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MEPER 14th September 2021 01:17 PM

I also have the option to convert the amp to use other devices when "VFET less" kits are released. But we will see if it is possible to get a spare VFET.....or a new pair :-)

What do we know about the "VFET less" kits if one of those a made for e.g. THF-51 .....and can run using 36 VDC so I can reuse the PSU?

But first priority is still to get the amp running using VFETs......without any noise issues.

egellings 14th September 2021 09:42 PM

With trimmer pots, the value of the total resistance is usually not important--it's the divider ratio you set off by adjusting the pot that's important.

MEPER 14th September 2021 09:57 PM

No, the headline of the thread is "misleading".
In the beginning I was convinced that the on/off noise I could hear in one channel was caused by a bad connection in the Bourns trimmer pot.
But at the end it turned out to be the VFET. It was quite early suggested by Nelson that some VFETs could develop such "habit" and it should not mean a lot. Amp can play nicely but when some of these "noise bursts" get as high as 20 mV......I think it is a bit too much. So now I see if I can get another pair of 2SJ28.......which is not easy.
I play my 300B amp until then :-)

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