hi Imaclean, could you please send your schematic by email? I only want to check if your amp is KSA50 elder version or MKII. Could you? thanks in advance.
I have had a couple of queries on why the schematics have gone missing from my KSA100 Mk II rebuild page at:
Krell
I received a message from my ISP that read as follows:
"This morning we were contacted by an agent from Krell Industries, the
manufacturer of high-end audio equipment, with reference to some
documents that you are hosting on your personal web space. The documents
in question are schematics for some of their amplifiers which are
copyrighted material and therefor may be in violation of our Terms of
Service agreement if you did not obtain permission to publish these
documents.
The agent from Krell Industries politely requested that the documents be
taken off the web site. We recommend that you contact Krell Industries
to determine if the content qualifies as fair usage of their copyrighted
material, or if you could obtain permission from them to host the
content and add copyright holder information on the site."
Read into it what you will, this is consistent with their treatment of us whule we were their distributor. By the way, they typically would not provide us with schematics of their products even though we were expected to repair them (often). Those posted were drawn by me from the actual amps...
Regards,
L
Incredible! that even reverse engineering are copyrighted
I do not believe that Krell has any protection under copyright law to schematics draw by others. Copyrights are protection for one's expression of an idea not the idea itself.
I would not be surprised if they would have some type of non-disclosure clause in their contracts with distributors/service centers (maybe they forgot to do this).
As described, either the lawyers are mistaken in assuming the schematics came from Krell; or they are bluffing and bullying.
Here a (not original Krell) schematic of the KSA-100 EUR 1989. I did create self with help of the disass'y PCB boards to get the possibility of troubleshooting. The cabinet (enclosure) design outside is more like the KSA-250 design without used fan
Attachments
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Looks like a KSA 80 to me
A friend of mine has one, if it's a stereo power amp it'll definately be either the KSA 80 or KSA 80B (which had balanced inputs as well as single ended phonos). If it's a monoblock it'll likely be the KMA 160.Here's another one
Hope the link is ok, please feel free to remove it if not & accept my apologies.
Now all i need is a schematic for my KSA 250
Now all i need is a schematic for my KSA 250
"audioman54" who posts here occasionally; could use that schematic too.
He has a blown KSA 250, and I think he as a good one as well. He might take a reasonable offer for one or both of them.
Hey i'm lucky as mine's not popped
In fact it had a rather good service by a chap that used to service & repair these things just before i bought it. I guess it should be good for about another 10 years yet!Can you imagine the shipping costs of 160lbs + to the UK?
Not saying that's where your man is of course but it'd be a horror story Take it from me, i have been looking at all sorts of stuff from stateside. It's the shipping & import taxes that scare the hell out of me though, i think i'd rather pay what you'd regard as slightly over the odds to avoid these complications.
KSA200S Schematic
Hi Benchtester and group,
I have a working Krell KSA200S and a second one in pieces that had a power supply failure. It has some blown power up relay series resistors. I also took the unit totally apart as I thought the output stage was blown but it turned out the transistors measured good. (That was sure a big waste of time!)
If I had a schematic maybe I could get the totally dismantled one working again. Especially since I have a working model to compare with.
Since I have not worked in now over a year and I don't need the amps (as my LME49811 amps are in my reference system now) I would sell both the working and non-working Krell KSA200S's if anyone really wants them for a good deal? But having a schematic to fix the blown unit would be great. With time on my hands fixing the bad one would be fun!
Also does anyone have any idea what a working or non-working KSA200S is worth?
Thanks,
Mark / audioman54
Hi Benchtester and group,
I have a working Krell KSA200S and a second one in pieces that had a power supply failure. It has some blown power up relay series resistors. I also took the unit totally apart as I thought the output stage was blown but it turned out the transistors measured good. (That was sure a big waste of time!)
If I had a schematic maybe I could get the totally dismantled one working again. Especially since I have a working model to compare with.
Since I have not worked in now over a year and I don't need the amps (as my LME49811 amps are in my reference system now) I would sell both the working and non-working Krell KSA200S's if anyone really wants them for a good deal? But having a schematic to fix the blown unit would be great. With time on my hands fixing the bad one would be fun!
Also does anyone have any idea what a working or non-working KSA200S is worth?
Thanks,
Mark / audioman54
hi audioman54, by your opinion on using above amps, do you like amp of LME49811 drivering transistors than Krell amps likes as KSA200 or others (KSA50/100)? Or not because of sounds much better, just only 49811 saving power or more easy to be built?
La Mer,
The LME49811 power amp measures better and sounds better than the KSA200S and since one of my two KSA200S's died I would even say my proto unit is more reliable as it has been running full time for several years now in the same setup in my soundroom where the Krell died! But the output power (current) of the KSA200S is HUGE and it is a very good amplifier!
Mark / Audioman54
The LME49811 power amp measures better and sounds better than the KSA200S and since one of my two KSA200S's died I would even say my proto unit is more reliable as it has been running full time for several years now in the same setup in my soundroom where the Krell died! But the output power (current) of the KSA200S is HUGE and it is a very good amplifier!
Mark / Audioman54
Read into it what you will, this is consistent with their treatment of us whule we were their distributor. By the way, they typically would not provide us with schematics of their products even though we were expected to repair them (often). Those posted were drawn by me from the actual amps...
Regards,
L
Not that it matters, Krell has no basis for this claim. You can buy a schematic for the latest Pentium a few months (weeks) after release totally legally from a reverse house for LOTS of money. I think Intel would stop this if they could. This is just intimidation.
Krell knows this too, I think. And I suspect a complete another reason, why many small brands don't publish anything of documents and schematics:
The creating of a good to understand service manual is very complicated and therefore there are in most cases only first handcraft drawings, in which this brands ashamed to publish this.
The same I have mentioned regarded the Cyrus models above Cyrus II - go to
http://www.diyaudio.com/forums/soli...hematics-later-models-wanted.html#post1998327
And it is amazing to me that Krell was (some years ago) not even able to send me an orig. data sheet and a spice model to the JFET type of NEC (small signal) 2SJ44, 2SK163, because it supposedly can no longer find (by the good known online portals like datasheetarchive and alldatasheet still I can't find explicite datas, only short form). So I (and Krell too !!) can't simulate their topologies.
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To be clear, scanning a service manual and putting it up is not the same thing. I was refering to legally buying an amp on the open market and redrawing the circuit inside. NOT having a schematic in this case is good.
If there are this resistors on the secundary site? If yes, I haven't idea. If no, then this resistors together with relay and some other devices form a inrush current limiter unit to prevent large peak currents from your main connection on the wall while switch on.
If you are technican with great experience in electronic, disconnect the transformers from the inrush current limiter and from the amp PCB's (for an investigation of the transformer(s) itself) and create a separate simply inrush current limiter circuit as you can see in my schematic (i. e. the Krell transformer is connected in series with a halogen lamp). But don't short the halogen lamp !!! Now you can measure the distribution of the main voltage.
If the highest voltage drop on the halogen lamp (i. e. it shines almost as brightly as it would normally connected to the mains connection), I suspect a primary interturn (winding short) in the main toroidal transformer.
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Sometimes this is right. In some cases I found - when I got the original circuit in retrospect and could compare with my drawing - significant misprint in the orig. circuit drawing.
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