Hi there,
thought I would say a few things as I have just got my KSA 150 back from repair. The report stated that the fault was due to the soft start and two relays were replaced. I thought this was a bit weird that only the relays were damaged. I have little experience in this stuff but your posts here have opened my eyes. I wonder if the service center were as diligent as you have been.
Only cost me $800 :S
In 2006 I had a much more serious problem which I discribed as a very slow saw wave of about 0.5hz on the output. I could watch the cone of my speaker moving, also had a slight white noise leak too. This took the service center 11 months to repair and they basicly rebuilt the whole amp after parts were sent back to krell.
The service report for this basicly stated that each stage was rebuilt over and over and problem could not be found. It was a very vague report and never gave a clear report on what the fault was but it was finally fixed at the cost of $2000 with the service center saying it was the most compicated amp they had ever worked on. :S
thought I would say a few things as I have just got my KSA 150 back from repair. The report stated that the fault was due to the soft start and two relays were replaced. I thought this was a bit weird that only the relays were damaged. I have little experience in this stuff but your posts here have opened my eyes. I wonder if the service center were as diligent as you have been.
Only cost me $800 :S
In 2006 I had a much more serious problem which I discribed as a very slow saw wave of about 0.5hz on the output. I could watch the cone of my speaker moving, also had a slight white noise leak too. This took the service center 11 months to repair and they basicly rebuilt the whole amp after parts were sent back to krell.
The service report for this basicly stated that each stage was rebuilt over and over and problem could not be found. It was a very vague report and never gave a clear report on what the fault was but it was finally fixed at the cost of $2000 with the service center saying it was the most compicated amp they had ever worked on. :S
I replaced all the Electrolytics on the power start PCB and that were easy to reach on each channel. The entire output stage must be disassembled to do it right. Bias adjustment does not seem feasible with the design arrangement. I hope they have nailed it this time, the unit should work for years to come.
Further to my post #26
I have had my Krell KSA150 back from service for about 2 months, in that time it was running some Behringer studio monitors with it at very low volume. (8ohm)
I have since had my Duntech Princess (4ohm) completely rebuilt and have had them running on the Krell for less than 1 week.
The Krell is clicking it's relays within 4 minutes of running. I swapped in different source (LP, Bal), different interconnects and swapped back the behringers but the problem still exists.
It trigger the 15 amp circuit breaker on the house too after clicking the 4th time in 15 minutes.
the music keeps playing and there is no noticeable interference to the sound at all, just clicking.
Once I turned on the Krell to hear it buzzing quietly from the amp, not the speakers.
It is still under warranty for the repair but is there something specific I should challenge the repairer on when he looks at it again?
Thanks for any help. I have shallow pockets.
I have had my Krell KSA150 back from service for about 2 months, in that time it was running some Behringer studio monitors with it at very low volume. (8ohm)
I have since had my Duntech Princess (4ohm) completely rebuilt and have had them running on the Krell for less than 1 week.
The Krell is clicking it's relays within 4 minutes of running. I swapped in different source (LP, Bal), different interconnects and swapped back the behringers but the problem still exists.
It trigger the 15 amp circuit breaker on the house too after clicking the 4th time in 15 minutes.
the music keeps playing and there is no noticeable interference to the sound at all, just clicking.
Once I turned on the Krell to hear it buzzing quietly from the amp, not the speakers.
It is still under warranty for the repair but is there something specific I should challenge the repairer on when he looks at it again?
Thanks for any help. I have shallow pockets.
It plays fine with the 8 ohm Behringers, but not the 4 ohm Duntechs. The question then is what impedance minima does the Duntechs have? they could be a really nasty load going to less than 2 ohms in places with horrible reactances that simply cause the Krell to overheat and then shut down, so it's possible the fault is not with the amp at all, and the repairer is not to blame. It's only a possibility but I do suggest you don't return to him with guns blazing, but simply fut all the facts as you understand them and he'll be much more agreeable to helping solve the problem.
Thanks for your reply,
Sorry I should be clearer, the problem did not exist with the Behringer speakers prior to getting the Duntechs speakers fixed but I only ran them at a super low level as near fields at night. The amp probably never put out 1 watt during this time with the Behringers. It was only after I got the Duntechs back that I wound the wick up a little.
After the problem occurred with the Duntechs, it was still evident when switching back the the Behringers so either the Duntechs messed up my amp and it stayed messed up or the amp created a fault it's self which is evident on any speaker load.
Apparantly the Krell is supposed to be able to drive loads lower than 0.5ohms, It is stated in the manual and also gives a rating of something like 1200 watts into 0.5 ohms.
So maybe you are correct - the Duntechs have a problem giving a super low load on the amp and it pulled too much current out of the wall, tripping my 15amp circuit breaker?
The owner of Duntech wants to take the speakers back and test them again. He told me they tested really great and he was super happy with them so he was very concerned that they may be playing up.
It's one of those things, getting gear fixed at the same time. It's hard to problem solve the issue.
The Amp repairer gave me a problem solving exercise to run through but it hasn't really pin pointed any one fault.
I'll see how it goes and post back.
in the meantime a lot of Krell audio amplifier models listed about youtube with repair/maintenance instruction steps and good pictures about the faulty components (some examples):
Krell KSA-150 Repair and Restoration - avoid Trevor Lees Audio... - YouTube
Kosol KRELL KSA-50 Amplifier Repair and Restoration August 2011 - YouTube
Krell KSA-250 recapping - YouTube
Krell KSA-150 Repair and Restoration - avoid Trevor Lees Audio... - YouTube
Kosol KRELL KSA-50 Amplifier Repair and Restoration August 2011 - YouTube
Krell KSA-250 recapping - YouTube
I can't really add anything concrete to all this without seeing one for real and seeing the circuit details but t sounds an absolute disaster for what is "supposed" to be an ultimate kind of amp.
No matter what the cost and prestige of the product the same basic principles and testing apply though...
Your speakers if they are these,
PRINCESS
don't appear to be a particularly difficult load. The impedance is quoted as 3 to 5 ohms and if true then that should be easy for something like the Krell. And very rare in a spec sheet is the phase angle they present... and that looks relatively easy tbh
You say it trips a 15 amp breaker ? Is that an overcurrent breaker (like a fuse) or an RCB type that can trip if an earth leakage is detected ? If it's just current tripping it and if I'm correct in that you are on 230 volts then that implies around 3.5Kw being drawn. So something 'aint right somewhere.
From all you say and all the work hat as been done I would I'm afraid be thinking that the amp is duffer, or that there is a long standing issue hat the service centres have been unable to resolve.
$800, if that was the price of the repair then that is scandalous imo.
No matter what the cost and prestige of the product the same basic principles and testing apply though...
Your speakers if they are these,
PRINCESS
don't appear to be a particularly difficult load. The impedance is quoted as 3 to 5 ohms and if true then that should be easy for something like the Krell. And very rare in a spec sheet is the phase angle they present... and that looks relatively easy tbh
You say it trips a 15 amp breaker ? Is that an overcurrent breaker (like a fuse) or an RCB type that can trip if an earth leakage is detected ? If it's just current tripping it and if I'm correct in that you are on 230 volts then that implies around 3.5Kw being drawn. So something 'aint right somewhere.
From all you say and all the work hat as been done I would I'm afraid be thinking that the amp is duffer, or that there is a long standing issue hat the service centres have been unable to resolve.
$800, if that was the price of the repair then that is scandalous imo.
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Yep those are the speakers. They have just been rebuilt with new cross overs and drivers. The Speakers I picked up today after the Owner of Duntech wanted to check them again to be certain it was not the fault of the Speaker. It is not, the speakers measured to spec in every regard and were tested on some Denon mono block amps which would have completely failed if there was a problem with the load.
The problem is defiantly the amp now. I have sent it back under it's 3 month repair warranty and hopefully it will return ok.
The amp in the state it was in tripped the 15 amp house breaker (fuse) once after about 5 mins of use. The amp was not even warmed up at this time.
Yes 240volts in Australia. Something is not right. I am glad it did not blow up with a bang.
I am looking at a newer alternative for amplification now but my pockets are shallow.
The problem is defiantly the amp now. I have sent it back under it's 3 month repair warranty and hopefully it will return ok.
The amp in the state it was in tripped the 15 amp house breaker (fuse) once after about 5 mins of use. The amp was not even warmed up at this time.
Yes 240volts in Australia. Something is not right. I am glad it did not blow up with a bang.
I am looking at a newer alternative for amplification now but my pockets are shallow.
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