Sony VFET Amplifier Part 2

Since the Maggies love current, I'm curious what minimum quantity of complementary paralleled pairs of the 2SK82/2SJ28 VFETs would be needed to properly drive them full range.
Thanks Botte.

Actually they just need power. If it takes some current to make that then that's how it goes; the formula is described by P=Isquared x R.

When I showed at the MN Audio Society last month, the amp I used only made 140 watts and was a zero feedback OTL, not an amp known for 'current'. But I had plenty of power to drive the room no worries.
 
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...the amp I used only made 140 watts...

Only 140 watts? That's 7 times more wattage into 8 ohms than the amp we're talking about in this thread. BTW atma, did you ever get some vfets to play with?

My Maggies were power hungry and lacked bass. Although I thought about it, I never went as far as bi-amping them. I think that the VFET 2 might work nicely for the mids and highs if the the heavy lifting is left to the subs.

Botte, how did you come to your decision to roll off at 80hz and not higher?
 
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Botte, how did you come to your decision to roll off at 80hz and not higher?

Well the demo went well, I was quite surprised how well the V-FET pt 2 did on the big Maggie's in a large room.

The 80hz was just an arbitrary decision and I had a cap in a box for use with my subs. Worked great, they drove it much louder than I would have expected and no one went running.

Once again people were impressed by the dynamics which on the 3.6's is saying something.

I do run my amp at a little higher bias 1.5 amps.

:)
 
Only 140 watts? That's 7 times more wattage into 8 ohms than the amp we're talking about in this thread. BTW atma, did you ever get some vfets to play with?

:)

I did! Thanks to Michael R. for his help and generosity!

Now to make an amp- I've been working on a Circlotron circuit. Probably a topic for a different thread so as not to derail this one.
 
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Here's an update:

The DIY versions of the circuit boards are here and will be tested for errors
later today. Also I am working up the test procedures for DIYers to check
their work during the process of assembly (don't want to lose any of those
VFETs).

The samples of the brackets contained errors which are being corrected, but
I am using my own samples to do the work.

6L6 is being provided with the materials he needs to get one of his
construction guides together for this.

400 pair of VFETs have been tested.

Shouldn't be long now.

:cool:
 
The one and only
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2 hours later...

It appears to be fine.

:cool:
 

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