Studio 350 bias problem

[Ian Finch]

I'm inclined to go along with your final resolution.

 

[daviddsailor]

Thanks for taking an interest in my little project. Any further comments on progress will be posted on the L20 page. Regards.

 

[amptech]

Hi guys..this may be a little late on this..

But I built my own scaled down of this amplifier using to-3 devices and it works great.

I used mpsa92 ... plus changed the 100 ohm preset in the tail pair to 220 ohm and same in the bias set up.
Rail decoupling caps at 220uf instead of 470uf. I did not like how the zobel parts was set put so I used a heavy air coil to the output and a 6.8 ohm plus 220nf decoupled to ground.

If you have trouble with the amplifier use a mains lamp limiter to aid in repairs. Offset can be 0 volts to say 40mv and mv across the .047 emitter resistors can be 10mv.

I will be happy to help and if need be use voltage readings from my own amplifier to solve yours.

Hope you all solved things.

Regards.