Powering Vintage AR larger speakers.

[frankmarsi]

Is there anyone out there using Phase Linear amplifiers to power their larger sized AR speakers? I've been doing so since 1974 and I have nothing but praise and satisfaction to report back. I'm curious to hear from other large size AR speaker collectors about their experiences using this much heralded for good and bad amp.

Frank Marsi

[frankmarsi]

Let me correctly state that I wasn't implying any negatives towards these vintage Phase Linear amps as I solely use them and still continue to buy more on the 'bay'. I was merely curious as to what is being used 'out-there' for AR speakers. I say this because I personally feel that these amps 'support' (in computer terms and the natural way of things) all that the bigger AR speaker models require. I'm more than happy in my choices of these vintage but yet wonderfully good sounding amps and components.

Some body up there likes me. How many times was that line used?

His own friend, Frank Marsi

[Guest pbda]

I'm powering my LSTs with a Marantz 2600 receiver (400 wpc into a 4 ohm load). The combination sounds magical, but I am floored by the power demands placed on the receiver by these speakers. The LSTs seem meaningfully less efficient than my AR-3as, which themselves are not exactly shining examples of efficiency.

I was powering my 3as with a Yamaha CR-2040 receiver (120 wpc into 8 ohms, don't know the power into 4 ohms), and while the combination was great for "reasonable" sound levels, the receiver would clip if I really cranked a particularly fine Telarc recording of the Saint-Saens organ symphony (yes, that last movement).

I have yet to "test" the LST/2600 combination in this way!

[dynaco_dan]

I'm powering my LSTs with a Marantz 2600 receiver (400 wpc into a 4 ohm load). The combination sounds magical, but I am floored by the power demands placed on the receiver by these speakers. The LSTs seem meaningfully less efficient than my AR-3as, which themselves are not exactly shining examples of efficiency.

I was powering my 3as with a Yamaha CR-2040 receiver (120 wpc into 8 ohms, don't know the power into 4 ohms), and while the combination was great for "reasonable" sound levels, the receiver would clip if I really cranked a particularly fine Telarc recording of the Saint-Saens organ symphony (yes, that last movement).

I have yet to "test" the LST/2600 combination in this way!

Hi there;

With the AR-3A's causing your receiver to clip, be more cautious with the LST's.

Make sure that you have the receiver fuses checked, if there are any, and the LST fuses installed as well.

The LST is one heck of a load on amplifiers.

[frankmarsi]

11-8-07

How did I know you’d show up looking for me? Seems you have my secret disguise (the basket hat) down pat and you can see me coming.

Well I’m happy that you’re here along with me on this on! Let’s have some fun!

Vern is completely correct about his opinion about them ‘dere LST’s being power hungry, and I believe most who own them know that story well. Of course that’s if they’re enjoying realistic music levels as I often do. “The LST is one heck of a load on amplifiers”, that’s what Vern said, gees, he ain’t kidd’in!

Although I fuse my speakers, again as Vern insists, I still prowl the ‘bay’ looking for 2 Phase Linear 700’s constantly, I’ve realized to get 2 well conditioned amps it’s gonna set me back ‘way’ too many dollars for now. However, for those who have read ‘back in the day’ test reports. AR-LST’s were first tested by many notable individuals back then and these amps seemed to be ‘the’ amp to power them with. I also realize that if in a good size budget, I’d recommend a hefty ‘Bryston’ (it’s from the Vern area I believe) or something in that price range. I’ve also heard good things about using another vintage amp such as the ‘Hafler’ DH500 and Adcom 555 which both are reported as being tolerant below 4 ohm steady driving.

Personally, I at this point and maybe for ever more can only afford these old PL400’s, but I’ll tell you that the degree of out-right ‘bass-slam’ they put forth is quite astonishing to be frank, and after all that is my name. Not that the high end register is lacking by any stretch either.

Let me throw a wrench in the gears here and cause some distain here from all you ‘purists’. Let’s briefly talk room acoustics; Presently my main room is extremely ‘acoustically-challenged’, my LST’s are in terrible shape and on top of it all, I’m ‘tweeter-challenged’ if there’s such an expression? There’s gotta be cause I’m living it! I just haven’t had any time to address my speaker problems, oh, I’d say for a couple of years now. A real shame and very embarrassing too!

To the rescue: An S.A.E. 1800 equalizer has been the only way I’ve been able to postpone all of my worries. And to be quite honest I can attest to the AR-LST’s being a tad ‘dark’ sounding compared to my AR-3a’s even though they have so many more mids and tweets. So I feel even after I repair all of my system faults I’ll continue to use this equalizer as it seems to ‘put-back-in’ to my system what I feel may be lacking according to modern opinions regarding sound reproduction, and because I still use ten inch tape and other older sources. My lack of time makes me tired enough where my ’work-in-progress’ speakers tire me even more just to stare at them, they’re that ‘needy’. I even feel sad for them, as they can’t even help themselves, but that EQ does ‘medicate’ my system to sound amazingly good on most program material.

In general if you or anyone else was considering a vintage amp, do be careful, as they’re very much like an old but powerful car from the ‘60s or seventies. When you step of the gas pedal, you’ll know what it feels like to have ‘real-raw-power’. And then sometimes you’ll be afraid to hit the pedal cause you feel it may cause some damage or shut it down altogether, although that is an exaggeration.

All in all you’ll be satisfied with more power than most will admit to requiring, but really know is the best way to go. I’ve used Dynaco, Marantz, B&K, but I always come back to the old PL400 because I feel I’m most happy there with its qualities and even if some may claim it’s somewhat bright or what ever,I don’t agree that they are but, ‘it’s all about the program-material’, to paraphrase another CSP member. I’m curious what you may end up with, keep us informed.

Frank Marsi, man of 1970’s vintage everything, right here in the 2000’s.

P.S. On the good old '90s CD player tonite is a great treat for high powered AR's; "Vivaldi's Cello" by yo-yo MA, with "The Amsterdam Baroque Orchestra" on the Sony Classical label CD.

[Guest pbda]

Hi there;

With the AR-3A's causing your receiver to clip, be more cautious with the LST's.

Make sure that you have the receiver fuses checked, if there are any, and the LST fuses installed as well.

The LST is one heck of a load on amplifiers.

Excellent advice; I had my tech install fuses in the Marantz receiver for just this reason. It's meaningfully more powerful than the Yamaha, but even so... I've had varying advice on whether I should be using 4 amp slow blow fuses or 7-8 amp fast blow fuses. At the moment 7 amp fast blow fuses seem to be doing the job...of course you don't know if they are "doing the job" until they blow.

My LSTs have a single fuse each in the back...is there further fusing in the speakers that is recommended?

[dynaco_dan]

Excellent advice; I had my tech install fuses in the Marantz receiver for just this reason. It's meaningfully more powerful than the Yamaha, but even so... I've had varying advice on whether I should be using 4 amp slow blow fuses or 7-8 amp fast blow fuses. At the moment 7 amp fast blow fuses seem to be doing the job...of course you don't know if they are "doing the job" until they blow.

My LSTs have a single fuse each in the back...is there further fusing in the speakers that is recommended?

Hi there;

A 7 amp fuse is a disaster waiting to happen, not protection.

My advice is, use a 4 amp fast blow fuse absolutely maximum.

It would be more convenient to have fuseholders at the amplifier end of the cables, usually.

I don't remember the details but the AR-3A and the LST were well noted for their very, very difficult amplifier loading characteristics.

The low impedance, below 2 ohms and also the very high bass impedance, about 35+ ohms at it's maximum in the bass end, probably buried a lot of lower end amplifiers/receivers.

An amplifier of about 100 - 200+ watts per channel would be needed, full bandwidth, into 35 ohms, to minimize clipping for loud listening.

Loud can be interpreted by everyone to be something different, so let me say, you can't sit and have a conversation with this level.

The only documented fuse information for fast blow fuses is from AR/Heathkit.

Added note: Dynaco also listed their speaker fuses as fast blow only, not slow blows.

Added note: Advent listed their one only, Buss FNM 8/10 amp slow blow fuse, for both the Larger and Smaller Advent speaker systems.

The fuse of choice for the AR-3A/AS-103/AS-103A speaker kit, was 3 amp fast blow, installed in a chassis mounted fuseholder.

With the cost and availablity of Buss FNM 2amp slow blow fuses and their compatible open style fusesholder, another reasonaable option will be needed.

In the, "Other forum", under the , "Fast blow fuses", topic, I have mentioned a very reasonable source for the FNM 2 amp fuse.

Limited to stock on hand NOS, surplus, and excellent service.

I have had a thought about subbing or adding in series, with the slow blow fuse, a safe value fast blow fuse for all speakers.

Using this thought, the AR-3A/AS-103/AS-103A speaker system would have been quite protected back when new.

A FNM 1 1/4 amp slow blow and a open style fuseholder, also with a 3 amp fast blow fuse in it's own open style fuseholder, would have offered quite, if not complete accident protection.

The slow blow is primarily for the woofers.

The fast blow primarily for the mids and highs and accidental destructive transients.

With the aging of the drivers, maybe a 2 1/2 amp fast blow and 1 amp FNM slow blow fuse is best.

This is for the AR speakers mentioned here or as AR has listed in their fusing sheets with equal speakers.

The LST's have the 2 amp FNM slow blow fuse and perhaps reducing it to 1 1/2 or possibly 1 3/4 amp FNM for added protection, also with an open style fast blow fuseholder with a 4 amp fast blow fuse in series.

On this same subject, OEM tweeters are becoming more scarce as time advances.

Please go to, "News forum", and read the topic, "Sound advice", that I wrote recently regarding my massive work related hearing loss.

If you are finding that you need to elevate your treble control or add an equalizer, to increase the highs, you may give this some serious thought.

My loss, is your gain.

[dynaco_dan]

Hi there;

A 7 amp fuse is a disaster waiting to happen, not protection.

My advice is, use a 4 amp fast blow fuse absolutely maximum.

It would be more convenient to have fuseholders at the amplifier end of the cables, usually.

I don't remember the details but the AR-3A and the LST were well noted for their very, very difficult amplifier loading characteristics.

The low impedance, below 2 ohms and also the very high bass impedance, about 35+ ohms at it's maximum in the bass end, probably buried a lot of lower end amplifiers/receivers.

An amplifier of about 100 - 200+ watts per channel would be needed, full bandwidth, into 35 ohms, to minimize clipping for loud listening.

Loud can be interpreted by everyone to be something different, so let me say, you can't sit and have a conversation with this level.

The only documented fuse information for fast blow fuses is from AR/Heathkit.

Added note: Dynaco also listed their speaker fuses as fast blow only, not slow blows.

Added note: Advent listed their one only, Buss FNM 8/10 amp slow blow fuse, for both the Larger and Smaller Advent speaker systems.

The fuse of choice for the AR-3A/AS-103/AS-103A speaker kit, was 3 amp fast blow, installed in a chassis mounted fuseholder.

With the cost and availablity of Buss FNM 2amp slow blow fuses and their compatible open style fusesholder, another reasonaable option will be needed.

In the, "Other forum", under the , "Fast blow fuses", topic, I have mentioned a very reasonable source for the FNM 2 amp fuse.

Limited to stock on hand NOS, surplus, and excellent service.

I have had a thought about subbing or adding in series, with the slow blow fuse, a safe value fast blow fuse for all speakers.

Using this thought, the AR-3A/AS-103/AS-103A speaker system would have been quite protected back when new.

A FNM 1 1/4 amp slow blow and a open style fuseholder, also with a 3 amp fast blow fuse in it's own open style fuseholder, would have offered quite, if not complete accident protection.

The slow blow is primarily for the woofers.

The fast blow primarily for the mids and highs and accidental destructive transients.

With the aging of the drivers, maybe a 2 1/2 amp fast blow and 1 amp FNM slow blow fuse is best.

This is for the AR speakers mentioned here or as AR has listed in their fusing sheets with equal speakers.

The LST's have the 2 amp FNM slow blow fuse and perhaps reducing it to 1 1/2 or possibly 1 3/4 amp FNM for added protection, also with an open style fast blow fuseholder with a 4 amp fast blow fuse in series.

On this same subject, OEM tweeters are becoming more scarce as time advances.

Please go to, "News forum", and read the topic, "Sound advice", that I wrote recently regarding my massive work related hearing loss.

If you are finding that you need to elevate your treble control or add an equalizer, to increase the highs, you may give this some serious thought.

My loss, is your gain.

Back again;

In the AR library amplifier visitors comments is the spec's of the AR amplifier.

The spec's are 60 watts at 4 ohms, usually testing out at over 100 watts in reviews, 50 watts at 8 ohms, and 30 watts at 16 ohms, this is RMS 20 - 20,000 Hz at a specified distortion rating.

At 35 ohms there would be about 10 -15 watts, maybe.

If the AR-3A, the 10 pie and AR-LST may also apply, drops to about 35 ohms in the low bass frequencies, there is not a lot of steam there even with this great amp to cleanly drive these woofers.

It would seem that the AR amp was not designed to drive the 12" woofer to it's optimim at low bass output.

But it sure gave all other amps a run for their money.

I'm still happy with mine, all these many years in use, I've owned one since they were first out.

[Kuja]

Is there anyone out there using Phase Linear amplifiers to power their larger sized AR speakers? I've been doing so since 1974 and I have nothing but praise and satisfaction to report back. I'm curious to hear from other large size AR speaker collectors about their experiences using this much heralded for good and bad amp.

Frank Marsi

I'm using a Kenwood KA-907 to drive my pair of AR-98LSi. It drives them without any effort.

It is "only" 180W at 4 Ohms, but it's dual power transformers draw 1000W of AC.

http://www.thevintageknob.org/KENWOOD/KA907/KA907.html

[cliffe]

11-8-07

How did I know you’d show up looking for me? Seems you have my secret disguise (the basket hat) down pat and you can see me coming.

Well I’m happy that you’re here along with me on this on! Let’s have some fun!

Vern is completely correct about his opinion about them ‘dere LST’s being power hungry, and I believe most who own them know that story well. Of course that’s if they’re enjoying realistic music levels as I often do. “The LST is one heck of a load on amplifiers”, that’s what Vern said, gees, he ain’t kidd’in!

Although I fuse my speakers, again as Vern insists, I still prowl the ‘bay’ looking for 2 Phase Linear 700’s constantly, I’ve realized to get 2 well conditioned amps it’s gonna set me back ‘way’ too many dollars for now. However, for those who have read ‘back in the day’ test reports. AR-LST’s were first tested by many notable individuals back then and these amps seemed to be ‘the’ amp to power them with. I also realize that if in a good size budget, I’d recommend a hefty ‘Bryston’ (it’s from the Vern area I believe) or something in that price range. I’ve also heard good things about using another vintage amp such as the ‘Hafler’ DH500 and Adcom 555 which both are reported as being tolerant below 4 ohm steady driving.

Personally, I at this point and maybe for ever more can only afford these old PL400’s, but I’ll tell you that the degree of out-right ‘bass-slam’ they put forth is quite astonishing to be frank, and after all that is my name. Not that the high end register is lacking by any stretch either.

Let me throw a wrench in the gears here and cause some distain here from all you ‘purists’. Let’s briefly talk room acoustics; Presently my main room is extremely ‘acoustically-challenged’, my LST’s are in terrible shape and on top of it all, I’m ‘tweeter-challenged’ if there’s such an expression? There’s gotta be cause I’m living it! I just haven’t had any time to address my speaker problems, oh, I’d say for a couple of years now. A real shame and very embarrassing too!

To the rescue: An S.A.E. 1800 equalizer has been the only way I’ve been able to postpone all of my worries. And to be quite honest I can attest to the AR-LST’s being a tad ‘dark’ sounding compared to my AR-3a’s even though they have so many more mids and tweets. So I feel even after I repair all of my system faults I’ll continue to use this equalizer as it seems to ‘put-back-in’ to my system what I feel may be lacking according to modern opinions regarding sound reproduction, and because I still use ten inch tape and other older sources. My lack of time makes me tired enough where my ’work-in-progress’ speakers tire me even more just to stare at them, they’re that ‘needy’. I even feel sad for them, as they can’t even help themselves, but that EQ does ‘medicate’ my system to sound amazingly good on most program material.

In general if you or anyone else was considering a vintage amp, do be careful, as they’re very much like an old but powerful car from the ‘60s or seventies. When you step of the gas pedal, you’ll know what it feels like to have ‘real-raw-power’. And then sometimes you’ll be afraid to hit the pedal cause you feel it may cause some damage or shut it down altogether, although that is an exaggeration.

All in all you’ll be satisfied with more power than most will admit to requiring, but really know is the best way to go. I’ve used Dynaco, Marantz, B&K, but I always come back to the old PL400 because I feel I’m most happy there with its qualities and even if some may claim it’s somewhat bright or what ever,I don’t agree that they are but, ‘it’s all about the program-material’, to paraphrase another CSP member. I’m curious what you may end up with, keep us informed.

Frank Marsi, man of 1970’s vintage everything, right here in the 2000’s.

P.S. On the good old '90s CD player tonite is a great treat for high powered AR's; "Vivaldi's Cello" by yo-yo MA, with "The Amsterdam Baroque Orchestra" on the Sony Classical label CD.

Hi there as far as power goes ,you really can`t go wrong with Bryston big heavy ,built to last and wth the 4b your in the 250 + per side lots of power and lots for head room.