kevin gilmore

krell ksa5 klone

621 posts in this topic

I didn't fare any better with the output devices but this amp will be as close to stock as is possible. 

 

+1

 

-- o --

Rodrigo

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Krell used Motorola sand in the stock amp but they should be identical to the current ON Semi stuff. 

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I didn't fare any better with the output devices but this amp will be as close to stock as is possible. 

 

 

Most of that doesn't make any sense to me.  Rolling caps which look mostly vintage... why would anybody do that? 

 

someone over at a Chinese DIY site has a working KSA5 clone based on the schematic Kevin posted.

He used his own boards, replaced mpsa06/mpsa56 with BC546/BC556, and changed the cap values a bit.

He seems to like the sound (obviously.) Right now.. he is playing with different caps.

 

Here is the link.

Chinese diyers use vintage caps because they can get them at a very low price.

you can get used UCC 81d 8200uf as low as $1 each.

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That's a riot. Bet they are on ebay soon.

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Chinese diyers use vintage caps because they can get them at a very low price.

you can get used UCC 81d 8200uf as low as $1 each.

 

I get that but it doesn't change the fact that an electrolytic capacitor only has a shelf life of about 20 years.  Doesn't matter if it is used or not... 

 

There is also the small matter of the massive improvements in capacitor technology over the last 20 years. 

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i would love to do a version with NOS non polarized black gates,

no chance of that now. not even for stupid amounts of money.

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Some progress on my end but now I have to wait for the panels to be laser marked. 

 

p044PQAh.jpg

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so that's what a correctly assembled amb power supply looks like.

I sure know what an incorrectly assembled one looks like.

Edited by kevin gilmore

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This thread makes me want to be more DIY adept :(

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hoping that the pcb layout file can be released eventually or someone have extra board, so that i dont need to use perfborad to build one.  ::)

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hoping that the pcb layout file can be released eventually or someone have extra board, so that i dont need to use perfborad to build one.  ::)

Asks Kevin, he is really very friendly and will give you everything you need 8) 

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Anybody who wants to order unproven PCB's is free to do so but none of these have been operational yet. 

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Sketched up front and back panels for the KSA-5V just now:

 

9N48Ebs.jpg

 

f93saoP.jpg

 

They will naturally not be colored like that...  :)

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A balanced version of this would be very, very big so that is the first major issue.  There are also a lot of parts needed and to match all of them.  Not under 2K$ with free labor would be my guess built to our standards. 

 

For a balanced amp the Dynalo Mk2 would be a better fit as it is cheaper to build, it's super symmetry so you can use either a SE or balanced source for balanced output and it's performance should be on par or even superior to the KSA-5. 

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but it's not a Krell. <_<

I'm planning to build a SE version just to see how good krell is and also for fun of course. I'll keep it simple, not fancy engraving, just the very basic, and the cost should be under $600 total.

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That is true but they are more similar than not minus the usual Krell overindulgence.  They really are transistor mad, didn't the old CDP's have something like 200+ transistors in the output stage?

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That is true but they are more similar than not minus the usual Krell overindulgence. They really are transistor mad, didn't the old CDP's have something like 200+ transistors in the output stage?

Old? Hasn't changed. Most of this is due to everything being SMD. Not paralleling transistors and using larger dies is probably better. I think Kevin's design is better, imho.

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I've pretty much given up on finding one at a reasonable price. If I had reasonable DIY skills I would build the clone.

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I've pretty much given up on finding one at a reasonable price. If I had reasonable DIY skills I would build the clone.

Perhaps take a trip up to Ann Arbor? I bet we could do it in a day and I could walk you through the process :)

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i'm sure you could probably get it done in a day if you have all the parts

and a pre-punched chassis. No high voltages to cause any grief.

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Maybe a fall trip up to Ann Arbor is in order. I hear they also have beer up there. If I give a seminar at Michigan I can probably even get the trip paid for.

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