AR3a's...Tubes or S.S.

[fran604g]

Hi folks,

In no way am I trying to start a war or pissing contest with this topic, and maybe it's already been fully explored in the past, but here goes:

In regards to my newly rehabbed 3a's I've been using a TAD 60 amplifier (6550C's in UL mode) to drive them and I'm very happy with the results. I prefer UL to strapped triode mode, as the sound seems more accurate and articulate to my ears. I've been thinking of using my venerable Adcom GFA-555 (original model, not 555ll or the recently introduced model.)

Being that my AR3a's, in particular, appear to have been manufactured in the early '70's, I wonder if the design was specifically centered on using solid state amplification or were there still many audiophiles using their old tube gear to drive them, thus the design of this speaker system were centered around the later group of consumer?

As we all know, to some degree, S.S. amps are regarded by many to be faster and have lower distortion numbers (albeit different types of distortion) than tube amps. Therefore, if I am correct, the speakers, if manufactured for S.S. would have been designed for the "brighter" sound of the S.S. amplification? And, perhaps, the "warmer" sound of tubes might have warranted the design of the high frequency driver to be slightly "brighter" to compensate for this difference in circuitry?

I would like to discuss what everyone here uses to drive their 3a's and how they've arrived at their conclusions. I am mostly interested in the end stage of amplification, as opposed to the source or type of media used.

I will rotate my Adcom into system and listen to the differences for myself as well.

Fran

[xmas111]

I'm using a Yaqin MC-100B with KT120's in the ultra-linear mode and think the 3a's sound wonderful.

It only puts out 65 watts/channel but seems to do the job.

Just my 2¢

John

[fran604g]

Thanks, John. Have you ever used S.S. with them?

[xmas111]

Not yet, but I plan on stacking the two sets of 3a's and drive them with the QSC 1450 amp I got a while ago.

I'll let you know how it works out.

John

[HarryM]

I only use SS amps for all my speakers. I am not in hurry to get tube amps because I use a Marantz 2252b as my pre amp and when I hook up either of my Hafler dh200's or my Crown XLS 1000 there is no noticeble change in sound, only volume. Which is what I want.

[fran604g]

Thanks for the replies, guys.

I'm 54 years old and can remember the huge shift to SS gear in the late 60's/early 70's. My Dad and I were big fans of diy and built many Lafayette and Heathkit projects. My Dad was pretty much on the cutting edge of the emergence of transistor development and usage in the early to mid 1960's, as he worked at General Dynamics designing and testing F-111 fighter jet communication and operation electronics. He was very much convinced that audio devices using transistors were better than the tube stuff of the past. I didn't really remember the differences until just a few years ago when I took the time to retrieve and revive our old Lafayette Stereo 250A down from my attic, where it had lived for 25 years or so. I was stunned by the sound and particularly, the volume it put out.

This is why I am interested in knowing how Kloss, Vilcher and others, perceived the use of AR's designs.

[bhamham]

Love my AR-3a with a Fisher 400 (7868 tubes) packs plenty of punch for a mid-size room. Seems like a perfect match.

[xmas111]

Finally got around to stacking the 3a's.

Got to tell ya......sound is unbelievable with awesome bass.

I'm running them with the QSC 1450.

I replaced the fan in the QSC because the stock one sounded like a jet engine!

It's running a little warm but no problems.

Now I need to find another set of LST's so I can stack those suckers too!

John

[dynaco_dan]

Hi there

Have you tried inverting the top pair so that the tweeters will be closest together, as in the Double Advents example?

Frank has been enjoying using stacked AR-LST's for a while now.

[xmas111]

Hi there

Have you tried inverting the top pair so that the tweeters will be closest together, as in the Double Advents example?

That's the way I have them. I flipped the grills so they don't look funny.

Frank has been enjoying using stacked AR-LST's for a while now.

Lucky bast*rd!.....I'm very jealous!

John

[genek]

As we all know, to some degree, S.S. amps are regarded by many to be faster and have lower distortion numbers (albeit different types of distortion) than tube amps. Therefore, if I am correct, the speakers, if manufactured for S.S. would have been designed for the "brighter" sound of the S.S. amplification? And, perhaps, the "warmer" sound of tubes might have warranted the design of the high frequency driver to be slightly "brighter" to compensate for this difference in circuitry?

That's a nice theory, except that there really wasn't a significant change in "the AR sound" during the period when tube gear was being supplanted by ss as the dominant amplifier type. It wasn't until the mid 70's, well after the transition had completed, that the the sound of ARs changed, and then they got brighter.

[dynaco_dan]

Hi there

If you only flipped the grilles then you have the cutouts over the wrong drivers.

Do you mean you re-located the logo?

[tysontom]

Finally got around to stacking the 3a's.

Got to tell ya......sound is unbelievable with awesome bass.

I'm running them with the QSC 1450.

I replaced the fan in the QSC because the stock one sounded like a jet engine!

It's running a little warm but no problems.

Now I need to find another set of LST's so I can stack those suckers too!

John

John,

Your installations look great, and everything is neat and tidy! From the pictures, it appears that the AR-3a logo on the top speakers is larger than the other, but it may be an illusion. Nevertheless, everything does look great.

I've tried both stacked AR-3as and AR-LSTs, and the sound is powerful and forceful. I've even tried stacked Bose 901s (using my QSC 2450), and it does well with potent bass energy—subwoofers not needed here. Stacked 901s don't get quite the same benefit as the AR-3a, Advent or LST (or other similar) with the woofers close together. The reason for this is that the woofers close together couple with what's known as "mutual-radiation" impedance, a boost of approximately 3 dB starting around 500 Hz (this is the frequency of "ultimate-radiation impedance") and working all the way down to resonance. This would also be similar to placing the speaker in the corner. This 3 dB boost is relative to the rest of the spectrum, so the speakers can sound a bit heavy on some musical content. Stacked speakers don't go any lower in bass, but distortion is lower relative to the output, and the speakers can pump out significantly higher volumes of bass energy—as if the AR-3a needed even more bass power!

Regarding tubes vs. solid-state amps for the AR-3a, there should not be any great differences if each amp has equivalent output power. Some early tube electronics rolled-off at the highest frequencies (and low frequencies, too), thus giving a "warmer" sound with less high-frequency output, but high-quality tube amps—with sufficient power—can drive the AR-3 and AR-3a without difficulty. Typically, solid-state amps can drive lower impedances with higher current, but there is no reason to think that a solid-state amp is "faster" (e.g., rise time, etc.) to the extent that it would ever be audible in a speaker that is properly designed. In other words, AR speakers will not exhibit differences with damping factors down to very low numbers or with amplifier slew rates that are "average." AR used tube amplifiers (Dyna Mk IIIs) for all of the live-versus-recorded concerts, and the success of this effort was confirmed with the thousands of listeners unable to detect the switchover from live to recorded. The first solid-state amp used in a LvR setting was the Mattes Amplifier demonstration using an AR-3 and the Mattes SSP-200 stereo amp, reproducing the live output of a Steinway piano. This demonstration was done to show the power requirement for live-sound levels of reproduced piano music. The Mattes was one of the first solid-state amp introduced.

--Tom Tyson

[fran604g]

That's a nice theory, except that there really wasn't a significant change in "the AR sound" during the period when tube gear was being supplanted by ss as the dominant amplifier type. It wasn't until the mid 70's, well after the transition had completed, that the the sound of ARs changed, and then they got brighter.

Thanks genek, that's precisely the answer I was looking for. It must have been fascinating to have been present when the design was being tested and compared by AR back then.

[fran604g]

John,

Your installations look great, and everything is neat and tidy! From the pictures, it appears that the AR-3a logo on the top speakers is larger than the other, but it may be an illusion. Nevertheless, everything does look great.

I've tried both stacked AR-3as and AR-LSTs, and the sound is powerful and forceful. I've even tried stacked Bose 901s (using my QSC 2450), and it does well with potent bass energy—subwoofers not needed here. Stacked 901s don't get quite the same benefit as the AR-3a, Advent or LST (or other similar) with the woofers close together. The reason for this is that the woofers close together couple with what's known as "mutual-radiation" impedance, a boost of approximately 3 dB starting around 500 Hz (this is the frequency of "ultimate-radiation impedance") and working all the way down to resonance. This would also be similar to placing the speaker in the corner. This 3 dB boost is relative to the rest of the spectrum, so the speakers can sound a bit heavy on some musical content. Stacked speakers don't go any lower in bass, but distortion is lower relative to the output, and the speakers can pump out significantly higher volumes of bass energy—as if the AR-3a needed even more bass power!

Regarding tubes vs. solid-state amps for the AR-3a, there should not be any great differences if each amp has equivalent output power. Some early tube electronics rolled-off at the highest frequencies (and low frequencies, too), thus giving a "warmer" sound with less high-frequency output, but high-quality tube amps—with sufficient power—can drive the AR-3 and AR-3a without difficulty. Typically, solid-state amps can drive lower impedances with higher current, but there is no reason to think that a solid-state amp is "faster" (e.g., rise time, etc.) to the extent that it would ever be audible in a speaker that is properly designed. In other words, AR speakers will not exhibit differences with damping factors down to very low numbers or with amplifier slew rates that are "average." AR used tube amplifiers (Dyna Mk IIIs) for all of the live-versus-recorded concerts, and the success of this effort was confirmed with the thousands of listeners unable to detect the switchover from live to recorded. The first solid-state amp used in a LvR setting was the Mattes Amplifier demonstration using an AR-3 and the Mattes SSP-200 stereo amp, reproducing the live output of a Steinway piano. This demonstration was done to show the power requirement for live-sound levels of reproduced piano music. The Mattes was one of the first solid-state amp introduced.

--Tom Tyson

Thank you, Tom, for the very thorough explanation to both topics. I have stacked my KLH 6's with a pair on OLA's and really liked the bass extension that was gained. With the Advents on the bottom and both tweets being closest. This combination works especially well for Rock music, IMHO.

As for my own experience with driving the 3a's with tubes, the TAD 60 exhibits wonderful high and low freq. extension, and the mids are excellent. I still haven't tried the Adcom, but when comparing these 2 amps with any of my other speakers, I've been pleased by both amps in similar ways, so I can assume the 3a's shouldn't be much different.

[xmas111]

From the pictures, it appears that the AR-3a logo on the top speakers is larger than the other, but it may be an illusion.

Tom,

It's an optical illusion, the badges are the exact same size.

John

[johnfalc]

Today I stacked my AR-3a's and I concur with the previous poster's appreciation of the resulting sound. This is my bedroom system.

Somehow, along the way (i've had one of these pairs for forty years) I've lost all but a pair of the model plates, really do need to get some.

https://skydrive.live.com/redir?resid=4D65BE4013BD416A!2656&authkey=!AIQlr_y_IeG2MYc is a link to a picture of the setup cobbled together this afternoon.

[soundminded]

Hi folks,

In no way am I trying to start a war or pissing contest with this topic, and maybe it's already been fully explored in the past, but here goes:

In regards to my newly rehabbed 3a's I've been using a TAD 60 amplifier (6550C's in UL mode) to drive them and I'm very happy with the results. I prefer UL to strapped triode mode, as the sound seems more accurate and articulate to my ears. I've been thinking of using my venerable Adcom GFA-555 (original model, not 555ll or the recently introduced model.)

Being that my AR3a's, in particular, appear to have been manufactured in the early '70's, I wonder if the design was specifically centered on using solid state amplification or were there still many audiophiles using their old tube gear to drive them, thus the design of this speaker system were centered around the later group of consumer?

As we all know, to some degree, S.S. amps are regarded by many to be faster and have lower distortion numbers (albeit different types of distortion) than tube amps. Therefore, if I am correct, the speakers, if manufactured for S.S. would have been designed for the "brighter" sound of the S.S. amplification? And, perhaps, the "warmer" sound of tubes might have warranted the design of the high frequency driver to be slightly "brighter" to compensate for this difference in circuitry?

I would like to discuss what everyone here uses to drive their 3a's and how they've arrived at their conclusions. I am mostly interested in the end stage of amplification, as opposed to the source or type of media used.

I will rotate my Adcom into system and listen to the differences for myself as well.

Fran

When AR introduced its own amplifier to power AR3a it was a solid state unit. About the only drawbacks to solid state amplifiers IMO is the instability and vulnerability to damage of some of them to very low impedance loads Like AR3/3a and serious crossover notch distortion for early ones. If you are going to use a solid state amplfier, stay away from cheap HT model receivers, they are not adequate no matter what their power ratings say (they are safe with AR2/5 series, AR 4 series and all other 8 ohm versions.) High quaility solid state amplfiers have many advantages over tubes and they are especially evident with AR speakers. Relatively low cost, extended bass power and FR, high electrical damping factor, and extended clear treble. However, some still prefer the sound of tubes. They may be useful in taming the high end peak of some MC phonograph cartridges if you don't want to use an equalizer. Personally I bought my last tube amplifier in 1962 and never bought another tube amplifier since. The first solid state amplifier I bought was AR's.

[fran604g]

Impressive, John! Are you using one amp for each pair of speakers, or are they biamped?

[fran604g]

When AR introduced its own amplifier to power AR3a it was a solid state unit. About the only drawbacks to solid state amplifiers IMO is the instability and vulnerability to damage of some of them to very low impedance loads Like AR3/3a and serious crossover notch distortion for early ones. If you are going to use a solid state amplfier, stay away from cheap HT model receivers, they are not adequate no matter what their power ratings say (they are safe with AR2/5 series, AR 4 series and all other 8 ohm versions.) High quaility solid state amplfiers have many advantages over tubes and they are especially evident with AR speakers. Relatively low cost, extended bass power and FR, high electrical damping factor, and extended clear treble. However, some still prefer the sound of tubes. They may be useful in taming the high end peak of some MC phonograph cartridges if you don't want to use an equalizer. Personally I bought my last tube amplifier in 1962 and never bought another tube amplifier since. The first solid state amplifier I bought was AR's.

Thank you for your reply, soundminded. I think it's time I got my Adcom in system and give it a listen with the 3a's.

[Sonnar]

My father used Marantz 7 and 8b to drive his AR 3. I have the original AR Universal amplifier, but the best sound I' ve ever heard from my AR 3 and AR 3a is with my actual Crown PSA2, designed to drive 2-ohms loads with absolute stability. Best regards, Adrian, Rome, Italy

[johnfalc]

@fran604g - not biamped, each pair powered by one of the Sansui amps, with one of them serving as preamp for the two of them. But a slight detour today as the AU-717 had a Zener fail in the regulated supply for the non-power section. Need to replace that Zener before I'm back to an operating stack.

[fran604g]

Thanks John

[fran604g]

So I finally tried my Adcom GFA-555 with the 3a's and I definitely prefer tubes over SS, in this particular instance.

The Adcom sounds a very little boring and lifeless to my ears (my wife said she could tell the difference, too, and it isn't an improvement.)

Not to say it doesn't sound good, it does, but maybe it's the more "clinical" sound that I no longer like...?

I didn't perceive any increased brightness, the balance of highs and lows was good and the mid range was a bit forward, just the way I like it, and the way I have them tuned for the TAD 60.

Nice either way, but the tubes have the edge with me.

[tysontom]

So I finally tried my Adcom GFA-555 with the 3a's and I definitely prefer tubes over SS, in this particular instance.

The Adcom sounds a very little boring and lifeless to my ears (my wife said she could tell the difference, too, and it isn't an improvement.)

Not to say it doesn't sound good, it does, but maybe it's the more "clinical" sound that I no longer like...?

I didn't perceive any increased brightness, the balance of highs and lows was good and the mid range was a bit forward, just the way I like it, and the way I have them tuned for the TAD 60.

Nice either way, but the tubes have the edge with me.

The only way to know for sure is to do an A-B comparison with the two amps with levels adjusted for equal output. This isn't easy, but without doing this, you cannot rely on your memory. The ear's memory is poor. It's nearly impossible to remember subtle differences that happened only seconds apart, let alone days; and this, incidentally, includes your wife. She probably has better hearing than you, but her ears' memory is poor as well. By the way, when you say an amp is "boring and lifeless," this usually means that the amp is not adding to or subtracting from the program material. It is simply reproducing the signal fed to it.

There is likely little difference when an A-B test is done the correct way. I believe the TAD 60 puts out about 50 watts/channel at rated distortion, and this is significantly less than the Adcom GFA-555. Nevertheless, there may be subtle differences, but if both amps are functioning properly and if the tube amp has sufficient power, etc., the differences should be very small, if at all. The big differences come when there are big, high-power peaks in the music, and at this point the Adcom is easily the winner.

--Tom Tyson