I tried this idea to drive the balanced output of my Roland E660 in a gainclone. Used chips are OPA549. No bad smell, no DC on the output but also no sound They are powered with 2 12v batteries wich gives a -12 and +12 rail. Also there's a 0,1 µF cap over the 2 rails.
Even when i connect just one on a unbalanced output still nothing.
The only thing i hear is a slight *pop* in the speakers when I power the 549's.
An externally hosted image should be here but it was not working when we last tested it.
Even when i connect just one on a unbalanced output still nothing.
The only thing i hear is a slight *pop* in the speakers when I power the 549's.
SpaBlauw said:both are connected to the ground, wich in this case is the plus and minus from each batterie. -12 gnd +12
yes.
sorry to hear about the hum. i cant really help more, as i dont know anything about balanced inputs/outputs.
I just red the datasheet over again, in wich stated that ref. pin must be als low as the negative voltage if V- is used. So in my case -12. Sadly enough I don't have anymore samples avaible so this project has to wait.
@carlosfm, actually this is a bridgeclone. But you can call it a balanced amplifier since you use the - in / + in to drive it.
@carlosfm, actually this is a bridgeclone. But you can call it a balanced amplifier since you use the - in / + in to drive it.
SpaBlauw said:I just red the datasheet over again, in wich stated that ref. pin must be als low as the negative voltage if V- is used. So in my case -12. Sadly enough I don't have anymore samples avaible so this project has to wait.
@carlosfm, actually this is a bridgeclone. But you can call it a balanced amplifier since you use the - in / + in to drive it.
oops, sorry. i forgot that they go to -v.
Matttcattt said:
oops, sorry. i forgot that they go to -v.
what do you mean by that?
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Mad_K said:Right. As I look closer on your schematic on top of the page, it seems that you have reversed the psu lines? V+ should be connected to 10,11 and V- to 5,7.
Yup you are right, but i solderd it the right way. So +V is on pin 10/11
SpaBlauw said:
Yup you are right, but i solderd it the right way. So +V is on pin 10/11
What kind of DC offset do you get at each amp/output to GND?
Mad_K said:
what do you mean by that?
i meant that i forgot that in my amp, i connected the ref and Ilim pins to the -v rail. (before i said that i connected them to ground).
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