Guest Tube747 Posted April 14, 2006 Report Share Posted April 14, 2006 Hello!What type of coil the LST's crossover uses? Air Core or metal core?Thanks! Link to comment Share on other sites More sharing options...
r_laski Posted April 14, 2006 Report Share Posted April 14, 2006 Air Core.Rich Link to comment Share on other sites More sharing options...
Guest Tube747 Posted April 15, 2006 Report Share Posted April 15, 2006 Hello!Can I replace the stock LST's inductor by either Jensen Air core inductors or Duelund Coherent Audio Toroid Inductors?Or just leave the stock one alone?These are the link of both mfg. who makes the inductor I'm talking about.http://www.duelundaudio.com/startside.htmhttp://www.jensencapacitors.com/audio/products/aircore.htmlI'm certainly would like to replace the stock cap and resistor for my LST with Duelund VSF capacitors and graphite resistors.Any comments?Thanks! Link to comment Share on other sites More sharing options...
johnieo Posted April 15, 2006 Report Share Posted April 15, 2006 >Or just leave the stock one alone?I am not familiar with this speaker, but in those AR crossovers that I explored, the value of the inductor's internal resistance was part of the crossover network. If you replace it with a coil of less resistance, it would be prudent to add the difference as a series resistor.Perhaps, one might ask, why would one replace an inductor? What could have gone wrong with it? A capacitor, especially an electrolytic or earlier type, can become leaky and change its characteristics with time. Link to comment Share on other sites More sharing options...
Guest Tube747 Posted April 15, 2006 Report Share Posted April 15, 2006 Yes, you should be correct. I have the same answers about changing inductor issue after talking to many people who familiar to vintage AR speakers.Now, it just leaves me one question, can I upgrade the LST crossover using film capacitor such as Auricap? Or replace with modern non-polar electrolytic capacitor? Black Gate non polar speaker capacitor no hopes, because they don't have the value for LST. However, the Bennec non-polar does have the value for LST.Anyone able to give me an advice? What about film cap from Auricap?Unfortunately, I just figure out Duelund does not have the value of LST's crossover needs -- 40mf and 150mf. >>Or just leave the stock one alone?>>I am not familiar with this speaker, but in those AR>crossovers that I explored, the value of the inductor's>internal resistance was part of the crossover network. If you>replace it with a coil of less resistance, it would be prudent>to add the difference as a series resistor.>>Perhaps, one might ask, why would one replace an inductor?>What could have gone wrong with it? A capacitor, especially an>electrolytic or earlier type, can become leaky and change its>characteristics with time. Link to comment Share on other sites More sharing options...
r_laski Posted April 16, 2006 Report Share Posted April 16, 2006 >>Any comments?<<I did some work on my brother’s AR-LST crossovers a few years ago. >>Or just leave the stock one [inductors] alone?<<This gets my vote too. Unless you see visual damage (heat related) or can measure abnormal inductance or resistance of a coil, there is really no need to replace them.>>Now, it just leaves me one question, can I upgrade the LST crossover using film capacitor such as Auricap? Or replace with modern non-polar electrolytic capacitor?<<I replaced the midrange (40uF) and tweeter (6uF) caps with North Creek Zen caps. Cost wise, these are a little more than Solens, but less expensive than Auricaps. I did not replace the 150uF woofer cap, but it can be done. I did not replace the 2500uF caps – very difficult to find suitable replacement. Just realize the LST crossover board is very crowded and there isn’t a lot of room to replace the old electrolytics with larger film caps, but it can be done. One thing I found particularly significant with replacing the caps in the LST - If you use caps that are directional, that is, they have a preferred orientation of the leads, like the North Creek Zens, and possible the Auricaps, you must pay attention to which way (direction) you attach the leads. When I attached the Zens in one direction, the LSTs sounded flat and lifeless. Reversing the leads made a substantial improvement in restoring the LST's "voice". >> I'm certainly would like to replace the stock cap and resistor for my LST with Duelund VSF capacitors and graphite resistors.<<You should be able to read the resistor “power rating” you asked about in another post. I don’t remember what it is, but many AR speakers of that era had 10-watt resistors in the crossovers. If you do replace the resistor (0.5 Ohm in midrange) my advice is to NOT glue it to the crossover board. To avoid heat buildup and possible heat damage to the resistor bend the leads to suspend the resistor above the crossover board. Good luck with your project and please let us know what you decide to do and how your LST project turns out. Rich Link to comment Share on other sites More sharing options...
Guest Tube747 Posted April 17, 2006 Report Share Posted April 17, 2006 This is absolutely helpful! Thank you very much! I already made up my mind by using Bennic 5 x 1000mf and Auricap for 6mf, 40mf (2x20mf), 150mf (3x150mf).I will leave the inductor alone, and Duelund graphite resistor for the 0.5 ohm resistor.The project will take a while, because the speaker is going to strip down for cabinet refurbishment and make it look new! The carpenter I am dealing with is very busy and probably take a while to complete the task. I will keep you inform. Thanks Again!>>>Any comments?<<>>I did some work on my brother’s AR-LST crossovers a few years>ago. >>>>Or just leave the stock one [inductors]>alone?<<>>This gets my vote too. Unless you see visual damage (heat>related) or can measure abnormal inductance or resistance of a>coil, there is really no need to replace them.>>>>Now, it just leaves me one question, can I upgrade the>LST crossover using film capacitor such as Auricap? Or replace>with modern non-polar electrolytic capacitor?<<>>I replaced the midrange (40uF) and tweeter (6uF) caps with>North Creek Zen caps. Cost wise, these are a little more than>Solens, but less expensive than Auricaps. I did not replace>the 150uF woofer cap, but it can be done. I did not replace>the 2500uF caps – very difficult to find suitable replacement.>Just realize the LST crossover board is very crowded and there>isn’t a lot of room to replace the old electrolytics with>larger film caps, but it can be done.>> One thing I found particularly significant with replacing>the caps in the LST - If you use caps that are directional,>that is, they have a preferred orientation of the leads, like>the North Creek Zens, and possible the Auricaps, you must pay>attention to which way (direction) you attach the leads. When>I attached the Zens in one direction, the LSTs sounded flat>and lifeless. Reversing the leads made a substantial>improvement in restoring the LST's "voice". >>>> I'm certainly would like to replace the stock cap and>resistor for my LST with Duelund VSF capacitors and graphite>resistors.<<>>You should be able to read the resistor “power rating” you>asked about in another post. I don’t remember what it is, but>many AR speakers of that era had 10-watt resistors in the>crossovers. If you do replace the resistor (0.5 Ohm in>midrange) my advice is to NOT glue it to the crossover board.>To avoid heat buildup and possible heat damage to the resistor>bend the leads to suspend the resistor above the crossover>board. >>Good luck with your project and please let us know what you>decide to do and how your LST project turns out. >>Rich Link to comment Share on other sites More sharing options...
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