Heat heat and more heat??


My Jeff Rowland model 8 amp seems to be giving off more heat than I can ever remember. The sound still seems great, but the amp gets hot quicker than I ever remember ( heats up the room quickly!) and it is still warm even after several hours after shut down. Any ideas as to what's going on? Is it time for a trip back to Mr.Jeff?
128x128daveyf
Al, that is very interesting. I think the amp is balanced,and I do connect the subwoofer (REL) as suggested. I will experiment with removing the sub...hopefully this will solve the heat issue. In order to connect the sub, do you know what is the correct way to do this? Thanks.
Ideally the black wire from the sub should be connected to a circuit ground point on the amp, but it appears that the Rowland 8 does not provide a binding post or other terminal corresponding to its circuit ground. (There are some balanced amps, such as some of the Pass models, which do provide such a terminal). Given that, connecting the black wire to a chassis screw on the amp will most likely work well, and at least some of the REL manuals suggest doing exactly that when connecting a sub to the outputs of a balanced (or bridged) amp.

Although it is unlikely, if doing that results in a hum or some other issue, and if your connections to the amp's inputs are balanced (so that its RCA input connectors are not in use), you could solder the black wire to the ground sleeve connection point of an RCA plug, leaving the center pin unconnected, and insert that into one of the RCA input jacks on the amp. That would establish a suitable circuit ground connection.

The issue that I indicated I was envisioning, given that on a balanced amp the negative as well as the positive output terminals have full amplitude signals on them, is that depending on the internal grounding configurations of both the sub and the amp connecting the black wire to the negative output terminal could result in a near-short being applied to that output. For example, if as is commonly done both components connect their circuit grounds to their chassis through a low resistance, by connecting the black wire to the negative output terminal a path would be established from the negative output terminal of the amp through that low resistance in the sub to the sub's chassis/AC safety ground, then through the AC power cords of both components and the external AC wiring to the chassis/AC safety ground of the amp, then through another low resistance to the amp's circuit ground. Voila, a near short will have been created between the amp's negative output terminal and the amp's circuit ground! And perhaps over time the resulting excessive current flowing through those resistances, and the resulting heat, have caused one or both resistors to become lower in value, or even to short out completely, increasing the load on the amp and causing it to heat up more than previously.

In any event, even if this is not what turns out to be causing the problem, it would be good practice (and perhaps sonically beneficial) to connect the ground wire as I've described.

One final point: You might have to readjust the level control on the sub a bit after changing the connection of the black wire as I've described, to keep the sub and main speakers in balance.

Good luck. Regards,
-- Al
Al, thanks for the excellent response. I am hoping that the amp is not damaged by the prior hook-up procedure ( which was approved by my REL dealer!). The main issue is going to be finding a hook-up for the ground wire from the subwoofer to a point on the amp. There are no screws on the chassis that I think will allow for this. I also use the single ended RCA's as the inputs. I will have to experiment a little. Thanks again.
You're welcome! Pin 1 on the XLR connectors would also be a circuit ground point. Perhaps a convenient means of making use of that would be to obtain an XLR-to-RCA adapter, such as this one, inserting it into one of the unused XLR inputs, connecting the black wire to the ground sleeve connection point of an RCA plug as I described, and inserting the RCA plug into the adapter.

That and most such XLR-to-RCA adapters will connect the RCA ground sleeve to XLR pin 3 as well as to pin 1, but I'm pretty certain that won't matter in this case.

Regards,
-- Al
Correction to my previous post. When I said:
That and most such XLR-to-RCA adapters will connect the RCA ground sleeve to XLR pin 3 as well as to pin 1, but I'm pretty certain that won't matter in this case.
... upon looking at the manual for the 8T (I couldn't find one for the 8) I see on page 8 a statement that "When the RCA position is selected, pin 2 of the XLR input is shorted to pin 1." That is unusual, as in most cases involving USA equipment if any of the two signal pins on the XLR connector were grounded when the RCA input is being used it would be pin 3.

Given that, I suspect that the center conductor of the RCA connector is connected internally to XLR pin 3, so using an XLR-to-RCA adapter which connects pin 3 as well as pin 1 to the RCA ground sleeve would kill the input signal on the RCA connector.

I believe that Cardas can supply, at least on special order, XLR(male)-to-RCA(female) adapters that do not ground pin 3. Those would be suitable.

But surely there must be some screws on the case of the amp to which you could attach the wire?

Best regards,
-- Al