Sony amp

[StanleyB]

I still use a VFET power amp and have been doing so for decades. It's far better sounding than MOSFET and transistors.

[Reid Malenfant]

I'm assuming you mean in your opinion vfets sound better than class B or AB amplifiers with mosfet or transistor output stages

If so i'd probably agree with you. Output stage quiescent current tends to be higher (or can be higher) with vfets due to there inherent negative temperature coefficient. They are also much easier to drive due to lower gate capacitance than most mosfets which is beneficial also.

It probably explains how come the old Maplin 150W vfet amplifier kit was so popular

[DSJR]

Can you still get V-FET's?

Anyone who now drives the price of the Sony's upwards would need to get them serviced while they're working. I understand the output trannies came in very expensive matched sets and for a couple of diodes to check and replace (from summat I read on t'web), well worth doing. The 5650 and 8650 (less in the latter case) didn't like floppy, bassy speakers, but I suspect they'd love IB type speakers and "proper" Tannoy DC's with the lighter cones and corrugated surrounds

[Rare Bird]

You can pick up say 2SK60/2SJ18 if you look hard enough

[Reid Malenfant]

Can you still get V-FET's?

Yes It might not be easy to source stuff like the 2SJ49 or its complement the 2SK134 or other slightly different voltage vertions of the same thing, but other manufacturers make them.

BUZ900 & BUZ905 are exact copies & readily available, there are plenty of others as well including TO3P types

[swampy]

It probably explains how come the old Maplin 150W vfet amplifier kit was so popular

The Maplin kit was Mosfet BTW, not Vfet. It was based on the Hitachi application notes for the 2 output transistors used in the kit.

It was popular. I made one which is still in use today 20 years later by a relative.

[Dave Hewitt]

The 2sj 49 are not v fets they are Hitachi mosfets.
Dave.

[Dave Hewitt]

It appears that replacement v fets should have the same pinch number as the one its going to replace.Dont know what the pinch number refers to but probably is something to do with matching so that with parralel output devices they share the current equaly and one is not doing too much compared to the other.
Dave.

[Reid Malenfant]

Oooh cripes You chaps are right, just remembered they are lateral mosfets Just ignore me

[Vinyleyes]

Anyone know if this Technics SU 7300 is a V FET amplifier.

http://cgi.ebay.co.uk/Rare-Technics-...item3cb3356a24

Thanks