this is the schematic
and this the pcb ....your comments are very welcome
thank you
An externally hosted image should be here but it was not working when we last tested it.
and this the pcb ....your comments are very welcome
thank you
An externally hosted image should be here but it was not working when we last tested it.
R1 is too high of a value for the 5534 input off-set current.
Do you think you can get away with not using a compensatin cap for the opamp? It's de-compensated and not stable at gains of less than x5.
No temperature compensation for the bias, Suggest you look at the NJL0281/0302 ThermalTrac devices as drivers (as you need to track driver temp with this kind of output stage).
http://www.onsemi.com/pub_link/Collateral/NJL0281D-D.PDF
Only two pair of plastic outputs on ±74V? Resistive 8R load only please!
Do you think you can get away with not using a compensatin cap for the opamp? It's de-compensated and not stable at gains of less than x5.
No temperature compensation for the bias, Suggest you look at the NJL0281/0302 ThermalTrac devices as drivers (as you need to track driver temp with this kind of output stage).
http://www.onsemi.com/pub_link/Collateral/NJL0281D-D.PDF
Only two pair of plastic outputs on ±74V? Resistive 8R load only please!
djk said:
djk thanks for your comment ......
though the question is about the pcb since this is a comercial allready working amplifier
the only issues where about the original pcb since it was made very messy and disigned to fit inside a sassi with comfort but without any consideration to earth& signal rooting signal cables mixed with ac or dc cables and so on and on
this particular working amplifier has only stability and ocilation issues and has only thermostat and ventilators to preserve thermal stability ( dont know if its enough though )
the only question is about the pcb .... the circuit it shelf as we speak is not on judjment at least at this point
PCB revised by alex mm
Hello Sakis ,
At the first look , I see pin nr. 6 and 7 from IC connected nowhere , so PCB no good to me . You can replace PCB whith my PCB if correct . I keep same places for the componnents with smalls changes
any comment ? http://i27.tinypic.com/vxlso2.jpg . all the best alex mm
sorry for same bad english
Hello Sakis ,
At the first look , I see pin nr. 6 and 7 from IC connected nowhere , so PCB no good to me . You can replace PCB whith my PCB if correct . I keep same places for the componnents with smalls changes
any comment ? http://i27.tinypic.com/vxlso2.jpg . all the best alex mm sorry for same bad english
Re: PCB revised by alex mm
at this point i am not willing to mess up with the circuit ...... this i will find later ...the question was only about the pcb
fotios thanks man
alex mm said:Hello Sakis ,
At the first look , I see pin nr. 6 and 7 from IC connected nowhere , so PCB no good to me . You can replace PCB whith my PCB if correct . I keep same places for the componnents with smalls changes
sorry for same bad english
at this point i am not willing to mess up with the circuit ...... this i will find later ...the question was only about the pcb
fotios thanks man
no offence my friend
but for once i dlike people to understnd what i am talking about .....
A) you lower my tail voltage !!!! why ???
B) you skiped my secondary power sup for the op amp !!!! why ???
can you guarantee that the changes you made will produce a nice and stable amp ????? i presume not ....
the thing is that this circuit is acomercial working and many years on the market amplifier ( i cannot say if its good or not ) but the fact remains that its an existing amplifier.
to my understanding this amp suffers from ocilation and other issues since the box inside is a total mess menaing no ground rooting no signal rooting a cable mess mixed ac with dc mixed out and input and so on .....
that is the only reason i want to change the pcb ....after that i am willing to take a look at all the usefull advices given here and see if there is any improovement to be made .....
i know very well that what you did takes time to do but as you can understand thats not the point .....
thank you
alex mm said:Hi , Sakis
First of all , please fogive mee , my intend to help you , not to offence you . I spend time to make this PCB , and I hope to bee helpful to you .
but for once i dlike people to understnd what i am talking about .....
A) you lower my tail voltage !!!! why ???
B) you skiped my secondary power sup for the op amp !!!! why ???
can you guarantee that the changes you made will produce a nice and stable amp ????? i presume not ....
the thing is that this circuit is acomercial working and many years on the market amplifier ( i cannot say if its good or not ) but the fact remains that its an existing amplifier.
to my understanding this amp suffers from ocilation and other issues since the box inside is a total mess menaing no ground rooting no signal rooting a cable mess mixed ac with dc mixed out and input and so on .....
that is the only reason i want to change the pcb ....after that i am willing to take a look at all the usefull advices given here and see if there is any improovement to be made .....
i know very well that what you did takes time to do but as you can understand thats not the point .....
thank you
hei djk
hei djk .... beyond the pcb thing it seems that this thing is not working ..... just now i managed to make a demo pp wiring and it works but draws a hellof a lot of curent driving my limmiters to shut down after rail voltage goes up to 15+15 volts .....
then the schematic i did was exactly the same except outs were 1943+5200 otherwise all was the same and 5534 was replaced with tl071
can you please take a look at it ????
djk said:
hei djk .... beyond the pcb thing it seems that this thing is not working ..... just now i managed to make a demo pp wiring and it works but draws a hellof a lot of curent driving my limmiters to shut down after rail voltage goes up to 15+15 volts .....
then the schematic i did was exactly the same except outs were 1943+5200 otherwise all was the same and 5534 was replaced with tl071
can you please take a look at it ????
there you go djk
there is two things that changed in the circuit one that outputs are now 1943+5200 and also the op amp is tl 071 since 5534 wasnt available in my shop yesterday ( sunday ) there is also a post i ve made in the forum about this and there i picked some opinions and a lot of math but most of them forgot that this design is a working design from hill audio and has been on production for some time in the past ....
i cannot tell if it was good or stable but it has been on production as you see it
there is the schematic ...thanks djk
there is two things that changed in the circuit one that outputs are now 1943+5200 and also the op amp is tl 071 since 5534 wasnt available in my shop yesterday ( sunday ) there is also a post i ve made in the forum about this and there i picked some opinions and a lot of math but most of them forgot that this design is a working design from hill audio and has been on production for some time in the past ....
i cannot tell if it was good or stable but it has been on production as you see it
there is the schematic ...thanks djk
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