Home Tube DIY Asylum

Do It Yourself (DIY) paradise for tube and SET project builders.

RE: Questions about 6BG6G amp build (schematic) Grommes 216BA

You dont have to change the circuitry for the 12AU7 but I would use adapters and run 6CG7s because the difference in distortion and bandwidth is noticeable and measurable.Steve is right in that you want to beef the bias supply. You can use a 20uf film cap there but a lytic there is fine.
Why do you want to cut the charging cap to 20uf off the 5U4? I would use a 50uf film cap there and keep the existing choke because if you go to a 6Hy,that can kill dynamics and roll off the high end.What is the factory value of the choke? If it is 6Hy,then you should be ok because it was probably calculated.The 220k resistor from the 6BG6 plate is a loop feedback resistor for the driver.One more thing,if the output trafos in the amp are small,you may have to use some global NFB to keep the amp stable.

"For every complex problem there is an answer that is clear, simple, and wrong" H. L. Mencken

This post is made possible by the generous support of people like you and our sponsors:
  Kimber Kable  

Follow Ups Full Thread
Follow Ups


Post a Message!

Forgot Password?
Moniker (Username):
Password (Optional):
  Remember my Moniker & Password  (What's this?)    Eat Me
E-Mail (Optional):
Message:   (Posts are subject to Content Rules)
Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:  Automagically notify you when someone responds.