You could build it with just the pot on the mosfet powered from the negative rail if you don't need both positive and negative phase harmonic adjustment.
If you aren't matching or selecting devices, sometimes having the pot on the
top also is helpful.
😎
Gyuri, while not a guarentee, if devices are nicely matched, I found I liked no resistance on top fet and from .05-.1 ohm of resistance on the lower fet. An LM329dz is a nice quiet alternative to a zener and gives you a little headroom over the LED.
Hi guys,
Thank you for the hints!
I'm not in hurry with it, so I welcome any other hints in the future.
Pots will be on positive and negative sides as well, it is for sure.
All the more so because they could only find couples among themselves.
These were from the last batches at Farnell.
I hope so these are genuine.
I have four of them yet, (two from Farnell, two from Generg).
These are working in my DIY J2.
I don't think that I disassemble it in hope of I would find close matched pairs.
And these four are from different batches for sure.
Thank you for the tips Buzz!
Thanks especially to you Papa!
You do not even think of that you teach at university?
Your presentations even I can understand more or less, despite my crappy english and my lack in knowledge in electronics.
Kind regards,
Gyuri
Thank you for the hints!
I'm not in hurry with it, so I welcome any other hints in the future.
Pots will be on positive and negative sides as well, it is for sure.
All the more so because they could only find couples among themselves.
These were from the last batches at Farnell.
I hope so these are genuine.
I have four of them yet, (two from Farnell, two from Generg).
These are working in my DIY J2.
I don't think that I disassemble it in hope of I would find close matched pairs.
And these four are from different batches for sure.
Thank you for the tips Buzz!
Thanks especially to you Papa!
You do not even think of that you teach at university?
Your presentations even I can understand more or less, despite my crappy english and my lack in knowledge in electronics.
Kind regards,
Gyuri
I think Buzz's suggestion is a very good one.
It is also the simplest solution that should produce the predicted effect most people are probably hoping for.
If you can produce curves of Id vs Vgs for your parts that would be very informative/useful to give the correct advice.
Edit: To get the AC degeneration on the diyaudio pcb like Buzz is suggesting the cap lead needs to be routed to other side of resistor lead wire.
Sounds like you are interested in installing the pots for maximum adjustment though rather than choosing a fixed result.
It is also the simplest solution that should produce the predicted effect most people are probably hoping for.
If you can produce curves of Id vs Vgs for your parts that would be very informative/useful to give the correct advice.
Edit: To get the AC degeneration on the diyaudio pcb like Buzz is suggesting the cap lead needs to be routed to other side of resistor lead wire.
Sounds like you are interested in installing the pots for maximum adjustment though rather than choosing a fixed result.
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If you are certain you want pots on both mosfets (which is certainly ok/desirable), you won't need to produce curves of Id vs Vgs. You can just adjust the pots by ear.
Or can I put two more pots/channel for bias and DC offset on the front panel?
I think it will needs then two voltmeter/channel also on the faceplate.
It seems to me a quite wacky idea.
I think it will needs then two voltmeter/channel also on the faceplate.
It seems to me a quite wacky idea.
those pots in parallel to source resistors will not influence biasing and offset
they're effective just for AC operation , while Iq and offset are (mostly) factors in DC realm
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