btran33 Posted March 8, 2018 Share Posted March 8, 2018 Hi All: I have a pair of Klipsch KSP-400 tower speakers, which has a build-in 15" subwoofer on each speakers.http://images.klipsch.com/KSP400C6S6...5637990000.pdf I love this speaker pair in my home theater as they sound extremely good, very easy to drive and the subs are very well integrated with the mid and high. However, in the last few months, one of the sub started to make a loud buzz/hum sound when first turn on (wake-up from auto standby); the buzz sound is very loud for the first minute or so then getting softer and softer then completely gone in about 5 minutes. After that, the sub is working perfectly fine, until it goes to sleep (standby) then wake up again! My questions: 1) is there any quick and easy fix to the amp? or what is the problem? 2) if I leave the amp on all the time, not in auto standby, then I don't have this problem. I have let it on for most of a day and the heat sink behind the speaker is not much warmer than the one on standby. However, I'm very worry about the heat and fire hazard, if I leave the amp on all the time. What do you think? I did some search, a few folks had replace the amp on this speaker with an external amp and the speaker is still working fine, but I don't want to do so as that would add another equipment to my space-limited rack, also modify to the speakers and cost. Thank you for any suggestion. BT 1 Quote Link to comment Share on other sites More sharing options...
T2K Posted March 8, 2018 Share Posted March 8, 2018 https://community.klipsch.com/index.php?/topic/175276-ksp-400-cap-replacement-question/ https://community.klipsch.com/index.php?/topic/145978-attn-technical-gurus-amp-assistance-needed/&hl=%2Bksp400%2B%2Bschematic https://community.klipsch.com/index.php?/topic/169648-ksp-400-amp-repair/&tab=comments#comment-2130351 Link for service manual includes schematics. Print it while you can. https://community.klipsch.com/index.php?/topic/173890-klipsch-ksp-400-service-manual/ This should get you started. If you can solder or have a friend that can then the parts should be relatively cheap. Keith 1 Quote Link to comment Share on other sites More sharing options...
btran33 Posted March 8, 2018 Author Share Posted March 8, 2018 Hi T2K Thanks for the info, greatly appreciate that. As for repair of the Amp, I'm not very comfortable of doing so myself, but want to see which parts should I replace? those two big black thingy in the pictures above??? Thanks, bT Quote Link to comment Share on other sites More sharing options...
btran33 Posted March 8, 2018 Author Share Posted March 8, 2018 Also, some one mentioned in one of the posts that you sent, said they order an after market plate amp, pop in the current amp and run the sub as an independent subwoofer. Wonder if you know where I can get that after market amp plate? Thanks, BT Quote Link to comment Share on other sites More sharing options...
T2K Posted March 8, 2018 Share Posted March 8, 2018 1 hour ago, btran33 said: Hi T2K Thanks for the info, greatly appreciate that. As for repair of the Amp, I'm not very comfortable of doing so myself, but want to see which parts should I replace? those two big black thingy in the pictures above??? Thanks, bT There should be at least one, if not two instances in the links above where previous members have repaired their amps and discussed their problems and discussed solutions. The last guy replaced the caps and the bridge rectifier. They are pictured in the first picture above. You can see the values on the capacitors (6800uF 80V). The bridge marked KBL602. Those fixed his problem if I remember correctly. I'll post a picture of the bridge that he actually used, (from E-boy) don't remember which particular caps he used. You can search the individual forums here and find more information. https://www.ebay.com/itm/5PCS-PBU603-Diode-Rectifier-Bridge-Single-200V-6A-4-Pin-PBU/321893502269?hash=item4af2590d3d:g:ORkAAOSw5ZBWHnMX:sc:USPSFirstClass!35215!US!-1 I'm imagine there may have been some variation but those capacitors are exactly like those in my amps. Look around, you should be able to find someone local that can easily repair your amps. Good luck. Keith Quote Link to comment Share on other sites More sharing options...
T2K Posted March 8, 2018 Share Posted March 8, 2018 1 hour ago, btran33 said: Also, some one mentioned in one of the posts that you sent, said they order an after market plate amp, pop in the current amp and run the sub as an independent subwoofer. Wonder if you know where I can get that after market amp plate? Thanks, BT He used a separate amp to power the sub. There's a long thread here, I'll see if I can find it. More trouble than it's worth to me. I'd rather use the stock amp myself but that's me. If you strap/jumper the 3 speaker binding posts single-wire you'll probably get some bass, I just don't know how much. Worse case scenario you could check E-Bloy for repair. I don't know anything about them and the price is a little high IMO. Keith 1 Quote Link to comment Share on other sites More sharing options...
btran33 Posted March 31, 2018 Author Share Posted March 31, 2018 All: I just want to post a solution to this problem with the KSP-400 amp here and hope that it might help someone down the road. To recap, the amp section on one of my KSP-400 has a loud hum or buzzing when first turn on from auto-on or manual on for around 5 minutes or so, then it would get less and less loud then dead silent and working perfectly fine for however long it's on. Then the cycle repeat again, when it goes to standby and on again! Anyway, I remove the amp section out of the speaker, remove all the connectors, and give it a very thoroughly clean with the electrical cleaning solution then completely dried off using the air-can. For some reasons, that seems to fix the problem, now it only hum/buzz for 30-40s after turns on and dead silent, working fine after that. I don't know how long this will last but so far so good and I can live with this short humming problem for now. Hope it helps, BT Quote Link to comment Share on other sites More sharing options...
RW51 Posted August 25, 2022 Share Posted August 25, 2022 Could someone please post a working link to the service manual for the Klipsch KSP-400 amplified subwoofer? I have one not working due to a voltage surge from a lightning strike. Thanks. Quote Link to comment Share on other sites More sharing options...
OO1 Posted August 27, 2022 Share Posted August 27, 2022 good luck with the repair Quote Link to comment Share on other sites More sharing options...
001 Posted August 27, 2022 Share Posted August 27, 2022 i doubt the... Quote Link to comment Share on other sites More sharing options...
OO1 Posted August 30, 2022 Share Posted August 30, 2022 On 8/25/2022 at 9:29 AM, RW51 said: Klipsch KSP-400 did you take the amp out , can you post pictures Quote Link to comment Share on other sites More sharing options...
Bjornar Posted May 30 Share Posted May 30 (edited) I have found a work-around for the hum-problem. Simply disconnect the power from the left speaker. The sub in the left speaker will no longer play any bass, but the right one will. The hum will be gone. Since most system only use one sub, this might work fine for some of you. Some experiment with the cross-over settings might be useful for best bass from the system. Edited May 30 by Bjornar 1 Quote Link to comment Share on other sites More sharing options...
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