That is one very, very, nice looking amp -- how much time did you invest into the build? Enjoy the sound!
Hi all, for what it'sworth.
I built a KSA50 clone with reduced supply rails and biased to give 30W at 8 Ohm. I used passive cooling with heatsinks along either side of a case I constructed from 10mm aluminium plate. The heatsinks were approx 400x 125x 40mm. They would run at about 50C which was OK, but the other components, Filter caps, transformers, etc would also reach this type of temperature due to heat convection.
Although all worked fine I have decided that I was not happy with those sort of temps so I am now re-building using fan cooling.
I have a heatsink similar to the original Krell but taller and a 120mm Papst 240V fan with a speed control. The fan has rubber mountings and fitted to the bottom of the heatsink. After a lot of playing I have found that I can dissapate the heat and maintain a temperature of approx 25C above ambiant and the fan running at 150V is virtually silent. Plus everything else in the case remains cool.
How you guys with KSA100's manage to get rid of the heat beats me, I'm full of admiration.
Hope this thread or the original KSA50 thread keeps going, it's given me a lot of pleasure.
Cheers
Alan
I built a KSA50 clone with reduced supply rails and biased to give 30W at 8 Ohm. I used passive cooling with heatsinks along either side of a case I constructed from 10mm aluminium plate. The heatsinks were approx 400x 125x 40mm. They would run at about 50C which was OK, but the other components, Filter caps, transformers, etc would also reach this type of temperature due to heat convection.
Although all worked fine I have decided that I was not happy with those sort of temps so I am now re-building using fan cooling.
I have a heatsink similar to the original Krell but taller and a 120mm Papst 240V fan with a speed control. The fan has rubber mountings and fitted to the bottom of the heatsink. After a lot of playing I have found that I can dissapate the heat and maintain a temperature of approx 25C above ambiant and the fan running at 150V is virtually silent. Plus everything else in the case remains cool.
How you guys with KSA100's manage to get rid of the heat beats me, I'm full of admiration.
Hope this thread or the original KSA50 thread keeps going, it's given me a lot of pleasure.
Cheers
Alan
Being very new to all this and searching the prices of various heatsinks and capacitors for this type of project has got me bug eyed. 
Maybe I am looking at the wrong places at first glances, but for now I think I had better stick with tubes (well a first tube amp) for now and save my money for something of this magnitude as I would love to build a Krell one day.
I find all this very, very impressive...
Maybe I am looking at the wrong places at first glances, but for now I think I had better stick with tubes (well a first tube amp) for now and save my money for something of this magnitude as I would love to build a Krell one day.I find all this very, very impressive...
You see that he used 30 WPC class A with very real heat problems. Don't try this (or any other) 50WPC Class A amp without knowing that it will be VERY hot, needing huge heatsinks or huge sinks/fan combo. 100WPC KSA 100, probably much too hot to cool easily, doable with effort.
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