I have had my M200s (2) for a couple of weeks now. I was listening to music in stereo mode (each M200 driving a Def Tech BP2002) at a fairly loud level and had one of the M200s shut down apparently from heat, the unit was quite hot to the touch. What surprised me was that it was the unit on top, not the bottom. I powered them down and let them sit for about 20 minutes, powered back up and they were fine. Can someone tell me if this is normal for the M200. I was driving them pretty hard but I didn't suspect they would have any problem wih this load. BTW, there is about 6" of airspace above the top amp (the one that shut down). Any ideas?

Thanks!

[This message has been edited by Roland (edited June 22, 2004).]

It's odd that yours powered down. Mine have never done that and I've played them very loud for extended periods.

Remember that the top one has to get rid of its own heat plus whatever is added from the one below.

Thanks for the reply JT. Do you have your amps stacked? I thought it odd as well and I am trying to determine if I have a faulty unit, but I have not had any other issues with it. I don't believe the Def Techs are an extremely difficult load, that is why I was surprised it shut down.

Ed

Try to make the shutdown repeat under the same conditions. If it does it again, try swapping the amps locations and channels with each other and do it again. If the same amp does it in it's new location driving the other speaker, then it must be an issue with that amp. If the other amp does it, it may be the location generates too much heat, or the load from the speaker may be different...I'm no electrical engineer so I'm speculating here. If the amps both function without issues after swapping them, ENJOY!!!

Cadboy:
Thats good advice,I'll do that.

Thanks,
Ed

Yeah, I had one on top of the other. They even had a line of duct tape wrapped all the way around so that I could carry them better.

Amp carrying strap? Made from duct tape? Now there's a wild mental picture -- sort of a DIY version of one of these wrapped around a pair of Model 200's.

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gonk -- 950 Review | LFM-1 Review | Pre/Pro Comparison Chart | Saloon Links

Well, I just swapped the speakers going to each amp and the same unit dropped out in a fairly short time. So now I have switched the amps from top to bottom, as soon as it cools off I'll try it again.

[This message has been edited by Roland (edited June 22, 2004).]

[This message has been edited by Roland (edited June 22, 2004).]

The amp shutting down is the one on top. After feeling the bottom of the top one I can see why, it is extremely hot. I am now spacing them with 2x4s being careful not to cover the vent holes. As soon as they cool off I will try it again and report back.

[This message has been edited by Roland (edited June 22, 2004).]

Well, they both went red on me this time. I think separating them just allowed them to heat up evenly instead of the top one cutting out first.

Ed

I didn't carry them by the duct tape. That was so they wouldn't slide around as much in my hands, in the car, or be bumped apart as easily.

Huh? How did you put the 2x4s on there? Did it take longer for them to overheat/fail?

By feeling the bottom of the top one you noticed what I was saying earlier. The top one has more heat to get rid of.

I simply laid a 2x4 on top of the bottom amp down each side to give an additional spacing of 1.5" between the units (the top amps feet rested on the 2x4s). It did not appear to take much longer for them to shut down, however, keep in mind the amps weren't starting cool for any of the test after the first one. The were cool enough to give me a green light but still warm from the previous tests.

This was AFTER you swapped them, correct? The top amp must dissipate it's own heat as well as the heated air it is drawing in from the amp below. It sounds as if you need to isolate their air intake to get cool air to both units.

What's the surrounding area look like for these amps? From what I understand, the 200's are not prone to getting all that hot, so seeing first one and then both exhibit significant heat build-up makes me suspect that they are being starved for cool air somehow or being forced to reject heat into an already warm airstream. Are they in an enclosed space or adjacent to other heat sources?

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gonk -- 950 Review | LFM-1 Review | Pre/Pro Comparison Chart | Saloon Links

Gonk:
Yes, this is the direction I am leaning as well. The amps are in a rack in a closet. I have done a little more trouble shooting as suggested by Steve, the only test I have left is to move them out of the closet and see if it persist. My guess is that they will not shutdown when placed outside the closet. I will not be able to do this today, but I will try it this weekend.

Thanks to all for their responses.

Ed

It sounds like you've pinned down your problem; I would be surprised to see them shut down if they are outside the closet (or even if the closet door is left open, depending on the layout of the closet). A rack in an enclosed closet has a strong likelihood of heating up to an excessive degree. There are some ways to add ventilation to alleviate the problem: high and low door grilles in the door, a louvered door, or an undercut door and a ventilation "stack" or fan discharging into the attic would all allow the equipment to receive proper ventilation.

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gonk -- 950 Review | LFM-1 Review | Pre/Pro Comparison Chart | Saloon Links

I'm thinking that Gonk is on the right track here. Does you entire closet have a ventilation problem or is it just your component rack? If you have two M200s stacked in a closed-sided equipment rack inside a closet, that could easily present a problem. If the closet itself is OK, you might try a rack-mounted silent fan, activated either thermostatically or whenever you switch on your preamp (using the AC output in the back). Some of these are a bit pricey given the ridiculous markup always applied to high-end audio gear, military equipment, and women's footwear.

If you are a DIY type, you could go to Radio Scrap or CompUsa and get some "silent" computer cooling fans and rig those up to the sides of your amps. I don't normally like fan noise in my listening room, but if you have your components in a closet, that shouldn't be a problem.

I doubt that you have an electrical problem with both M200s. Mine has always stayed cool, even with a Jolida tube amplifier stacked on top and running through multiple movies at high volumes. It is mounted on top of my equipement rack, but open to the air around the sides. When driving my 4-Ohm, power hungry Magnepan CC1, you can definitely tell the M200 is throwing off some heat, but there is enough venting to dissipate it effectively. It makes sense that the top amplifier would overheat more, since the bottom one would be convecting heat right into the ventilation grille on the bottom of the upper amp. If there is poor airfloor around the sides of your components, there would be no place for the hot air to go other than roasting the upper amp. If your component rack has closed sides close to the edges of your components, you might be able to take care of your problem by cutting a slit in it where the gap between your M200s is located. If you set up a fan system, I would recommend directing the airflow between the two amplifiers, which should help keep the bottom amp from cooking the top one.

Of course, you could always go to the nearest beer distributor and get a 50-lb block of ice to set on top of your amps whenever you plan on a heavy listening session... Let me know how that one works out for you!