brother Posted March 11, 2003 Share Posted March 11, 2003 I finally finished my first order crossovers for the LaScalas this weekend. These are inspired from PWK's preference and the quest for simplicity in design. I thought you guys might like to see them. I've only listened to them for a couple of days, but the sound is simply sparkling. The improved clarity and definition of string instruments is the most noticeable and harmonizing vocals are improved as well. The bass is strong for the LaScala and as expected is very tight. I played the Eagles "Hell Freezes Over" DVD and it was remarkably improved over the stock Type AA crossovers. I lost my electronic version of the wiring diagram in a hard drive crash, but will soon redraw it and will post it as well. Quote Link to comment Share on other sites More sharing options...
Guy Landau Posted March 12, 2003 Share Posted March 12, 2003 This one is simpler. Quote Link to comment Share on other sites More sharing options...
Cut-Throat Posted March 12, 2003 Share Posted March 12, 2003 Very nice neat job. I am currently working a on Pair of Type 'A's What did you fasten the coils to the board with? Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 12, 2003 Share Posted March 12, 2003 Hi guys, If it means anything, the networks Brother built is the first order design I posted a few months ago. It is very similar to the ones I build, but with fewer elements. They are true multiplexers and constant impedance. I highly recommend them (obviously!). BTW, Brother did a very nice job building them. His use of electrical wiring components rather then solder and terminal posts to make the interconnections is very interesting. That should work fine. Al K. Quote Link to comment Share on other sites More sharing options...
brother Posted March 12, 2003 Author Share Posted March 12, 2003 Thanks Al! Actually, all the terminals are soldered; I used the ground lugs because of difficulty obtaining the posts you use. The connections are banded, soldered, and then placed in the lugs to secure them. The ring connectors are tin plated copper crimped and soldered onto the wiring before attaching to the terminal strips. The circuitry is a low pass, bandpass, high pass with each element directly fed from the positive signal terminal ( a variation of the published crossover). Many of the other circuits I've seen pull the tweeter cap from inside the bandpass cap. I chose to do it differently. The inspiration (?) comes from a 1958 article by PWK on LPads where he shows a new crossover similar to this one. The idea is to eliminate all possible insertion losses, etc. Obviously, the bandpass section is more complicated due to the squawker driver characteristics. Cut Throat, the inductors are mounted just as Al K does using holes drilled into the mounting board and plastic tie wraps threaded through. The Al's design helped me a lot on these types of details. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 12, 2003 Share Posted March 12, 2003 brother, Ok.. The lowpass - bandpass - highpass circuit performs exactly as the dual diplexer version I use. As it happens, the part values are the same for this paarticular case too. The only drawback is that the crossover points are harder to control making the dual diplexer a much better choice for higher order networks. For first order network, that isn't important becasue the horns actually determine the crossover. Both types are constant impedance if they are done properly. Al K. Quote Link to comment Share on other sites More sharing options...
JohnA Posted March 12, 2003 Share Posted March 12, 2003 I have heard the new networks and I have to say they are an unqualified success. There is a purity to the sound that is immediately apparent, but a little difficult to describe. I listened to The Eagles DVD and a Trisha Yearwood CD the brother's wife likes and that I'd heard several times before through a pair of ALK crossovers. The difference was not "life affirming" or "earth-shattering", but plain to hear none the less. Be forewarned if you build a set of these, the tweeters are hung out there to be blown easily. I'm still trying to persuade brother to go back and add djk's auto lamp tweeter protection (bulb #561). Quote Link to comment Share on other sites More sharing options...
Stovebolt6 Posted March 12, 2003 Share Posted March 12, 2003 Hello All, I am building a pair using Altec 515E (16ohm), 909-16A/511b(16ohm) and EV T-35s (8ohm). Could this 1st order crossover be used in this application? would the values of the components change with the impeadance of the drivers? Brother, Looking foward to that schematic Dan Quote Link to comment Share on other sites More sharing options...
JohnA Posted March 13, 2003 Share Posted March 13, 2003 The crossover design probably could be used with the altec setup you describe. It will depend on the efficiency and impedance of the drivers. The component values WILL change based on the crossover frequencies and woofer impedance you will need. The autoformer is limited in the attenuation steps it has. Most, if not all are 3 dB. Quote Link to comment Share on other sites More sharing options...
Klewless Posted March 13, 2003 Share Posted March 13, 2003 Hey Guys, I am wondering if the first order xover will sufficiently protect the tweeter driver???? Xovers are a bit more than just splitting the audio spectrum into bands. Quote Link to comment Share on other sites More sharing options...
JohnA Posted March 13, 2003 Share Posted March 13, 2003 It's plenty of protection if you behave yourself. Even anvils can be blown up. I still advise adding a light bulb or polyswitch in a 1st order crossover. The most modern K-77-Ms and ones with recent diaphragm replacement have a power rating of 5 watts continuous/50 music. That's 111 dB continuous! you shouldn't be doing that often, or you won't be able to hear any tweeter! Quote Link to comment Share on other sites More sharing options...
brother Posted March 13, 2003 Author Share Posted March 13, 2003 Klewless concern is valid. The crossover rolls off at 6K @ 6dB / octave which is more than enough to stay out of the driver's lower limit if you project the curve on the tweeter response plots I had for evaluation. John's suggestion of utilizing the light will aditionally help limit the power to the tweeter and is an addition I will make to help protect the driver. That additional component was intended to be included, I just didn't get them before I had the time to build the networks. It's an easy mod. I've just got to keep the teen out of the volume until then. Quote Link to comment Share on other sites More sharing options...
TBrennan Posted March 13, 2003 Share Posted March 13, 2003 Stovebolt---Those Altec 909s oughta be good out to 16khz on axis when used on 511B horns. Have you tried them without tweeters? Most Altec fans prefer the clear, though slightly soft, sound of Altec 2-ways with tweeters. If you prefer a tweeter I think you should bring it in at a very high frequency, say 10-15khz, and let the 909 do it's thing. Just use the T-35 as a supertweeter for a little added sheen. The 909 is much smoother than the T-35. Quote Link to comment Share on other sites More sharing options...
JohnA Posted March 14, 2003 Share Posted March 14, 2003 Hey Tom, The only trouble with using the T-35A as a supertweeter is that it isn't! It remains pretty flat to about 15k and then starts down. If the 909 can hit an honest 15k, it would be redundant. Quote Link to comment Share on other sites More sharing options...
brother Posted March 14, 2003 Author Share Posted March 14, 2003 This is the schematic for the crossover including the tweeter protection. Quote Link to comment Share on other sites More sharing options...
Al Klappenberger Posted March 15, 2003 Share Posted March 15, 2003 brother, I have my doubts about the simple light bulb as a tweeter protetor. I think a "poly switch" is required also. A light bulb only protects if it lights up. Only then will its resistance increase. That requires sustained power. A tweeter will blow in an instant! AL K. Quote Link to comment Share on other sites More sharing options...
Cut-Throat Posted March 15, 2003 Share Posted March 15, 2003 ALK, Can a 8 watt per channel tube amp blow a tweeter? Quote Link to comment Share on other sites More sharing options...
Guy Landau Posted March 15, 2003 Share Posted March 15, 2003 ---------------- On 3/15/2003 7:43:58 AM Cut-Throat wrote: Can a 8 watt per channel tube amp blow a tweeter? ---------------- No. I have used my Khorns with type A crossover and 20 WPC,Marantz model 2 monoblocks that didn't cause any damage to the tweeters. Quote Link to comment Share on other sites More sharing options...
JohnA Posted March 15, 2003 Share Posted March 15, 2003 Hey Al, Using my new digital meter (cool Meterman that directly measures L & C), the #561 limits the power through the tweeter to about 2 watts steady state, from about 5V to 10.6V. Perhaps it is a bit too limiting. It begins to glow at 1.5V. Quote Link to comment Share on other sites More sharing options...
Stovebolt6 Posted March 15, 2003 Share Posted March 15, 2003 What is the 10ohm 10 wat resistor for? Dan 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.