Acoustic Research LST-2

[Frank]

I have a pair of Acoustic Research LST-2 speakers. They have been lying in the lounge unused for a number of years. The reason being that the speaker terminals on the back of one of the speakers had come out. Having a closer look at them I noticed that the 10" woofer surrounds on both speakers have perished and will need replacing. Other than that the speakers are in very good condition except for a stain on one of grill cloths from a leaking pot plant. No damage to the interior. Also the wood is a bit faded but can easily be restored.

I was thinking of selling this speakers on EBAY. Would I obtain a better price if I was to restore them, or sell then in the condition they are in? Obviously it all depends on what someone is willing to bid on them, but what do you think they are worth?

Also if there is any interest out there I would like to hear from you.

Thanks

Frank

[JKent]

hi Frank

Looking at your previous thread I would conclude that you should not try to restore them yourself. It's not a good "first" project and you could screw them up. Why not put an ad in the "For Sale" section here? You could specify "local pick-up" and give a general idea of where you live. Many CSP members appreciate the LST and LST/2 and would love a chance to own and restore a pair.

What are they worth? Well, this is not the forum for that. I see that recently a set of 4 LST-2s in excellent condition sold for 1250 on ebay. Your 2, needing quite a bit of work, would obviously fetch much less than that.

Kent

[Frank]

hi Frank

Looking at your previous thread I would conclude that you should not try to restore them yourself. It's not a good "first" project and you could screw them up. Why not put an ad in the "For Sale" section here? You could specify "local pick-up" and give a general idea of where you live. Many CSP members appreciate the LST and LST/2 and would love a chance to own and restore a pair.

What are they worth? Well, this is not the forum for that. I see that recently a set of 4 LST-2s in excellent condition sold for 1250 on ebay. Your 2, needing quite a bit of work, would obviously fetch much less than that.

Kent

Thanks for your reply.

Its only the foam woofer surrounds on the 10" dome that need replacing. Whether its due to age or because the speakers have not been used for a long time I have no idea.

The foam surrounds appear available from speaker repair suppliers, and does not appear to be a over complicated task, but I will definately take your comments on-board and give it a bit of thought.

Thanks

Frank

[genek]

A local dealer will do a pair of 12" woofers for me for $50 including parts. With refoam kits running an average of $20-$25 after shipping, I'd have to do both woofers in about 45 minutes to break even on what I charge for an hour of my time. Add to that the fact that I have an established track record of never completing a project involving sharp blades without bleeding, and I don't do my own refoaming.

[Frank]

A local dealer will do a pair of 12" woofers for me for $50 including parts. With refoam kits running an average of $20-$25 after shipping, I'd have to do both woofers in about 45 minutes to break even on what I charge for an hour of my time. Add to that the fact that I have an established track record of never completing a project involving sharp blades without bleeding, and I don't do my own refoaming.

Many thanks, sound advise. I live in the UK and will look around to see if I can find a repair dealer who will do it for me.

Regards

Frank

[Frank]

Hi

How do you remove the spectral balance knob on the front of both speakers? Do they just pull off?

I need to remove the centre grill to gain access to the woofers, so I can send them away for refoaming.

Regards

Frank

[xmas111]

There's two little set screws you have to loosen then the knobs should pull right off.

I think the set screws are on the bottom side of the knobs.

Hope this helps.

John

[Frank]

There's two little set screws you have to loosen then the knobs should pull right off.

I think the set screws are on the bottom side of the knobs.

Hope this helps.

John

Hi John

Many thanks for your help. Wasn't aware there were two screws holding the knob in place. Used a fine Allen key to loosen the screws and the knobs came off.

Regards

Frank

[JKent]

I live in the UK and will look around to see if I can find a repair dealer who will do it for me.

Hi Frank

There are certainly outfits on your side of the pond that do such work. One CSP member referred to Wembley Loudspeakers. I'm sure there are others. Good luck with the project.

Kent

[Frank]

Hi Frank

There are certainly outfits on your side of the pond that do such work. One CSP member referred to Wembley Loudspeakers. I'm sure there are others. Good luck with the project.

Kent

Thanks for your message. I think I will give Wembley loudspeakers a try.

The screw back terminals on the back of the speakers, for the wire connection do not seem designed for heavy gauge speaker wire. Would I be better off replacing them with banana plugs or sticking with the originals? Is there really any difference between thin and thick speaker cable? Also older amp's built in the 70's with push connectors for the speaker wire had small holes making it difficult to insert thick speaker cable.

Thanks

Frank

[JKent]

You're looking for controversy! See the thread Roy started regarding speaker wire:

http://www.classicsp...?showtopic=6523

I am not familiar with the connectors on the LST/2 but looking at some photos on the web it appears they have the red and black binding posts. I believe those accept banana plugs. Maybe you could post a photo. Other AR speakers of that era used screw terminals with knurled nuts. They work well if you put ring terminals on the speaker wires.

Unless you have very long runs, 18 gauge (don't know the European equivalent--maybe the same) is fine. 16 AWG is also good. No need for big fat wires in most settings unless you feel that your wallet is getting too heavy. Amazon.co.UK has this marine-grade speaker wire that should be good but there are others:

http://www.amazon.co...11866329&sr=1-4

Yes--those '70s amps with push connectors are annoying. Even on my McIntosh 4100 they used those crummy connectors. You can find pins for your wires, like this: http://www.amazon.co.uk/Belkin-GOLD-SPEAKER-PINS-4-PACK/dp/B001894Z4O/ref=sr_1_3?s=electronics&ie=UTF8&qid=1311866696&sr=1-3

Kent

[Frank]

Hi Kent

The terminals are screw terminals. You just loosen the screw. There is a small gap where you place the speaker wire and then just tighten. The gap is very small so not suitable for thick speaker cable. They are not designed for banana plugs. Putting ring terminals on the ends of the speaker wire is a good idea and will make connection a lot easier. Thanks!!

Contacted Wembley loudspeakers. They quoted £46 to refoam each woofer. £92 for the pair. Is that reasonable? There is a pair of new drivers on ebay for £85 plus around £30 postage from the United States?? Difficult choice!!

This is probably a silly question but I will ask it anyway. ON the crossover board on the inside of one speaker the white wire goes to the red terminal and the green wire to the black terminal.

Would this be the same on the other speaker. The reason I ask this is because the terminals on the back of one speaker had fallen out.

Many thanks for all advise given to me. This is an interesting site.

Best Regards

Frank

[dynaco_dan]

Hi Kent

The terminals are screw terminals. You just loosen the screw. There is a small gap where you place the speaker wire and then just tighten. The gap is very small so not suitable for thick speaker cable. They are not designed for banana plugs. Putting ring terminals on the ends of the speaker wire is a good idea and will make connection a lot easier. Thanks!!

Contacted Wembley loudspeakers. They quoted £46 to refoam each woofer. £92 for the pair. Is that reasonable? There is a pair of new drivers on ebay for £85 plus around £30 postage from the United States?? Difficult choice!!

This is probably a silly question but I will ask it anyway. ON the crossover board on the inside of one speaker the white wire goes to the red terminal and the green wire to the black terminal.

Would this be the same on the other speaker. The reason I ask this is because the terminals on the back of one speaker had fallen out.

Many thanks for all advise given to me. This is an interesting site.

Best Regards

Frank

Hi Frank

Forget buying new woofers, they are not the equal of the originals, a step backwards even.

Refoam kits are about $25.00 U$ on ebuy for a pair, well worth you considering buying for do-it-yourself.

Please take a photo of your speaker terminals and post it here.

The wiring should be identical for both LST-2's.

I did my very first refoaming on my AR-3A's about 15 years ago.

I had no prior experience or knowledge of the procedure.

It took me about 1 1/2 hours to do the first one and 10 minutes for the second one.

I am considered a patient, methodical and systematic person, but not talented in this regard.

My suggestion is attempt to refoam them yourself with a friend or two.

[Frank]

Hi Frank

Forget buying new woofers, they are not the equal of the originals, a step backwards even.

Refoam kits are about $25.00 U$ on ebuy for a pair, well worth you considering buying for do-it-yourself.

Please take a photo of your speaker terminals and post it here.

The wiring should be identical for both LST-2's.

I did my very first refoaming on my AR-3A's about 15 years ago.

I had no prior experience or knowledge of the procedure.

It took me about 1 1/2 hours to do the first one and 10 minutes for the second one.

I am considered a patient, methodical and systematic person, but not talented in this regard.

My suggestion is attempt to refoam them yourself with a friend or two.

Hi Vern

Many Thanks..I will follow your advise

Regards

Frank

[Frank]

Hi Vern

I replaced the foam surrounds on both woofers with a do-it-yourself kit purchased on EBAY.

The speakers are working fine now, after having being left unused for some 16 years or so.

Many thanks for your earlier detailed instructions, and tips and advise from other members as well.

Regards

Frank

[Frank]

Hi

I just replaced the woofer surrounds on both speakers and they sound great now, however I thought I would check all drivers to see if there is a sound coming from them.

On the sides of both speakers where lower down you have the twitter and above another driver.

On the driver above the twitter on all 4 sides I cannot hear any sounds.

Would this indicate a fault?

The twitters (dome shaped with mesh) all appear ok

Regards

Frank

[JKent]

On the sides of both speakers where lower down you have the twitter and above another driver. On the driver above the twitter on all 4 sides I cannot hear any sounds.

The twitters (dome shaped with mesh) all appear ok

Hi Frank

Glad the refoam job was a success.

I am not familiar with the LST-2, so maybe should not comment, but it seems to be yet another iteration of the AR3a or 2ax, both of which I AM familiar with.

Here is a shot of the side of an LST-2, in our Library here

http://www.classicsp...#previous-photo

First of all, the lower driver (with the mesh) is the mid-range and that's where MOST of the sound will come from. The top drivers are the tweeters, or more accurately, supertweeters. They reproduce only the highest frequencies. Not sure what the crossover point is in that speaker, but don't expect a lot of sound from those.

And if you are over 50 or have worked in very noisy environments, you may not have a lot of acuity in that range.

Try listening with your ear close to the tweeter, or ask a teenager to it for you, and see if (s)he can hear the high frequency sounds. Seriously. Do you know there are cell phone ring tones marketed for kids, so adults can't hear them? They're called "mosquitos." Check out this page:

http://www.freemosquitoringtones.org/

If you are 50 years old, your high frequency acuity probably tops out around 12 KHz. 60? drop down to 10 KHz.

"Someone" here will know the crossover point for the LST-2's tweeters, but I suspect they may just be near the limits of your (and my) hearing range.

Sorry. Old age ain't for sissies

If you REALLY have absolutely no sound from all 3 tweeters on both speakers, it's probably a wiring error. Very unlikely they would ALL be bad. Take a look at Tom Tyson's diagrams and parts list for the LST-2 here:

http://www.classicsp...ls_schematicss/

Good luck. Let us know how it works out.

Kent

[mike tarelli]

Hi Frank

Glad the refoam job was a success.

I am not familiar with the LST-2, so maybe should not comment, but it seems to be yet another iteration of the AR3a or 2ax, both of which I AM familiar with.

Here is a shot of the side of an LST-2, in our Library here

http://www.classicsp...#previous-photo

First of all, the lower driver (with the mesh) is the mid-range and that's where MOST of the sound will come from. The top drivers are the tweeters, or more accurately, supertweeters. They reproduce only the highest frequencies. Not sure what the crossover point is in that speaker, but don't expect a lot of sound from those.

And if you are over 50 or have worked in very noisy environments, you may not have a lot of acuity in that range.

Try listening with your ear close to the tweeter, or ask a teenager to it for you, and see if (s)he can hear the high frequency sounds. Seriously. Do you know there are cell phone ring tones marketed for kids, so adults can't hear them? They're called "mosquitos." Check out this page:

http://www.freemosquitoringtones.org/

If you are 50 years old, your high frequency acuity probably tops out around 12 KHz. 60? drop down to 10 KHz.

"Someone" here will know the crossover point for the LST-2's tweeters, but I suspect they may just be near the limits of your (and my) hearing range.

Sorry. Old age ain't for sissies

If you REALLY have absolutely no sound from all 3 tweeters on both speakers, it's probably a wiring error. Very unlikely they would ALL be bad. Take a look at Tom Tyson's diagrams and parts list for the LST-2 here:

http://www.classicsp...ls_schematicss/

Good luck. Let us know how it works out.

Kent

Hello Frank,

According to my AR brochure from those times the tweeter crossover is 5000 Hz. It's basically an AR5 with three mids and three tweeters.Interestingly it does not give power handling figures but does say "Data on request"

Mike.

[KlausDK]

Regarding the power handling capabilities of the LST-2, there is some, however conflicting, advise in the the documents in the library, fusing document, with the recommended 1 6/10 Amp fuse, or the LST/LST-2 speaker connecting document, where 2 Amp fuses are advised.

LST2fuses.bmp

LST2fuses2.bmp

BRgds Klaus

[Frank]

Hi Kent

Many Thanks for your reply, comments and advice. As you have probably gathered I am not very technically minded, but I have surprised myself by getting the speakers working and they sound just as good as they did back in 1975.

As you mentioned the tweeters are designed to produce only the highest frequencies, I decided to try out different music ranging from classical to easy listening (instrumental). I am sure now I can hear the tweeters but it is very difficult to tell with sound coming from the lower midrange drivers. Signs are good though that all drivers are working ok.

Thanks for your tip on using spade (clip) terminators for the speaker wire. It makes connection a lot easier especially with thicker gauge speaker wire.

I was thinking of changing my amplifier. Any thoughts out there on amp's available that would match the LST-2's. Just a thought!!!!

Regards

Frank

[JKent]

Hi Frank

Terrific to hear all is well with the LST-2s. I'm sure you will enjoy them!

You have a nearly unlimited choice of amps, since the 2s (I believe) are 8 ohm speakers. If they were 4 ohm, like the LST or 3a you would have to select an amp that could handle that load.

More power is better than less, so I'd look for at least 100 watts rms per channel.

What will you be using these for? Just music? Surround sound? Home theater? All of the above?

You can't go wrong with a NEW amp. I have an Onkyo TX-NR1008 receiver that I use for home theater, driving a concoction of classic speakers: AR4, Minimus 7, Cizek HTA, Cambridge Soundworks, RHB center. Kind of a mishmash but the Onkyo can handle it.

For simply listening to music, a stereo amp is all you need. You will get MANY opinions on that subject. First, you have to decide whether you want a separate amp, integrated amp or receiver. PartsExpress sells AudioSource power amps that give a lot of bang for the buck. Some have extolled Crown amps for the same reason.

Many people like to use vintage amps with their vintage speakers. Japanese receivers from the '70s were respected for putting out tons of power. There was good American gear back in the day, too. Sort of wish I still had my hafler 220 amp. BUT...BEWARE! Old stuff has a lot that can wrong with it and should be carefully gone over by a competent tech! You could blow up your amp and your speakers by using old electronics.

Having said that, my vintage setup consists of an old Scott tube tuner, a CD player, maybe soon my old AR turntable, a McIntosh MAC4100 receiver, and a succession of classic speakers (currently AR3a and AR91).

The MAC is over 30 years old, so I took it to an authorized McIntosh repair center to have it all checked out and adjusted. Then, after using a while I replaced every single electrolytic cap in the beast. A big job with many potential pitfalls. And if you don't do it yourself, you will pay a fortune for that kind of service.

Sorry for the rambling post, but the point is: Vintage gear is really cool and, if you're like me, you may want an "All American" vintage stereo system, but there is a price to be paid for that. You don't know how that vintage piece was treated over the past 30 or 40 years. Parts are hard to come by. Old stuff (like electrolytics) just normally wear out, technicians who are younger than the amp may not have the knowledge or interest to work on it. Etc. Owning old electronics is a commitment (and yet I'm determined to get my Marantz 4270 up & running)

Good luck!

Kent