wayne makowicki Posted June 10, 2010 Share Posted June 10, 2010 I just bought 2 Klipsch KSP-300 for $150.00 both have a hum that comes from the sub amp, I tried without a ground same thing any fix for this? Thanks they look like good speakers I want them up and running soon. Quote Link to comment Share on other sites More sharing options...
djk Posted June 10, 2010 Share Posted June 10, 2010 Does it hum with no input cable attached? Quote Link to comment Share on other sites More sharing options...
wayne makowicki Posted June 11, 2010 Author Share Posted June 11, 2010 Yes I am using the speaker wires for a feed not the Line Level. It hums as soon as the sub is plugged to the wall and in the on position. If its plugged in and in the auto position the hum starts as soon as music is appied then stay humming. Quote Link to comment Share on other sites More sharing options...
djk Posted June 11, 2010 Share Posted June 11, 2010 If it hums with no speaker wires hooked up, the amplifiers need servicing. Unhook the wires and turn the amplifers on. Does it hum now? Quote Link to comment Share on other sites More sharing options...
wayne makowicki Posted June 11, 2010 Author Share Posted June 11, 2010 So who would service these and is it a common problem? both speakers will hum with not speaker wires hooked up if they are pluged in. I have read others have had the same issue. Can the amp be fixed or should I just find some sort of replacement? any help would be great Quote Link to comment Share on other sites More sharing options...
wuzzzer Posted June 12, 2010 Share Posted June 12, 2010 I had a pair of KSP-400s that had a similar problem. I was directed to a company that does work on Klipsch amps once they are out of warranty. I believe I was quoted around $250 per amp to fix them. Quote Link to comment Share on other sites More sharing options...
wayne makowicki Posted June 13, 2010 Author Share Posted June 13, 2010 So did you get them repaired? I am considering putting in a low pass filter and bi-amping not sure how that would work out. I also see $125.00 sub amps that might fit the box. I have two of these and both do the same thing. From what I am reading this was a common problem, it could be a simple fix on the amps. I have pulled one and will take a look at it. I work with some EE so maybe they might be able to find the problem the amp itself is not that big. Quote Link to comment Share on other sites More sharing options...
wuzzzer Posted June 13, 2010 Share Posted June 13, 2010 I didn't get them repaired and sold them as-is. Quote Link to comment Share on other sites More sharing options...
wayne makowicki Posted June 13, 2010 Author Share Posted June 13, 2010 I can understand that, the fix cost is high. Did you like the speakers when they worked? I don't want to spend money on something that is junk. Quote Link to comment Share on other sites More sharing options...
wuzzzer Posted June 13, 2010 Share Posted June 13, 2010 I had intended to replace my Fortes with them but they were not nearly as dynamic and live sounding. I was then going to use them as surrounds and utilize their built-in subs to have a total of 3 subs but that never happened due to the high cost of repairing the amps. Quote Link to comment Share on other sites More sharing options...
EdmundGTP Posted June 15, 2010 Share Posted June 15, 2010 Previous assessments are correct that your sub amps are malfunctioning in some way. If you call Klipsch Tech Support, they will refer you to a 3rd party electronics repair facility to have the amps serviced and the cost will be anywhere between 100 and 200 for each amp. There are no aftermarket "mountable" subwoofer amplifiers that will fit the original amp mounting location in the KSP towers. Trust me; I've looked. I had to send one of my amps back for repair twice (at no extra cost for the 2nd repair, thank god) and decided that I was done screwing around with the Klipsh amps and pursued a different solution. Here is a relatively long thread detailing most of my ordeal and what I ended up doing with the speakers (KSP-400's). I can tell you that they are now working perfectly and I'm more than happy that I wont have to deal with sub amp failures any time soon. I like these speakers very much and wanted to keep them, which is why I put forth all the effort to get them working properly. http://forums.klipsch.com/forums/t/111984.aspx As you can tell from that thread, I've got a good bit of experience with these speakers inside and out, so if you have any questions about them don't hesitate to PM me. Quote Link to comment Share on other sites More sharing options...
wayne makowicki Posted June 16, 2010 Author Share Posted June 16, 2010 I got one of the amps to work I put in new caps on both the amp and "pre amp" don't think Pre amp fits perfect but its about as close as it gets. The caps on the main amp were starting to look like the end was near and one of the caps on the "pre amp" was just plain done. (all 4 caps are power supply caps) the hum is a 60 hz ripple. The second amp I will do the same however it looks like it might have other issues, at first glance none of the caps look blown but they are along in life. I will post to let you know how I do, the one I did fix sounds very good so the drive to get the other going is raized. I bought these plus a klipsch sub woofer and center for $200.00 so I know nothing of history. One thing I did notice is poor grounding of the board perhaps this leads to the failure. I did put in large caps in both places the higher voltage rating should help with the life. I will write more soon just pressed for time now. Wayne 203 417 2327 if anyone has questions call. Quote Link to comment Share on other sites More sharing options...
EdmundGTP Posted June 17, 2010 Share Posted June 17, 2010 I'd be very interested to hear more about the details of your fix circuit board fixes on these amps and look forward to hearing how it turns out. Some pictures would be great! I still have the amps for my KSP-400s; theyre in a box in a closet somewhere. One of them I know still works fine, but I dont recall exactly what state of disrepair the other is in. I wish I had the small electronics know-how to dive into trying to fix the amps myself, but since I don't I took the different repair route. Quote Link to comment Share on other sites More sharing options...
wayne makowicki Posted June 28, 2010 Author Share Posted June 28, 2010 Both amps are working fine, both needed new decoupling caps on the low side. I used caps that have a higher voltage rating so hopefully they won't leak/blow. I haven't put the speakers to much high poer test yet but I will soon. When I get some time I will put a picture up of what was failing on both amps. BOth amps have a very poor grounding issue, they both had the area where the switch is located sanded/ground a bit to make contact. Aluminum will not work so good this way I put in a dedicated ground wire on both amps. Its possible a poor or failing ground could cause a voltage rise on the low amp side. Quote Link to comment Share on other sites More sharing options...
Blade Runner Posted April 9, 2012 Share Posted April 9, 2012 After speaking to Steve at Klipsch and him sending me the Manual for my KSP-300 and following some of the advice from Wayne.M. I was able to repair my KSP-300 from the dreaded hum I just started having about a week ago or so. For me it was just a matter or replacing two 4700uf 63v caps and two 470uf 25v caps. If I remember correctly the 470uf 25v was 105 degrees and the 4700uf 63v was 85 degrees. After the repair my speakers sound great again! Just like day one! Could not be happier. Oh also as another side note none of the capasitors I replace had a visable damage or leakage to them. So it is best to just replace what the Manual sugest. Quote Link to comment Share on other sites More sharing options...
ricardo3166 Posted May 13, 2012 Share Posted May 13, 2012 can you send me the part number of everything you replaced? just on one amp, please? it would be really helpfull Quote Link to comment Share on other sites More sharing options...
Blade Runner Posted May 13, 2012 Share Posted May 13, 2012 They are listed in my post on page one. However please keep in mind what I replaced does not always cure the problem. I tested each of my caps as well as the coil and other areas of the board. You can not replace this board. Klipsch stoped sellng the replacement part years ago. Dont mess with it unless you know what you are doing. That is of course you don't mind wreaking one of the best sounding speakers next the the KSP-400, imho. Find someone that knows their way around a board and can read a schematic. Quote Link to comment Share on other sites More sharing options...
Delta_Kilo Posted October 18, 2017 Share Posted October 18, 2017 I realize I'm resurrecting an old thread here. I have a pair of KSP-300's that I am using in a 2ch set up. I absolutely love them. I noticed a hum developing and took to the internet to see if I could find the repair manual. I ended up writing Klipsch and was told that they don't "have that information available". I'm not entirely sure what that means. Perhaps, they are tired of supporting speakers that aren't in their current catalog. But, I digress. So, after searching Ebay and really everywhere else, I can't find a schematic for this series. I've found the threads that are linked in this post, as well as others, are no longer valid. If anyway could help point me in a direction, it would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
gnryfan Posted November 4, 2017 Share Posted November 4, 2017 Delta_Kilo: Here isKSP300 service manual.pdfKSP300 service manual.pdf a copy of the KSP-300 Technical Manual that Klipsch sent me. It has the diagrams you're looking for. KSP300 service manual.pdf Quote Link to comment Share on other sites More sharing options...
Deang Posted November 4, 2017 Share Posted November 4, 2017 On 10/18/2017 at 9:39 AM, Delta_Kilo said: I ended up writing Klipsch and was told that they don't "have that information available". I'm not entirely sure what that means. Perhaps, they are tired of supporting speakers that aren't in their current catalog. You're close. They want you to buy new speakers, not fix old ones. Quote Link to comment Share on other sites More sharing options...
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