Eimac 100TH SE

[sganti]

I just posted this in dht driving dht, I built two variants of 100Th amplifier, one with choke loaded 6E5P driver and one with choke loaded 801A Driver. Both amps use Ale's Source Follower and Rod Coleman designed a positive bias supply. For 801A filament I used Guido's module and for 100Th I used Daitrons low noise smps supply. Attached are the circuit, outside picture and one of the amps inside picture. The plate chokes for Monolith Magnetics FeSi chokes, and the output transformers are Monolith Magnetics 3.6K Amorphous Core with 36 ohms cathode feedback winding. The power transformer is also monolith magnetics. The sound is awesome, punchy, clear without fatigue

 

[suwaned]

It's working in too "cold" operating point, isn't it?

Hi. it runs on autobias , current 22mA. still using C coupling 0.22uf / 1000V for 809 with B+ 650Vdc. haven't used fixed positive bias for 100TH. for all the transformers I made everything myself. I am still with this and the output is sufficient to drive my Fostex speakers.
Can you suggest for this, thank you

Sound of this Amp.

 

[suwaned]

I made repairs to the PSfilament VDC regulator of the 809 tube ( C /20.000uf), to decrease of humming.
it make be better but still have little noise. eimac 100TH used filament Vac.