Hello romanescu,
at these high railvoltages you will need 2 pairs of JFets and cascode (per channel). The amount of JFets
depends on how much output-Mosfets you want to drive.
The cascode-voltage on your frontendboard will have to be adjusted (anywhere inbetween 12- 15 V).
the formula is: rail voltage/(R26+R28)*R28 = cascode voltage
I think you have read the F5T -article of Mr. Pass?
https://www.firstwatt.com/pdf/art_f5_turbo.pdf
The build guide and discussion guide for the F5T has become very long. I was also reading through more than 450 pages...
Most important information is in the build guide from 6L6:
https://www.diyaudio.com/community/threads/f5turbo-illustrated-build-guide.254056/
Very important is the section with the bias -up- procedure.
But first you have to build it...
Build your PSU - check it
Build your frontend - check it and adjust the trimpots correctly
Build your outputstage -check it
And use an DBT (dim bulb tester) at each first start up. Can be a life-insurance for your amp!
Have fun! This is an excellent poweramp!
Cheers
Dirk
at these high railvoltages you will need 2 pairs of JFets and cascode (per channel). The amount of JFets
depends on how much output-Mosfets you want to drive.
The cascode-voltage on your frontendboard will have to be adjusted (anywhere inbetween 12- 15 V).
the formula is: rail voltage/(R26+R28)*R28 = cascode voltage
I think you have read the F5T -article of Mr. Pass?
https://www.firstwatt.com/pdf/art_f5_turbo.pdf
The build guide and discussion guide for the F5T has become very long. I was also reading through more than 450 pages...
Most important information is in the build guide from 6L6:
https://www.diyaudio.com/community/threads/f5turbo-illustrated-build-guide.254056/
Very important is the section with the bias -up- procedure.
But first you have to build it...
Build your PSU - check it
Build your frontend - check it and adjust the trimpots correctly
Build your outputstage -check it
And use an DBT (dim bulb tester) at each first start up. Can be a life-insurance for your amp!
Have fun! This is an excellent poweramp!
Cheers
Dirk
