Wrap up of my amplifier
-For a decade, I have been spending days on direct heating, triode transmitting (plus bias) tubes amps.
-For reference purpose, built a 801A x 3 in parallel (negative bias and non NFB) to monitor plus bias amps for comparison.
-No tangible differences observed between amps to use grid current flowing and conventional 801A with negative bias.
-For my B&W N-802 SP-system, more than 30W power is desirable to drive I feel....
-Finally, it is my pleasure to be able to participate in ETF 2008, and could have a lot of valuable discussion with group members, Arigato and thank you all.......
|Tube name||811A||100TH||838||8025A||801A X 3|
|Distortion( % at 1 KHz)||2||3.4||4.3||3.6||5.3|
|Plate DC Input(W)||51||72||81||27.5||42|
|Grid bias Voltage(V)||18.5||39||26.6||-18||-58.5|
|Grid exiting Voltage(RMS in V)||43||82||74.5||33||56|
|Grit current(Resting / Max. in mA)||13 ~ 18||21~ 48||11 ~ 21.5||0 ~ 6||0|
|D/F(on/off method at 1KHz)||2||2.85||1.6(local NFB)4.0 (global NFB)||4||2.6|
|Plate Dissipation(W)||45(CCS)65(ICAS)||100||100||30No air cooling||20 X 3|
|Filament(V / A)||6.3 / 4||5 / 6.3||10 / 3.5||6.3 / 1.9||7 / 1.25|
Ham shack & Service Bench