Why is my M<arantz receiver getting warm with a separate amp?

[06'goat]

This is weird... I am running an Acrurus A100x3 amp through my Marantz SR4002 receiver to 2 tower speakers and a center. I am not running any surround speakers whatsoever. So why is my Marantz receiver still getting warm with music? I have the amp hooked up right and everything. Any ideas why this is happening?

[Legairre]

My Pioneer Elite VSX-92TXH receiver has an option to completely turn off the amps and I run separate amps for all 7 channels. It still gets just as warm as it did using the amps. Sounds like both our receivers are still powering the amps even though there no load on them.

Also a lot of true pre amps get pretty warm and they don't even have amps so maybe it's just the processing.

[06'goat]

Cool thanks.. I am glad thats cleared up.

[Glen B]

What you guys are experiencing with your receivers is the heat being dissipated in the output transistors from the standing bias on them. These transistors are turned on to some degree and conducting at all times, even while the receiver is idling. The heat generated by preamps can come from voltage regulators in the power supplies. These are often heatsinked to help dissipate the heat.

[Legairre]

Mine even gets warmer the higher the volume and length of time it's in use. I assumed it wouldn't get as warm as when the amps are used but it's the same.

[Ken49r]

SSP's get very warm too, but AVR's do get hotter.

Orinially posted by Glen B
What you guys are experiencing with your receivers is the heat being dissipated in the output transistors from the standing bias on them. These transistors are turned on to some degree and conducting at all times, even while the receiver is idling. The heat generated by preamps can come from voltage regulators in the power supplies. These are often heatsinked to help dissipate the heat.

Do AVR's use smaller parts that output more heat in order to make everything fit inside the unit or just the lack of space to allow for heat absorption within?

[Glen B]

The AVRs I've owned do pack a lot into limited space, coupled with less than generously sized heatsinks.

[Legairre]

SSP's get very warm too, but AVR's do get hotter.


Do AVR's use smaller parts that output more heat in order to make everything fit inside the unit or just the lack of space to allow for heat absorption within?

Mine Pioneer Elite AVR used a s pre amp get's warm, but not hot. By comparison my Rotel RSP-1066 that was a true pre amp was very hot.

[keltor]

It's all about the choices the EEs made in designing.

Most of the units I've looked in ran the Preamp's power off the main Amp Power Supply, especially those with large Torroidal power supplies. This would mean the power supply output transistors and the Torroidal transformer itself are both heating up.

Some of the units don't actually turn off the Amps, they just relay switch off the speaker connections. Probably, they should turn off both the amp and the amp psu when it's turned off, but it sounds like they do not. My ancient Sony receiver does though turn off both when you have the amp turned off and are just using it as a pre/pro.

[audioqueso]

Has anyone ever measured with a volt meter to see what really happens with a receiver when you choose no speaker (like when using a dedicated amp with it)? Use the receiver's amp, turn it up moderately, and take a measurement of how much voltage it's pulling. Then select the to turn off all the speakers, and do the same test again.

[chrispy35]

I think the observations noted so far just indicate how little power is required by the output transistors to generate the volumes needed and how much power is required to run the DSPs/processors/display in the pre-amp. Basically, you're running a computer+amp and, surprise surprise, the 'computer' draws more power than the 'amp' so when you turn the 'amp' off, it doesn't make a huge difference.

Check where the heat is coming from, I'll bet it's not the output transistors. The AV circuitry is getting more and more complex/power-hungry as time goes on...

Chris P.

[Glen B]

Has anyone ever measured with a volt meter to see what really happens with a receiver when you choose no speaker (like when using a dedicated amp with it)? Use the receiver's amp, turn it up moderately, and take a measurement of how much voltage it's pulling. Then select the to turn off all the speakers, and do the same test again.

I've thought of doing something similar to satisfy my own curiousity. I've just been reluctant to move my HT equipment rack to gain access to the AVR connections. BTW, its current one would be looking to measure, not voltage.

[audioqueso]

Yes, correct indeed.