Tubes and forced air cooling ...


Hello,

Time for another tube question. First of all, thanks to the folks who post good information on this site. I know the sharing of information freely can be a pain but it's the backbone of Audiogon in my opinion. You all help to keep my tube equipment in good health and that makes me happy.

Ok, down to business. I am running the following setup in a home made rack.

ARC VT-60 and a Mark Levinson ML 27.5 on the bottom shelf the amps have about 6" of vertical clearance to breathe before the next shelf.

The next shelf has a Levinson 360S DAC and a No 37 Transport side by side and they have about 2 inches of vertical clearance to breathe.

The next shelf holds my Modwright SWL 9.0 Linestage and my Dynalab Tuner side by side they have about 3" of vertical clearance.

The amps get hot ... especially when I add ale on a Friday night. Too hot? I'm not sure ... but hot enough for me to put a small desk fan behind them to keep the air flowing. The fan works well but my question is :

How does this affect the amplifier? Tube amplifiers are designed to get hot ... that's the idea ... right? At what point do I risk negative impact on sound quality? Do I even want to go down this road? I see that ARC has put fans in the VT-100 so I don’t think I'm too far off base. I don’t like the fan noise so I am having fan mounts built and I am going to use 12 volt 120mm ultra silent PC fans. A little less air flow but very, very quiet. They will be easily replaceable and will only cost about $7-12. I figure I will get a couple years out of a set. I'll run one across the pre and one across the amps.

What do you think?


128x128horseface

Showing 1 response by newbee

McFarland (and Horseface), There is no harm in placing a small fan behind a tube amp and draw air accross the entire amp. I think the no-no is putting a fan in front of the tubes themselves and forcing air on the tubes.

Tube amps need no fan assistance unprovided by the manufacturer if you are running it in an open area with sufficient ventilation under, over and on the sides of the amp. If you need to enclose an amp, simply measure the temp in the enclosure close to the top of the amp. So long it is within normal temp ranges for your personal living it shouldn't be a problem for your amp.

Unfortunately, in this situation, Horseface has a SS amp which generates some heat and interferes to some degree with the ventilation under the tube amp (I'm not sure how hot the Levinson gets but its a heavy duty amp and the competitors models I've owned there was a fair amount of heat to the touch. He has 6 inches clearance above the top of the tube amp. Under normal circumstances I would think that would be, marginal but adequate (he could check the temp at amp level and see how much hotter the air was there to be sure. But IMHO, his piling up the two amps has the potential to overheat both amps. I think his solution by placing small fan(s) behind the amps drawing air away from them is an excellent idea. It might be overkill, it might not, but there is no down side if he can control the fan noise.

At least that is my experience with tubes and fan YMMV.