Krell KSA 100mkII Clone

[Flodstroem]

still4given:

You are right, I did complain about the fan noise.

A tip,
Have you seen this:
http://www.coolermaster-usa.com/Products.aspx?pid=889
13dB-A not any bad value. Very cheap to.

Maybe this fan is to small, I dont know because I always use convection cooling.

Regards

[jacco vermeulen]

Just a little over 1.5 feet per second, you'll need at least 4 to 5 times as much to avoid a big heatsink.

The 50.000 hrs is likely taken at 20C/~70F, don't expect heaven at 50C/~120F for such a fan type.
For the price you can toss one after a couple of years.

[TomWaits]

I picked this six pack up today for $20. It looks very Krellish to me, at least I think it could be with a little love.

Cheers,

Shawn.

[TomWaits]

I put the calipers on them and each one measures verbatim to the attached Wakefield. I don' tknow how to calculate what it can cool, nor do I know how to estimate such things on an amps output devices. I was wondering if you guys could give me some approximations? I aquired the amazing KSA-50 boards recently, perhaps a fit or even the 100? I guess it is pending bias current and number of output devices.

I'm looking for ball park #'s if possible.

Cheers,

Shawn.

[Stuart Easson]

they are rated at 1c/w for each 3" length

A nice find...

Stuart

[Stuart Easson]

missed the number and length part...

you have a total of about 0.1c/w, so you can dissipate the output from a ksa100 with little or no fannage...cool, literally and figuratively

Stuart

[TomWaits]

Originally posted by Stuart Easson
you have a total of about 0.1c/w, so you can dissipate the output from a ksa100 with little or no fannage...cool, literally and figuratively

Stuart

Thanks!

Good for two channels or one? I don't want fannage!

Shawn.

[Stuart Easson]

...as in all things there are way too many variables to make really definitive statements...

But if you build the amp with 44v (loaded, ~48v unloaded) rails (minimum for 100w/8ohms), and run the bias at 2.5A (~100w class A/8ohms) you have 2x44x2.5 watts per channel, or 440w total. With your sinks and close to perfect distribution of heat and airflow you would get a 44c rise above ambient, normally assumed to be 20c, for a total heatsink temp of 64c, ~160f. Your sinks would be a little too hot to touch, but nothing would explode...personally I'd start at 1.5A bias and slowly run them up to the point where the heat was about 'right', ie no burning of people/cats etc, but enough so the amp is 'slamming' properly.

So both channels, no fans needed there, but not a whole lot of extra headroom either...

As I said before, good find...

Stuart

[TomWaits]

Excellent. Thats a keeper. Printing...

Shawn.

[Zen Mod]

Originally posted by Zen Mod


even if I saw more than few amps with 150-180 K in feedback leg (and I mean on bip based diff stage ,not jfet or mosfet) ......mebbe is 100K and 4K1 and 10UF more appropriate........in that case- 3db corner will be under 4Hz
I'm sure that difference will be audible.
who knows?
mebbe even without 10UF,just dc coupled,with one eye on the scope

just an example