with Ug=0V is good applicable for 833 also.
However, I personally do not accept pure A2 operation. I would prefer -40-50V grid bias.
In my 833 monoblocks design I use -30V grid bias, 1970V plate voltage, 160mA plate current. A2 is coming only at very high output power.
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Do you have a separate fillament transformer? if So i would put a NTC in series or a turn on delay to limit thermal shock in the fillaments
Only output voltage on reaistive load 8 ohms 200w dummy load got the rms voltage monitor with ossiloscope
Amazing work! The guy who ran UltraAnalog was working with that tube but he shut his site down many years ago and no copies exist even in the wayback machine.
I once found a broken one in a lab here, they are impressive tubes even when the glass is shattered!
If you do it in correctly the sound of a2 class just like a1 but a bit of power and dynamic sound can gat mor power full and lower distrotion as negative grid bias a1
