TSSA - The Simplest Symmetrical Amplifier

[Jay]

Originally Posted by homemodder

What nasty clipping ?? I happen to have repaired a Stark for a friend, it clips perfectly even without the clipping module.

Hehe then it must be my mistake

Originally Posted by homemodder

Just recieved some interesting info regarding audiolabor, its designer is Christopher Schürmann who is responsible for the design of the Soulution. That explains many things. The Soulution is regarded by many as the best solidstate amps ever made.

I love the look of the Soulution systems the most. I downloaded every pictures from their site, including Schurmann sitting next to a computer monitor showing complex circuit.

On another thread, Tommy and... uhmm... Ontoaba thought that the Soulution was inspired by AR D400, but I knew they were wrong because I read the history of the Soulution...

You should read his thoughts about feedback...

[mikelm]

Originally Posted by jacco vermeulen

>350 square inch total exposed surface.

That's a relief to hear. For a moment there I thought we were losing touch with reality . . .

[Jay]

Originally Posted by jacco vermeulen

Back panel of the Schnell is an 8mm aluminum plate, thermally coupled to the solid square bars.
Outer shell is an alloy tubular with 3mm wall thickness, pressed to the framework with bolts (the back panel plus square side bars have threaded holes in the bottom side), >350 square inch total exposed surface.

The diodes (and transformer size ) tell me that it is not a class-A amp. I have cloned the amp and even if with different circuit (slightly) it will be hard to believe if it is biased below 400mA.

For class-A, such thick panel is not enough. No heat compound connecting the case and the body. But it is not class-A so...

Originally Posted by jacco vermeulen

Fetching half of the MSRP, more than two decades later, likely means they're still much sought after amps..

Damn, this is internet era... you can check that none of amplifiers with such topology sound bad. I think amp designers should also study statistics

I think DartZeel also uses the same "topology". But I couldn't find schematics I thought I had.

And there are many possibilities with this T/SSA topology. Even tho it is all very good, I believe there is a big room for "improvements". For example, I don't believe in BiGBT output. Let the statistics works, again...

[homemodder]

Originally Posted by Jay

Hehe then it must be my mistake



I love the look of the Soulution systems the most. I downloaded every pictures from their site, including Schurmann sitting next to a computer monitor showing complex circuit.

On another thread, Tommy and... uhmm... Ontoaba thought that the Soulution was inspired by AR D400, but I knew they were wrong because I read the history of the Soulution...

You should read his thoughts about feedback...

Well my take on the soulution is that its not far removed from the ideas from audiolabor. I do believe it has diamond buffer outputstage with a little feedback applied to be able to have the specs it does.
The audiolabor circuit with diamond buffer outputstage would be good design, lowish distortion with very high bandwith. Thats what I built 20 years back when still only a student and under some guidence from my prof and JLH.

[jacco vermeulen]

Originally Posted by homemodder

regarding audiolabor, its designer is Christopher Schürmann who is responsible for the design of the Soulution.

Not just Christopher Schürmann, though he did still design the last Audiolabor product line (500, 511, CD player 531), some Soulution products still show his tubular chassis preference.
The Audiolabor Konstant turntable was Helmut Brinkmann's first commercial TT design.
Later loudspeaker designs were by Reinhard Wachowiak, gathered he learned his trade at MB quart (appears to be in the DIY parts scene since the late '90s, hifisound.de)

[Jay]

Originally Posted by homemodder

Well my take on the soulution is that its not far removed from the ideas from audiolabor. I do believe it has diamond buffer outputstage with a little feedback applied to be able to have the specs it does.
The audiolabor circuit with diamond buffer outputstage would be good design, lowish distortion with very high bandwith. Thats what I built 20 years back when still only a student and under some guidence from my prof and JLH.

I have never heard the Soulution. If it is considered the best sounding SS by many, then it means that amplifiers' output stage is not critical for that "kind" of performance level (because I don't believe in an output stage that I thought was Soulution 700). I attached the schematic (I don't think it is good at all).

Originally Posted by homemodder

The audiolabor circuit with diamond buffer outputstage would be good design, lowish distortion with very high bandwith. Thats what I built 20 years back when still only a student and under some guidence from my prof and JLH.

Inspired by Accuphase? I think you said you have published for public but I have none in my hard drive?

[jacco vermeulen]

Originally Posted by Jay

The diodes (and transformer size ) tell me that it is not a class-A amp.

Transformer of the late production Schnell is 300VA, and bias for 75W peak is also regarded Class A by many.
Fun part of residing here is having seen, felt, and heard these amps several times, plus talking to the man in charge at Audiolabor during the High End show in Germany.
The Schnell runs in Class A up till 1W, with the built-in emitter ballast resistance of the Sanyo output devices that corresponds to a Vt of ~25mV and optimum Class AB.

[Jay]

Originally Posted by jacco vermeulen

Transformer of the late production Schnell is 300VA, ...

The Schnell runs in Class A up till 1W, with the built-in emitter ballast resistance of the Sanyo output devices that corresponds to a Vt of ~25mV and optimum Class AB.

1W is so small! I don't know about the 2SD/SB devices. If what you mean is it has the built-in capability to limit the current, then that answers my curiosity.

You mentioned that there are more than one versions of Schnell. So other possibility is that the amp picture is not for the schematic I have seen.

The schematic shows 240VA rating (26V). For an EI transformer, the size would be big. I don't think the transformer in the picture is big enough?

[jacco vermeulen]

Originally Posted by Jay

The schematic shows 240VA rating (26V).

Older schematic.
(me is the audio janitor, oldfashioned paper is more reliable than the internet)

Why not take a look at the Vbe/Ic graph in the Sanyo datasheets.

[homemodder]

Originally Posted by Jay

I have never heard the Soulution. If it is considered the best sounding SS by many, then it means that amplifiers' output stage is not critical for that "kind" of performance level (because I don't believe in an output stage that I thought was Soulution 700). I attached the schematic (I don't think it is good at all).



Inspired by Accuphase? I think you said you have published for public but I have none in my hard drive?

Accuphase have never used diamond topology in outputstages for their designs. In those years they didnt produce any current feedback amps either that Im aware of. When I was 18 I couldnt be inspired by anyone or anything except the university prom queen.
I have never published any of my designs and never will but a couple are out there not of my doing but the comany has free reign to do with it what it pleases after it has exchanged ownership.