BEC Posted March 31, 2007 Share Posted March 31, 2007 I don't know how many are interested in such stuff, but thought I would post a bit about some KP-250 crossovers on the bench here this weekend. I am repairing and rebuild them two sets of them. The sets are a bit different, even though they are labeled the same. Here is one variety. Notice that this one has zener diodes for tweeter protection. These are 9.1 volt 10 watt zeners rather than the 5.1 volt zeners we see in the AA crossovers. Bob Crites Quote Link to comment Share on other sites More sharing options...
BEC Posted March 31, 2007 Author Share Posted March 31, 2007 Now this one is a bit different. It has the resistor and polyswitch type of tweeter protection I expected to see. Bob Crites Quote Link to comment Share on other sites More sharing options...
BEC Posted March 31, 2007 Author Share Posted March 31, 2007 This is the schematic that came from Klipsch. I took the liberty to label the attenuation (3 db measured) for the autotransformer that feeds the squawker. Notice the rather elaborate band bass on the squawker. Also note the polarity reversal for both the squawker and tweeter. Bob Crites Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted March 31, 2007 Share Posted March 31, 2007 Thanks for posting Bob, say I just got a pair of KP250's myself, haven't taken a look inside but they are loud and pretty smooth, although down a bit on the low end. Could you give a read of what that network is doing? And I wonder when/if mine need updating? I'm getting a pair of Heresies with your networks and CT125's soon, that should be fun listening compared to the other pairs I have around here. Do those KP250's have the cloth grille with perf board behind the woofer section? I thought it an awful 'pretty' grille for an industrial set. Would have preferred perf metal like my 201's have. Michael Quote Link to comment Share on other sites More sharing options...
BEC Posted March 31, 2007 Author Share Posted March 31, 2007 Michael, I haven't seen the speakers, just the crossovers. They are a mess. The zener diodes are shot and I can't imagine how much power went into the speakers to fry the diodes. Been "Rode hard and put away wet" as we are prone to say 'round these parts. Looks like the crossovers are a good design to me and my spectrum analyzer. The caps are moderately bad on ESR and need replacing. I will get them fixed up. Bob Crites Quote Link to comment Share on other sites More sharing options...
Guest " " Posted March 31, 2007 Share Posted March 31, 2007 It really uses a 20 amp fuse? Quote Link to comment Share on other sites More sharing options...
BEC Posted March 31, 2007 Author Share Posted March 31, 2007 I haven't seen the fuse. It would be on the back of the cabinet I suppose. I am still marveling at how they managed to get the 20 watts to the tweeter zeners it would take to burn them up. Guess a big honking 20 amp input fuse would help be able to do that. Let's see, we normally think of about 2 percent of the total energy going to the tweeter, so we know we got at least 20 watts to them. So total power into the speaker would calculate to 1000 watts. That is good, looks like the fuse would blow at 3200 watts if it is an 8 ohm speaker. Bob Quote Link to comment Share on other sites More sharing options...
whamo Posted April 3, 2007 Share Posted April 3, 2007 What caps are you gonna replace the 47uf ones with? My kp301's had a 68uf cap so I used two of the parts express non-polarized electrolytic type there in series. Also was that ok to use those ? They sound ok to me. Mark Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted April 3, 2007 Share Posted April 3, 2007 Klipsch shipped PRO gear with massive fuses so they would be sure to work in all conditions. There was an instruction sheet that gave PROPER values to use for either the voltage or the speaker attached to the fused circuit. Leaving a 20 amp fuse in place and expecting any degree of driver protection would not be appropriate. I'll see if I can find the fuse chart and post it here. Michael Quote Link to comment Share on other sites More sharing options...
BEC Posted April 3, 2007 Author Share Posted April 3, 2007 Mark, I used a 47 uF non-polarized for that. Why did you not just use a 68 uF non-polarized for yours? What values did you series there? If you put two 68 uF in series (for instance) you would have a total of 34 uF. In parallel, the two 68 uF would total 136 uF. Bob Quote Link to comment Share on other sites More sharing options...
whamo Posted April 3, 2007 Share Posted April 3, 2007 Bob, I used 68uf . It's been along time since I went to school. I thought putting them in series would keep the value the same. Alright I guess I need to fix that. So what would 34uf do to the performance of the woofer? Thanx for your help again. Quote Link to comment Share on other sites More sharing options...
BEC Posted April 3, 2007 Author Share Posted April 3, 2007 Bob, I used 68uf . It's been along time since I went to school. I thought putting them in series would keep the value the same. Alright I guess I need to fix that. So what would 136uf do to the performance of the woofer? Thanx for your help again. Anything other than the specified value for that cap will change the woofer roll off frequency. Stay with the specified value. Bob Quote Link to comment Share on other sites More sharing options...
whamo Posted April 3, 2007 Share Posted April 3, 2007 Bob, My intention was to keep the values the same. I'm glad I participated in this discussion otherwise I would've never discovered my error. Thanx alot, Mark Quote Link to comment Share on other sites More sharing options...
TeachJava Posted November 29, 2008 Share Posted November 29, 2008 What is the proper fuse size/type for the kp-250? Mike Quote Link to comment Share on other sites More sharing options...
bhendrix Posted November 29, 2008 Share Posted November 29, 2008 What is the proper fuse size/type for the kp-250? Mike AGC 2.5 amp Quote Link to comment Share on other sites More sharing options...
djk Posted November 29, 2008 Share Posted November 29, 2008 "I am still marveling at how they managed to get the 20 watts to the tweeter zeners it would take to burn them up. " A blast of feedback above the crossover point would take them out in a hurry, a 200W amp could do it. Quote Link to comment Share on other sites More sharing options...
WMcD Posted November 29, 2008 Share Posted November 29, 2008 Thanks for the info Bob. It looks to me that the schemetic shows a second order bandpass for the mid. And of course second order in the bass as third order in the tweeter. Is not the unit as a whole a Hersey for professional use? I wonder if the HIII uses a similar topology. From what is out there, PWK favored running the mids with a simple high pass. This was, therefore, quite a break with tradition. Wm McD Quote Link to comment Share on other sites More sharing options...
colterphoto1 Posted November 30, 2008 Share Posted November 30, 2008 There have been a lot of stripped-down pro speakers sold on eBay recently. I just missed a pair of KP201 (ProH II) networks, but picked up a 5-pack of horns, drivers, and nets for KSM2 monster monitors. I've also seen parts for 250's sold separately. Makes me wonder what the difference between a H II and KP201 network might be. To my ears, I really enjoy the 201 sound (it beats the 250 in smoothness of range), but most folks prefer a H over H II. Could it be the network? Here's the primer: Heresy Heresy Industrial HI and Heresy Industrial Ported HIP feature K42 woofers and pro networks H II = KP201 (same components exactly but different networks), there is also a HP1, Heresy Pro that predates the KP201 and has HII network. KP250 is heavy duty components and differnet network, is also ported for more db at sacrifice of low end HIII features different internals completely In some curves and listening evaluations that Doc and I did years ago, we preferred the Heresy and KP201 over the HIP and KP250 in a volume balanced comparison. The ported models were somewhat louder overall, but sacrificed bass to do so. These models would frequently be used with the the 'speaker on a stick' setup over a sub bin (KP115 generally), so that would smooth out overall response. M Quote Link to comment Share on other sites More sharing options...
djk Posted November 30, 2008 Share Posted November 30, 2008 "PWK favored running the mids with a simple high pass" PWK was frugal. http://www.google.com/patents?id=tBE4AAAAEBAJ&pg=PA3&dq=4,237,340&source=gbs_selected_pages&cad=1_1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.