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need help - ksp 400s - bad sub amps

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rumble    1

hello

 

i recently got a pair of ksp 400s and the rear surrounds and center channel speakers.

 

when i applied ac power to the sub amps there was a nasty buzz and hum (both speakers).

after doing a little search on google i've found that this is pretty common and the fix is to replace the caps (or bypass the internal amps and use an external amp)

 

i'd prefer to fix the amps that are in there but all the links to the schematics i've seen are bad, so if someone has them or can direct me to a good link where i can download them i'd appreciate it.

 

another thing that puzzled me was how bad the owner's manual was written.

i have a sony surround amp and it has a single line out for the sub woofer which i ran to one of the speakers (thinking that maybe it needed to see a signal before the noise would stop (i was wrong), but the manual makes no mention of how you are supposed to get the sub line level out to the other speaker since the surround amp only has one line level sub out.

 

are you supposed to jump it over via the LFE jack beside the line input on the sub amps on the speaker?

 

 

 

the other thing was, i had no sound coming out of the 3 drivers on the tops of the ksp 400s when i hooked my front speaker outputs from my surround amp to them.

they did not feel fried when i pushed on the cones....

 

i know those are not connected to the sub amps, but do the sub amps have to work before the upper speaks work?

 

thanks

 

ray b

Edited by rumble
spelling error

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billybob    5898

Welcome to the forum!

There are some owners here that can help when they see your post. Meanwhile do a search of the forum using the model ans see wat you can find to review. About to have a storm here so may lose power...Good fortune!

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billybob    5898

With no speaker wires hooked just ac power cords to either one, they should basically be quiet with no buzz or loud hum.

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billybob    5898
35 minutes ago, billybob said:

With no speaker wires hooked just ac power cords to either one, they should basically be quiet with no buzz or loud hum.

There is more but, a start:

 

 

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rumble    1
9 hours ago, billybob said:

d

Welcome to the forum!

There are some owners here that can help when they see your post. Meanwhile do a search of the forum using the model and see what you can find to review. About to have a storm here so may lose power...Good fortune!

 

the search didn't turn up much, or i wasn't successful at it. i need the scematics and other technical pdf.

 

good fortune is right - i got them for nothing off of freecycle.org.

 

i also bought a pair of klipsh cornwalls for $40 at a salvation army about 2 years ago.

 

 

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T2K    757

Welcome rumble. Click topic below for a PDF of the KSP-400 service manual.

 

Keith

 

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T2K    757

Read this thread rumble.  This members amp issue is generally the same amp issue most KSP-400 speaker experience after many years of service

 

Keith

 

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T2K    757

The manual can be confusing as far as connections go. There are many variables since the speakers are tri-wireable. Keep it simple for starters. There should be jumpers between the 3 pairs of speaker binding posts (positives and negatives linked). If not use speaker wire, which may be better than the original metal jumpers anyway. The subwoofers will get a signal from your receiver via speaker level input. See the owners manual for illustration.

 

Simply run speaker wire from your receivers speaker outputs to any of the speaker binding posts on the speakers, that is if you have the jumpers in place on the 3 sets of speaker binding posts on the speakers.

 

The sub amp does not need to be plugged in but you'll get pretty crappy sound without the working sub.

 

As for the 2 speakers sub cables from your single receiver sub output goes, or for the LFE inputs on the speakers, simply use one of the below to feed those inputs a signal from your receiver single sub output. They are available in several configurations, male or female connections.

 

I hope this isn't too confusing. It's early. Re-read the manual. It gets easier to understand.

 

You should be able to find someone locally to repair the amps. I would guess for less than $100 each. I got an estimate of $75 recently for 1 amp repair locally. Where are you located?

 

Any more questions just ask away. The speakers will surprise you when you get them up and running correctly.

 

 

Keith

 

 

Y cable.jpg

y adapter.jpg

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T2K    757

Jumpers for speaker binding posts. Make your own if needed.

 

 

jumper.jpg

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T2K    757

Cook this for dinner and invite me over.

 

 

Greek Chicken Sheet Pan Dinner with Green Beans & Feta.jpg

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rumble    1
9 hours ago, billybob said:

With no speaker wires hooked just ac power cords to either one, they should basically be quiet with no buzz or loud hum.

 

yes.

 

when i turn the left speaker on to AUTO it is silent.

if i slide the switch to ON it buzzes, then still buzzes when i slide the switch to AUTO, and when i slide the button to OFF.

 

the right speaker buzzes immediately when i turn it to AUTO and ON

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billybob    5898
Quote
8 hours ago, rumble said:

 

yes.

 

when i turn the left speaker on to AUTO it is silent.

if i slide the switch to ON it buzzes, then still buzzes when i slide the switch to AUTO, and when i slide the button to OFF.

 

the right speaker buzzes immediately when i turn it to AUTO and ON

 

Just a thought, and  @T2K gave some info for you, there was an occasion recently where some solder needed to be repaired on an RP-5, a similar but different model. Thinking he was lucky though to fin it and repair. Your issue is more than likely near same in both amps.

Another thought(likely wrong is to leave the am on to aee if buzz dimishes over a couple of minutes after the caps charge.

Anyhow, going beyond my experience base with these. Hope you are handy if you do a DIY Careful around those caps as they

can deliver a whallop of juice.

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T2K    757

If you follow the link above to the "KSP-400 amp repair" thread the last post in that thread from member aswego explains what he did to repair his amps and the parts needed. The likelihood is high that your amps need the same repair/parts that his did.

 

Keith

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rumble    1
On 08/14/2017 at 9:43 AM, T2K said:

The manual can be confusing as far as connections go. There are many variables since the speakers are tri-wireable. Keep it simple for starters. There should be jumpers between the 3 pairs of speaker binding posts (positives and negatives linked). If not use speaker wire, which may be better than the original metal jumpers anyway. The subwoofers will get a signal from your receiver via speaker level input. See the owners manual for illustration.

 

Simply run speaker wire from your receivers speaker outputs to any of the speaker binding posts on the speakers, that is if you have the jumpers in place on the 3 sets of speaker binding posts on the speakers.

 

The sub amp does not need to be plugged in but you'll get pretty crappy sound without the working sub.

 

As for the 2 speakers sub cables from your single receiver sub output goes, or for the LFE inputs on the speakers, simply use one of the below to feed those inputs a signal from your receiver single sub output. They are available in several configurations, male or female connections.

 

I hope this isn't too confusing. It's early. Re-read the manual. It gets easier to understand.

 

You should be able to find someone locally to repair the amps. I would guess for less than $100 each. I got an estimate of $75 recently for 1 amp repair locally. Where are you located?

 

Any more questions just ask away. The speakers will surprise you when you get them up and running correctly.

 

 

Keith

 

 

Y cable.jpg

y adapter.jpg

hi keith

 

the manual has connections in the diagrams that have no explanation!!  ;)

only the 2 pairs of binding posts from the right are jumpered - that's ok, i plugged my speaker wires into them and finally got a signal to the other drivers, so at least i know those work now however i wasn't that impressed by the sound. i thought the rear surround speakers sounded fantastic though when i tested those separately, so i'm hoping when i get the subs working the ksp 400s will come to life... i'm more used to listening to my ads L900s and L710s...

 

i have a guy that fixes electronics at my friend's musical instrument store that seems pretty adept at amps and things of that ilk, i'm just wondering if people have done modifications to make the amp better or used higher quality parts to overcome the problem.

 

i think i grabbed the pdf manual the other night, so that will help, providing that i don't have a different version of the board that what's in the manual.

 

does anyone know the year(s) these were made?

 

btw - i'm in new hampshire

 

(and for some reason i'm not being notified of replies, so forgive any delays in replying.)

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rumble    1
On 08/14/2017 at 9:46 AM, T2K said:

Cook this for dinner and invite me over.

 

 

Greek Chicken Sheet Pan Dinner with Green Beans & Feta.jpg

 

what the heck is this? looks amazing.

 

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rumble    1
15 hours ago, T2K said:

If you follow the link above to the "KSP-400 amp repair" thread the last post in that thread from member aswego explains what he did to repair his amps and the parts needed. The likelihood is high that your amps need the same repair/parts that his did.

 

Keith

 

umm... i'm not seeing the link...

 

i'm a little confused trying to navigate around this site.

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T2K    757

https://community.klipsch.com/index.php?/topic/169648-ksp-400-amp-repair/&page=2

 

Greek Chicken with green beans/feta

 

The speakers were built from 1997 to 1999. Your amps are 17 years old. They need capacitors and probably a bridge rectifier. Those are the parts pictured in the above thread and shown in the pictures that I posted in that thread. Original amps/parts are shown in those pics, my pics are of 'new' KSP-400 amps. Your amps should be the same unless they have had a previous repair or modification.

 

The speakers will sound like any other speaker with non-working drivers. You shouldn't judge their sound until they are working properly. One more time, jumper all 3 speaker binding post pairs together then run your 'Y-cabled' receiver single sub output to each speakers LFE Input and adjust LFE and Bass volume controls to taste. The manual offers starting suggestions which you can fine tune

.

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rumble    1

i managed to get the amps out and over to a friend of mine that is pretty adept at electronics (more so than i am...)

 

i told him to use higher quality parts than what was originally in the amps.

(are the capacitors what always made these amps fail?)

 

re: run your 'Y-cabled' receiver single sub output to each speakers LFE Input and adjust LFE and Bass volume controls to taste.

 

are you saying don't connect to the sub inputs on the speakers?? why should i use the LFE instead?

 

thanks

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T2K    757
6 hours ago, rumble said:

i managed to get the amps out and over to a friend of mine that is pretty adept at electronics (more so than i am...)

 

i told him to use higher quality parts than what was originally in the amps.

(are the capacitors what always made these amps fail?)

 

re: run your 'Y-cabled' receiver single sub output to each speakers LFE Input and adjust LFE and Bass volume controls to taste.

 

are you saying don't connect to the sub inputs on the speakers?? why should i use the LFE instead?

 

thanks

 

You need to read the Owners Manual.

 

On the control panel on the rear bottom of each speaker you have 3 pairs of speaker level inputs (binding posts for speaker wire) marked LOW IN > MID IN > HI IN . You can use the LOW IN Line Level RCA input and not connect speaker wire/ jumpers to the far left pair of binding posts (they're marked 'LOW IN'). See that? Then connect RCA cable from sub output on receiver to LFE IN on each speaker. If you have only one Sub Out on back of your receiver then you'll have to use a 'Y' Cable to feed each speaker. You'll have to set your receiver SUB OUT to LFE ONLY in your receiver menu.

 

Easiest thing to do? Speaker wire to binding posts that are all (3) jumpered together. RCA cable from receiver sub out to LFE IN on speaker. Adjust both volumes level controls (Low and LFE) to your preference.

 

You're making it harder than it is. Good Luck.

 

Keith

 

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