It should still measure 9V after R103/R203 at the gate when measured between gate and ground.
My brain is starting to have a melt down. Hahahaha
All I can think of is faulty jfets or faulty input cap or you have attached the power supply opposite polarity
My brain is starting to have a melt down. Hahahaha
All I can think of is faulty jfets or faulty input cap or you have attached the power supply opposite polarity
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looking at the scheme it is supposed that Q100/Q200 and Q101/201 are Nchannel Jfet but J74 should be Pchannel Jfet, does it make some sense?
They should be both N channel.
You should be using 2 x 2sk170 or 2 x lsk170 per channel.
You should not be using P Channel (J74) devices anywhere in this circuit
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I just used the 4 Jfet that I received with the board. I'll try to buy some paired Nchannel and see.
Thank you pico I'll post the result as soon as possible.
Thank you pico I'll post the result as soon as possible.
If you reverse the polarity of the electrolytics and the diodes in the B1 and feed it from -18 Volts it should work with the J74 (if they are still alive).
Mrupp they should be still alive. does anyone know if there is a simple circuit to be implemented using the two J74?
You could do a preamp with a differential j74 front end and maybe 2sk2013 on output like mini Aleph J topology.
Or build a full size Aleph J
Or build a full size Aleph J
Cipo, you simply order here the two pairs matched, BL and cheap
Build them in and enjoy your Pass B1 like me..... 🙂
4X Toshiba Original 2SK170BL 2 Matched Pairs | eBay
That's £1.70 each ($10.87 for 4)
I should think about increasing my pricing (to UK buyers) and make an enormous profit to augment my pension, like some other Members are doing.
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