Tube Hybrid Amp Gain Calculation

atiq19 · 21st November 2009, 10:03 PM

Does anyone know how to calculate the gain of this amp?

Allen Wright · 21st November 2009, 10:40 PM

The tube stage has zero gain (x1), as it's a pushpull cathode follower sitting on a current source.

The MOSFET stage I can't make any sense out of - where's the load in that weird drawn schematic? Are the loads meant to be the two boxes marked "0.5"??

Simulation schematics don't mean much to real engineers...

Regards, Allen

atiq19 · 21st November 2009, 10:54 PM

well, the circuit is owned by Broskie, design development discussed here:

index

he mentioned 10dB gain, I wanted to find out gain equation. i could not get hold of him though..

Allen Wright · 21st November 2009, 11:21 PM

He almost never answers questions by email.

Can't help you with a simulation circuit. His real circuit makes a little more sense - but I believe he almost never builds any of these circuits he publishes, so why chase fairies?

There are hundreds of great proven circuits out there.

Regards, Allen

jerluwoo · 22nd November 2009, 06:46 AM

There are several SS amps that use this output stage I have seen posted around here from time to time. Successful commercial amps at that. Sorry I cant recall the names of them at the moment.

revintage · 08:51 AM

Quote:

Simulation schematics don't mean much to real engineers...

By "real engineers" I suppose you mean those old goofs with white coats and a slide ruler sticking out of their breastpockets

.

The schematic(with or without simulation) doesn´t make sense anyway......

jmbee · 22nd November 2009, 09:10 AM

it looks like the transnova Hafler.

http://www.hafler.com/techsupport/pd..._P4000_man.pdf

revintage · 22nd November 2009, 09:39 AM

Ooops,
Checked the Broskie article and it seems that there is some sense afterall

.

woody · 22nd November 2009, 10:23 AM

I believe that circuite has 6db gain. If you look at broskie's article on power boosters
he describes a push pull power follower circuite where the output is grounded and
the output is taken from the junction of the + and - power supplys. That changes
the push pull follower from unity gain to 6db.

atiq19 · 22nd November 2009, 10:57 AM

Woody,

How do we get 6dB?

Regards

Atiq

21st November 2009, 10:54 PM	#3
atiq19 diyAudio Member Join Date: Jun 2007	well, the circuit is owned by Broskie, design development discussed here: index he mentioned 10dB gain, I wanted to find out gain equation. i could not get hold of him though.. __________________ Atiq19

22nd November 2009, 09:39 AM	#8
revintage diyAudio Member Join Date: May 2007	Ooops, Checked the Broskie article and it seems that there is some sense afterall.

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21st November 2009, 10:40 PM	#2
Allen Wright R.I.P. Join Date: Dec 2001 Location: Schaffhausen Switzerland	The tube stage has zero gain (x1), as it's a pushpull cathode follower sitting on a current source. The MOSFET stage I can't make any sense out of - where's the load in that weird drawn schematic? Are the loads meant to be the two boxes marked "0.5"?? Simulation schematics don't mean much to real engineers... Regards, Allen

21st November 2009, 11:21 PM	#4
Allen Wright R.I.P. Join Date: Dec 2001 Location: Schaffhausen Switzerland	He almost never answers questions by email. Can't help you with a simulation circuit. His real circuit makes a little more sense - but I believe he almost never builds any of these circuits he publishes, so why chase fairies? There are hundreds of great proven circuits out there. Regards, Allen

22nd November 2009, 06:46 AM	#5
jerluwoo diyAudio Member Join Date: Feb 2006 Location: Ashland,Ky U.S	There are several SS amps that use this output stage I have seen posted around here from time to time. Successful commercial amps at that. Sorry I cant recall the names of them at the moment.

22nd November 2009, 09:10 AM	#7
jmbee diyAudio Member Join Date: Sep 2008	it looks like the transnova Hafler. http://www.hafler.com/techsupport/pd..._P4000_man.pdf

22nd November 2009, 10:23 AM	#9
woody diyAudio Member Join Date: Jan 2002 Location: Tyrone Ga. U.S.A.	I believe that circuite has 6db gain. If you look at broskie's article on power boosters he describes a push pull power follower circuite where the output is grounded and the output is taken from the junction of the + and - power supplys. That changes the push pull follower from unity gain to 6db.

22nd November 2009, 10:57 AM	#10
atiq19 diyAudio Member Join Date: Jun 2007	Woody, How do we get 6dB? Regards Atiq