EL34 A2 Cascode SE triode

[Doug De Young]

It’s a pair. The shipping can be quite high though. Still it’s pretty good value.

 

[Francois G]

Also following this design with interest. The Mosfet in the schematic 10N60C seems to be obsolete. Will this one work in its place?

https://www.mouser.com/ProductDetail/STMicroelectronics/STP10N60M2?qs=DqCdCwOw4/5AmMf4xasHww==

Is this based on the Tubelab UNSET, or am I confused?

 

[Doug De Young]

That MOSFET isn’t rated for DC in the SOA so I’d look for one that can handle DC. 600v is unnecessary and RDS ON is not important in this application. 400v is more than sufficient. The 10N60 is still available.

I was unaware of TubeLab’s UNSET when I designed this and any similarities are coincidental.

 

[Doug De Young]

Preliminary test results. Here is calibrated voltage noise into 8R. The amp input is shorted. All hum components below 100uV. Pretty good for SE cascode with AC heaters. PSRR is very poor.

 

[Doug De Young]

Preliminary 1w FFT. I may roll tubes to see if I can lower this. Still .17% mostly second is not bad.

 

[Drewaudio]

Nice!