Right On!
Hi fcel,
Glad you found it. This is kinda what I expected to hear from you. I didn't think it would be that difficult.
Anyhow, congratulations sir!
-Chris
Hi fcel,
Glad you found it. This is kinda what I expected to hear from you. I didn't think it would be that difficult.
Anyhow, congratulations sir!
-Chris
Hey there,
Sorry to pull this thread out from the dead, but I'm currently auditioning a KSA 300S that seems to have the same "sizzling" sound at startup...
So, when I switch it on, all teh bias lights are lit, and no sound is coming from the amp. Slowly, the lights go down one by one over a good part of a minute, and then theres a sound like something rushing in, and then a sizzle that lasts for about ten seconds.
Only difference from your case is this: The sizzle never really dies out, even when the music is played. I've hooked the amp up to my Klipschorns (very efficient), and I can hear the ocassional popping / cracking from that sizzle during the course of the music... almost like surface noise of a dirty lp.
Does it sound like the same problem of the slow start board? If so, even though I'm not nearly technical enough to do it myself, I can get a friend to do it for me.
Any help is appreciated soon, as I have to give the amp back in a day or so if I'm not gonna buy, and I LOVE LOVE LOVE the way it sounds when it's not sizzling...
All the best,
Fauzi
Sorry to pull this thread out from the dead, but I'm currently auditioning a KSA 300S that seems to have the same "sizzling" sound at startup...
So, when I switch it on, all teh bias lights are lit, and no sound is coming from the amp. Slowly, the lights go down one by one over a good part of a minute, and then theres a sound like something rushing in, and then a sizzle that lasts for about ten seconds.
Only difference from your case is this: The sizzle never really dies out, even when the music is played. I've hooked the amp up to my Klipschorns (very efficient), and I can hear the ocassional popping / cracking from that sizzle during the course of the music... almost like surface noise of a dirty lp.
Does it sound like the same problem of the slow start board? If so, even though I'm not nearly technical enough to do it myself, I can get a friend to do it for me.
Any help is appreciated soon, as I have to give the amp back in a day or so if I'm not gonna buy, and I LOVE LOVE LOVE the way it sounds when it's not sizzling...
All the best,
Fauzi
Hi Fauzi,
What you are hearing sounds more like differential pair or Vas transistor type noise. Transistors later in the circuit would not be as audible. It's is also possible that a small capacitor or resistor in making this noise, but it would be in the same general area.
-Chris
Edit: spelling
What you are hearing sounds more like differential pair or Vas transistor type noise. Transistors later in the circuit would not be as audible. It's is also possible that a small capacitor or resistor in making this noise, but it would be in the same general area.
-Chris
Edit: spelling
same problem with ksa300s
i am testing all start upcircuit on the front board and tested for that 4 resistors(they seems to be like that) i measured them and all four were open
i replace them for a hughe resistor connectesd out boards and it fired up. i dont know what is happen.no voltage entered in the mains transformer.so protection area problem is resident
pls any help????
i am testing all start upcircuit on the front board and tested for that 4 resistors(they seems to be like that) i measured them and all four were open
i replace them for a hughe resistor connectesd out boards and it fired up. i dont know what is happen.no voltage entered in the mains transformer.so protection area problem is resident
pls any help????
Krell ksa 100 s
I had a problem with my KSA-100s on the left chanel at low volumes there would be no sound only when i turn it up a bit the sound would come back and after when the amp is worm it would be ok and olso there would be a big pop sound on the left chanel when i press the phase button on my preamp.
I wrote to Krell sevice department and it looks like i have too change all the caps on the driver and bias board.
I got that the “sizzling” sound at turn on too so im going to re-soldered the 2 pins at j-10 and hope that will go away
Wish me luck
Stevan
I had a problem with my KSA-100s on the left chanel at low volumes there would be no sound only when i turn it up a bit the sound would come back and after when the amp is worm it would be ok and olso there would be a big pop sound on the left chanel when i press the phase button on my preamp.
I wrote to Krell sevice department and it looks like i have too change all the caps on the driver and bias board.
I got that the “sizzling” sound at turn on too so im going to re-soldered the 2 pins at j-10 and hope that will go away
Wish me luck
Stevan
The Krell is finished and the problem is gone😀
Im going to test it for a couple of days to be 100% sure but i think that every thing is ok😎
I want to point out that i contacted the Krell sevice dep. before and during my servicing and they where a lot of help on answering all my questions no matter how stupid they where so i can recomend you to do so if you have any problems with your Krell amps.
And i have to say it was a lot harder to change all the caps because they were hard to get to but very worth the efort.
Now i know why they charge so much at the factory 😀
Im going to test it for a couple of days to be 100% sure but i think that every thing is ok😎
I want to point out that i contacted the Krell sevice dep. before and during my servicing and they where a lot of help on answering all my questions no matter how stupid they where so i can recomend you to do so if you have any problems with your Krell amps.
And i have to say it was a lot harder to change all the caps because they were hard to get to but very worth the efort.
Now i know why they charge so much at the factory 😀
I need to change the power suply voltage from 220V to 240 Volts in my Krell KSA300S...Can somebody send me the higher resolution file picture with the schematics or where in the board can change this main suply (the J10 conector is fixed and i don´t know where is the selector or alternative method.
Thanks in advance. Daniel.
PD: My mail is: bunker@ono.com
Thanks in advance. Daniel.
PD: My mail is: bunker@ono.com
I have seen the fix be as simple as replacing some ( all ) the electrolytic caps on the start pcb. 470uF 63V. Sometimes the marking is burnt off. It gets that hot. Also the small caps on the driver circuits.
I have a KSA150 with similiar trouble, but the unit will not power up and the only fuse is a push button 20 breaker and a 3 amp fuse on the start pcb. Gotta love the fuses in other products.
Dangerous ? Indeed when powered up a lot of current is potential at the cap lugs and amp output. Monitor with extra DVM.
I feel there must be a way to bypass the dead portion with a manual over ride of jumpers.
Question is now : What do the white and black wires do that run to the channels? How to isolate some aspect of the device ?
Ideas welcome.
Having entered into the foray of working with some of these units I can say, it is big job to replace the many smaller devices and the main caps. I prefer Thresholds of course.
I have a KSA150 with similiar trouble, but the unit will not power up and the only fuse is a push button 20 breaker and a 3 amp fuse on the start pcb. Gotta love the fuses in other products.
Dangerous ? Indeed when powered up a lot of current is potential at the cap lugs and amp output. Monitor with extra DVM.
I feel there must be a way to bypass the dead portion with a manual over ride of jumpers.
Question is now : What do the white and black wires do that run to the channels? How to isolate some aspect of the device ?
Ideas welcome.
Having entered into the foray of working with some of these units I can say, it is big job to replace the many smaller devices and the main caps. I prefer Thresholds of course.
Best to check the 7.5 ohm 10 W resistors as well. Just found all 4 of them are open circuit. They handle a lot of current.
That is the beauty of the forum. And somebody else can come by 3 years from now and find the answer. I am certain many Krell amplifiers will face this fate.
FYI
I tried a 22ohm 5 W just for testing purposes and they fried like fuses. I will have to wait 3 days for parts to continue.
FYI
I tried a 22ohm 5 W just for testing purposes and they fried like fuses. I will have to wait 3 days for parts to continue.
Good day,
When turning on my Krell KSA 300s, we heard the sound and saw the light of arcing, and the amp turned off together with the shut down of house's main power supply circuit breaker.
I disconnected the power cord to the amp and saw the circuit connecting to the power transformer broke. Please see the images attached, one in normal operation state and one in broken state.
Could you give me advice to check and repair my amp? Thank you.
When turning on my Krell KSA 300s, we heard the sound and saw the light of arcing, and the amp turned off together with the shut down of house's main power supply circuit breaker.
I disconnected the power cord to the amp and saw the circuit connecting to the power transformer broke. Please see the images attached, one in normal operation state and one in broken state.
Could you give me advice to check and repair my amp? Thank you.
Attachments
Hello everybody,
May I know where can I get a schematic for a Krell KSA200S Power Amplifier?
Many Thanks!
May I know where can I get a schematic for a Krell KSA200S Power Amplifier?
Many Thanks!
Does anyone know the function or have the schematic of the small board "unclesums" posted two posts above?
Except I briefly tracked down the wires attached to it, and one side is coming from the primary breaker on the back, and the other side is going to the panel board which is selecting the primary windings of the transformer. Yes, there are two bridge rectifiers and four caps, and the caps are wired in series pairs (opposite, from each other like two configurations of non-polarized caps). It looks more like some sort of power correction circuit I don't quite understand yet.
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It could be a "ground isolator". It is not power factor correction. Anyway, it's easy to figure out.
I have to say ... these are generally not fun to work on. You must know exactly what you are doing if you intend on repairing one. You also cannot substitute transistor types without a clear knowledge, and a sub book or information on the internet cannot be counted on. If those are correct - it was a total fluke!
These are not amplifiers for even average technicians to fix, so not a DIY project! There are several amplifiers in this class and yet people still hack away at them.
I have to say ... these are generally not fun to work on. You must know exactly what you are doing if you intend on repairing one. You also cannot substitute transistor types without a clear knowledge, and a sub book or information on the internet cannot be counted on. If those are correct - it was a total fluke!
These are not amplifiers for even average technicians to fix, so not a DIY project! There are several amplifiers in this class and yet people still hack away at them.