EdmundGTP Posted May 1, 2012 Author Share Posted May 1, 2012 The subs are 4 ohms each according to the the schematics and repair guides that I've read. Unless you can somehow score a smokin hot deal on that amp, it's a LOT more than you really need to accomplish the outboard amp mod. You could get all the capability of that unit (and more) with a sub $500 Crown, QSC or similar pro-audio amplifier and a $80 Behringer Feedback Destroyer. That amp is probably way overkill as far as wattage is concerned, but it probably would work. Quote Link to comment Share on other sites More sharing options...
chacal Posted May 11, 2012 Share Posted May 11, 2012 Okay, you're probably right. Now, can you tell me why you chose to go with an outboard EQ (feedback destroyer) as opposed to using the EQ (etc.) capabilities of the Crown amps (especially on the XTi series amps)? Quote Link to comment Share on other sites More sharing options...
EdmundGTP Posted May 12, 2012 Author Share Posted May 12, 2012 No specific reason really. I just happened to have been able to get those components at great prices. Plus the feedback destroyer has amazing equalizing capabilities. Being that I run "two" concurent subwoofer systems at the same time, the 2 channels of the BFD allow me to eq both easily and independently of one another. I actually also run a behringer ultragain mic2200 (before the BFD) in the subwoofer signal chain for basic signal boosting going from RCA singal level to XLR connector level (which is the only kind of input my particular amp has), subsonic filtering for the KSP's For just the pair of KSP subs, an XTi amp should probably be more than adequate. 2019 EDIT: I no longer run the Behringer Ultragain Mic2200 in the sub signal chain. Not necessary. Quote Link to comment Share on other sites More sharing options...
chacal Posted May 13, 2012 Share Posted May 13, 2012 EdmundGTP, I really appreciate your help, thanks. Since you seem to be someone who really knows this stuff, I was wondering if I could run a couple of other Q's by you.....mostly so I can understand what I'm getting into more fully......... Reading the specs for the Crown XTi1002, it states that is has both input and output EQ filters......what is the purpose of having EQ ability on both input and output? For driving subwoofers, does it matter which is used (or should both be used?). I would think that the output EQ, being closest in the supply chain to the subs, would be of more "importance"? Also, the input EQ has "adjustable high and low shelving filters"............what is a "shelving" filter as opposed to any other kind of filter? Next, there are crossover filters: Crossover Filters: -Adjustable highpass and lowpass per channel. -Butterworth 6/12/18/24dB per octave. Linkwitz-Riley 24/48dB per Octave. -Also includes ± 15 dB bandpass gain and polarity control. - what is "highpass" and "lowpass" refer to? How about "bandpass" gain? Finally, is this the same as "phase control"?: Delay: For signal alignment of driver; 50 mS of total delay. My AV receiver has only a single subwoofer pre-amp output (RCA), so I would need to get to use a "Y" splitter coming off of that output which turns into dual XLR's for the Crown amp inputs, correct? Sorry to bug with so many (probably trivial) questions but I'm not used to all the features and nuances of this pro equipment which you seem to be very familiar with. I just want this conversion to go properly (the first time!). Thanks. Quote Link to comment Share on other sites More sharing options...
EdmundGTP Posted May 13, 2012 Author Share Posted May 13, 2012 No prob. There's actually a few of those questions that I might not have much valuable input on. I actually had to glance throught he manual for that amp to check on some of the things. It's usually a good idea to read through the amp owners manuals to understand their full capabilities before actually pulling the trigger on one. The manual for the XTi1002 can be seen here. http://www.crownaudio.com/pdf/amps/143060.pdf As far as the input and output EQ. The difference between those is that the input one EQ's the signal BEFORE the internal crossover and the output one EQ's the signal after it. If you aren't actually using the crossover feature of the amp, then it may not matter which of those 2 EQ options you use. I'm guessing you could use both if you really had to. I didn't see any reference to it in the manual but the "shelving" filter may be what would amount to another crossover option that would most likely be employed as a sub-sonic filter. All crossovers are of some type of "pass". Crossovers are set to operate at a certain frequency, (for example say 80 Hz). High pass crossovers would allow everything from 80 Hz and up to be heard, and Low pass crossovers would allow everything from 80 Hz down to be heard. Pass band gain allows you to increase the magnitude of the singal which the crossover is passing through. You probably wont have to use any of the amps crossover features, since your receiver will already limit the signal going to the subs to be bass only, and I'm guessing it would be adjustable from probably 80, 100, or 120 Hz. The only crossover option that I would probably use on the XTi is a high-pass crossover set to 20 Hz @ 24 dB/Octave. The 3 dB down point of the KSP subs is rated at 27 Hz according to their specs, and you'll want to limit the amount of subsonic frequencies (20 Hz and below) going to them in order to avoid over excursion damage. Polarity is essentially the same as phase control. You can also get the same type of phase/polarity control results by playing with the delay a little bit. Admittedly I don't know much about those options and haven't messed with them much in my own system. According to the amp manual, there is a mode in which it applies the channel 1 input signal to both channel 1 and channel 2 outputs. So you could skip the Y splitter in your signal line. Just run a single RCA cablewith an XLR adapter at the end of it to the Channel 1 input and set the amp's input mode to "Input Y". I believe there are other Pro audio amps that actually have RCA inputs on them if you want to skip the RCA to XLR conversion. Not sure which specifically; it's been a while since I did any serious looking at them. But there are many options aside from Crown. QSC, Samson, Behringer, etc. When it comes down to actualy EQ'ing your subs, the menu and controls of the Crown EQ system may prove to be cumbersome to operate. The sub EQ process can be tedious but the results are worth it. Quote Link to comment Share on other sites More sharing options...
chacal Posted May 14, 2012 Share Posted May 14, 2012 Thanks, all of that really helps. So, if I understand correctly, and..........just for ghits and shiggles, lets pretend that the receiver sub-ot doesNOT have a lowpass (correct?) filter for 80/100/120 Hz, then I could use INPUT filter as a lowpass (the 80/100/120Hz selection) and then use the OUTPUT filter as a highpass (set at 20Hz or so with a 24db/octave slope)..........this would end up with only frequencies between 20 Hz and 80/100/120HZ going to the sub, right? I guess the Crown XTi1002 offers EQ abilities as follows: 8 parametric filters per channel with adjustable Q, ±15dB boost/cut. which seems that if the filter ranges are user definable (?), then I could fine-tune the frequency response with having up to 8 "bands" worth of adjustment available in the 20 - 80/100/120Hz range, right? About the only thing missing that I would consider very useful is an auto-on function (via a voltage trigger or signal sensing), any specific recommendations on a device that accomplishes that somewhat affordably? Thanks again for all your help. P.S. what is "Q" as it relates to equaluzation? Quote Link to comment Share on other sites More sharing options...
EdmundGTP Posted May 16, 2012 Author Share Posted May 16, 2012 I believe all of the assumptions in your first paragraph are correct, and spot on. Though I seriously doubt any receiver would output a sub signal that wasn't High Passed somewhere in the 80-120 Hz range. 8 Filters should be more than enough to equilize the frequency range between 20 and 80 Hz. On my BFD, I believe I only use 4 filters for the sub signal going to my KSP's and 5 filters for the signal going to my other subwoofer. Each filter will have a base frequency which appears to be user defineable on the XTi. This is the frequency around which you either boost or cut the signal. The Q factor comes in where you decide the "spread" over which you decide to apply the boost/cut and this is general defined in fractions of octaves. For example (and this is a seriously simplified dumbed down example). You do a frequency response chart of your subwoofer system, and find you have a large "Hump" that peaks at +8 dB or so and it is centered right at 60 Hz and tapers down to "normal" volume ranges at 45 Hz on the low side of the chart and 75 Hz on the higher side. You would create a filter for 60 Hz. And you would assign a Q value to the filter. It's based on octaves of your principal filter frequency. So if your Q factor is set to 1 whole octave, that means that your filter will apply a boost or cut to a frequency range that spreads from 1 octave below your filter frequency to 1 octave above. In other words, this would be a very "broad" filter and would boost/cut the entire frequency range from 0 Hz to 120 Hz. Since your "Hump" is much narrower; it only extends to 15 Hz below and 15 Hz above your peak at 60. You would use a Q factor of 1/4 octave. 1/4 of 60 Hz is 15 Hz, and thus would define a range of 45 Hz to 75 Hz to which a signal boost or cut would be applied. In this case you would experiment with cutting the signal by 6 dB or so to begin with, to see how that "levels out" your frequency response graph. You may find that you need to cut the signal by as much as 10 dB on this particular filter to tame the hump. If that paragraph was totally confusing try reading through this article at home theater shack on the BFD. http://www.hometheatershack.com/forums/bfdmeasure/ Towards the bottom it explains a bit more about how to set up the filters to most effectively correct your frequency response curve. As far as auto turn on functions. The quickest and cheapest way to do this, is by using a current sensing surge protector. I use one myself, but AFTER a stand-alone power conditioner. This is the same unit actually. http://www.amazon.com/Belkin-Conserve-Socket-Energy-Saving-Outlet/dp/B003P2UMQ2/ref=pd_bxgy_e_img_c I plug this into my power conditioner. Plug my receiver into the master outlet, and plug the amplifier into one of the "master controlled" outlets. When I turn my receiver on, the surge unit senses the current and sends power to the amplifier. Most amplifiers have roughly a 5 second internal turn on delay, which menas 5 seconds pass between when the amp powers on, and acual audio signal is allowed to pass through. This makes the amp turn on automatically with my receiver and the amp has enough of an internal delay to avoid any turn on "pops" or "thumps". Unless your receiver and sub amplifier each pull enough current to justify separate electrical breakers in your main panel, this thing should be more than adequate. Quote Link to comment Share on other sites More sharing options...
drewzter Posted January 26, 2013 Share Posted January 26, 2013 Thanks to this thread, I successfully converted my 400s last night. Got the amp for myself for Christmas and have had it sitting until I made time to mess with everything... actually it didn't take much time at all. Since the OEM amps are rated down to 10hz I wanted a replacment that would do the same. I found a Parasound HCA1000A on Audiogon and jumped on it (for far less than original price, of course). So far, sounds awesome... I've got my bass back after waiting 3 years since the OEMs failed! Woo! Quote Link to comment Share on other sites More sharing options...
Lovebohn Posted January 28, 2013 Share Posted January 28, 2013 (edited) Where did you buy the caps at? I assume Digikey would be a good start. How have things been working for over a year now?. I just had my left channel go bad with a very loud hum, right side seems to be OK, just the normal very quite buzz like always. Dave Edited April 2, 2014 by Lovebohn Quote Link to comment Share on other sites More sharing options...
Lovebohn Posted April 2, 2014 Share Posted April 2, 2014 Over a year later and I have still done nothing with this amp. Any thoughts on where to look for the replacment caps? I have not found any old KSP, KSW15 or KSW300 amps around. Quote Link to comment Share on other sites More sharing options...
EdmundGTP Posted April 24, 2015 Author Share Posted April 24, 2015 Over a year later and I have still done nothing with this amp. Any thoughts on where to look for the replacment caps? I have not found any old KSP, KSW15 or KSW300 amps around. Blast from the past I know, but there is a local guy here in AZ who advertises to fix most brands of speaker amplifiers. http://edwardselectronics.net/1901.html Saw him by chance with a listing on ebay. No personal experience with them though. I tried messaging him to offer my unused KSP400 amps to him but never heard back. Either way, if anyone else has a use for a pair of KSP400 amps let me know. I'd be happy to mail them out for the cost of shipping. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted April 24, 2015 Share Posted April 24, 2015 Pay them before you ship the amp and they even look at it? Quote Link to comment Share on other sites More sharing options...
EdmundGTP Posted April 25, 2015 Author Share Posted April 25, 2015 Pay them before you ship the amp and they even look at it? Huh... Yeah I didnt even notice that at first. Seems like a strange way to do business. Unless maybe they just charge a flat fee to fix depending on which amp it is? I dunno. Quote Link to comment Share on other sites More sharing options...
Lovebohn Posted April 25, 2015 Share Posted April 25, 2015 Over a year later and I have still done nothing with this amp. Any thoughts on where to look for the replacment caps? I have not found any old KSP, KSW15 or KSW300 amps around. Blast from the past I know, but there is a local guy here in AZ who advertises to fix most brands of speaker amplifiers. http://edwardselectronics.net/1901.html Saw him by chance with a listing on ebay. No personal experience with them though. I tried messaging him to offer my unused KSP400 amps to him but never heard back. Either way, if anyone else has a use for a pair of KSP400 amps let me know. I'd be happy to mail them out for the cost of shipping. Sorry I didn't read back through the posting, but are your amps in good working order? Quote Link to comment Share on other sites More sharing options...
EdmundGTP Posted September 9, 2015 Author Share Posted September 9, 2015 Over a year later and I have still done nothing with this amp. Any thoughts on where to look for the replacment caps? I have not found any old KSP, KSW15 or KSW300 amps around. Blast from the past I know, but there is a local guy here in AZ who advertises to fix most brands of speaker amplifiers. http://edwardselectronics.net/1901.html Saw him by chance with a listing on ebay. No personal experience with them though. I tried messaging him to offer my unused KSP400 amps to him but never heard back. Either way, if anyone else has a use for a pair of KSP400 amps let me know. I'd be happy to mail them out for the cost of shipping. Sorry I didn't read back through the posting, but are your amps in good working order? Sorry for taking forever to reply here. I know for certain one of them is NOT good. It's been so long since I pulled them out that I don't remember exactly, but I THINK one of them is still in good working order. I wouldn't bet the farm on it though.. Quote Link to comment Share on other sites More sharing options...
Blue11 Posted October 1, 2015 Share Posted October 1, 2015 Over a year later and I have still done nothing with this amp. Any thoughts on where to look for the replacment caps? I have not found any old KSP, KSW15 or KSW300 amps around. I just ordered six main power amp replacement caps from DigiKey (2 of each): Part Number Manufacturer Part Number Description 493-8716-ND LGY1K682MELC45 CAP ALUM 6800UF 20% 80V SNAP (C4 and C15) P10275-ND EEU-FC1E471 CAP ALUM 470UF 20% 25V RADIAL (C3 and C5) 493-11833-1-ND UPV1C101MGD1TD CAP ALUM 100UF 20% 16V RADIAL (C9 and C10) They should be here in a week or so. Around $25-$30 shipped. I made a guess as to the largest ones' lead pin spacing... If anyone who replaced their own caps is reading this, how did you deal with the power transistors that are screwed directly to the heatsink when disassembling/reassembling the amp? Quote Link to comment Share on other sites More sharing options...
RockinRobin Posted July 16, 2016 Share Posted July 16, 2016 (edited) Really delayed answer but just repaired my KSP 400 sub amp. Just took out all the screws (10) on the amp board and pried the board up gently off the heatsink, left everything else alone. Then replaced the caps and put it back together. Works great again. Edited July 16, 2016 by RockinRobin Quote Link to comment Share on other sites More sharing options...
dubuque99 Posted January 5, 2017 Share Posted January 5, 2017 (edited) (I know this is an "old thread" that I'm replying to). -I just wanted to express my sincere thanks to Mr. EdmondGTP, for the detailed description of the amp removal. -It has helped tremendously! ....Jeff Edited January 5, 2017 by dubuque99 Quote Link to comment Share on other sites More sharing options...
EdmundGTP Posted January 6, 2017 Author Share Posted January 6, 2017 No problem! This thread has been kicking along for a while, and I'm still using my KSP's in their modified state. Though I did recently upgrade the amplifier I'm using to power them. Previously, I was using a Crown XLS-202, which made adequate power, but even after modifying the cooling fan it was still bothersome. In an otherwise perfectly quiet room, the fan could be heard at my listening spot (~12 ft away, and behind a closed cabinet), resulting in a bit more than whisper level background noise. Picked up an XLS-1002 and got it all plugged in last night. For anyone who might still be looking to do this modification, this is probably the best/most cost-effective amp solution. ~$280. Each KSP sub is getting ~350 watts and the thing is absolutely silent. Has +12VDC trigger-on capability, dim-able control panel and lighting, input sensitivity adjustment for low voltage source signals (i.e. most Receiver sub/LFE outputs), built-in crossover capability. Not quite as many bells and whistles as the Crown XTI2 series, but there's no sense paying for them if you're not going to use them. I had to do a bit of modification to the 19" wide rack-mount chassis in order to get it to fit into the 18-5/8" wide shelves of my entertainment stand. I folded back the mounting flanges and ground down the outer ends of the front decorative bezel, until the max width was 18-1/2". Quote Link to comment Share on other sites More sharing options...
EdmundGTP Posted March 11, 2019 Author Share Posted March 11, 2019 Bump for an oldie.. Re-linked all the old relevant pics that got messed up with photobucket. 1 Quote Link to comment Share on other sites More sharing options...
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