Matthews Posted July 23, 2016 Share Posted July 23, 2016 I have these new crossovers (pictured). From my understanding, they are switchable between type A and type AA networks. The white jumper is used to switch between the two types. I do not know where the jumper would go to manipulate between the two crossover designs. Also, what differences are there between the two? Is there certain sonic differences or is this, more simply, for the delicate K77 tweeter protection. Which configuration to use for what? Any help, much appreciated. Matt ♪ ♫ ♪ Quote Link to comment Share on other sites More sharing options...
Matthews Posted July 23, 2016 Author Share Posted July 23, 2016 So after some research, it seems that yes, the type AA provides tweeter protection for the delicate K77. I am inclined to think the crossovers are currently wired as such, type AA. Still at question is how to wire (use of white jumper) for type A on this pair? Also, is the only reason to wire as such, type A, if one were running an upgraded tweeter? Hmmm? Quote Link to comment Share on other sites More sharing options...
mustang guy Posted July 23, 2016 Share Posted July 23, 2016 The 245uH inductor, the extra 2 uF cap, and the zener diode were added in the AA. See below: Quote Link to comment Share on other sites More sharing options...
Marvel Posted July 23, 2016 Share Posted July 23, 2016 The two caps on the laft are paralled to get the 13uF. There must be a second 2uF under the 2uF on the right. Pull the white wire off the top cap (this will take the diodes out off the circuit). Or it's the black on the bottom right. You need to locate the 245uH choke. If it is on the black wire on the left of the 2uF cap, you probably just pull both the black and white and replace with the jumper. Since the jumper is wire tied to those two, it makes sense. Bruce 1 Quote Link to comment Share on other sites More sharing options...
Matthews Posted July 24, 2016 Author Share Posted July 24, 2016 Holy Smokes! Just mailed Bob about these. I have on my hands something of a rarity A quote from Bob himself... "Most of the A/AA convertibles (hundreds probably) were built from scratch. I doubt we did more than perhaps 2 or 3 of the original AA conversions to A/AA." These crossovers folks are one pair of those 2 or 3 ever made ...now I really don't know what to do Quote Link to comment Share on other sites More sharing options...
Zim. Posted July 24, 2016 Share Posted July 24, 2016 x Quote Link to comment Share on other sites More sharing options...
Matthews Posted July 24, 2016 Author Share Posted July 24, 2016 Effectively making them the same as what you have Well take the wind right out of my sails don't you "Zim" -LOL- Notice the instructions from Bob. ...and that's what is missing from mine, per the thread -all good now- Matt ♪ ♫ ♪ Quote Link to comment Share on other sites More sharing options...
ZEUS121996 Posted July 24, 2016 Share Posted July 24, 2016 Holy Smokes! Just mailed Bob about these. I have on my hands something of a rarity A quote from Bob himself... "Most of the A/AA convertibles (hundreds probably) were built from scratch. I doubt we did more than perhaps 2 or 3 of the original AA conversions to A/AA." These crossovers folks are one pair of those 2 or 3 ever made ...now I really don't know what to do That's easy, PM me and I will send you my address. Obviously they weren't popular so they probably wont work for you :D Mark 1 Quote Link to comment Share on other sites More sharing options...
Marvel Posted July 24, 2016 Share Posted July 24, 2016 So... I was right... Quote Link to comment Share on other sites More sharing options...
Matthews Posted July 24, 2016 Author Share Posted July 24, 2016 That's easy, PM me and I will send you my address. Obviously they weren't popular so they probably wont work for you :D Mark Yeah, nothing special anymore ...said no one -LOL- So... I was right... a skilled marksman, home on the range Matt ♪ ♫ ♪ Quote Link to comment Share on other sites More sharing options...
MookieStl Posted July 24, 2016 Share Posted July 24, 2016 I'd keep looking for another pair of AA on the cheap. That way you don't have to make any snap decisions. There are always more La Scalas in your future whether you admit it or not. The next owner of one of your pairs of La Bellas may pay a little extra for the upgrade especially moving up from ALs. jweber was spotted in St. Louis yesterday and heading to Mid MO. Maybe he needs some fancy x overs for his Medium-Well La Scalas that were overcooked not too long ago. 1 Quote Link to comment Share on other sites More sharing options...
ZEUS121996 Posted July 24, 2016 Share Posted July 24, 2016 That's easy, PM me and I will send you my address. Obviously they weren't popular so they probably wont work for you :D Mark Yeah, nothing special anymore ...said no one -LOL- So... I was right... a skilled marksman, home on the range Matt ♪ ♫ ♪ Yeah, nothing special anymore ...said no one -LOL- That hurt Matt, cut me to the bone. :mellow: Mark Quote Link to comment Share on other sites More sharing options...
Matthews Posted July 24, 2016 Author Share Posted July 24, 2016 That hurt Matt, cut me to the bone. I don't understand, Mark? I thought "Zim" made it very clear. To paraphrase, that these are nothing special. There are up to two other pairs out there you know. Not to mention, Bob said said to me in an email that these only have about 10 years of life left in them. Certainly nobody would want them? My apologies, Mark... Matt ♪ ♫ ♪ Quote Link to comment Share on other sites More sharing options...
JohnA Posted July 27, 2016 Share Posted July 27, 2016 (edited) I have these new crossovers (pictured). From my understanding, they are switchable between type A and type AA networks. The white jumper is used to switch between the two types. I do not know where the jumper would go to manipulate between the two crossover designs. Also, what differences are there between the two? Is there certain sonic differences or is this, more simply, for the delicate K77 tweeter protection. Which configuration to use for what? Any help, much appreciated. Matt ♪ ♫ ♪ I'd run them as Type AA. The Type AA did 2 things. It added the KLiP Circuit (diodes) to protect the tweeters and added contouring the smooth and lower the tweeter's response. If you have K-77-Ms, remove the KLiP from the circuit. It adds distortion (clipped off waveforms) at higher volumes and the -M can take 50 watts program/100 watts peak. If you look at the 2 response curves, you can see the AA knocks a dB or so off the tweeter's 105 db/w/m output and adds a sag in the response from 6k to about 10k. Edited July 27, 2016 by John Albright 2 Quote Link to comment Share on other sites More sharing options...
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