Reverse engineering Krell KMA 160

[K-amps]

K-amps, you can use any program that can view Gerber 274-X and Excellon files. An example, for Windows, is Viewmate . For Unix, use gerbv.

Thanks, but the webpage did not work... it's ok.

 

[jwb]

Sorry, it is (url removed)

Edit: oh I see, they are being jerks about deep linking to their site. In that case, I recommend you do not use their products. Please use anything else.

 

[jwb]

Project is coming along nicely. I repaired the original equipment, and it works great. I'm almost finished with my first board, and the second one has a few parts on it as well.

Full-resolution photo (1.7MB, 2272x1704)

 

[X.G.]

Post #19

Thank you very much,jwb


Encouraging by you,I work hard at writing a post to share my experience/idea which repair/build a normal PP power amp.

But my English is poor.... wish to finish it in a week.

X.G.

cause I had no time to write the post in English,I just spent 6 hours to post the thread on here.

Share my methods to repair/build a discrete power amp

sorry for late.

X.G.

 

[jwb]

Thanks XG, very good information!

 

[Mike Gergen]

It's been fun following this thread. I still remember many years ago listening to a KSA100 in a local store. I still have dreams about that day. And I still dream about owning one.

 

[jwb]

Mike, I'll sell you two boards and the schematic, you'll be well on your way to ownership

 

[Mike Gergen]

drool! drool!
Let's talk. Don't know the proprieties of a discussion like this are on the thread. Email me if it's a bad thing.
Mike

 

[jwb]

Are we having any fun yet?

A: No, but after I add 14 more parts to this board, then we will be!

 

[jwb]

Whatever you do, don't shake this piece of paper!

 

[anatech]

Hi JWB,
Ever sneeze after finishing the matching? I have.
-Chris

 

[bear]

J A P A N E S E S E M I s

I am frustrated in finding replacements for 2sk163 and 2sj44. 2sk170 and 2sj74 look like good substitutes, but I need to find them from a reliable supplier, and both in the BL grade.

I can supply both K170BL and J74BL (usually).

The 2SK163 also seems available to me, but not the J44, J43 is but grade on these may or may not be selectable and may or may not be the one desired - but this can be checked.

There needs to be a reasonable quantity, unless I already have them in my bins already.

So, let me know

(bear at bearlabs dot com - for email)

_-_-bear

 

[Sze]

Hi JWB

What circuit are you using to match your transistors?

Thanks
Dan.

 

[jwb]

Dan:

An externally hosted image should be here but it was not working when we last tested it.

 

[jwb]

Viva la resistance. It'd done, and it works great. The only hacks I made were where I used a TO-92 (actually E-line) MOSFET where I had put a TO-220 footprint, and I accidentally specified 100V Schottky rectifiers where I really meant to use 200V. In the end I used a 1000V 1N5408G.

Note that my board has substantially better heatsinking than Krell's. The original KMA-160 must have had a reputation for blowing up the drivers. On the board I fixed, the strip of metal that passes for a heatsink runs in excess of 85C.

Full-resolution photograph

Back to the listening.

 

[Mike Gergen]

JWB
You are having WAY to much fun. NOT

 

[bear]

Just checking, and mildly curious...

We want a Krell 160 clone because??

Great work, but still curious.

_-_-bear

 

[jwb]

Because we got one for free, that was on fire, and would like a stereo amp, and if we can sell it on ebay for $300 we come out even?

Basically, I'll screw around with any circuit that comes along. Otherwise I'd be bored out of my mind.

 

[Mike Gergen]

I'd like to do it for the same reason one of my brothers rebuilt a '70 Dodge Challenger, a friend of mine rebuilt a '69 Camaro or my dad refinishiing antique furniture. Because it's fun, we can and we can enjoy seeing the creativity and construction of the time.

Mike

 

[jwb]

Stick a fork in it, it's done. Kinda hard to see my boards when they are installed, but here's the photos anyway. I couldn't get the older Neutrik connector, so I had to stick the new model in sideways. Alas.

High-res photo #1
High-res photo #2