Heat heat and more heat??

Thanks guys, I am not comfortable with wiring up XLR connectors. So, my next option is to ask the factory how the heck one is supposed to use this subwoofer with their 'balanced' amp. I have never used the amp in the balanced mode, my preamp is single ended. Frankly, I have never seen a need to go balanced in my home. As a former pro musician, we would run cables that were lengthy to our gear....across full stages etc., these cables were 40-60' in length. The cables were not that well insulated and I can see how running balanced was beneficial. In the home environment, where I am running cables that are what...1.5meters typically ( and VERY well shielded) I just don't get it. The extra expense and hassle for balanced..why??
Now with this issue, I really don't get it!
Main question is have I damaged my amp due to the subwoofer hook-up. It seems so based on the heat it is now giving off.Ugh.
Al, one more question...could I connect the ground wire from the sub to my preamp, with the other two connections going to the amp? The preamp has a ground connector for a turntable, which I use for that purpose; could I hook up the sub ground there too?

Daveyf,

Curiosity killed the cat. Did you disconnect the Sub from the amp to see if that was the cause of the heat?
(I assume the heat is coming from the power transistors heat sink fins on each side of the amp.)

If you did disconnect the sub and the amp still runs hot.......

Al, (Almarg),
If the bias was off for the power transistors of one channel or both, wouldn't that cause the amp to run hot?
.
Jim

Hi Jim,
I disconnected the sub last night and the amp still runs hot. Sound seems to be ok, but I am now concerned that continuing to run the amp may do some damage.
Thanks.

09-05-15: Daveyf
Al, one more question...could I connect the ground wire from the sub to my preamp, with the other two connections going to the amp? The preamp has a ground connector for a turntable, which I use for that purpose; could I hook up the sub ground there too?

That might work ok, and it's well worth trying. In fact REL manuals I've seen suggest doing that if a single sub is being used with monoblock amps. The one downside I can envision is the possibility that hum might result. It would be prudent to turn down the level control on the sub before powering up the system with it connected that way, and bringing the level control up gradually while listening for hum.

09-05-15: Jea48
If the bias was off for the power transistors of one channel or both, wouldn't that cause the amp to run hot?

Yes, that's certainly a possibility, as are a number of other things of course. As I mentioned, though, even if the problem is being caused by something other than the way the sub's ground has been connected, it would still be a good idea, and very possibly sonically beneficial, to change that connection as I've described.

09-05-15: Daveyf
Main question is have I damaged my amp due to the subwoofer hook-up. It seems so based on the heat it is now giving off.Ugh

I don't think we can say at this point, with any certainty. It could be that some damage has occurred as a result of the connection issue, but of course it could also very well be that the overheating is being caused by something else altogether, such as a bias problem as Jim mentioned.

Best regards,
-- Al

Dave, if you happen to have a multimeter there are some measurements you could make that might provide insight into whether the overheating problem has resulted from the sub connection issue.

You would disconnect the sub and the amp from each other and from everything else, including the AC outlets, and on each of them you would measure the resistance between the AC safety ground pin on the power plug and the ground sleeve of an RCA connector. If that resistance is just a few ohms or less in both cases, it would increase the likelihood that damage resulted from the connection issue. If either or both resistances are significantly higher, say tens of ohms or more, it would mean that the cause of the overheating is most likely something else.

Although it's probably all academic at this point, as it seems probable that the amp has to be sent in for repair in any case.

Best regards,
-- Al