Symasym - the next generation (supersym)

[Piersma]

OS,

With 77V rails you don't easely approch clipping, ofcourse i understand that. But I guess you are gonna make this amp also available to the community and I don't think everybody is going to use railvoltages like you do. I think there should be an option.....

Thanks !

[ostripper]

Thanks for keeping it "straight" , Andrew. Forgot about the cascode.
(reality below)

OS

[ostripper]

But I guess you are gonna make this amp also available to the community and I don't think everybody is going to use railvoltages like you do. I think there should be an option.....

I have not been able to blow it up yet.. I had my earlier version on 60v rails , and overdrove that one to collapse the rails , no blown components. we could baker clamp it , but I don't see many other DIY amps with those kind of considerations (quasi's , dx, even the symasym). The back to back diodes are all right , and protect against gross overdrive. No burning amps here !!
OS

[Rafael L]

Ostripper, what is the function of these diodes and resistor 22 Ohms?

Fig:

[jaycee]

To add some isolation between signal ground and power ground

[Pingrs]

Should Q6b,R17,R18 junction really go to signal ground? It doesn't in the original Symasym.

Brian.

[AndrewT]

I certainly would not take that cascode voltage reference to Power Ground.

[AndrewT]

Originally posted by Rafael.luc
what is the function of these diodes and resistor 22 Ohms?

Signal Ground is part of the input flow and return circuit.

The Ground can be exposed either at the amplifier or at the far end of the interconnect.
This exposed part must be connected to the Safety Earth.

The diodes should provide the high current route from Signal Ground to Safety Earth.

Signal diodes are the wrong choice for this duty.
1n4001 would be better.
1n5401 better still.

Do we need the 22r?
What effect does it have on the amplifier's performance?

[alex mm]

Hi ,

I'am ready, to hear some comments, regarding my PCB for supersym , and
I will fix any error http://i39.tinypic.com/jgirk9.jpg

Regards Alex mm.

[Rafael L]

Originally posted by AndrewT


The diodes should provide the high current route from Signal Ground to Safety Earth.

Do we need the 22r?
What effect does it have on the amplifier's performance?

I do not understand why anti-parallel two diodes, do to improve Safety Earth.

Originally posted by AndrewT

Do we need the 22r?
What effect does it have on the amplifier's performance?

Discussion started here:
http://www.diyaudio.com/forums/showt...086#post739086

But, I do not agree with the use...