MP-1 A channel much quieter than B

[Mxzx]

Thanks, I'm guessing by master volume you mean master gain?

I did put that on 9 with with output level full open, and it still is quiet.

Thanks

[MarshallJMP]

Try replacing U10,it's a NE5532,very common opamp.Maybe a tip,when you replace put a ic socket first.

[Mxzx]

Will do, where exactly is it and where would I get a new one?

Thanks

[MarshallJMP]

U10 is just behind the vol pot,it's a 8 pin ic,there is NE5532 printed on the top.Normally you can get it in any electronics store.
Where are you from?

[Mxzx]

Thanks I'll check it out.

I live just outside of Louisville KY.

[MarshallJMP]

Well in your case mouser does carry these.Or check out the local electronics store if there is one in your neighborhood.

[Mxzx]

I called electronics store and no one seems to have it.  I don't mind ordering one, but Mouser lists a bunch of them.  Is there one in particular I should get?  Also if you could recommend a IC socket too that would be great.

Just so I am sure, is this the correct opamp?



Thanks again!

[MarshallJMP]

NE5532   http://mouser.com/ProductDetail/Texas-Instruments/NE5532P/?qs=sGAEpiMZZMtCHixnSjNA6Araa3jp4DVBKprmLw7OjBo%3d

socket  http://mouser.com/ProductDetail/3M-Electronic-Solutions-Division/4808-3000-CP/?qs=sGAEpiMZZMs%2fSh%2fkjph1tvt1%2fmEPT%2fXoueZQAPgo6HQ%3d

[Mxzx]

Got it, thanks!

Just ordered them. 

I'll let you know how the install goes.

[MarshallJMP]

BTW that's the correct opamp,so lets hope this is the problem.

[Mxzx]

Update:

Just replaced the opamp with new socket and opamp, no difference.  One side still much quieter, when I swap the red plug around, it switches sides like before.

Any other ideas?

[MarshallJMP]

-The top switch.
-Caps C56 or C49
-The front pot.

[Mxzx]

Okay, thanks.

What do I need to do to test these?  The front volume knob works correctly when the red plug is switched back and forth, so would that eliminate it as a potential problem?

Do I need to replace the switch or is there a way to test.

Where are the caps on the board and can I test them installed with a meter?

Thanks again for your help on this.

[Sparker]

You could try shorting C56 (connecting both pins together) then C49 and see if any difference to the volume.

[Mxzx]

It was the switch!!  Started jiggling it around when plugged into a little practice amp and the volume came up.  Sprayed it with contact cleaner and worked switch back and forth, seems okay now.

Guess I'll be doing the switch mod to get it out of there and replace switch!!

Thanks all who helped!!