jaudio said:
I'm really confused since this is not the first time for this DRV134 board. I used this drv134 board with "hard-wire" LM3875. All boards worked very well. Then I created the PCB for LM3875. The LM3875 PCB alone works well too. Anyway, I will try to remove 22K.
Hi HaloD925,
A. Whats powering your DRV134, regulated or shunts and what voltage? [It's regulated by LM317/337.]
B. Are your power supply pins V+ V- bypassed to gound with a 1uf or similar cap? [Yes I use. It's Wima 0.1uf MKP]
C. Are you useing 10uf NP caps on the sense lines? [No I don't]
D. Are you useing the suggested 300ohm resistors on the outputs? [No, I dont. I will try] and if you are, are they in conjunction with 1Kohm input resistors on the LM3875 boards? [I use 10 k @ input.]
E. Do you have an input network on the DRV? i.e. 1k input resistor
22k shunt and 220pf bypass. No, not at all just connect it directly from my step attenduator.
F. Have you issolated the power and input grounds form the LM3875 boards from the DRV134, it is sometimes very important to lift the grounds............... OK it's isolated.
G. Our your output R/L going to the R/L sense lines ? [I'm not sure. Let me recheck.]
H. Input cap?? what value?? [No input cap for Drv134, but I use 2.2 uf for the LM3875 board]
Thank a lot for your help.
Shouldn't one of the LM3886 be in inverting mode and the other be in non-inverting mode? As I see it if there both in inverting mode then you'll get nothing from the amp (or am I incorect?)?
As for the hiss (ignore this if it's been asked already) have you put good de-coupling caps on the all of the op-amps?(that means buffer and lm3886)
As for the hiss (ignore this if it's been asked already) have you put good de-coupling caps on the all of the op-amps?(that means buffer and lm3886)
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