Older Krell Schematics

[PB2]

"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.

I could also use a KSA-250 schematic if anyone has it.

Pete B.

 

[jacco vermeulen]

totally dismantled one

Mr Brasfield,

why not post a couple of digital shots of both sides of the boards for the backengineer types to have a swing at it ?

 

[homemodder]

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

I have original Krell schematics, according to them the following models have the same buffer and voltage amplification stages and only the amount of output devices differ, KSA80, KMA160, KSA200 and KMA400. At a quick glance it seems the posted KSA100 is also the same.

Audioman54, drop me a mail with yours, these will be useful for your problem, they are complete schematics with power supply, relay board, soft start, oscilation sense, well the works, just promise not to try push those nasty sounding LM chips to me

 

[La Mer]

Hi audiman54. Thank you for your information. Just wonder if LM49811 power amp could sound same soft as class A amps like as KSA50 do. Anyway, I'm not interesting on huge machines.

 

[scott wurcer]

just promise not to try push those nasty sounding LM chips to me

I hope audioman54 has a thick skin and sense of humor.

 

[homemodder]

I hope audioman54 has a thick skin and sense of humor.

I think he does, he s a regular guy, people take things too personally around here, but I m just being honest, I dont like the sound of those chips, although Im experimentig with the new AD4898 which I like and will be using to replace AD817 and AD829 which Ive being using for over 10 years in certain audio applications.

Anyway Ill give him a copy of the schematics if he needs them, I would place them here but I dont want Krell sending me any mail.

 

[tiefbassuebertr]

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

Where is the internal circuit of LME49811?

I don't find it about
http://cache.national.com/ds/LM/LME49811.pdf
By the ST power amp TDA7294V there is at least a basic circuit diagram at page 2/17 so as a circuit description at page 8/17 about
http://www.st.com/stonline/products/literature/ds/1057.pdf

 

[audioman54]

Inner schematics of National parts not available

tiefbassuebertr,

National does not usually publish the actuall schematics of the inner circuits of new parts. Sometimes we did a block diagrams but in this case even the apps engineers did not get a complete schematic. Sorry. I wanted it also! I just know it measured better than anything else we "ever" had in the lab.

...And Homemodder have you been able to get those schmatics together for me? I want to see if I can fix the second KSA200S amplifier and then sell it.

Thanks,

Mark / audioman54

 

[tiefbassuebertr]

tiefbassuebertr,
National does not usually publish the actuall schematics of the inner circuits of new parts. Sometimes we did a block diagrams but in this case even the apps engineers did not get a complete schematic. Sorry. I wanted it also! I just know it measured better than anything else we "ever" had in the lab.
Mark / audioman54

this brand new TI (formerly Burr-Brown) operational amplifier schows their functional schematic - go to
Precision Amplifier - Low Noise - OPA211 - TI.com
Very interest details
Regarded older Krell Schematics I have start this thread:
http://www.diyaudio.com/forums/soli...ter-reference-amplifier-schematic-wanted.html

 

[gerhard]

Hi,

I have an old Krell KST-100 that still works, but could need
some refurbishment.

It has a large PCB and must be quite different from the KSAs.

Are there any circuit diagrams of the KST-100 floating around?


Gerhard

 

[tiefbassuebertr]

In this case post #2 and #3 about
http://www.diyaudio.com/forums/solid-state/199965-krell-fbp-200-a.html#post2775873
are of interest