Solid Solid State Power Amplifier

[Federmann]

I also add the results of measurements

 

[stinius]

I can't see any compensating capacitors. Are they not needed
(drain-gate capacitance may be enough)? If You simulated
that circuit, can You show open loop Bode plots?

PMA asked me if I could post this for him.

 

[wahab]

indeed, a classical and very good topology..
the only drawback i could imagine is the differential input
common gate using irf s...bjts could make the work better..
and the differentials are connected in serial fashion through R1,
thus, the two symetrical stage are serial connected
even in ac mode...
isn t it better to use classical current generators connected
to the relevant supply lines?...

 

[plk]

I also add the results of measurements

Which amplifier was measured ?

 

[BV]

Clearly visible SR limited, SR about 10v/us, 10Vp-p....Headamp or line stage without load?

 

[john curl]

This is because the VCA driver devices have too much capacitance. 100V/us is possible with this design. I have made that number,100V/us, with this topology, for the last 35 years. In other words, the design is 'overcompensated'.

 

[john curl]

Apparently the actual slew rate should be 60V/us. This should be adequate, but I do think that the mosfets should be smaller in die size, still.

 

[BV]

Mr. Curl, measurements posted by Federmann have nothing to do with PMA amplifier . It sholud be "something" created by Federmann according his "revolutionary" principles.

 

[john curl]

PMA told me that his design has a slew rate of 60V/us and I believe him. It is a more appropriate slew rate for this design.

 

[Sendy]

Which amplifier was measured ?

Real measurements from PMA "s laboratory, no smoke, no fog, no fantasy :
http://web.telecom.cz/macura/step_response_pa2.png

 

[mos57]

Real measurements from PMA "s laboratory, no smoke, no fog, no fantasy :
http://web.telecom.cz/macura/step_response_pa2.png

SR= 90%-10% Vout

From you grafic Vout=40 V
so: 36-4=32V for 500mSec = 64V/uSec as said John.

Francesco.

 

[mos57]

SR= 90%-10% Vout

From you grafic Vout=40 V
so: 36-4=32V for 500mSec = 64V/uSec as said John.

Francesco.

500nS not mS, sorry

 

[Sendy]

Sorry, its difference between definitions....

-SR represents the maximum rate of change of a signal at any point... max(abs(dV/dt))
Slew rate - Wikipedia, the free encyclopedia

-90-10% - it may be used for measuring rise or fall time, not SR.
Rise time - Wikipedia, the free encyclopedia

 

[wahab]

Sorry, its difference between definitions....

-SR represents the maximum rate of change of a signal at any point... max(abs(dV/dt))
Slew rate - Wikipedia, the free encyclopedia

-90-10% - it may be used for measuring rise or fall time, not SR.
Rise time - Wikipedia, the free encyclopedia

agree, but let say that 64V/uS is the mean SR of this amp, as the
(abs(dv/dt)) is the instataneous value...so MOS57 is also right...

 

[BV]

Federmann, what you measured in post 61? It is far away from your simulations and it is very poor result. Or you must it heavily compensate, because it was oscilator?

 

[Federmann]

Federmann, what you measured in post 61? It is far away from your simulations and it is very poor result. Or you must it heavily compensate, because it was oscilator?

I know it's not the best result. I used the probe 10:1, and the voltage was greater. As I wrote, yet I can not disclose more.

 

[danhard]

So you let the secret to another thread. It does not belong here.

 

[EDDELARUE]

Hi Pavel,

what do you think about lateral mosfets as output transistors? No regarding measurements but sound quality ?

regards
eD

 

[danhard]

PMA this amplifier described on its Web
PA2 power amplifier

 

[Mooly]

Hi Pavel,

what do you think about lateral mosfets as output transistors? No regarding measurements but sound quality ?

regards
eD

For what it's worth I can tell you what I think... absolutely the best

Based on listening to many amps over the years