Hi
I have the circuit diagram for the KSA 100 Mk1. Let me know if you want it. It does not give much details re the bias setting.
I enquired if one can set the bias to 50 watt Class A so that the amp does not run so hot and hopefully lengthen it life longer. The advice I received was not to do it and rather to replace the transistors and main capacitors which are well beyond their safe liefspan.
The question is however is it worth it as the these amps are plus minus 20 years old and entering their high risk period for breakdowns. Was it not for the high risk aspect I would love to buy a secondb KSA100 Mk2.
I still like this amp and find it still very much to my liking. It very dynamic and really kicks ***. The modern sliding bias class A amps I have heard just does not have the power and authority of the older more classical class A Krells. I am using the amp with a home build Nelson Pass single ended pre-amp and the combination works better than with the Krell pre-amp.
Jozua
Cape Town
South Africa
I have the circuit diagram for the KSA 100 Mk1. Let me know if you want it. It does not give much details re the bias setting.
I enquired if one can set the bias to 50 watt Class A so that the amp does not run so hot and hopefully lengthen it life longer. The advice I received was not to do it and rather to replace the transistors and main capacitors which are well beyond their safe liefspan.
The question is however is it worth it as the these amps are plus minus 20 years old and entering their high risk period for breakdowns. Was it not for the high risk aspect I would love to buy a secondb KSA100 Mk2.
I still like this amp and find it still very much to my liking. It very dynamic and really kicks ***. The modern sliding bias class A amps I have heard just does not have the power and authority of the older more classical class A Krells. I am using the amp with a home build Nelson Pass single ended pre-amp and the combination works better than with the Krell pre-amp.
Jozua
Cape Town
South Africa
Alex, what was your problem really? Did you only want to "calibrate" the amp or was something else?
bias KSA 100
Hi,
I have a KSA 100 MK1 to adapt at KSA 100 MK2.
My KSA 100 hath the driver board from KSA 100 MK 2, but the power supply is KSA 100 MK1.
How must I the Bias to adjust ?
Is the bias for KSA 100 MK 1 and MK 2 identic ?
Many thanks for your answer
Best regards
Alex
Hi,
I have a KSA 100 MK1 to adapt at KSA 100 MK2.
My KSA 100 hath the driver board from KSA 100 MK 2, but the power supply is KSA 100 MK1.
How must I the Bias to adjust ?
Is the bias for KSA 100 MK 1 and MK 2 identic ?
Many thanks for your answer
Best regards
Alex
The design seems surprisingly conventional 
so I think you can go by the temperature. If you remember how hot the amp is or was (someone else maybe can tell you?), just turn up the bias carefully and check the temperature.
so I think you can go by the temperature. If you remember how hot the amp is or was (someone else maybe can tell you?), just turn up the bias carefully and check the temperature.Bias for Krell KSA 100
Hi
If anybody has rebiased their KSA 100 amp to a lower Class A rating It would like to know how it sounded once it was done ?
Has anybody buildt the KSA100 based on the schematic provided ? I for one would love to take on such a project.
I also have the KSA200s which is much younger than the KSA100 but it has broken down 3 times upon switch on!! Could it be that this design is more unstable than the original KSA 100?
Is it worthwile to repair once again or should I just sell it ?
Jozua
Hi
If anybody has rebiased their KSA 100 amp to a lower Class A rating It would like to know how it sounded once it was done ?
Has anybody buildt the KSA100 based on the schematic provided ? I for one would love to take on such a project.
I also have the KSA200s which is much younger than the KSA100 but it has broken down 3 times upon switch on!! Could it be that this design is more unstable than the original KSA 100?
Is it worthwile to repair once again or should I just sell it ?
Jozua
I repaired and biased a KSA-100 recently.
I set bias to 500mV across two output transistor emitter resistors I think.
The original spec is 600mV I think.
Do not quote me on this until I find out the correct figures in the next day or so.
Either way I set the bias 20% or so less than the spec, and the owner informs me that it sounds better now than before, and is reliable.
Eric.
Eric.
I set bias to 500mV across two output transistor emitter resistors I think.
The original spec is 600mV I think.
Do not quote me on this until I find out the correct figures in the next day or so.
Either way I set the bias 20% or so less than the spec, and the owner informs me that it sounds better now than before, and is reliable.
Eric.
Eric.
Bias for Krell KSA 100
Hi
MY KSA 100 has broken down (first time in nearly 20 Years !!) and I took it to a guy who was quite hesitant to work on the amp. I suspect the mere brute power and size put him off. He did some quick test and told me that the Transistors were fine and not leaking.
Visibly there is nothing burnt or damaged on the amp but when you switch it on the fans start and stop after a split second.
I have found another "expert" and would appreciate any advice I can give him as to what he can be on the lookout for. I also want him to set the bias lower - maybe to 500mV. I am also toying with the idea of replacing the flimsy wire running from the RCA input with some Van den Hull wire. Would this be safe to do ?
Any advice would be appreciated.
Thanks.
Jozua
Hi
MY KSA 100 has broken down (first time in nearly 20 Years !!) and I took it to a guy who was quite hesitant to work on the amp. I suspect the mere brute power and size put him off. He did some quick test and told me that the Transistors were fine and not leaking.
Visibly there is nothing burnt or damaged on the amp but when you switch it on the fans start and stop after a split second.
I have found another "expert" and would appreciate any advice I can give him as to what he can be on the lookout for. I also want him to set the bias lower - maybe to 500mV. I am also toying with the idea of replacing the flimsy wire running from the RCA input with some Van den Hull wire. Would this be safe to do ?
Any advice would be appreciated.
Thanks.
Jozua
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