triple check values of all resistors, especially at buffer input and after buffer
most likely there is some heavy load, eating the signal
I mean - if you are able to set Iq and output node (prior to coupling cap) to prescribed values, you're almost there
reminder - post #2, almost everything you need it to sing
https://www.diyaudio.com/community/threads/the-singing-bush-tips-n-tricks.357497/post-6279704
most likely there is some heavy load, eating the signal
I mean - if you are able to set Iq and output node (prior to coupling cap) to prescribed values, you're almost there
reminder - post #2, almost everything you need it to sing
https://www.diyaudio.com/community/threads/the-singing-bush-tips-n-tricks.357497/post-6279704
Making some progress. I traced the signal and managed to short one of the jfets, eliciting the magic smoke. The jfets were toasted so I replaced them with matched lsk170bl (8-11mA Idss) from the diyaudio store. I fried the mosfet, the optocoupler and one of the diodes so I ended up replacing all semiconductors except for the 2sk182 which was fine. Replaced the jfets with Lsk170 in the other channel to match. Biased again both channels, 38.5V and 2.8A. one channel gives 22V out into 4R for 2V in, the other one 14.2V out for 2V in. What can I do to adjust this imbalance? Should I simply stick a pot in the input of the higher gain channel, and dial the input down to match the other channel? Thanks
pics
you did something wrong, I can hardly believe that difference in SIT gain is that high
first compare signal you get in and out of input buffer, either with scope or DMM
GND as reference is fine in both cases, meaning - where black probe goes
we will rather introduce some NFB than kill good signal simply with resistive divider
you did something wrong, I can hardly believe that difference in SIT gain is that high
first compare signal you get in and out of input buffer, either with scope or DMM
GND as reference is fine in both cases, meaning - where black probe goes
we will rather introduce some NFB than kill good signal simply with resistive divider