Audible Nectar Posted May 16, 2004 Share Posted May 16, 2004 All this talk of these crossovers has me worse than a woman: I think I'll go A. Maybe I'll go AA. Then again, maybe I'll go convertible. But should I really go PIO? AAAAAAAAAAAAAAAAAAAAAAAHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH One question I have is this: Is it possible to have my stock AA crossovers (1976 Belles) tested to determine what it is losing?? Would this deterioration (if there is any) be detectable through bench testing, or is this a matter of listening?? Has anyone replaced the stock crossovers (A or AA) with the Bob Crites versions?? I very much look forward to the reviews on these. I'm very much considering a replacement of the stock AA in the Belles - my hunch says try the type A, especially given the comments on these when mated with tube amps (which are on the way). I think if I were to get new ones though, my hunch is with the PIO's - especially after hearing the ALK's (too "hot" for my tastes, at least in the setups I've heard). I am watching very intently, and want to hear impressions of these PIO's....especially in the A configuration. Quote Link to comment Share on other sites More sharing options...
Guy Landau Posted May 16, 2004 Share Posted May 16, 2004 I've also found the ALK's to be too hot and settled for the type A's. I think that Jazman is using a pair of Bob's type A's. Maybe he can respond and share some info. Quote Link to comment Share on other sites More sharing options...
BEC Posted May 16, 2004 Share Posted May 16, 2004 Audible, I can test them if you want to send them to me. A bad one shows up pretty easily on the spectrum analyzer. I have been thinking of doing some "loaner sets" of Type AA (A) convertible crossovers to allow people to still have music while their crossovers are sent to me for a rebuild. This would have to be a sort of purchase/refund arrangement that would allow a customer to hear immediately what a rebuild of the old crossovers would sound like. Let me know if any are interested in that program. Bob Crites bobcrites@centurytel.net Quote Link to comment Share on other sites More sharing options...
leok Posted May 16, 2004 Share Posted May 16, 2004 Dean, I missed the first order (this is for 2.0uF caps right?). If you are ordering more 2s I'd like 4. How much? where do I send $? Leo Quote Link to comment Share on other sites More sharing options...
Audible Nectar Posted May 16, 2004 Share Posted May 16, 2004 Bob - I would very much be interested in this. My situation definitely dictates not being without crossovers right now, as the MC-30's will soon be here. Self torture would certainly ensue if my amps got here and had no working speakers to play them through! The convertibles (A and AA) would be ideal, since I could compare the A and AA new vs. the stock versions. That would clarify which crossovers I really want, as well as verification of the quality of my stock AA's. I'll PM you on this later today. Quote Link to comment Share on other sites More sharing options...
Deang Posted May 16, 2004 Author Share Posted May 16, 2004 Anything Bob can do, I can... ...take twice as long to do, and charge twice as much for doing it. Quote Link to comment Share on other sites More sharing options...
Deang Posted May 16, 2004 Author Share Posted May 16, 2004 I went to bed last night and actually dreamed about capacitors. They were hunting me down, and discharging when they caught up with me. I woke up this morning with burn marks on my arse. Truly though, The Type A should be a little hotter sounding than the ALKs, especially with tube gear. Besides having a slope that feeds more energy to the tweeter than the ALKs, the Type A has a wicked imedance curve, starting at 5 ohms and shooting up to 30 ohms. Not ideal by any stretch of the imagination for some tube gear. Since the Type A was developed early on, and I'm sure PK was still using tube gear when he was doing the voicing. He was a pretty smart fellow, and it is possible that knowing the K77 didn't have the greatest extension, purposely developed the Type A to have rising impedance at the higher frequencies to tweak the treble somewhat. It seems odd to me to think that he would have been ignorant of this particular characterisic of his design -- and not dealt with it if he thought it was "a problem". Staying with this same line of thinking -- open to consideration should be the possibility that PIO capacitors, with their somewhat higher series resistance (as compared to film and foil or metallized types -- whether plastic or oil), may in fact sound better in these circuits -- since these circuits were designed with a little bit of resistance in them to begin with. Paper in oil capacitors also have some other properties unique to themselves, and this shouldn't be discounted either. At any rate... ...with the advent of solid state and higher power comes the Type AA. Since the Type A allowed more tweeter energy, and offered no tweeter protection -- K77s were burning up left and right. So, we end up with a little less energy to the tweeter, and the use of diodes to offer tweeter protection from powerful transients. Also, I believe the Type A allows the K77 to overmodulate and spit at higher SPLs -- hence "earbleeders". So maybe your choice of crossover should be determined by your gear and listening habits -- the same way you make other system related choices. The Type A's I built with Auricaps and loaded into JohnnyDBs LaScalas sounded really good with his ASL tube integrated, but the midrange output was attenuated by the use of the #3 tap on the autoformers. I'm certainly curious what the effect would be like with the #4 tap, and a little bit of series resistance back into the circuit as originally designed. Quote Link to comment Share on other sites More sharing options...
BEC Posted May 16, 2004 Share Posted May 16, 2004 Dean, That sounds like a challenge. Guess I will have to get to work on my new A/AA/B/C/E convertible model with all mods ever mentioned on the forum (all types of caps and inductors and 1 mfd bypass) and all the mods switchable in or out. Options might be to add one of Leo's Tripath amps on the board to separately power the woofer if the user wants to use a very low power amp for the mid and tweet and perhaps a large rectifier tube (an 83 perhaps) with just the filaments powered (for looks). Where to mount the quarter sheet of plywood required for the base may be a problem. Still some details to work out. Bob Quote Link to comment Share on other sites More sharing options...
Deang Posted May 16, 2004 Author Share Posted May 16, 2004 rotflol Quote Link to comment Share on other sites More sharing options...
leok Posted May 16, 2004 Share Posted May 16, 2004 Hello Dean & Ryan, I can try a set of PIOs on the Chorus-IIs If Dean includes 4 2uFs for me on his next order (Dean say cost and address). Right now I have conditioned Hovlands on the tweeters. I don't know anything about older motor run caps. I haven't found Jensens "dark." I just think they sound like a lot of distortion is removed, making the top end much cleaner, less powerful due to lack of what didn't belong there in the first place. I think any change that removes high end distortion will result in something that sounds "less bright." If older motor run caps are less dark than Jensens which one is right? Good question. I don't know. I wouldn't doubt that they do sound less dark, however. I find the Jensens in the RF-7s provide a balance that is very much like what I hear from unamplified acoustic instruments. Maybe the older motor run caps would be even better. Leo Quote Link to comment Share on other sites More sharing options...
Cut-Throat Posted May 16, 2004 Share Posted May 16, 2004 The type 'A's that I built, have a Oil Cap from an E-2 network on the tweeter and 2 motor run caps for the 13uf. These are the best sounding crossovers, I have had in my Belles! Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted May 16, 2004 Share Posted May 16, 2004 As usual, Kevin, very nice and clean work. Great picture, too! Quote Link to comment Share on other sites More sharing options...
NOSValves Posted May 16, 2004 Share Posted May 16, 2004 I'll second that very nice Kevin you don't actually mount thise beauties inside the speaker do you Quote Link to comment Share on other sites More sharing options...
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