F5m kit

[mordikai]

I was just saying what you wanted to hear.

 

[Nelson Pass]

The 5m sounds better. The pace is more relaxed. It's more forgiving as-well. I think the og F5 has maybe a little more bass control.

This corresponds roughly to my own impressions. The F5m input stage has more push-pull square law cancellation
and operates with a higher impedance feedback network. Less feedback, less damping, more 2nd harmonic,
less nervous energy...

Just the sound for me at my advanced age....

 

[kannan_s]

is there a turbo F5m planned?

 

[mordikai]

This corresponds roughly to my own impressions. The F5m input stage has more push-pull square law cancellation
and operates with a higher impedance feedback network. Less feedback, less damping, more 2nd harmonic,
less nervous energy...

Just the sound for me at my advanced age....

Damn! I guessed right!

 

[gary s]

Many thanks Nelson, sounds very good to me.

 

[nitsk]

@kannan_s The F5m was introduced by Nelson at Burning Amp last year: https://burningampfestival.com/videos/

The f5m bit starts at 21:10. The turbo question was asked and answered at 34:09.

 

[tonyEE]

Yeah, I remember that question about the turbo.

There's always the F5T v3... hmm... 100 wpc... Hmm... an F5mT v3?

 

[Holzarbeiter]

There's always the F5T v3... hmm... 100 wpc...

It must be built, it will be built.

 

[EUVL]

The F5m input stage has more push-pull square law cancellation and operates with a higher impedance feedback network. Less feedback, less damping, more 2nd harmonic,

Like the original Selectronics ProFet.
https://www.diyaudio.com/community/...162-amplifiers-collection.185824/post-2702047
https://www.diyaudio.com/community/threads/recommendation-for-5-10w-amp.255523/post-3910072


Patrick

.

 

[lhquam]

Without any source degeneration of the JFETs.

 

[EUVL]

Without any source degeneration of the JFETs

Only possible with VFETs, not with laterals.
Else too little gain for the frontend.


Patrick

 

[lhquam]

I was referring to the lack of source degeneration of the F5m JFETs.

 

[EUVL]

Me too.

The laterals used in the ProFet don't need source resistors.
Their Vgs is much lower at around 1V.
If you run the JFETs at Idss, the drain resistor is only about 130R.
That will only give a gain of ~4.

VFET + Resource will be about 5V.
Factor of 5 more gain.


Cheers,
Patrick

 

[tonyEE]

What's the status of the F5m kit in the store?

 

[WBS]

Photos for the store website will be taken soon.
The completion kit is shipping to the store tomorrow and should arrive in about a week.
The essentials kit will follow shortly once the final touches are made on the PS board.

All of the pieces are falling into place for a fantastic kit! 🍿

 

[tonyEE]

How about an interest list?

 

[6L6]

There is plenty of interest!!

 

[WBS]

@tonyEE there are 100 essential and completion kits that are going to the store. They should be available for at least a little while when they become "live."

 

[tonyEE]

OK... send me a heads up?

 

[6L6]

Watch the store.