Parasound Preamp Troubleshooting

[mura]

I recently changed 3 Opamps in my Parasound P/HP-850.

(AD 712 to BB OPA2134)


Now the left channel has lower High frequency response.


Any ideas why it is so?

I also tried going back to the original AD 712 but the problem does not go away.

 

[anatech]

Hi mura,
Check the solder joints around where you were working. You either have a solder bridge, or short, or you have desoldered a component. Also give the unit a shake in case you have some stray solder bits.

-Chris

 

[mura]

I have compleatly checked all solder joints , loose components ect,

Any idea what component can cause reduced HF response?

 

[anatech]

Hi mura,
I am not familiar with this unit. Does it have tone controls? Possibly a broken tone control pot? Normally you would have to replace a capacitor with the wrong value.
Can you have another tech look at it? Another set of eyes can fix any things.
-Chris