Amps

[frankmarsi]

Yesterday a site member told me I was doing the wrong thing using Phase Linear 400 amps with my ART-LSTs'. A few days prior I hooked up a second PL400 amp to the speakers. Running a single amp per set of LSTs' each.

I've been using a PL400 since 1974 with my 3a's and have loved the combo since. Finally I have all 4 LSTs' with 2 PL400s', this is I guess the ultimate for my budget and ears, and I've waited for this sound for many years!

Anyone have any comments?

frankmarsi@verizon.net

There's a Eric Clapton CD from 2002 that has some extremely deep bass a great treat for bass lovers and old AR's. I have not yet been able to describe the effect to my friends, it's that good!

Respectfully, Frank Marsi

[Guest SteveG]

Frank,

a LSTs sounds like a great setup. I have only a pair run off a single Adcom 555. Seems like plenty of power reserve. The only possibility of a problem with the PL 400 would be if they are not particularly stable at low impedance, like down around 2 ohms where the ARs (3a, LST, etc at nominal 4 ohm impedance)occasionally venture. I don't know what the PL400 characteristics are, but I am sure many on this site will. Good luck and enjoy!!

SteveG

[dynaco_dan]

>Yesterday a site member told me I was doing the wrong thing

>using Phase Linear 400 amps with my ART-LSTs'. A few days

>prior I hooked up a second PL400 amp to the speakers. Running

>a single amp per set of LSTs' each.

>I've been using a PL400 since 1975 with my 3a's and have loved

>the combo since. Finally I have all 4 LSTs' with 2 PL400s',

>this is I guess the ultimate for my budget and ears. I've

>waited for this sound for many years!

>Anyone have any comments?

>frankmarsi@verizon.net

>There's a Eric Clapton CD from 2002 that has some extremely

>deep bass a great treat for bass lovers and old AR's. I have

>yet been able to describe the effect to my friends, it's that

>good!

>Respectfully, Frank Marsi

Hi Frank;

Not a bad poor man's system, for sure. lol

What pre-amp are you using?

You say you have only 2 - PL-400's, and 4 - LST's, if only more owners had those.

Are you using a four channel setup?

Maybe to prevent a future accident, a fast blow fuse in series with each speaker might be most adventageous.

With the 2 amp Buss slow blow fuse the woofer is pretty well protected, the mids and tweeters aren't adequately protected at all, though.

A 3A/LST 4 ohm tweeter runs around $25.00 ea plus on ebay and the mids around the same, when they are mint and not nippled in.

I worked at a hifi warantee depot quite a long time ago and saw numerous LST's with all of it's tweeters blown.

On ebay the odd 3A/LST has tweeters and/or mids dead.

In case you aren't aware, the OEM tweeters, mids and woofers haven't been available, for many a year.

There has been drop in replacements available, but there may be a difference in wiring, front versus rear leads and sound output.

I haven't seen this discussed to great extreme, but this is as good a time as any to start this topic.

The Crown Audio site has an interesting discussion on power handling verus fusing speakers.

At a listening level of 85 dB they suggest 150 watts per channel.

At a listening level of 95 dB they suggest 1,500 watts per channel.

They seem to feel that the woofer follows the fusing characteristics of slow blow fuses and the mid - tweeters should have a fast blow fuse.

Without tapping inside an LST's enclosure and cutting wires, perhaps put a jumper into the existing fuseholder, then install a fast blow fuse in series in an open style fuseholder.

FYI Heathkit used a 3 amp fast blow fuse in a chassis style fuseholder for their own AS-103/AR-3A speaker kit.

Maybe this can be used as a starting point, considering the present age, value and scarcity of our drivers.

As far as impedance is concerned, unless you are running sine wave signals or electronic synthesizer music, where only a sustained pitch is obtained, you are more apt to worry about whether you have enough oomph when it's impedance reaches 30 ohms and higher.

If you were running them in parallel, to only one amp, then you have a low impedance probability not worth taking a chance with, as it was mentioned previously that the PL-400 is not as stable below 4 ohm loads.

Always nice to read about the boy who grew up and finally gets his toys.

[Guest Bret]

Frank,

Stacked LSTs. . . Wow. Congratulations and a "way-to-go."

I don't know why your friend would say, "Don't do that!" with LSTs and Phase 400s. If there is a notorious problem with the combination, I'm unaware of it.

But I'll tell you why I wouldn't do it even though I still think the Phase 400 is possibly the "coolest" classic amp on the planet; reliability. Your speaker set-up is irreplaceable and almost unrepairable. I would want amps that haven't been seeing heat for 29 years, preferably low-impedence tolerant/high-current amps with a modern "protection" circuit or . . . something, anything to help protect my investment in speakers. It isn't so much the $2,500. . . what am I saying? Even counting that if a Phase 400 dies badly it's going to flame an irreplaceable piece of audio history, ultimately it's the $2,500.

But that's got to be one "sexiest" amp/speaker combinations of all times; the very audio definition of "cool."

Oh, the other possible reason is that newer amps should sound better unless you've rebuilt the 400s.

Bret

[Pete B]

Hi Frank,

I think the concern with the amps is that they're getting old and as Bret mentions if one fails there are a lot of drivers to loose/burn in those LSTs. The amps probably will fail someday and some of the PL amps used selected components. Have you seen this site:

http://www.vintagephase.com/

I suggest changing at least the tweeter caps, and any Collins type caps since as several have reported here they seem to not hold up with age.

Pete B.

>Yesterday a site member told me I was doing the wrong thing

>using Phase Linear 400 amps with my ART-LSTs'. A few days

>prior I hooked up a second PL400 amp to the speakers. Running

>a single amp per set of LSTs' each.

>I've been using a PL400 since 1975 with my 3a's and have loved

>the combo since. Finally I have all 4 LSTs' with 2 PL400s',

>this is I guess the ultimate for my budget and ears. I've

>waited for this sound for many years!

>Anyone have any comments?

>frankmarsi@verizon.net

>There's a Eric Clapton CD from 2002 that has some extremely

>deep bass a great treat for bass lovers and old AR's. I have

>yet been able to describe the effect to my friends, it's that

>good!

>Respectfully, Frank Marsi

[frankmarsi]

>Frank,

>a LSTs sounds like a great setup. I have only a pair run off

>a single Adcom 555. Seems like plenty of power reserve. The

>only possibility of a problem with the PL 400 would be if they

>are not particularly stable at low impedance, like down around

>2 ohms where the ARs (3a, LST, etc at nominal 4 ohm

>impedance)occasionally venture. I don't know what the PL400

>characteristics are, but I am sure many on this site will.

>Good luck and enjoy!!

>

>SteveG

AR Fellow SteveG, thanks for the complement.Yes there is plenty of reserve power at my finger tips, but that's a good thing,because it looks good and of course sounds great,I must admit. I've been using a Phase400 with my AR-3as' since 1975, you can imagine I've been through some terrible experiences mainly because of the amp going crazy and having to be shut down immediately as it took a tweeter with it(AR Co. gladly provided replacements). The other problem was the AR-3a's (since new for me in 1972), always burning tweeters with my then 'self built' Dynaco ST120 and PAS3x. And no I never drove it to clipping in a small room, the tweeters simply can't take much power without failure period! Later '78 to '82 had the AR-3s' in a room 25X35, that was something to behold with the PL400 and 'Micro-Static' tweeters on top. In fact they easily sounded better 'then',than those super high priced "Cremora", whatever they're called tiny speakers sound 'now', relatively speaking.

So, yes the PL400 is a 'dog' at times, but a 'good-lover' at others, so I 'put-up' with it!

And you can quote me in Ste--oP-ile Mag any time! LOL!

Stay in touch,

Frank Marsi

[frankmarsi]

>>Yesterday a site member told me I was doing the wrong thing

>>using Phase Linear 400 amps with my ART-LSTs'. A few days

>>prior I hooked up a second PL400 amp to the speakers.

>Running

>>a single amp per set of LSTs' each.

>>I've been using a PL400 since 1975 with my 3a's and have

>loved

>>the combo since. Finally I have all 4 LSTs' with 2 PL400s',

>>this is I guess the ultimate for my budget and ears. I've

>>waited for this sound for many years!

>>Anyone have any comments?

>>frankmarsi@verizon.net

>>There's a Eric Clapton CD from 2002 that has some extremely

>>deep bass a great treat for bass lovers and old AR's. I have

>>yet been able to describe the effect to my friends, it's

>that

>>good!

>>Respectfully, Frank Marsi

My Answers Are Below Your's

>

>

>Hi Frank;

>

>Not a bad poor man's system, for sure. lol

>

>What pre-amp are you using?

"A Phase Linear 4000" 'Poor' man's only choice for vinyl playback"

>

>You say you have only 2 - PL-400's, and 4 - LST's, if only

>more owners had those.

"Yes I am fortunate, but I've been a devotee to the Phase,AR since the days of their introduction"

>

>Are you using a four channel setup?

"No tried that in '78 with AR-2ax's for the rear thru a Phase, it's no big deal and not worth the effort."

>

>Maybe to prevent a future accident, a fast blow fuse in series

>with each speaker might be most adventageous.

"You're absolutely correct, I felt that since the beginning as I learned the hard way, constantly burning AR-3a tweeters. No matter how careful and aware of my habits, they still always failed"

>

>With the 2 amp Buss slow blow fuse the woofer is pretty well

>protected, the mids and tweeters aren't adequately protected

>at all, though.

" Again you're correct to state that,however with my 4 LST's I still have managed to blow a couple of tweeters, although some were gone when I first acquired them. But amazingly so 1 out the 4 seems to have kept all of it's tweeters going with out failure. To para-phrase Julian from Stereo-Review mag back in 1974 I believe, he tested them with a Phase Linear 700B and found that the LST can generally handle even more power with aplomb."

>

>A 3A/LST 4 ohm tweeter runs around $25.00 ea plus on ebay and

>the mids around the same, when they are mint and not nippled

>in.

"I have to say every time I chose to buy them that way I always get 'burnt' by shipping damage. Those little guys should really be carried by your hand only and no one else except AR, they can't handle shipping at this stage.However I'm in the process of replacing most of my tweeters with AB-Tech 'replacements'. I know, I know, I really rather have original and or later 80's-early 90's factory AR, but thats difficult. Or even Dynaudio stuff, or salvage Cello Amati, but all that is too costly for my dabblings"

>

>I worked at a hifi warantee depot quite a long time ago and

>saw numerous LST's with all of it's tweeters blown.

" Don't 'rub' it in and put me on edge, I'm starting to appreciate your wisdom, why do have to be so hurtfully honest! lol"

>

>On ebay the odd 3A/LST has tweeters and/or mids dead.

"Your merciless! Let the poor man get along, will ya!"

>

>In case you aren't aware, the OEM tweeters, mids and woofers

>haven't been available, for many a year.

"Let's not talk age, I just turned 56, been doing this crazy stuff for many years now. Seemingly an addiction that won't go away. It's mostly for my love of music most assuredly,, however the power of vintage AR and Phase Linear is certainly a inexplicable mental 'trip'!"

>

>There has been drop in replacements available, but there may

>be a difference in wiring, front versus rear leads and sound

>output.

"O.K. now you're talking! This is why I came to this site, besides taking in other's views. I've been sitting back pondering this over and over. I bought the AB-Tech replacements and need to install them.I've tried a couple and they pretty closely match the older guys, except they can handle more it seems and certainly are more 'pronouned'in their own way, but I still like those old guys, just that they're so frail, years ago and now. Coal is it must be neat and professional looking for me and that presents a problem as the new are rear connected and I have the issued AR with front connection cabinets. I hope some one out there can offer some advice. I emailed another gentleman from this site briefly, but that's all. I'm still 'stumped' about it. Understand I have good mechanical ability, but this may ask more effort and I'm lazy."

>

>I haven't seen this discussed to great extreme, but this is as

>good a time as any to start this topic.

"Let's go men!,Rah rah,... no...? OK then in that case let's talk plainly, whichever, somebody let's hear it"

>

>The Crown Audio site has an interesting discussion on power

>handling verus fusing speakers.

>

>At a listening level of 85 dB they suggest 150 watts per

>channel.

>

>At a listening level of 95 dB they suggest 1,500 watts per

>channel.

>They seem to feel that the woofer follows the fusing

>characteristics of slow blow fuses and the mid - tweeters

>should have a fast blow fuse.

"Your're right. But I strongly felt Mark Levinson did it with his version of 'tri-amp' connections.I gotta do something and soon before I start getting carried away with it. I've tried a number of times to 'get-crazy' with the sound leveland all fared well, and some how still felt confident while doing so, but I'm -a scared Alice!."

>

>Without tapping inside an LST's enclosure and cutting wires,

>perhaps put a jumper into the existing fuseholder, then

>install a fast blow fuse in series in an open style

>fuseholder.

"Explain how? Help me, will ya!It's late and I'm tired and slow."

>

>FYI Heathkit used a 3 amp fast blow fuse in a chassis style

>fuseholder for their own AS-103/AR-3A speaker kit.

"I've ran many values experimenting with fuses back in the '70s, I can tell you this, the AR-3a woofer and X-over can absorb much power, as can the midrange, they're great about those things,.. just the tweeter can't handle most dreams of sonic bliss."

>

>Maybe this can be used as a starting point, considering the

>present age, value and scarcity of our drivers.

"Would some one speak up please!"

>

>As far as impedance is concerned, unless you are running sine

>wave signals or electronic synthesizer music, where only a

>sustained pitch is obtained, you are more apt to worry about

>whether you have enough oomph when it's impedance reaches 30

>ohms and higher.

" You're always right,I gotta watch what I say to you,but I now have the power to cruise easily, just like my old 1973 Buick Riviera 455C.I. did when I went crazy with it!"

>

>

>If you were running them in parallel, to only one amp, then

>you have a low impedance probability not worth taking a chance

>with, as it was mentioned previously that the PL-400 is not as

>stable below 4 ohm loads.

"You're scaring me again! I've lived with this fear for many years. Anyone want to donate (for keeps) a set of 'Bryston' 4 or 7's, I'll gladly accept and report back with the outcome"

>

>Always nice to read about the boy who grew up and finally gets

>his toys.

"Damn, I deserve it! The '50s thru the 2000's have been draining. As I stood at Battery Park Sept.11th. and watched the second plane hit the south tower I kinda felt my 'love' for anything is all I can offer back to this earth! I love music, so maybe my mania with reproducing it for my ears with old historically valued equipment ain't a negative thing. Life is short my friend, especially when you "Get Your Toys Late" "

Respectfully, Frank

[frankmarsi]

My response. Answers below your words.

>Frank,

>

>Stacked LSTs. . . Wow. Congratulations and a "way-to-go."

"What'a ya kidding? Aren't your fifties the last chance one has before admitting that there's no resolve to anything and you happen to have these speakers and stuff and it's maybe the only thing that comes close to filling the void just a little bit? I thank you for your appreciation, I'll try to be modest. I'm cracking though,as I have never heard bass this powerful or physically commanding in all my 45+ years of loving the sound known as 'bass'.I even played in local bands in the mid '60s to early '70s.I even still have my 1968 Fender BassMan amp.That's it! It feels like playing on the band stand with a full rock complemented band, bass, ,drums,guitar,, singer.You want more examples? I'm getting tired,,it's late, but I'm listening to it right now, it's trying to command me.Idiotic commentary maybe, but this affection may become too "Dwight-Zone" like if I continue to let this fling with vintage '70s 'playback' equip. control me"

>I don't know why your friend would say, "Don't do that!" with

>LSTs and Phase 400s. If there is a notorious problem with the

>combination, I'm unaware of it.

"He's freaking jealous, no doubt!"

>

>But I'll tell you why I wouldn't do it even though I still

>think the Phase 400 is possibly the "coolest" classic amp on

>the planet; reliability. Your speaker set-up is

>irreplaceable and almost unrepairable. I would want amps that

>haven't been seeing heat for 29 years, preferably

>low-impedence tolerant/high-current amps with a modern

>"protection" circuit or . . . something, anything to help

>protect my investment in speakers. It isn't so much the

>$2,500. . . what am I saying? Even counting that if a Phase

>400 dies badly it's going to flame an irreplaceable piece of

>audio history, ultimately it's the $2,500.

"You're right, but a man's gotta be a boy! I mean ya gotta take your chances, I've done worse. I don't actually have any budget for this craziness right now, ,but I do enjoy my limits just the same.The amp theory is exactly correct, I know for certain. Money is always how we must live in this century and I, maybe more than most must be prudent.

But this is all this guy's got till further notice"

>

>But that's got to be one "sexiest" amp/speaker combinations of

>all times; the very audio definition of "cool."

"I'm-a rocker since way back and I can honestly tell you it's the best I've heard in my world. I once auditioned I beleive they were Apogees, about 5 feet tall with either Krells or something else 'huge' and that was really cool, in fact way cool! But my vintage system is the best I can 'put-together' and in it's own right many years ago,some of the best there was( so were the living conditions for many), and now finally after all these years of dreaming I'm here. I gotta watch out for the evil eye though, I'll tell ya,,'mamma look at me top of the world' and all that stuff. Easy come and easy go awareness of life I hate more than the next guy, but this is all that the '70's have left me with in terms of material objects, it ain't hurtin' no one! And as far as anyone may ask, yes I feel very good because of this fact of listening to this classic level of equipment.

And to para-phrase you, it is sexy and really cool to a person like me. I dig all kinds of things, too lengthy to go into here, but this 'throw-back' of equipment from that era is most satisfying to 'partake-in' to be modest. I use a Revox A77 also and a Shure Type3 and everyone's happy"

>

>Oh, the other possible reason is that newer amps should sound

>better unless you've rebuilt the 400s.

"Sound better? That's another whole can of worms, that's been a common perception for many years, not just now, I'm leaning towards that topic as being relative and subject to interpetations and tastes mostly. I feel electronically the full extension of possibilities has been reached and can only either repeat itself or stall in one place politically, given the current trends of the culture, history is a great teacher, I feel economy is the basis here, so I'll say goodnite!"

Frank Marsi

>Bret

10-19-05 I't