AX11 under....test!
Exactly as your shematic or maybe by other transistors but this is a weekend amplifier in any case .With that I had and a home made pcb...waiting parts for sr200.
Best regards.
Mr mile that is one of my next steps!
Exactly as your shematic or maybe by other transistors but this is a weekend amplifier in any case .With that I had and a home made pcb...waiting parts for sr200.
Best regards.
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AX11 under....test!
Supose you confused.
If we say for Apex AX11 NOT HX11 rail voltage as Mr apex sai is +/-25 min to +/-50max.
In my AX11 i start to test it from +/-12v next to +/- 15v and finall to +/- 22v.It is the limit of my power supply.
Now i think is safe to operate AX11 with +/- 42v and test it again.
HX11 is another amplifier .
Supose you confused.
If we say for Apex AX11 NOT HX11 rail voltage as Mr apex sai is +/-25 min to +/-50max.
In my AX11 i start to test it from +/-12v next to +/- 15v and finall to +/- 22v.It is the limit of my power supply.
Now i think is safe to operate AX11 with +/- 42v and test it again.
HX11 is another amplifier .
AX11 under....test!
Hi Mr Apex.
I think the increased supply voltage would have the effect of increasing the quiescent current but this did not happen.
With rail voltage +/-42v CURRENT is MINIMUM ,continues to be unmeasurable on 0.22r.
Where can we put a trimer on the attached shematics
?
Finally is my probleme because of the replecements parts?
Hi Mr.
As i promise the AX11 is here today🙂
bf 872 instade of mpsa92 diferent base
2n6427 instade of mpsa13 same base
2sa1943
2sc5200 final out
Tested rail voltage +/- 23v from two stabilized power supplies
Thats for now ....coming soon on youtube!
For listening of cource.
Thanks Mr Apex.
Pai attention ..in first two photos bd139 and bd140 wrong position!
Hi Mr Apex.
I think the increased supply voltage would have the effect of increasing the quiescent current but this did not happen.
With rail voltage +/-42v CURRENT is MINIMUM ,continues to be unmeasurable on 0.22r.
Where can we put a trimer on the attached shematics
?
Finally is my probleme because of the replecements parts?
Attachments
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The left diagram shows the bias voltage trimmer.
The right diagram has the trimmer on the wrong side of the transistor.
The right diagram has the trimmer on the wrong side of the transistor.
AX11 under....test!
This maybe more efficiency
trimmer 2k2
Let's wait for Apex opinion.
This maybe more efficiency
trimmer 2k2
Let's wait for Apex opinion.
Attachments
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Max bias voltage will be ~ Vbe * {1+3k3/2k2} ~ 2.5Vbe
But you have 4Vbe in the output stage.
Measure the bias voltage as you change the trimmer.
Measure the Vdrop of that 220r as you change the trimmer.
Now do you understand why the output bias is near zero and appears not to change?
But you have 4Vbe in the output stage.
Measure the bias voltage as you change the trimmer.
Measure the Vdrop of that 220r as you change the trimmer.
Now do you understand why the output bias is near zero and appears not to change?
Placing a trimmer 10k in place of 4k7 resistor of original shematic idle curent is controled and easy setting to 33mv on 0.22r emitter resistor but in this case idle current isn't stable and continuas rice .Vas transistors come very hot because of no temperature monitor by the current source?
AX11 under....test!
it's mine wrong mr apex say +/-15mv on 0.22r
lets try it this afternoon.
it's mine wrong mr apex say +/-15mv on 0.22r
lets try it this afternoon.
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Set bias after 20 min runing amp whan VAS transistors are hot, and reset after 10 min whan output transistors are warm.
ok Mr Apex but how can set bias in the original shematic?
Finally is this modification the right way?
Attachments
SG(signal ground) ?
I suppose its already connected to ground directly on the board, and should only connect to input signal wires shield/connector
but could still sound like you might have a missing connection(ground ?) somewhere