Racked amp running {{{HOT}}}

[3rdBass]

I'm using an SWR 550x and a single space FX unit above it in an SKB 3 space (shallow) Roto Rack.
Lately I've noticed that when I run it with 2 cabinets @ 4 ohms it gets REALLY HOT...
Especially at the end of a long night, even the amp handles are almost impossible to touch, in spite of the fan working.
I'm wondering if I should consider a deeper or larger (4 space) rack.
I don't think the width of the case would make any difference although the fan intake & exhausts are on each side of the amp.
Maybe I could stay with the current 3 space and open a couple of holes on each side of the plastic case for extra ventilation ?
I posted a couple of pics of one like this from eBay.
Any & all opinions are welcome and appreciated...

[DRafalske]

Originally Posted by 3rdBass

the fan intake & exhausts are on each side of the amp.

I believe that's your problem right there.
Have you contacted SWR about the issue?

[3rdBass]

Originally Posted by DRafalske

Have you contacted SWR about the issue?

Not yet, hadn't considered it was an inherent problem with these models.
Just did a google search and found some similar issues but no failures due to it.

[okcrum]

The cooling design in the SWR amps I have seen, from the 400 onward, is less than sufficient without some external fan help.

[DRafalske]

Originally Posted by 3rdBass

Not yet, hadn't considered it was an inherent problem with these models.
Just did a google search and found some similar issues but no failures due to it.

With vents on the side, it's always going to run hot in a rack. I just thought it might be good idea to check with SWR and make sure it's ok to run hot.
IMO, having vents/fans anywhere but on the front or rear is a bad plan with rack mounted equipment. I ran into a similar issue with my old GK head. The intake was on the front, but the fan was on top. It didn't like having anything above it in the rack, and would go into thermal protection mode every now and then if I was really givin' it to it.
D

[JimmyM]

if it's so hot you can't touch the handles, it's something to worry about.

[3rdBass]

Thanks all for your input. I'll try mounting it in a rack with a spare slot and cut a couple of openings on each side of the case as pictured.

This was somewhat reassuring from the SWR site:

"Most musical instrument amplifiers on the market today use steel for their chassis, which does not conduct heat as well as aluminum. The 550x uses an all aluminum chassis and front panel because it has less impurities than steel, is less susceptible to rust, and is a better conductor of heat. This results in the chassis acting as an additional heatsink, drawing heat away from heat-producing components inside and thus extending their life. In this manner, we feel we have produced a more reliable amplifier, but at the same time, the outside of the 550x will get warmer than cases made out of steel."

"SWR also recommends at least one empty rack space in your rack to allow for the best possible airflow."

[rbonner]

The SKB Roto-Racks are great devices, I give them a total thumbs up. My experience is with AMPEG SVT-4PRO's... My SVT-4PRO's intake and exhaust air from the sides and the Roto-Rack doesn't have but about 3/8th of an inch clearance from the vents on either side. In this case the SKB shock rack is a better device.

Whenever mounting a head in a rack, the owner should look over the amplifier and figure out the airflow through his head. In the case of the 4PRO it is in through the right side and some slots in the rear and exhausts all out the left side after passing all the air through the amp's heat sink.

If you block off the left side's exit the amp will overheat in short order.

This same goes for any amp out there and if you use separate amps and preamps. Never cover the cooling holes; even if it says nothing in the manual make sure your equipment has adiquate cooling ability.

I would not block side vents within 1", the 4PRO manuals at one time stated 3" of clearance but then changed that as there's no cases that provided that amount of clearance. If you are tight, you will need to SUCK the hot air out with a panel mounted fan. GC sells them. I consider tight anything below 3"...

Heat is the enemy of all electronics, it might not fail today, but I guaranty the heat buildup will cook the electrolytics in the power supply, melt insulation in the transformers, crack the power resistors used for biasing and set you up for a very expensive FAIL sometime down the road.

In your case I would say this rack is not the correct choice for your amplifier.

This is also why poor old Dave, buys his dream amp off CL or the bay and the thing toasts out on him two months later... The previous owner hitting the golden parachute at Dave's expense.

PS: I've done a lot of different things in my life, but one of my jobs out of college was an engineering tech for a computer manufacturer in MSP. I designed the rack mount case for the processing unit and all the cooling for the rack. I learned a lot about cooling rack mounted equipment. We never had a temp induced failure of that model of processor, that was pretty neat.

BOB

[countrybass007]

Any electronics store sells small fans to cool amps and such. I've mounted them in the back of my racks for extra cooling. and it works great.