McIntosh MC501's Running HOT

[hotmac]

A few months ago I purchased a pair of new MC501's. When I run them for 2-3 hours with the wattage meters peaking consistently between 50 and 500 They both get very hot to the touch, and will occassionally simultaneously shut down. Initially I thought I had a power supply problem, and have since invested in 2 separate dedicated 20amp circuits with no apparent improvement. The amps are paired with a McInctosh C46 preamp, and are driving Paradigm Signature S8 loudspeakers. I'd really appreciate any help.
Thanks!
hotmac

[Indytown]

A few months ago I purchased a pair of new MC501's. When I run them for 2-3 hours with the wattage meters peaking consistently between 50 and 500 They both get very hot to the touch, and will occassionally simultaneously shut down. Initially I thought I had a power supply problem, and have since invested in 2 separate dedicated 20amp circuits with no apparent improvement. The amps are paired with a McInctosh C46 preamp, and are driving Paradigm Signature S8 loudspeakers. I'd really appreciate any help.
Thanks!
hotmac

What taps are you using when you play them that loud for 3 hours.

Indy

[hotmac]

I'm using the 8ohm taps. Just to clarify, It's not redlining the meters at 500w that generates excess heat, but simply peaking consistently above 50w.

hotmac

[Race Car Driver]

Where did you purchase these? Off ebay per chance?
(the reason I ask is I just saw a few sets on ebay)

[hotmac]

Purchased new from an authorized dealer.

[jim777]

Most "8 ohm" speakers look a lot more like 3-4 ohm speakers in the middle-bass region where there is a lot of energy. I would go for the 4 ohm tap max.

[Jesse111]

A few months ago I purchased a pair of new MC501's. When I run them for 2-3 hours with the wattage meters peaking consistently between 50 and 500 They both get very hot to the touch, and will occassionally simultaneously shut down. Initially I thought I had a power supply problem, and have since invested in 2 separate dedicated 20amp circuits with no apparent improvement. The amps are paired with a McInctosh C46 preamp, and are driving Paradigm Signature S8 loudspeakers. I'd really appreciate any help.
Thanks!
hotmac

2-3 hours of 50 plus watts is some serious volume. I think many amps may either burn up or protect themselves like the Macs do in that situation. Are these volumes for parties you're having, or do you personally actually listen to that volume on a regular basis? If for large room party listening you may have to increase the size of your amps if the ohm suggestions doesn't work. I'm curious because my 501's have never failed me but I can't say that I've done that volume level for that long ever before. I'll go to 100 plus watts from time to time for a song or two but then back down to 1-10 watts to cool my ears off as well as the amp.

[Indytown]

2-3 hours of 50 plus watts is some serious volume. I think many amps may either burn up or protect themselves like the Macs do in that situation. Are these volumes for parties you're having, or do you personally actually listen to that volume on a regular basis? If for large room party listening you may have to increase the size of your amps if the ohm suggestions doesn't work. I'm curious because my 501's have never failed me but I can't say that I've done that volume level for that long ever before. I'll go to 100 plus watts from time to time for a song or two but then back down to 1-10 watts to cool my ears off as well as the amp.

I have to agree, when I run my 501's, 5 watts fills a decent size room. 50 watts is loud, and if you are peaking 500 watts sometimes then you are averaging well over 100 to 200 watts, I may be wrong.

What would be the benefits of running the woofers on the 4 ohm tap and the mids/twetters on say the 2 ohm or 8 ohm tap.

Indy

[jim777]

What would be the benefits of running the woofers on the 4 ohm tap and the mids/twetters on say the 2 ohm or 8 ohm tap.

You can't do that. They wont be at the same relative volume.

The whole things needs to be on the 4 ohm tap max. There will still be tons of volume and the amp will be working in a better range. You might even prefer the sound you get that way.

[Indytown]

You can't do that. They wont be at the same relative volume.

The whole things needs to be on the 4 ohm tap max. There will still be tons of volume and the amp will be working in a better range. You might even prefer the sound you get that way.

Maybe I'm confusing myself. If you were to passive bi-amp with two different amps you would have to be concerned with the gain of each amp.

This is one amp, same gain. The only difference would be the max. wattage you would receive from that tap per your speakers stated ohms. ???

[jim777]

The output of the 4 ohm tap is less than the voltage of the 8 ohm tap, but it can give you more amperage. If you consider constant power (volume), on the 4 ohm tap (vs the 8 ohm), the amp will be swinging more voltage but with less amperage through the output transistors. It will run a lot cooler but the max volume will be slightly lower. The difference is perceived as small though.

A mac on a different tap is like a another amp, with a different gain. The whole autoformer idea is that the amp will have the same power with a 8 ohm speaker on the 8 ohm tap as with a 4 ohm speaker on the 4 ohm tap. Here we are comparing the use of a specific speaker on different taps. The output will not be the same. The autoformer works like any other transfo, only that a part of the input and output winding is common.

[Aldo]

I have 802D and HTM1D that are both rated at 8 ohms, I had to use the 4 ohms out from the Macs because of the same problem plus a noise in the tweeters, Now everything is OK! Try 4 Ohms.