Class AB Super Symetry use Bipolar transistor

[Rembulan]

Hi Everybody,
Has any one have tried to made super symetry in AB class use bipolar transistor ?

[GRollins]

I seem to recall hearing of people building an Aleph-X with bipolars. I can't remember the particulars at the moment.
There's no reason not to use bipolar transistors. The topology is not explicitly based on MOSFETs (or JFETs, for that matter). Go for it.

Grey

[Nelson Pass]

The first one I built was with a bipolar OS.

[Rembulan]

dont mind to share the reason to use MOSFET in comercial amp ?
The reason I want to use the bipolar especially in pushpull are its easier to find but if any body can help to me to use FET but not in single ended especially in quasy complementary I very apreciate

[Nelson Pass]

Mosfets simply work well for me, I get the sound I want and they
don't break. I can get similar, although not identical, performance
from bipolar devices (or tubes for that matter).

Complementary power JFETs would be my preference, but I don't
want to invest the millions it would take to develop them.

[DarkOne]

Here's one nice bipolar X design. It's biased in Class-A, but I think it can be biased to Class-AB without problems.

ExtremA
and thread on the forums
ExtremA on diyaudio

[Rembulan]

Complementary power JFETs would be my preference, but I don't
want to invest the millions it would take to develop them.

Mr.pass
Dont mind to explain ? I am confuse

[Nelson Pass]

Originally posted by Rembulan
Complementary power JFETs would be my preference, but I don't
want to invest the millions it would take to develop them.

Mr.pass
Dont mind to explain ? I am confuse

Back in the 1970's, Yamaha and Sony developed some power
JFETs for use in the output stages of their amplifiers. This met
with only limited success, and they eventually discontinued their
manufacture of the amplifiers and also the power JFETs.

Since then, power JFETs have been unavailable, until a couple of
years ago when Lovoltech (now known as Qspeed) came out
with some N channel high current JFETs that could be used in
the output stage of a power amplifier.

As far as I know, I'm the only designer to put them to work, in
the First Watt F3 and the DIY version "ZV8" and "ZV9" projects.
I continue to sell F3's, and I have some more product under
development.

However, these are N channel parts only, and in addition, it would
be nice to get the Vds rating up above 25 volts and the chip
into a TO-3P package. I have been informed by the people at
Qspeed that all this would take vast sums of money, and they
don't have an interest in the audio market. Presumably they
don't see enough potential volume.

I can understand that - I myself am not willing to put a vast sum
of money into it. Nevertheless, the existing parts manage to
achieve distortion levels as low as .003% with only a single
gain stage - they can be very linear parts.

[Blues]

Originally posted by Nelson Pass

However, these are N channel parts only...

Please do the OS ala Aleph...Aleph JJ.

[Rembulan]

Mr Pass,
I understand your reason better. thanx
actually I want the class AB amp with super symetry because I need a power amp for my tiny rental company. I need at least 600 watt RMS to drive a pair my mid driver. single ended is out of question so class AB is a better choice for me. actually I can do it (calss AB) use MOSFET I have 200Pcs 2SK2698 but do not have a complementary made me nervous to try a quasy complementer. so next logical choice is complementary bipolar because its easier to find locally. any help or suggest are welcome