Hello Billhurst,
are your thermistors in good contact with the plastic case / surface of the Mosfets? Don't bend them to the metal washers on the Mosfets. The thermistors are well known to easily become damaged on the surfacecoating / colour.
If your new JFets have different values like your original ones - this could also explain a difference in the overall bias.
I would check the thermistors. You describe it as heating up equally , then one side goes / regulates down.
Only an asssumption from me.
And 20mV difference in bias is not so far away.
Cheers
Dirk.
are your thermistors in good contact with the plastic case / surface of the Mosfets? Don't bend them to the metal washers on the Mosfets. The thermistors are well known to easily become damaged on the surfacecoating / colour.
If your new JFets have different values like your original ones - this could also explain a difference in the overall bias.
I would check the thermistors. You describe it as heating up equally , then one side goes / regulates down.
Only an asssumption from me.
And 20mV difference in bias is not so far away.
Cheers
Dirk.
Take a look at posts #6982, 6993 & 6996, esprit was able to increase bias using 8 -11mA IDSS JFET's. Since you are NOT using the diodes, and your heat sink temps are OK, your DC offset is close to 0 mV it sounds like the JFET's are limiting max bias.
