Burning Amplifier BA-2

[gpsmithii]

Any chance we will see a version that would allow me to use up a box of "regular" (MJ15024/25) transistors left over from my Audio Art days?

[Nelson Pass]

A few of the BA chassis actually had those with 15030/31's as
drivers. I suppose I'll have to see...

[Nelson Pass]

Originally Posted by Zen Mod

second one is that Papa isn't so keen on kwayzee shunt regs ; not that he can decide instead of anyone what is good for your own amp , or not ..... but this playground is certainly his Oyster .....

I don't recall indicating that. I simply did not see any reason
for my intervention.

[gpsmithii]

Originally Posted by Nelson Pass

A few of the BA chassis actually had those with 15030/31's as
drivers. I suppose I'll have to see...

Fixed many an SAE 2200 & 2400 with those as drivers.

Thanks for the consideration and all you do for the group here Mr. Pass.

[Zen Mod]

Originally Posted by Nelson Pass

I don't recall indicating that. I simply did not see any reason
for my intervention.

Pa' , that was a spinnnnnnning joke

[metalman]

Originally Posted by Zen Mod

like this .........

btw - Papa just giv'sya basic of output stage of XA amps ( at least my small , often hurting , brain alarms on that ....... )

Yup, X'ing that should be pretty straightforward.

Only problem is that I only have the trafo and heat sinks for a sinlge stereo BA2, or one mono BAX2. Not sure I can cough up the dough for extras without my wife

[CBS240]

Hi Mr Pass, neat simple amp

I like the modular concept. A question though, could one use a depletion mosfet in place of the IR610, say a DN3525.pdf from supertex? Seems feasible to me but I've never used a depletion mosfet as a VAS before.

[Zero Cool]

If our gate drive is limited to about 9 volts by Zener Diodes D1 and D2, why couldnt we run the front end of 24V and the output stage off say +/- 70v? with lower bias. 6-8 pairs should be good for 200 watts of class AB power I would guess judging by other commercially available designs.

And i ask this question in ernst from a learning perspective. what is the stopping factor. I feel as if i am missing a bigger part of the picture. I have often heard N.P talk about never letting the gates get about 20V or the mosfets blow up. and that all that is needed is 4-5v on the gates. so that sounds like not much voltages is needed to turn a mosfet fully on. so what is the limiting factor?? why couldn't we use a low voltage supply for the front end and a higher voltage/current supply for the output stage???

(I have this big beautiful but sadfully dead Stasis chassis sitting here begging for a project!)


Zc

[Looneytunes]

Thank you Nelson.

Looney

[Zen Mod]

Originally Posted by Zero Cool

....... why couldn't we use a low voltage supply for the front end and a higher voltage/current supply for the output stage???
.....


Zc

re-read article few times .....

even if I didn't , I can bet that Papa explained that entire voltage swing is coming from front end .....

output stage is follower ........ not having voltage gain


edit:

anyway - you can still increase voltage for entire gadget , but with usual Voodoo needed for input diff stafge - cascoding with small bjts ....... blahblah