Article: Beast With a Thousand Jfets

[Blues]

supermosfets!

[Antoinel]

Originally Posted by Blues

supermosfets!

Blues, you have a great memory. Fortunately, time is on our side. It will show us the fate of the Beast.

Best regards.

[jacco vermeulen]

Originally Posted by Blues

almost 3 years ago

If you drive your search engine back a few more years, you'll find several posts of Papa about his parallel bank experiment with 100 small signal bjt's, mentioning on one occasion that he'll do it with JFETs one day.
That was before the SIT, so it was already in the works.

(then again, I don't even know what goes on in my own mind)

[Zen Mod]

Originally Posted by jacco vermeulen

..... my own mind)

lucky you - having one

[Antoinel]

Originally Posted by jacco vermeulen

If you drive your search engine back a few more years, you'll find several posts of Papa about his parallel bank experiment with 100 small signal bjt's, mentioning on one occasion that he'll do it with JFETs one day.
That was before the SIT, so it was already in the works.

(then again, I don't even know what goes on in my own mind)

I look forward to such exciting developments. Imagine Mr. Pass downsizing the hand-made Beast to a Sanyo-style STK-xyz amp package [5-pin]; to affix to a generous heat sink etc. In the interim, we'll dream on.

Best regards

[Nelson Pass]

Sounds like a good project for you.

[Antoinel]

Originally Posted by Nelson Pass

Sounds like a good project for you.

Mr. Pass. Thank you for your proposal. Unfortunately, my line of work is Chemistry. It will bury me. I wonder how often our diyAudio site is visited by Solid State Physicists, and Electronics Engineers from chip makers [worldwide] hunting for ideas and connections to make new devices. Since there is a great supply of the individual FETs, their makers are not inclined to change this profitable course. Your hand-made Beast is an engineering feat. A thousand DIYers practicing it will amount to a demand surge of 2 million pieces. TOSHIBA's execs are happy.



Allow me to return the favor of your proposal with the following ideas.

• Load both drains of the Beast with a bank of light bulbs and drive a pair of FR loudspeakers in push pull for the upcoming BA Festival. A De-Lite {R}Beast!
• A Baby Beast idling at 0.3 Amperes can be part of a STASIS {R} style output stage.
• The Beast is a fast power switch.

It all adds up to therapeutic fun reading and thinking about your creations.
Best regards.

[DougL]

What interested me was the sonic signature was not as predicted.
I am trying to think if this insight would indicate a direction for more practical development.

Doug

[Nelson Pass]

Speculatively, perhaps 2nd harmonic is not the only source of "sweetness".

[Antoinel]

Fortunately, this Mimick maybe as simple as a power buffer from a modified F5 and/or its descendants. A representative schematic is attached [jpg and identical pdf]. Note the following.

• The left part of the view is the parent schematic of F5 Amplifier by FW.
• The right schematic is the Mimick. The loop feedback resistors R5, R6, R7 and R8 were not used.
• The opposed drains of the complementary MOSFETs [Q3 and Q4] connect directly to the center point of the source resistors R1 and R2 of Q1 and Q2. This is the Power Output port.
• Be concerned with a possible oscillation with this [or any] power amp of unity gain.
• That's it.

Best regards.