Removing the noise that the fan makes, is there a point where too much fan can be detrimental to the amp?
You can cool a well matched power amplifier (and overload without failure) to the point where it can burn out it's power supply / transformer if that doesn't share the improved cooling as well.
Dust accumulation is a real problem with computer fans - you need a filter, and you need to
clean it regularly to stop it clogging with textile fibres and skin cells(!). Same issue in an
amp except than the running hours might be a lot less.
clean it regularly to stop it clogging with textile fibres and skin cells(!). Same issue in an
amp except than the running hours might be a lot less.
Computers tend to run 24/7 and gather lots of dust. Amplifiers tend to be used for fewer hours per day and would gather less dust. Same problem (dust) lower magnitude.
Dust aside, there're no issues with fan-cooling of amps. Cooler is better.
Tom
Dust aside, there're no issues with fan-cooling of amps. Cooler is better.
Tom
Very good point. In my youth when I worked in the Hafler service department, we encountered a DH200 amplifier that had fans applied to each of the two external heatsinks. When driven very hard, that kept the heatsinks cool enough to not trip the thermal cut-outs mounted on the heatsinks, but since the transformer received no additional cooling, it burned up and had to be replaced.
The point here is that a well-designed, convection-cooled amplifier shouldn't need any external cooling. If you use a fan to run the amplifier beyond its normal thermal limit, you risk damaging other parts of the amp.
The objective of the fan is to prolong the life of the small electrolytic capacitors and it friends in the amp, preventing repairs. I do not see myself driving the amp past it normal capabilities, the power transformer can sleep well tonight.
Thanks everyone.
Thanks everyone.
Ah OK. Ultra silent computer fans then may be a solution. Don't choose sleeve or ball bearing types but MagLev fans with FDB bearings.
FWIW in my 300W Bass Guitar amplifiers the fan is at a cabinet end and the first thing in the air flow path meets is the power transformer, go figure.
I use no end bells, so air not only goes around it, but also between copper winding and laminations (there´s a 2-3 mm gap all around).
In general in an amp driven balls to the ball, copper resistive losses are way higher than magnetic losses, which tend to be somewhat constant.
My concern was mainly for amps not originally intended for forced cooling, or these days a lot of consumer amps are even wall wart driven. Turns out none of this concerns OP.
I run all my classA amps with fans, because I am scared of too much heat, and I am into long term reliability. However, to prevent unwanted noise from fans, I use small voltage regulator to use lower than recommended voltage. Trick is to run them at such lower voltage so they reliably start, but are still effective, cooling enough, and silent.
Once the fan is running, you can carefully slowly lower the voltage even to half of recommended, but it may not start when you turn it of and on. So compromise needs to be made.
Once the fan is running, you can carefully slowly lower the voltage even to half of recommended, but it may not start when you turn it of and on. So compromise needs to be made.