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AR-LST problem


arken

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I have one speaker louder than the other. Switched speakers all good with the amp. pre-amp ………….. I really don't want to tear them apart. I'm good with a three way speaker but this looks like a complicated circuit. If it's not an easy fix I may take them to New York if he will let me. Anyone ever have this problem? I know one midrange wasn't sounding right(it would pop) in that speaker but no other problems. Also the switch in the front needs to be cleaned. I got the deal of a lifetime on a near perfect set of AR-LST's (cosmetically) from an older gentleman in Oklahoma who crated them and got them to me in the same perfect condition. I refuse to mess these up!!! I had the woofers redone (the surrounds were falling apart) Anyone have any thoughts? Thanks 

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26 minutes ago, arken said:

Switched speakers all good with the amp. pre-amp

Assuming you have the Spectral Balance controls at the same setting on both speakers and your electronics are not the source........ You may need new fuses.  Have you tried swapping the fuses to move the problem?  Failing fuses are reputed to cause this sort of issue in LSTs. 

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On 7/19/2020 at 7:09 AM, arken said:

I have one speaker louder than the other. Switched speakers all good with the amp. pre-amp ………….. I really don't want to tear them apart. I'm good with a three way speaker but this looks like a complicated circuit. If it's not an easy fix I may take them to New York if he will let me. Anyone ever have this problem? I know one midrange wasn't sounding right(it would pop) in that speaker but no other problems. Also the switch in the front needs to be cleaned. I got the deal of a lifetime on a near perfect set of AR-LST's (cosmetically) from an older gentleman in Oklahoma who crated them and got them to me in the same perfect condition. I refuse to mess these up!!! I had the woofers redone (the surrounds were falling apart) Anyone have any thoughts? Thanks 

I would also try the fuse swap as suggested by the previous poster and also run the spectral balance control all the way in both directions and listen for a smooth transition.

However beyond that, you (or someone familiar with the LST,) will need to evaluate each driver and array to determine where the drop in output is coming from. Not as complicated as it is methodical with all those drivers. The sound you describe from the midrange is indicative of a driver failing (or possibly the fuse).

 

Bill

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So I replaced the fuse, same lower sound. The whole speaker sounds lower in volume. Wonder if I could just replace the blown midrange as a start and see where that gets me. I have an extra from a 3a. It has to be fixed or replaced anyway? Cleaned the switch in front. No more crackle when you change spectral balance. Frustrating!  

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1 hour ago, arken said:

So I replaced the fuse, same lower sound. The whole speaker sounds lower in volume. Wonder if I could just replace the blown midrange as a start and see where that gets me. I have an extra from a 3a. It has to be fixed or replaced anyway? Cleaned the switch in front. No more crackle when you change spectral balance. Frustrating!  

arken,

A blown mid could easily cause the issue. Another possibility would be tweeters. Even though your LST's were treated well these tweeters often suffer from output issues these days.

Where in NY were you considering taking them to?

Roy

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10 hours ago, arken said:

So I replaced the fuse, same lower sound. The whole speaker sounds lower in volume. Wonder if I could just replace the blown midrange as a start and see where that gets me. I have an extra from a 3a. It has to be fixed or replaced anyway? Cleaned the switch in front. No more crackle when you change spectral balance. Frustrating!  

They are very old, so it should not be surprising to find more than one driver failing.

 The least invasive way to figure it out is to remove the grilles and allow music material to play softly enough to get your ear close to each driver, to figure out which ones are low, distorting or dead.
For my part, I would want to pull the drivers and check every internal connection.

 

Bill

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10 hours ago, RoyC said:

arken,

A blown mid could easily cause the issue. Another possibility would be tweeters. Even though your LST's were treated well these tweeters often suffer from output issues these days.

Where in NY were you considering taking them to?

Roy

Roy,

Just getting ready to contact you guys. If possible i would bring them to you guys.  Shipping is quite expensive but i could bring them to you one weekend. Drop them off,pick them up another weekend. I'm sure you guys don't want to be moving these around. I will literary set this where you want and pick them up in the same spot. These are to nice for someone like me to be working on. If that's not an option i can look into shipping. No one but you is touching them. I refuse to do any damage to a speaker that someone took such care of for 50 years. Let me know what you think, Ken

 

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15 minutes ago, arken said:

Roy,

Just getting ready to contact you guys. If possible i would bring them to you guys.  Shipping is quite expensive but i could bring them to you one weekend. Drop them off,pick them up another weekend. I'm sure you guys don't want to be moving these around. I will literary set this where you want and pick them up in the same spot. These are to nice for someone like me to be working on. If that's not an option i can look into shipping. No one but you is touching them. I refuse to do any damage to a speaker that someone took such care of for 50 years. Let me know what you think, Ken

 

Ken,

Send me a PM and we can discuss the possibilities.

Roy

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  • 2 months later...

Figured I would update this post: Turns out it was the fuses. When I first got the speakers they came with what appeared to be a new set of fuses in a bag. While my woofers were off getting new surrounds I figured I would change the fuses given all the horror stories I had heard. Turns out those fuses were bad. After changing the fuses with some new ones from Vintage-AR the problems were gone. They sound amazing after getting them dialed in with placement. I haven't changed the caps or had and of the tweeters reworked. Just want to enjoy them for a while them I will measure the caps and see what I got. All of the mids and tweeters appear to be working and I hear no evidence of any one speaker being louder or sounding different than any of the others. The man I bought them from really took nice care of them. The wood is near perfect. I'm really happy with how this all turned out. These are now my everyday speaker with the 3's being used with a fisher 400. 

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@ arken, regarding you mentioning the Fisher 400 vintage tube receiver. I strongly recommend a much higher power amplifier. These are AR-LST speakers and are known as super-power hungry.

With the receiver you mentioned you won't be receiving 25% of what these speakers are capable of and further more stand a high risk of damaging the tweeters quite easily.

I drive each of the two sets of LST's I use with way over 550 watts RMS power per-channel for each pair (550+ X 4 channels). Many folks haven't any idea of what these speakers and system sound like but, depending on the size and quality of your computer speakers this video will give a very small sample taste.

Regarding the 'fuses', I'd recommend applying a very light coating of a contact cleaner to the clips that hold the fuse and the ends of the fuse itself. This fuse/clip contact area is prone to oxidation in a very short amount of time.

 

 

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