JBryan Posted October 21, 2003 Share Posted October 21, 2003 Al, John, If the bass horn limits the woofer's frequency to 400dB then is the 2.5mH inductor in the circuit simply to control the impedance? This is all very interesting and I think I'm beginning to understand you 2 - kinda scary! Al, I already have the 2.2 mH foil inductor laying around and just wanted to know if I could use it in place of the 2.5 as called for in the type A schematic. If I'm reading you and John correctly, I may not even need the inductor at all which would be my preference. -Bryan Quote Link to comment Share on other sites More sharing options...
garymd Posted October 21, 2003 Share Posted October 21, 2003 I really wish I knew what the hell you guys were talking about. I can't understand one post in this entire thread! Sorry to interrupt but it's a slow night on the forum. (yawn) Quote Link to comment Share on other sites More sharing options...
John Warren Posted October 22, 2003 Share Posted October 22, 2003 (edited) ----------------On 10/21/2003 10:56:21 PM JBryan wrote: If the bass horn limits the woofer's frequency to 400dB then is the 2.5mH inductor in the circuit simply to control the impedance? This is all very interesting and I think I'm beginning to understand you 2 - kinda scary!---------------- Edited December 17, 2013 by John Warren Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted October 22, 2003 Share Posted October 22, 2003 Bryan, Sure, if you have a 2._ mHy foil inductor you certainly can use it. John, PWK experimented with running the Khorn with no inductor and wound up putting it back. He also tried for years to make a 2-way Khorn and couldn't because the woofer wouldn't go high enough. If throwing out the woofer inductor would have solved the problem he would have done it in a heartbeat! The mass rolloff is 6 dB / octave. The Khorn rolls of a lot faster than that above 400 (or 500 as the paper says)! Al K. Quote Link to comment Share on other sites More sharing options...
Arkytype Posted October 22, 2003 Share Posted October 22, 2003 Al, et al, (no pun intended) Back in the mid-seventies I worked for an audio dealer who sold both Klipsch and the then-new Advent loudspeakers. The Klipsch driver replacement policy at the time was to replace them at no charge, no questions asked. If the customer repeatedly had failures, we would make a visit to the home to investigate. Usually, the driver (almost always the tweeter) failure was due to a POS amplifier or receiver (rated at around 20-50 average watts) being driven into clipping. The customer (usually a young adult or teenager) had probably just sold his Sansui or Pioneer loudspeakers. With the purchase of Heresys or Cornwalls, he experienced lower distortion and higher output and, as a result, would turn up the volume until the tweeters fried. I don't think we ever replaced a squawker driver. We did replace a few woofers and those failures were usually due to massive over-powering. PWK's solution to keep the number of warranty replacement drivers at an acceptable level was to incorporate the Zener diode mod. He wrote about this crossover change in one of the "Dope From Hope" newsletters. The Advent loudspeakers were usually sold as part of a 20-40 watt receiver, turntable (remember those?) combination system. Most users were content to listen at moderate listening levels and never experienced driver failure. There were a few customers that would manage to burn out a tweeter on a weekly basis. After the first freebie replacement, the rest were the customer's responsibility. We examined many so-called defective tweeters and usually found the voice coil or former charred as if you had taken a blow torch to it. This from a 20 watt amplifier? Hmmm. One of the in-store tests we did to determine why low-powered amplifiers were frying tweeters was to connect a pair of Large Advent loudspeakers to a high-quality, high powered (300+ watt) McIntosh component system. With the tone controls set flat, you could play symphonic music (Telarc?) at levels that were painful and the Advents would never fail. Next we'd take a low-powered (20-40 watts) trade-in receiver and play the same material. Didn't take long for one or both tweeters to fail. Of course, the audible distortion before driver failure was a warning to turn the volume down. Monty Ross has written an interesting paper on power amplifier clipping. This is RaneNote 128 on the rane.com web site. Al is correct, the best tweeter protection is to turn down the volume control. IMHO, the best way to reduce driver failure is to keep the amplifier from clipping. Once the clipping-induced harmonics have left the speaker terminal, it's hard to design a passive circuit that will distinguish between a clean and loud signal and a "noise burst". After previewing this reply, I noticed that only part of the text is there. Apologies in advance if only part gets posted. Arkytype 1 Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted October 22, 2003 Share Posted October 22, 2003 Arkytype , INTERESTING! Your experience seems to suggest that it's slow heat built up in the voice coil over a period of time rather than an instanious "pop" that kills them. If that's really the case, the ballast lamp alone would do the trick. I would think a transient "pop" would just smash the diaphragm. I have only opened up one T-35 in my day, so I have not had the experience you have had. I personally can't immagine how you can even stay in the same room with a Khorn or Belle running loud enough to blow a tweeter! I would need to be wearing ear-plugs! Al K. Quote Link to comment Share on other sites More sharing options...
John Warren Posted October 29, 2003 Share Posted October 29, 2003 (edited) ---------------- On 10/20/2003 6:15:04 AM Al Klappenberger wrote: John Warren, I have been hoping somebody would post the impedance curve of the Khorn woofer. THANKS! It's interesting how it's a nominal 8 Ohms using a 4 Ohm driver. That's what I wanted to see confirmed. The same driver in the Belle Klipsch is 4 Ohms! ---------------- Edited December 17, 2013 by John Warren Quote Link to comment Share on other sites More sharing options...
UncleRobb Posted November 10, 2003 Share Posted November 10, 2003 Hi guys, you are having some interesting discussion here and it would be great if I could learn something from you. I have a pair of La Scalas that are powered by a 1-2 Watts SET amp. Thus there is probably no need to protect the drivers and I can afford a perhaps better sounding crossover. That being said, which crossover sounds better: A or AA? And what is the difference between these both? Starting with the type AA, do I get to the type A when I remove the 245uH inductor, one of the 2uF caps, and the two Zener diodes that are in front of the tweeter? Could somebody point me to a schematics of the type A crossover? Thanks, Robert Quote Link to comment Share on other sites More sharing options...
Guy Landau Posted November 10, 2003 Share Posted November 10, 2003 Robert, Here's the schematic. You are correct regarding the removal of the cap, diodes and inductor. Quote Link to comment Share on other sites More sharing options...
UncleRobb Posted November 10, 2003 Share Posted November 10, 2003 Guy, thanks a lot for the schematics. Now which crossover sounds better type A or type AA (with Zener diodes removed)? Thanks, Robert Quote Link to comment Share on other sites More sharing options...
UncleRobb Posted November 10, 2003 Share Posted November 10, 2003 Guy, thanks a lot for the schematics. Now which crossover sounds better type A or type AA (with Zener diodes removed)? Thanks, Robert Quote Link to comment Share on other sites More sharing options...
Guy Landau Posted November 10, 2003 Share Posted November 10, 2003 Robert, I haven't tried the AA with the diodes removed, but have moved from standard AA's to ALK's and then to type A's (with oil caps and Solen bass inductor). I found the type A to sound the best to my ears with better body and more detail than the other two. Guy Quote Link to comment Share on other sites More sharing options...
UncleRobb Posted November 10, 2003 Share Posted November 10, 2003 Guy, thanks for sharing your "crossover journey." Somehow, I believe that simpler is better. And although I am sure that Al knows very well what he is doing and although he uses premium parts and he can provide some impressive impendance and phase angle plots, I am not comfortable with the rather complicated ALK crossover. I also do not like having bypassed caps that are in the signal path. I think I modify my type AA with some switches so that I can change it to type A anytime. Robert Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted November 11, 2003 Share Posted November 11, 2003 Robert, I think the key to why Guy likes the "A" better than my network is becasue of the oil caps. They are high loss and when used in the "A" will have equally as smooth a response as my network using low loss polypropylene caps but at a reduced level. He probably like "mellow" highs. This is all a matter taste and justifed. I suspect you could do the same thing with an "L" pad in the tweeter circuit on my network though. Personally, I like the "crisp" sound of more highs myself. Al K. Quote Link to comment Share on other sites More sharing options...
Guy Landau Posted November 11, 2003 Share Posted November 11, 2003 Robert, I have built the type A's with Multicaps and Hovlands (that were taken out of my ALK's), at first, and still much prefered them to the AA's and ALK's. I didn't hear any loss of highs when I moved to the oil caps. The sound was more involving and rich. Guy Quote Link to comment Share on other sites More sharing options...
3dzapper Posted November 11, 2003 Share Posted November 11, 2003 Guy, Are you using the motor caps original to your networks or another oil type? and if other what type? I took the motor caps out of my AA networks and subbed in film and foils. The sound is much clearer since the change. I really did not take the oil caps out rather, I carefully cut the leads at their longest length and wired in the 2.2uF Auricaps and a 12uF poly cap. I also took the diodes out of the system. The HFs do sound clearer but if I ever return to SS devices I can reconnect them. Next I am building one of Al's networks to A/B them. I didn't realize how easy it was to convert to type A. I'll try that soon also. Rick Quote Link to comment Share on other sites More sharing options...
Guy Landau Posted November 11, 2003 Share Posted November 11, 2003 Rick, I no longer own my Khorns but have used the original type oils from my AA networks. I also thought that the Multicaps and Hovlands to sound clearer, at first. But after experimenting with the oils, I have found no loss in detail and the sound had more body and richer tone. Did you replace the woofer inductor? Guy Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted November 11, 2003 Share Posted November 11, 2003 Guy, I remember now that you tried the Hovlands in the "A". I have no explanation for what you hear simply becasue there is none! It's simply what YOU like and that's all that counts. With the "A" you may be letting yourself open to tweeter damage if you are not carefull though. The exta elements just keep the lows off the tweeter and reduce diaphragm motion below its range. That's not a good thing. Everything is a tradeoff! My ears tell me that extreme slope crossovers limit a smearing that I used to hear because everything gets to your ears twice, once form each driver if they are not time aligned. A 3rd order network isn't much better in that respect than a 1st order though. I am now working on a network for "sfog" that will have a slope of well over 100 dB / octave! He is going to do side-by-side comparison with the 1st order woofer / squawker filters in my "standard" network (which he built himself). It will be an interesting comparison! The tests and design will be posted in "Ods and Mods" in a few days for the DIY croud. Al K. Quote Link to comment Share on other sites More sharing options...
brother Posted November 11, 2003 Share Posted November 11, 2003 Robert, I built this modified type "A" and have been very pleased with it. The Tweeter protection is like the later Klipsch factory circuits as Al K has recommended. This one is a first order network using the high quality Hovland and Solen components. I understand someone else on the BB has built this network and is very pleased with the results as well. I built this network without any tweeter protection first and then added the bulb as John had previously posted as a later mod. Frankly, I thought the bulb had a negative effect on the HF section and removed it. After listening comparatively for weeks at a time, this is the choice for my LaScalas. Quote Link to comment Share on other sites More sharing options...
3dzapper Posted November 11, 2003 Share Posted November 11, 2003 "Did you replace the woofer inductor? Guy" Not yet Guy. Lately I have been playing with amps. And now it's black powder hunting season in Rhode Island. Had a buck in my sights today, broadside at 35 yards, "pop" the darn smokepole misfired! Always the optomist I will try again tomorrow. Rick Quote Link to comment Share on other sites More sharing options...
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