A very interesting amplifier schem , do someone knows more about??

gaborbela · 14th August 2010, 10:01 AM

Hello

Here is a amplifier schematic , for 2 different type power mosfet or to the new Sanken darlington .
Do someone know more about these ?
Any comment welcome since only the schematic and a couple words ,to me looks like Japanese .
Sorry if already somebody ask about these , I didn't find any info on the forum.
Please take a look .

Greetings

wahab · 14th August 2010, 10:21 AM

These are device with integrated diodes for thermal tracking.
They are at least 10 years old.
Elektor did use them in a few designs..

Rikard Nilsson · 14th August 2010, 10:50 AM

Interesting front end!

gaborbela · 14th August 2010, 04:41 PM

Hello

Yes the front end I think a bit over complicate but can be still good .
The output section actually very nice .
Probably for a few watt biased in class A or all the way ? 40V PS and 3 pair high power mosfet or darlingtons .
I was curious if anybody tried to clone these . Or the front end to scary?? It seems to me a bit over "the limit" .

Greetings

Rikard Nilsson · 14th August 2010, 05:14 PM

Well, the front end is probably good thanks to its relative complexity. I´m willing to try simulating it and if I can get it stable in the simulator I might build it and pair it with Cordell´s error correction output stage.

CBS240 · 15th August 2010, 08:09 AM

Not too complicated at all, cascodes with J-fet CCS's to set the cascode voltages and the current sources for the LTP legs, the VAS mirror is also cascode. The difference in current from the sum of the two LTP leg sources and common mode current source at the bottom for both sides drives the VAS. Quite a neat arrangement I think.

ostripper · 08:54 AM

Front end looks like Roender's "RMI" folded cascode. Only difference is the FET CCS for the cascode references. Another neat thing ... it looks like a modular setup , plug in any output stage. #1 is P-N vertical 2- quasi vertical 3 - a mystery?? (proprietary **)

OS

ostripper · 15th August 2010, 09:10 AM

Quote:

Originally Posted by gaborbela

Hello

Yes the front end I think a bit over complicate but can be still good .
The output section actually very nice .
Probably for a few watt biased in class A or all the way ? 40V PS and 3 pair high power mosfet or darlingtons .
I was curious if anybody tried to clone these . Or the front end to scary?? It seems to me a bit over "the limit" .

Greetings

Maybe if you compare it to a DX.

It is just a slighty augmented "symasym"...

I might sim it and put it on a 75mm X 75mm PCB module , just for fun (HX "mongrel").
OS

abraxalito · 15th August 2010, 09:49 AM

Quote:

Originally Posted by gaborbela

Any comment welcome since only the schematic and a couple words ,to me looks like Japanese .

Chinese I think. A couple of points - don't follow the input wiring arrangement shown - decoupling to the input ground (unless you want fairly poor sound). And the output stages have the zobel network on the wrong side of the output choke. According to Doug Self, the zobel is to help suppress VHF parasitics in the output stage, putting it on the far side of an inductor will reduce its effectiveness at that.

ostripper · 15th August 2010, 10:01 AM

Quote:

Originally Posted by abraxalito

Chinese I think. A couple of points - don't follow the input wiring arrangement shown - decoupling to the input ground (unless you want fairly poor sound). And the output stages have the zobel network on the wrong side of the output choke. According to Doug Self, the zobel is to help suppress VHF parasitics in the output stage, putting it on the far side of an inductor will reduce its effectiveness at that.

That is probably a HF input filter (220-470pF) OUR (DIY) zobels are standard ..

I don't think this was meant to be built , just an overview of some chinese design with a separate more specific BOM.
OS

15th August 2010, 08:09 AM	#6
CBS240 diyAudio Member Join Date: Aug 2005 Location: K-town	Not too complicated at all, cascodes with J-fet CCS's to set the cascode voltages and the current sources for the LTP legs, the VAS mirror is also cascode. The difference in current from the sum of the two LTP leg sources and common mode current source at the bottom for both sides drives the VAS. Quite a neat arrangement I think. __________________ All the trouble I've ever been in started out as fun......

15th August 2010, 08:48 AM	#7
ostripper diyAudio Member Join Date: May 2008 Location: Albany , NY (smallbany)	Front end looks like Roender's "RMI" folded cascode. Only difference is the FET CCS for the cascode references. Another neat thing ... it looks like a modular setup , plug in any output stage. #1 is P-N vertical 2- quasi vertical 3 - a mystery?? (proprietary *) OS __________________ Mongrel website , always current and updated : http://67.248.209.21/D%3A/WEBSITE/ Last edited by ostripper; 15th August 2010 at 08:54 AM.*

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14th August 2010, 10:21 AM	#2
wahab diyAudio Member Join Date: Nov 2009 Location: algeria/france	These are device with integrated diodes for thermal tracking. They are at least 10 years old. Elektor did use them in a few designs..

14th August 2010, 10:50 AM	#3
Rikard Nilsson diyAudio Member Join Date: Aug 2008	Interesting front end!

14th August 2010, 04:41 PM	#4
gaborbela diyAudio Member Join Date: Sep 2005	Hello Yes the front end I think a bit over complicate but can be still good . The output section actually very nice . Probably for a few watt biased in class A or all the way ? 40V PS and 3 pair high power mosfet or darlingtons . I was curious if anybody tried to clone these . Or the front end to scary?? It seems to me a bit over "the limit" . Greetings

14th August 2010, 05:14 PM	#5
Rikard Nilsson diyAudio Member Join Date: Aug 2008	Well, the front end is probably good thanks to its relative complexity. I´m willing to try simulating it and if I can get it stable in the simulator I might build it and pair it with Cordell´s error correction output stage.

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