Krell KSA 100mkII Clone - Page 245

samoloko · 4th February 2010, 12:57 PM

Hi Andrew

sorry to hear that
are you using original values for rails and bias
have you found something better since aug 2007

AndrewT · 4th February 2010, 01:22 PM

No, it is laid aside awaiting the experiences of other Klone builders. Still hoping more will complete and give me more tips on how they got theirs to work properly.

samoloko · 4th February 2010, 02:23 PM

Fix has very good results
what do you think about using 600VA 2 x 40Vac toroid with this amp

samoloko · 4th February 2010, 06:58 PM

regarding post Krell KSA 100mkII Clone and Krell KSA 100mkII Clone It can be used 600VA 2 x 40VAc per ch

Chmok · 21st February 2010, 10:48 AM

Can someone explain what the top-rear white resistor on the output board does? I ask because it is soldered with both ends on the same copper track. Page 228 has the pcb-layout photos showing this detail better.
Any comment Fix???

AndrewT · 21st February 2010, 01:39 PM

Quote:

Originally Posted by samoloko

can be used 600VA 2 x 40VAc per ch

i would say no, because the 600VA 40+40Vac is effectively a 7.5Aac transformer.

The extra rail voltage from a 40Vac transformer will require extra output bias for ClassA, maybe 3Adc rather than 2.6Adc. The extra voltage and extra bias will require more output dissipation capability.
Secondly the maximum DC current I would draw from the 600VA transformer would be 1.9Adc continuous (bias+quiescent) and this matches the KSA50 bias current.

The 900VA 37+37Vac used in the KSA100 can give a maximum continuous DC current of 3Adc and this is comfortably more than the 2.6Adc of bias.

amuseb · 29th June 2010, 06:39 AM

Hi,
Sorry to interrupt but I just bought this original KSA 100 where the fans have been replaced to somewhat strong (and noisy) ones (you can hear them in the next room when no music is played).
I'm very surprised by how cool this amp runs. I play low levels of volume and the amp is basically cold.
Is this normal? Could it be that the amp has been tweaked and no longer runs pure Class A or is it just that the very strong fans are keeping it cool?
Thanks
.

AndrewT · 29th June 2010, 10:11 AM

check the voltage drop across each of the outputs' emitter resistors.
The correct value is given by Krell.

amuseb · 29th June 2010, 10:57 AM

Thanks Andrew.
I'm not big on electronics; sorry.
Could you explain in more detail what is it exactly that I have to do and how?
Thanks.

AndrewT · 29th June 2010, 11:15 AM

I think the procedure might be in the owners manual.

If not then start posting pics of the inside particularly around the output stages.

There are a number of KSA threads and at least one website that already have pics of partially dismantled KSA shown.
You should be able to compare your version to some of these and from there identify the outputs and the emitter resistors.

4th February 2010, 01:22 PM	#2442
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	No, it is laid aside awaiting the experiences of other Klone builders. Still hoping more will complete and give me more tips on how they got theirs to work properly. __________________ regards Andrew T.

29th June 2010, 06:39 AM	#2447
amuseb diyAudio Member Join Date: Jun 2010	Pure Class A? Hi, Sorry to interrupt but I just bought this original KSA 100 where the fans have been replaced to somewhat strong (and noisy) ones (you can hear them in the next room when no music is played). I'm very surprised by how cool this amp runs. I play low levels of volume and the amp is basically cold. Is this normal? Could it be that the amp has been tweaked and no longer runs pure Class A or is it just that the very strong fans are keeping it cool? Thanks .

29th June 2010, 10:11 AM	#2448
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	check the voltage drop across each of the outputs' emitter resistors. The correct value is given by Krell. __________________ regards Andrew T.

29th June 2010, 11:15 AM	#2450
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	I think the procedure might be in the owners manual. If not then start posting pics of the inside particularly around the output stages. There are a number of KSA threads and at least one website that already have pics of partially dismantled KSA shown. You should be able to compare your version to some of these and from there identify the outputs and the emitter resistors. __________________ regards Andrew T.

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4th February 2010, 12:57 PM	#2441
samoloko diyAudio Member Join Date: Jun 2006	Hi Andrew sorry to hear that are you using original values for rails and bias have you found something better since aug 2007

4th February 2010, 02:23 PM	#2443
samoloko diyAudio Member Join Date: Jun 2006	Fix has very good results what do you think about using 600VA 2 x 40Vac toroid with this amp

4th February 2010, 06:58 PM	#2444
samoloko diyAudio Member Join Date: Jun 2006	regarding post Krell KSA 100mkII Clone and Krell KSA 100mkII Clone It can be used 600VA 2 x 40VAc per ch

21st February 2010, 10:48 AM	#2445
Chmok diyAudio Member Join Date: Jan 2010	Can someone explain what the top-rear white resistor on the output board does? I ask because it is soldered with both ends on the same copper track. Page 228 has the pcb-layout photos showing this detail better. Any comment Fix???

29th June 2010, 10:57 AM	#2449
amuseb diyAudio Member Join Date: Jun 2010	Thanks Andrew. I'm not big on electronics; sorry. Could you explain in more detail what is it exactly that I have to do and how? Thanks.

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