Starting Balanced CFP!

[Stee]

http://www.esafono.it/RHODI.htm
in my website you can see the balanced CFP amplifier
based on GHG thesis --> Global Hide Gain
using big BJT drivers to compense different hFE
between PNP and NPN devices.

also see a natural DC protection with big balanced capacitors on output

[AndrewT]

Hi,
do not connect the 100uF decoupling to Signal Ground.
I am having trouble working out how the output bias voltage controller operates.
Why slow devices to drive 3pair of fast 200W 150degC devices?

[Stee]

you can see how the output bias voltage controller have ground resistors,
so the zero reference works.

Slow devices to drive 3pair of fast 200W 150degC devices:
is my GHG thesis.
Global Hide gain on CFP is a method to compense hFE difference
between PNP and NPN.

If you have the same ratio(hFE) in two stages,
the complessive (hide, because at last G=1) gain is the same in each rail, so same speed on each rail, natural sound.

Better way is use exactly the same devices (as final) for drivers,
but need to change radiator

[blueskynis]

Those transistors just above differential...hmmm... Are those BC546's tied up as emitter followers or as wrongly drawn cascodes? To me it seems this will not work ...

[AndrewT]

I have no one else to blame but myself.

[blueskynis]

Originally posted by AndrewT
I have no one else to blame but myself.

What??

[sakis]

470 R /5W resistors from both drivers to ground ???? all your sonics are gone with this

[darkfenriz]

-whole input stage drawn in wrong polarity
-improper bias generator
-thermally unstable output stage

[CBS240]

Yup, it's bass ackwards.

How can you drive a BJT by it's collector? Some special transistor that is......

[sakis]

Originally posted by sakis
470 R /5W resistors from both drivers to ground ???? all your sonics are gone with this

Originally posted by darkfenriz
-whole input stage drawn in wrong polarity
-improper bias generator
-thermally unstable output stage

on the other hand in topology like that may be that the 470R5W are sonic killers but also they work as VI limiters meaning that since this is PA amplifier you might be ok with it after all taking as a fact that in PA amplifier top of the quality or hi end quality is not the target .

Originally posted by darkfenriz
the "thermaly unstable output stage " is working like hell and dont have stability issues ...its been like that in similar topology that HILL uses in the chameleon amplifier "

also let us not forget that this is a PA amplifier and the topology is AB+B meaning that the thermal stability issues apply for the first stage AB ...the B stage will follow hapilly and produce eficiency of almost 65% and related quality of class B

this will make an excelent subwoofer amp ... ( see also original drawings at Ebay ) very powerfull , reliable , with low power demands and made to last for ever ....but still let us not forget it is still a class AB + B

regards sakis