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Help - Adcom GFA-545 works in mono only

I just got my Adcom GFA- 545 amp from eBay, that's I'm using to power NS-10Ms for a studio solution and I noticed that the amp works in mono only, regardless of source panning.

Both RCA inputs are ok, I tried plugging only one and panning worked as expected - no sound when panned hard one side, normal sound when panned to the other, so there appears to be mono summing going on inside the amp.

The other thing I've noticed is that the right side of the amp runs significantly warmer than the left, which is barely emitting any heat.

Do you have any suggestions as to how to resolve this?
Thanks!
jacentys
14 responses Add your response
ahendler
416 posts
 
Sounds like one side of the amp is dead. Is it fused? Check the fuses
Post removed 
jacentys OP
3 posts
 
Ok, thanks for the replies.

It's a little weird that the signal is coming out as mono from both sides, if one side would be dead.
Sounds more like somebody did a rewiring job or something... or is that a wrong assumption?
Post removed 
somec59
245 posts
 
don't look back, not worth it, very unlikely you'll get satisfaction
wolf_garcia
6,696 posts
 
Baloney...if it doesn't work in stereo GET YER MONEY BACK! Ebay (and Paypal) are supposed to protect you...and I bet the seller would prefer a return over being blasted with a bad review.
polk432
1,142 posts
 
If you used your CC thru paypal, you can ask for a chargeback even if paypal rules in favor of the seller. The CC company is who makes the final decesion. Also put in a negative to help others. I had to do so (I really hate doing that) recently for a filthy steel top plate for a Linn Sondek TT. I felt bad about it till two weeks later, when the seller got 2 more negs then got suspended. No need for you to be stuck. Happy listening.
jacentys OP
3 posts
 
Thank you all for the help.

The seller has been great about it and I will be returning the amp.
Post removed 
polk432
1,142 posts
 
Jacentys, that's good of the seller. Leave a positive feedback, since he cares about what he sells. Good luck.
wolf_garcia
6,696 posts
 
The last 2 audiogon items I attempted to buy were confirmed purchases followed by, "Oh...sorry man...I sold that last week"...and this has never happened elsewhere. I did have a couple of other successful a'gon purchases though. Ya never know...
kirkus
502 posts
 
there appears to be mono summing going on inside the amp.
Is it possible you have this amp switched into a "bridged mono" mode?
jacentys OP
3 posts
 
I was looking in the manual and there is no mention of such switch.

If that is the case, then I'm guessing there was some manual rewiring going on but I'm not good enough with electronics to troubleshoot that.
somec59
245 posts
 
Too much reflection on the current state of affairs... see prior post
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