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krell ksa5 klone

kevin gilmore

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Both Birgir and I have wanted one of these for quite a while, and they never seem to show up.

So with a little help from one of the members here we were able to reverse engineer this one.



still have work to do on the power supply.

All the parts are still available, but identical and compatible parts also available.

mpsw06 and mpsw56 and lsk389

I think this one is fairly cheap to do. And easy to assemble.

Single channel is 10 x 3.65 inches.

Single ended not really a HE6 killer, but balanced, a HE6 heavyweight for sure.

If you replace the servo opamp with opa445, then you can go up to +/-35v rails.

Then its definitely a HE6 killer single ended.

picture of the original


single ended with +/-21 power supplies, it does 10 vrms into 4 ohms or more.

balanced 20 vrms into 8 ohms or more.

single ended with +/-35 power supplies, it does 16 vrms into 4 ohms or more.

balanced 32 vrms into 8 ohms or more.

Edited by kevin gilmore
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Hmm... Maybe I had some mistakes converting vrms into power. In any case I still love my Dynalo and have a feeling that utility wise it would overlap with the KSA 5 (both being current happy).

Still too lazy (and afraid what you'll say about the wiring) to do a proper post at the DIY build thread.

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The Dynalo and KSA-5 are similar is many ways but that is a very good thing in my book. I wouldn't try to use this for speakers though as the amp was never intended to do that. The PSU will not like it one bit too.

Huge thanks to Tom for his help on this and the reasons for me buying a HD-800 should be clear now. laugh.png It should be quite cheap to build as all parts or subs are available but the electrolytic caps should add up quickly. This run balanced at +/-35V will be a beast to reckon with...

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you need better eyes...


the relays are output relays driven by a simple delay circuit.

no real protection. there evidently was an issue with 24v relays

used on 21v.

Q14 is the Vbe multiplier thermally tied to Q23 for output stage bias.

Edited by kevin gilmore
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The blackgate caps and the dact are mikhail's handiwork.

here are the schematics for the 2 power supplies.

The first one is the original supply that tom owns.


this is the newer version


I think we will be doing the new version.

I'm sure they sound different.

Edited by kevin gilmore
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