>I found the top half of the wave was being clipped & got rid of the clipping by upping the 200R resistor R111 to 300R.
You do reduce the avaialble gain a bit by increasing the emitter feedback resistor. The value also depends on your design goals. Do you want more OLG or more symmetrical clipping?
After prototyping the push-pull version I believe that the single ended output sucks. It is more trouble than worth doing. Perhaps it is good as a headphone amp, but it is not so useful in this application. There are plans to put it on a 990 footprint board and the heatsinks required are very impractical on a little board like that. The push-pull version is still Class A if you bias the transistors sufficiently. We have 6ma running in the VAS. Running that throught two diodes you get pretty good Class A bias on the output. I measured 30mA standing current one time.
Try building it on a breadboard and see how well your simulations match reality. Come on, it is only five transistors and a few resistors!
Cheers,
Tamas
You do reduce the avaialble gain a bit by increasing the emitter feedback resistor. The value also depends on your design goals. Do you want more OLG or more symmetrical clipping?
After prototyping the push-pull version I believe that the single ended output sucks. It is more trouble than worth doing. Perhaps it is good as a headphone amp, but it is not so useful in this application. There are plans to put it on a 990 footprint board and the heatsinks required are very impractical on a little board like that. The push-pull version is still Class A if you bias the transistors sufficiently. We have 6ma running in the VAS. Running that throught two diodes you get pretty good Class A bias on the output. I measured 30mA standing current one time.
Try building it on a breadboard and see how well your simulations match reality. Come on, it is only five transistors and a few resistors!
Cheers,
Tamas