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Thoughts on Amps for 3's


DavidDru

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Most of the amps mentioned here are rare in The Netherlands, so finding them will even be harder.

Let alone the price...

I will be playing my AR5's and AR2ax with the following sets:

Marantz 4270 + Marantz 5220 + Dual 1229Q

Marantz 2245 + Marantz 5200 + Dual 1019

Marantz 1060 + Marantz 104

Luxman L58A + Luxman T50

Leak Stereo 70 + Leak Stereofetic Tuner

Although I believed I had everything I wanted, today I stumbled on something "new" to look for: a set of Rogers Ravenbourne Amp & Tuner.

I just fell in love with the looks :wub:

Soon as my AR's are up and running I will let you know how they sound on my various sets.

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David -

The AR-3 will certainly sound good with a Stereo 70.

There must have been thousands of systems in the '60s that paired the two, so you wouldn't be breaking new ground with this matchup; it's truly a classic.

A powerful solid state amp would allow greater SPL and bass control, of course, but it would also present the possibility of popping those tweeter domes across the room! :o

Given the fragility/scarcity/repair aspects of the AR-3 tweeter, caution is the word of the day.

As far as the ST-70 goes, if it's in original, unrenewed condition, watch out for the power supply caps, selenium rectifier, and the 5AR4 tube; don't push it too hard with that AR-3 load.

In all honesty, I can't think of any solid-state amplifiers from the '60s or '70s that I'd be interested in using with a fully-restored & functioning AR-3 or AR-3a; these speakers are so much better than the electronics of that era that it's almost a shame to not use them with modern amplification.

The AR-3a and Crown DC300 (or Dyna 400, Phase 700, etc.) were great combinations in 1970, but those amplifiers are hardly relevant today; while the 3a is still of significant quality, and able to compete with many modern loudspeaker designs.

On the other hand, while tube amplification of that period offered much less power, a '60s-era Dynaco, Marantz, or McIntosh combination could still afford a modern and musical presentation with the AR-3 or 3a - in this instance, vintage would not be a step down.

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Fine little write-up, ar_pro, but I have to ask if you are purposely side-stepping or merely overlooking the many fine low wattage tube amps produced by H.H. Scott during this same era? Also, please expand on why some of those older classic SS amps are no longer 'relevant".

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Scott, Fisher, and H/K had very well-regarded amplifiers from that era; my reference was to the Stereo 70 because that's the amp in question, and to Marantz and McIntosh, simply because of their place at the top of that decade's pyramid.

Since the AR-3 was a considerable investment, well-heeled buyers weren't reluctant to team it with more powerful amplifiers (than the Stereo 70) from Mac or Marantz, or the classic Dynaco Mark III mono amp - commonly known as "the poor man's McIntosh". In many more systems, though, the AR-3 was paired with the Stereo 70, and with very good result.

Speaking strictly of high-powered s-s amplifiers, I'll say "no longer relevant", because I've owned the mighty Crown DC300, and the later Crown PS-400 from the '80s.

There was no comparison in sound quality, with the PS-400 being a big improvement in every aspect over its famous ancestor.

Likewise, I've owned the Dynaco ST-400, and it's '80s-era counterpart from David Hafler - again, no comparison.

ALL of these amplifiers were bettered by Adcom products (among others) of the 1990s, and that decade's Adcom production cannot hold a candle to the McIntosh amplifiers that I'm currently using; so other than for reasons of nostalgia, my affection for 1960's-era solid-state amplifiers is really limited.

No offense is meant to anyone who uses any of these ancient amplifiers as their daily-driver, but my point was that the AR-3 or 3a is capable of significantly better performance than contemporaneous solid-state amplification would reveal.

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. . . . that decade's Adcom production cannot hold a candle to the McIntosh amplifiers that I'm currently using;

ar_pro,

You may have mentioned this before but what McIntosh amps do you like with the 3a?

I'm currently using an Adcom 555-II with a DB Systems preamp (in fact, that combo replaced my MAC4100 receiver).

Just wondering what Mac I might aspire to ;)

-Kent

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I'm no expert on any of these matters and that is one important reason that I am a member here. I hope that there are modern receivers available today with the convenience of a remote control that are capable of driving my AR3a cleanly. I'm currently using a HK 3480 receiver that I purchased second hand. The phono section went bad a while back and I now use a separate phono amp through one of the aux inputs. It is rated at 150 watts per at 4 ohms. It seems adequate to me but I can't do any comparison listening tests either. I know that the Harman-Kardon name is not what it used to be and like most other electronics these days is assembled in China.

Sorry if I strayed a bit off topic but I am interested in this thread and am wondering if it's worthwhile for me to pursue other amplification equipment.

der

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Hi, Kent -

For a vintage Mac, I wouldn't look any earlier than the MC2205, and then their immediate descendants - MC2255 and MC7270.

These are very powerful designs with autoformer outputs that match very well with the AR-3a's load, and give a pretty good representation of the AR-3a's capability.

Things got weird with McIntosh in the '90s, and their solid-state amplifiers kind of tread water for awhile.

Current-production McIntosh amplifiers are dead-quiet, and ultra-powerful; again with autoformer cicuitry for matching loads - absolutely perfect with acoustic suspension designs.

That said, the Adcom 555II is one of my favorite amps of all time - I've heard it with everything from AR-9 to electrostatic designs, and it never failed to please.

It's ultra-reliable like a big Crown, and has the Crown's tremendous bass capabilities; it's tube-like smooth through the midrange, and almost disappears in a system with a quiet preamplifier like your DB Systems.

If you ever get the chance, grab Adcom's passive preamplifier (I think it's the SLC-505), and listen to it with your 555II and the 3a's or AR-91 - you will be absolutely astounded by the depth of the presentation.

It's not an every day solution with the 555II - it lacks the punch that an active preamp like your DB Systems has, but for transparency of reproduction, it's on par with Stax electrostatic heaqdphones - uncanny!

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Hey, David -

The GFA-5500 is a more recent-production amplifier that uses MOSFET output circuitry instead of the 555II's bipolar devices.

I've never actually listened to one with an AR speaker, so I couldn't compare it against the outstanding performance of the 555II.

The Hafler DH-500 was an earlier MOSFET design, and it was an excellent match with the AR-9, although I feel it was bettered by the more recent 555II in the same system.

Clean 555II amps have been selling at $400 for about ten years - that's just an outstanding bargain. :)

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AR, do you mean the 5500 at $400 is a bargain?

I also wonder how it rates compared to my Dynaco ST400?

I am also needing something like this to better power my Maggies.

$400 for a cosmetically clean 555 II with no electrical or mechanical issues is about the going rate, but still a definite value; I'd be very surprised if you didn't consider it to be a noticeable improvement on your Dyna 400.

There were not so many of the 5500 produced, and since it's a significantly different design and I haven't really heard it with AR speakers, I'd just be guessing at the result.

Considering your ownership of both Magnepans and the AR-3, a clean, reliable, substantial power amplifier would be well-suited.

The Adcom 555II is a known quantity, and commonly available; and if 325 watts/channel into 4 ohms isn't adequate, it may be easily upgraded by buying a second 555II, and switching both to bridged mono for a rated output of 850 watts into 4 ohms (with the fan option installed).

In an earlier system, I've used two 555 II amplifiers in vertical bi-amp mode with the AR-9 with exceptional results - the speakers sounded significantly more open & alive than they did with previous solid-state power amps (including Dyna ST-410, Hafler, Crown, and the McIntosh MC2205).

The 555 II is a lot like the AR-3 and 3a, a vintage component that is still seriously competitive & enjoyable (as well as a great bargain), decades after the last one rolled out of the factory. :)

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ar_pro

I think you've convinced me to hold onto the Adcom for a while. I paid $225 + 40.00 shipping about a year ago and took it to my favorite tech who charged $87 to check it all out, change 3 caps, tighten connectors and set the bias. So $352 for a really nice amp. Its successor, the GFA-555SE is selling new on Amazon for $1.299, so I'd say I got a bargain. Here's a link to some info http://www.kenrockwell.com/audio/adcom/gfa-555-ii.htm

The rated 325 wpc are "big" watts and the amp is more powerful than the numbers suggest. AND it was built right here in NJ--perfect for my "All-American" vintage system (although Binghamton NY is almost as close to me as New Brunswick NJ). As sexy as the Macs are, this one is probably a keeper for now.

Some people prefer the original Nelson Pass-designed 555, some say the 555/II was an improvement. LOTS of "upgrades" are offered but I'll keep mine stock.

A few years ago a CSP member told me how to bi-amp the AR-3a. Too bad I didn't keep my Dyna ST-35 (little brother to the ST-70 but some say sweeter sounding) for the mids & highs....... ;)

-Kent

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I do love Kent's notion about staying true to "local"; in his case, the geographical pull between Adcom and Mac is sensibly dictated by his wallet. By the same token, I'd think his loyalty would be torn between Dynaco (Phila) and Rectilinear (Brooklyn, Bronx) speakers. This same thought does interest me as well, and if I were more "pure" to my origins, I'd be fully loyal to Crown amps and E-V speakers since I grew up in northern Indiana, a mere spittin' distance from both mfg. plants.

For some time, I have been trying to learn from others and get a more current (no pun intended) understanding and appreciation of recent (uh ..... the last 30 years?) developments in amplifier technology; but also, I really do appreciate hearing about everyone's individual situations regarding power source + speaker pairings and the subsequent attempts to describe the perceived audio experience. Count me among those souls who do not have four or five-digit liquid cash dollars available to throw at this enjoyable hobby pursuit, but I will admit that I am beginning to completely lose any connection with this ongoing watts vs. pleasure discussion.

While I certainly understand, appreciate, and fully enjoy hearing the historic reports of vintage AR bookshelf speakers providing fully demonstrative and impressive audio performance in large volume venues such as, or similar to, Carnegie Hall, Grand Central Station, or the Copenhagen Music Hall (I think I made that last one up), these loudspeakers were primarily designed and marketed for discriminating domestic applications. With that in mind, it is inconceivable for me to understand how/when a situation might possibly occur when 325 watts per channel is perceived as inadequate for any 50's-60's-70's-80's Acoustic Research speaker within its intended environment.

Many/most people on this site have a far better comprehension of the concepts, theories, and formulae of electrical science than I possess, so I sheepishly admit that I simply do not understand the desire or the implied need for mega-wattage power sources.

Saturday night here, feeling snowed-in yet again, listening to my 30-year all-time favorite weekend FM jazz program. Ten feet away in the next room, my very modest and seriously-aged amalgamation of audio components fills the entire house with very substantial musical reproduction. Small volume speakers (AR-4xa, AR-6, and AR-7) and small wattage (two sources, neither more than 50 w/channel) amplification are complementing each other very satisfactorily; plus, I almost never turn a volume control beyond the 9 o'clock position.

Obviously, I do not own TOTL AR-9's or AR-3a's or LST's or 325 watts per channel..... but exactly what am I missing here? Just how much SPL or audible hertz detection does a listener require in one's living room on a daily basis?

Just me, but I found post 9 very encouraging here:

http://www.classicspeakerpages.net/IP.Board/index.php?showtopic=8130

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Here is a rather simplified description of power requirements. I never did get around to buying a dbx unit but I always thought it would come in handy when listening at the extremes, either very soft or very loud levels. I didn't see any mention of clipping and associated problems with the harmonics produced, namely fried tweeters.

http://parttimeaudiophile.com/2012/04/03/speaker-sensitivity-dynamic-range-and-amplifier-output/

Then there is usable dynamic range which is one reason recorded music often falls short of a live performance.

http://www.learndigitalaudio.com/blog/dynamic-range-compression-pt-1-what-is-dynamic-range

Roger

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I'm in the same boat, ra.ra, but I'm virtually snowed-in - I crashed my bike on Thursday, and although I broke nothing, it feels like I broke everything!

Limping within about a 30 foot radius, gives me computer and Hi-Fi access, so talking about and listening to audio is still in the cards.

I can't explain the whole wattage thing, except to say that I've found that speakers like the AR-3, and 3a sound damned good with lots of beefy wattage in reserve.

This is not to suggest that the speakers need to be blasted - just the opposite!

At moderate levels, I don't think most owners would fail to hear a difference between the Adcom 555 II, and it's smaller brother, the 545 II; but it's important that the amplifier's first watt sound as good as its 200th, or there's no point.

I do agree with Roy's comment on power, especially as far as a requirement for attaining a certain SPL goes.

We'd settled on McIntosh amplification for our AR-9's a few years ago, and when we moved to the Magnepans last year, the Mac amps made the transition nicely; and I do believe it's because of the consistancy in performance from the first watt to the last, and that certain effortlessness that accompanies power in reserve.

Again, let me just say that the most impressive aspect of these 50 year-old speakers is how they continue to sound better as they are used with the best amplification from each successive decade!

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I do love Kent's notion about staying true to "local"; in his case, the geographical pull between Adcom and Mac is sensibly dictated by his wallet. By the same token, I'd think his loyalty would be torn between Dynaco (Phila) and Rectilinear (Brooklyn, Bronx) speakers.

Yo! Dynaco upgraded their location to Blackwood, NJ. And let's not forget that David Hafler stayed right here in Pensauken NJ wit his eponymous company.

And speakin of eponymous, whaddabout David Bogen's amplifiers, made in Paramus?

Dat's right! I said "eponymous." Twice. Youse wanna make sumpin of it?

An don say "Joisey".

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You guys are cracking me up, so I feel better now - - - last night I was beginning to feel like an emasculated audio geek since I do not have triple-digit wattage in any of my modest set-ups.

Thx for the interesting reads, Roger; and Kent, yep, you've laid a substantial claim for some serious audio production from the Garden State. Only thing that perplexes me is you neglected to mention the exit ramps from the turnpike to describe these companies, which is the only way that sensible people navigate thru New Jersey. :lol:

Hmmm....that'd be pretty weird if we could only own gear that was produced within a certain radius of our homes, eh? Come to think of it, looks like much or most of my gear was produced within 25 miles of my home here (AR, a/d/s, HH Scott, KLH, EPI).

Sorry to hear about that bike crash, ar-pro - - - man, that hurts just thinking about it. I still ride the two-wheelers, somewhat frequently, and I constantly have to remind myself that there's always just one rough curb cut, deep pothole or untimely car door between my face and a big bite of asphalt sandwich.

The thing I'll take away from this discussion of amps and wattage is ar-pro's last comment in post 65, which suggests to me that I just might want to join the big-boys club and eventually get myself some 21st century circuitry as a primary power source. When that day arrives, I'll certainly take a hard look at the line of Crown amps that Tom Tyson has lauded on this site for their stellar performance and exceptional value. To go along with it, I'll definitely need a nice big woofer like the one pictured here.

post-112624-0-08684900-1425236410_thumb.

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You guys are cracking me up, so I feel better now - - - last night I was beginning to feel like an emasculated audio geek since I do not have triple-digit wattage in any of my modest set-ups.

Thx for the interesting reads, Roger; and Kent, ....

The thing I'll take away from this discussion of amps and wattage is ar-pro's last comment in post 65, which suggests to me that I just might want to join the big-boys club and eventually get myself some 21st century circuitry as a primary power source. When that day arrives, I'll certainly take a hard look at the line of Crown amps that Tom Tyson has lauded on this site for their stellar performance and exceptional value. To go along with it, I'll definitely need a nice big woofer like the one pictured here.

attachicon.gifbig ass woofer.jpg

De nada.... That is the first "whole house" woofer I have seen to date. Does that have a butyl rubber surround? Might need a 10KW amp to drive it :)

I'm in the same boat, ra.ra, but I'm virtually snowed-in - I crashed my bike on Thursday, and although I broke nothing, it feels like I broke everything!....

Been there and done that several times ... sympathies.

I think you've convinced me to hold onto the Adcom for a while....

-Kent

Kent, I'm having amplifier blues at the moment and after working on my old SAE I'm starting to like your amp more. I'll see if I can snag one on the auction site. Not sure what the difference is between the original Adcom 555 and the Model II is. Was it a major design change or just mod/tweeks?

I'll probably gut the SAE and stuff a later model amp in the case at a later date :) Don't ask!

Roger

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Roger,

If you google "difference between adcom 555 and 555/II" you'll find many hits. I think this John Atkinson write-up in Stereophile is a good summary: http://www.stereophile.com/content/adcom-gfa-555-power-amplifier-john-atkinson-1990

When I first took mine to my tech he said it was too bad I didn't get the plain 555 because there was some unobtainium part in the II. I forget what it was, but he subsequently told me he'd found a source so no problem there.

The 555 was the original Nelson Pass design. The Mk II was supposedly "improved" but without Pass's input. I think they are very similar but J.A. is of the opinion that the Mk II was indeed an improvement.

Then there are all the modders and tinkerers........

Good luck and keep us posted.

-Kent

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Roger,

If you google "difference between adcom 555 and 555/II" you'll find many hits. I think this John Atkinson write-up in Stereophile is a good summary: http://www.stereophile.com/content/adcom-gfa-555-power-amplifier-john-atkinson-1990

When I first took mine to my tech he said it was too bad I didn't get the plain 555 because there was some unobtainium part in the II. I forget what it was, but he subsequently told me he'd found a source so no problem there.

The 555 was the original Nelson Pass design. The Mk II was supposedly "improved" but without Pass's input. I think they are very similar but J.A. is of the opinion that the Mk II was indeed an improvement.

Then there are all the modders and tinkerers........

Good luck and keep us posted.

-Kent

Kent, I took the plunge on an ADCOM GFA-555II with a 30-day return option if I don't like it. Thanks for the link.

I think I'll get a 545II and drop it into my old SAE case :)

Roger

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Roger,

Please let us know your listening impressions.

IMHO with an amp that age it's a good idea to have a qualified tech check it out. As I mentioned, my guy found 3 bad caps and set the bias so it was money well spent for 1 hour's labor and 3 inexpensive parts.

Enjoy!

-Kent

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Roger,

Please let us know your listening impressions.

IMHO with an amp that age it's a good idea to have a qualified tech check it out. As I mentioned, my guy found 3 bad caps and set the bias so it was money well spent for 1 hour's labor and 3 inexpensive parts.

Enjoy!

-Kent

I'll just recap it. Shouldn't be too hard to find a service manual and schematic around somewhere.

I believe the 555 II celebrates its 25th birthday this year.

I think you're in for a treat, Roger - enjoy!

I think you are right on that one. Looking forward to it.

Roger

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