Krell KSA 100mkII Clone

[bobgroger]

Sorry, didn't notice link went to main search page. Look at http://www.fischerelektronik.de/fisc...cher/D.1.E.pdf and see what you think would be best.

Bob G.

[jacco vermeulen]

LIKE THIS

[rjkdivin]

It appears that the LA 1 series has a higher dissipation capacity than the LA 2 (but also noisier), and the A-Type with the mounting fins offers the greatest device mounting flexibility. But Jacco's suggestion for the B-Type mounting looks promising also. I would prefer the LA-1-03-A (overall length 161.6mm) or the LA-1-04-A (overall length 198.1mm) for vertical mounting in 7"+ or 8"+ tall case.

Robert

[Zen Mod]

Originally posted by jacco vermeulen
LIKE THIS

hehe

http://www.diyaudio.com/forums/attac...amp=1173001256

[Flodstroem]

Originally posted by rolandong
I think Flod ran a groupbuy last year from conrad and they were able to get good deal - ~30% off. I'm actually interested in 4 pcs MF35-151 but no budget at that time. I heard quite good feedback from conrad buyers.

Yea we did. We ordered 86 pcs of the MF35-151.5 to a price of ca $ 39.00 each ± a few dollars depending on shipping destination in the world and this included the freight costs too. A very decent price I must say -unbeatable I think.

Regards

[Patrik Floding]

Originally posted by Flodstroem


Yea we did. We ordered 86 pcs of the MF35-151.5 to a price of ca $ 39.00 each ± a few dollars depending on shipping destination in the world and this included the freight costs too. A very decent price I must say -unbeatable I think.

Regards

I would be interested in a group buy, but I'm looking for something like a MF25-151.5 (25 cm wide), and 40 cm high. So it will be a standing design with the fins running vertically.
A single heatsink per monoblock -so it may have to be a bit wider or higher.

[PWatts]

Just out of curiosity, has anyone actually finished building his boards yet? Or is it still just organising the ancillary hardware?

[bobgroger]

I would be interested in a group buy, but I'm looking for something like a MF25-151.5 (25 cm wide), and 40 cm high. So it will be a standing design with the fins running vertically. A single heatsink per monoblock -so it may have to be a bit wider or higher

AndrewT in post 1040 calculated .09C\W @60c per channel as the minimum acceptable for passive cooling. The MF25-151 looks like .29C\W @80c. Seems way too small. In fact the selection of a pair of heatsinks less than .18C\W each is very limited. Someone estimated a usable heatsink at 10kg. This is why I am investigating forced cooling.

Bob G.

[Patrik Floding]

Originally posted by bobgroger



AndrewT in post 1040 calculated .09C\W @60c per channel as the minimum acceptable for passive cooling. The MF25-151 looks like .29C\W @80c. Seems way too small. In fact the selection of a pair of heatsinks less than .18C\W each is very limited. Someone estimated a usable heatsink at 10kg. This is why I am investigating forced cooling.

Bob G.

Yes, but the MF25-151.5 in the catalogue is only 15 cm high. I was going for 40 or more cm. So at 45 cm it's 3x the weight (3 x 1.78 = 5.34 kg), and about 0.1 C/W assuming termal resistance scales linearly. Perhaps 30 cm wide and 45 high will do the trick. I'll just make the rest of the case very thin, so the amp looks like one large heatsink standing on edge.

I'm not against forced cooling with a slow fan, but I really dislike the amount of dust that collects and degrades cooling. (And is generally dislikable.)

Anyway, I'll set Iq according to the thermal capacity of the heatsink, and I'm planning a low Iq setting for A/V use and as an always-on mode.

I can barely get my KSA 50S to go into the highest bias plateu without my ears bleeding, so the KSA100 is a bit of overkill anyway! ;-)

[troystg]

"assuming termal resistance scales linearly"

I was informed that doubling the height of a heat sink does not double the capacity. As the air rises it heats and is not the same as two separate heat sinks side by side.

Yours may indeed work; I am just repeating what I was told by a manufacturer about height.

The manufacturer disappointed me with news about my height, and my girlfriend disappointed me with news about my length. Rough times I tell ya..