F6 Amplifier

Nelson Pass

The one and only
Paid Member
2001-03-29 12:38 am
ZM has been nagging me for information on the F6. I have a very nice
sounding prototype, but the design and the article that accompanies it
have some details remaining.

However, I can afford to put out this teaser:

:cool:
 

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Uunderhill

Member
2008-12-27 11:27 pm
The Devil is in the details.

Having only n type output devices - reminds me of tubes.
Could a jFET be used as a phase splitter instead of the transformer ?

I take it the voltage gain stage would have active regulation
and the current section would have passive "regulation."
 
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Antoinel

Member
Paid Member
2012-01-01 10:23 pm
Pennsylvania
ZM has been nagging me for information on the F6. I have a very nice
sounding prototype, but the design and the article that accompanies it
have some details remaining.

However, I can afford to put out this teaser:

:cool:

Mr. Pass: Is it correct to assume that the secondary windings of the transformer turn on the attendant FET in a synchronous fashion; meaning one is on more ON while the other is more OFF? Are the FETs SIT and/or enhancement? Is there a Patent Pending,? Brilliant topology including the novel loop feedback.
 

Nelson Pass

The one and only
Paid Member
2001-03-29 12:38 am
The transformer secondaries are set up to drive the Fets in a matched
fashion, if that is what you're asking.

The Fets can be a wide variety of devices. In this case, R100's.

I no longer apply for patents.

I haven't seen this feedback mechanism as such, but you can be
sure it's been done one way or another, probably a long time ago.

:cool:
 

Antoinel

Member
Paid Member
2012-01-01 10:23 pm
Pennsylvania
Mr. Pass. Thank you for replying. The secondary windings [phase circles] as shown confused me. When the upper winding has a rising positive signal, the upper FET turns on. Simultaneously the lower FET has a matching negative signal to turn it off. Is this an approach similar to OTL [output transformerless] from the past; with identical polarity semiconductors. Then, audiophiles grumbled about an output transformer[phase abberations]; so the interstage one was kept as a compromise [and also absent complemetary devices] because it is inherently higher fidelity. I may have past articles from Radio and Popular Electronics on OTL topology.
 
ZM has been nagging me for information on the F6. I have a very nice
sounding prototype, but the design and the article that accompanies it
have some details remaining.

However, I can afford to put out this teaser:

:cool:

What disadvantages are to be expected by the use of a single ended input driver stages instead the here showed push-pull jFET version?

BTW - in this case this URLs are also of interest:
http://www.susan-parker.co.uk/zeus.htm
http://www.diyaudio.com/forums/solid-state/42259-zero-feedback-impedance-amplifiers.html
http://www.diyaudio.com/forums/solid-state/24744-push-pull-using-only-n-channel-mosfets.html
http://www.tubecad.com/2004/blog0006.htm
 
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