All right guys.
I've build a test platform and tried this design, driving a quad 6L6 power stage.
The good news is that it is working, voltages are within the simulation, and the distortion is really low.
The bad news is that despite working, there is not enough gain for the amp to develop reasonable power.
So, back to the drawing board, I'll try to leverage the unused 1/2 section of the 6SN7 as an DC AF stage after. Wish me luck.
I've build a test platform and tried this design, driving a quad 6L6 power stage.
The good news is that it is working, voltages are within the simulation, and the distortion is really low.
The bad news is that despite working, there is not enough gain for the amp to develop reasonable power.
So, back to the drawing board, I'll try to leverage the unused 1/2 section of the 6SN7 as an DC AF stage after. Wish me luck.
Ok Here is my new attempt.
I separated the PS rail for each tubes as one tube impacts the others so it is difficult to get the 3 tubes lined up correctly. The gain is quite good for that one iteration.
Last look before I try the real thing again. The NBF divider is an extrapolation. I'll have to adjust it to around 10 db in the real world.
I separated the PS rail for each tubes as one tube impacts the others so it is difficult to get the 3 tubes lined up correctly. The gain is quite good for that one iteration.
Last look before I try the real thing again. The NBF divider is an extrapolation. I'll have to adjust it to around 10 db in the real world.
Attachments
Hi guys,
I spent some time implementing this design, and testing it in the real world.
The simulation is correct, and voltages and performance was just a bit lower.
I had to adjust the feedback level and add a cap to tame some ringing.
At the end the amp performed well, with only 10+ db feedback.
I did an A/B test with the 2 amps with mono recording, one with cap coupled front end and my new DC front, last night for 3 hours.
The result is the DC amp had a better noise floor, was a bit clearer but not by much. I also had less gain so I had to adjust the setting so the amp played at identical level.
In conclusion, the result is not worth while the effort and difficulty of DC coupling, left aside tubes compatibility problem.
So I gave up this idea, but had fun in the process so it was worth doing it.
I thought it was good to post my results so others can start where I left it.
Cheers.
I spent some time implementing this design, and testing it in the real world.
The simulation is correct, and voltages and performance was just a bit lower.
I had to adjust the feedback level and add a cap to tame some ringing.
At the end the amp performed well, with only 10+ db feedback.
I did an A/B test with the 2 amps with mono recording, one with cap coupled front end and my new DC front, last night for 3 hours.
The result is the DC amp had a better noise floor, was a bit clearer but not by much. I also had less gain so I had to adjust the setting so the amp played at identical level.
In conclusion, the result is not worth while the effort and difficulty of DC coupling, left aside tubes compatibility problem.
So I gave up this idea, but had fun in the process so it was worth doing it.
I thought it was good to post my results so others can start where I left it.
Cheers.
