Must be time for another BA front end board.
hm,hm... I´m waiting Mr. Pass! A new front end will be born?
I just bought the PCB for the last version and will try it next days. I have to hurry up!
But the nice with DIY is, its not so expensive to follow your
paths.
Must be time for another BA front end board.
generg: " A new front end will be born? ..."
Oh boy! A new front end? Assuming that be like a pre-amp board to feed the output stage(s)?
... Balanced or unbalanced inputs?
.....some news, frontend works fine. I changed the feedbackresistor to 100kOhm, more gain for stripped F4. The outputstage is very similar to BA2 as far as I can see.
I was interested to compare the frontend as a pre with pumpkin. I did not forget to make the feedback from the output to D.
Sound is brighter, all singers seem to be younger, very good stage and more pointed.
Pumpkin darker, more dynamic, more colour, more crazy details.
Hi Zen Mod, how could I drive the BA1 outputstage with pumpkin? I am sooo cuuuurious to hear a single ended stage!
The points -D and +D from BA-1 are possible inputs for pumpkin without frying anything?
. I changed the feedbackresistor to 100kOhm, more gain for stripped F4. The outputstage is very similar to BA2 as far as I can see. I was interested to compare the frontend as a pre with pumpkin. I did not forget to make the feedback from the output to D.
Sound is brighter, all singers seem to be younger, very good stage and more pointed.
Pumpkin darker, more dynamic, more colour, more crazy details.
Hi Zen Mod, how could I drive the BA1 outputstage with pumpkin? I am sooo cuuuurious to hear a single ended stage!
The points -D and +D from BA-1 are possible inputs for pumpkin without frying anything?
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Oh boy .....
....... I must confess that I'm confused with all iterations ... I just mixed circuits and nomenclature .give me a link to exact output stage you wanna fry with
Hi speedy Zen Mod,
the link
http://www.diyaudio.com/forums/diyaudio-com-articles/154777-burning-amplifier-ba-1-a.html
thanks Gonzales
the link
http://www.diyaudio.com/forums/diyaudio-com-articles/154777-burning-amplifier-ba-1-a.html
thanks Gonzales
what's missing , for your purpose , in BA1 output stage is - biasing network for both halves (upper and lower ) ;
they're incorporated in BA1 front end , so - besides unnecessary complication to bring BA1 output to operation "just" as test bed for mate with
, I can't see any further benefit in using that , instead of F4 output stage .in fact - maybe you need some more heat in your room , but I already told you most efficient heath & sound-vise solution - make another F4 and make full balanced setup .
sorry - I was looking just on schematics in Papa's article ;
as one of rare spoiled kids without interest in BA amps ....... I'm guilty ... as Sin itself ......
have you exact schematic - generated to coincide with board , so I can help generg to try what he want ?
tnx cviller
@ generg
presuming that circuits from left and middle picture(s) in cviller's post are incorporated on same pcb - just shoot upper gates from positive output ; you must have output cap in place on pcb .
ground neg output ........ or shoot another BA1 output channel with it ..... and make bridged amp
@ generg
presuming that circuits from left and middle picture(s) in cviller's post are incorporated on same pcb - just shoot upper gates from positive
output ; you must have output cap in place on pcb .ground neg output ........ or shoot another BA1 output channel with it ..... and make bridged amp
hm, cviller....
I just saw the schematic from Nelson Pass shows a local feedback for BA-2 and a global feedback for BA-1. R204 (47k) for BA_1 comes from Out of the output stage. R204 (47k) for BA-2 comes from the output of the gainboard.
In your version of the gainboard the feedback is always the way BA-2 is described. Even when I use BA-1 biasboard?
Nelson Pass writes in the BA-1 description "We will be operating this output stage au naturale, outside of any feedback loop,..."
Correct? Is the difference between the two ways important or is there a fault in the BA-1 schematic??
I just saw the schematic from Nelson Pass shows a local feedback for BA-2 and a global feedback for BA-1. R204 (47k) for BA_1 comes from Out of the output stage. R204 (47k) for BA-2 comes from the output of the gainboard.
In your version of the gainboard the feedback is always the way BA-2 is described. Even when I use BA-1 biasboard?
Nelson Pass writes in the BA-1 description "We will be operating this output stage au naturale, outside of any feedback loop,..."
Correct? Is the difference between the two ways important or is there a fault in the BA-1 schematic??
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