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"Wall of Sound"


frankmarsi

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7-3-08

Dear CSP members, can anyone offer advice regarding another near-future project of mine?

Even though I haven’t finished any one singular AR speaker project, mostly due to ‘external-matters’ and ‘set-backs’ which take me away from my AR ‘sacred listening sessions’ and restoration work, I sometimes foolishly plan other vintage stereo events of merit. (You ask, does he have too much time on his hands, no he’s just plain nuts, no salt).

So up next is, six stacked (3 and 3) AR-3a’s powered by three vintage Phase Linear 400 power amps. Although I may be leaving myself open to certain criticisms’ regarding these pretty-much antique amps with their sometime difficulties, I can honestly attest to their sweet almost tube-like sound when properly warmed-up, also wall AC through a power conditioner is, I believe helpful in keeping them calm along with 4 inch fans. But non-cognoscenti view-points aside, I’m asking how would I hook-up three amps from one pre-amp?

My pre-amp has two outputs, but what about the third amp’s power?

I also have another pre-amp that only has one out-put, I may wanna use that one instead, what about hooking that one up with three amps?

‘Y’ plugs are a thought, but that's a bunch of signal losing wire hanging all over the place.

Is someone out there capable of making me a noise free black box, or at least sending a PDF schematic of one, I would be very happy? Also if anyone has an opinion about this project. I’d like to hear it. This whole idea stemmed from me winning on the bay a pair of AR-3a cabinets, with X-overs included, no drivers for the sum of $89.USD for both just yesterday. I already have plenty of spare woofers, mids and tweeters, and while I already have stacked AR-3a’s in one set-up, I thought; go-on moron give it a shot.

Although my aspirations may seem over-played and absurdly unnecessary, stop for a moment and try to visualize the potential virtual ‘wall-of-sound’ that I’m talking about here, not in a ‘live-concert’ sort of sense or ‘sound-re-enforcement’, just ‘big’ and scary, but still the classic beautiful AR sound. Those six AR woofers will no doubt be overwhelming in such a good way that I am extremely excited, maybe even mad, I’m mad I tell ya! Picture Dr. Frankenstein in his finest moments and those six 3a’s being the Karloff monster, just moving mountains of air and sound,-it’s alive! Now, if those 6 woofers are going to overwhelm the mids and highs, then I’ll install “Micro-Statics” on top of the 3a’s. I’m mad I tell ya! Mad!

FM

P.S. On another more sane note. Highly recommended especially for AR speakers and all you vinyl nuts out there is the wonderfully beautiful tracking AT440mla cartridge, tracks even better than my Shure V15 Type3. It gives you most of the 'highs' and musical 'edges' you may feel the AR's aren't. In a sense it tracks so well in portions of the vinyl that maybe hasn't been used yet, and even makes my original Beatles albums from '64 sound like a CD, great effect and allows old records to sound virtually new again- I swear to it! I was so impressed and with over 50 or so years of vinyl experience, well I went out and bought a second just to have on spare. Also highly recommended is the Denon DL-160, less forward than the Shure and AT440mla, but very sweet with AR's too. Tracks well and some how hides surface noise even better than the V15. Although I may be late with this, the standard 'carbon-fiber' brush from every manufacturer (the "Tonar" is the best & cheapest, ($13.in change) in the world is probably one of the best tools for my vinyl I've even had and I go back to the Cecil Watts 'Dust Bug' and "Disc-Parastat" in the late 60's. And in cables the Straightwire Symphony Twos are very nice, crisp and a sense of 'real-ness' to them(if there's such a quality to wire?).

Also recommended CD of the season, if you liked the Eagles way back when, their recent album "Long Road out of Eden" is very good indeed, they haven't changed much and still sound great. Also try Diana Krall's greatest hits and the original sound track to "Victory At Sea"(email me for the actual disc #) for all of you 50 year old somethings who sat there with their fathers in front of the ole' RCA 14 inch B&W screen in the mid to late fifties. Wonderfully powerful music, especially on the first two cuts-makes you feel like a 19 year old sailor in the Pacific in '42 to '45.

FM

7_3_08_CSP.doc

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Don't be afraid of good quality Y connectors, Frank - they'll work just fine.

A real consideration would be if all three of these vintage power amplifiers have identical outputs for the same input signal - if not, the speakers could all wind up playing at slightly different levels!

I once had two pairs of AR-3a systems powered by two Dynaco 400 amplifiers - unlike the inverted "stacked Advent" setup, these speakers sounded their best when horizontally stacked, with woofers toward the center.

This was the best-sounding AR-based system that I've ever heard that didn't include an AR-9 or AR-LST.

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Don't be afraid of good quality Y connectors, Frank - they'll work just fine.

A real consideration would be if all three of these vintage power amplifiers have identical outputs for the same input signal - if not, the speakers could all wind up playing at slightly different levels!

I once had two pairs of AR-3a systems powered by two Dynaco 400 amplifiers - unlike the inverted "stacked Advent" setup, these speakers sounded their best when horizontally stacked, with woofers toward the center.

This was the best-sounding AR-based system that I've ever heard that didn't include an AR-9 or AR-LST.

Hey Ar_pro

In response, I'm doubtful about using 3 sets of "Y" plugs, I can't visualize how it might look. My amps are all original for thr most part and all the same make,model and so forth, so I don't actually see any 'matching' problems.

I've been under the idea that woofers should be out on the ends, not inside.

You actually feel the stacked 3a's sounded better than the LST's perhaps ?

Most interesting, but I admit it's better in the horizontal position, I mean the speakers of course.

Also what do the Dyna 400's sound like? I go way back with Dynaco, even built them (in 1967) a PAS-3X(twice), a ST-35 and a ST-120, and often wondered how the 400 sounds. Can you recommend any quality 'Y' plugs?

FM

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I don't think you'll have any problem with a pair of Y connectors, Frank - since your preamp has two pairs of outputs, you'll just need one pair of Y adapters (1 RCA plug to 2 RCA jacks) to provide the third set of outputs. Monster made a very nice Y of this type a few years ago, but I'm sure that other manufacturers have similar-quality products.

My thoughts concerning equal output are just due to the practical considerations of stereo power amplifiers - in a simple 2-channel, 2-loudspeaker setup, a balance control will suffice for adjustment (assuming the amplifiers don't have their own level controls).

With a 2-channel, 4-loudspeaker system, you'll be asking two distinct (although identical model) power amps to have exactly the same response in all four channels. With a *six* speaker system...well, you see where I'm going with this.

The Dynaco 400 amps had individual level controls for each channel, so I was able to carefully adjust all four AR-3a speakers to what seemed to be a balanced configuration.

For certain, the slight difference in the distance of each loudspeaker from the listener's ear required these fine adjustments for a baseline setting...once adjusted in this manner, the preamp's balance control then provided the normal L+R compensation for different recordings.

The Dyna 400 was rated at 200 watts/channel, and was a contemporary of your Phase Linear super-amplifiers, although I don't think that it was anywhere near as reliable as the PL.

The stacked AR-3a set-up definitely sounded more open with the woofers centered, with excellent LF response - superior to a single pair of the LSTs in this one regard, but not on par with the LST's stereo imaging characteristics.

In a large room, I would prefer the double-3a system to anything but an AR-9, or the LST.

In a very large room, I'd imagine that a triple AR-3a system would be pretty impressive, although I doubt that you'd give up your stacked LST system.

Your stacked LST system with an AR-9 woofer section might be an interesting experiment!

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I don't think you'll have any problem with a pair of Y connectors, Frank - since your preamp has two pairs of outputs, you'll just need one pair of Y adapters (1 RCA plug to 2 RCA jacks) to provide the third set of outputs. Monster made a very nice Y of this type a few years ago, but I'm sure that other manufacturers have similar-quality products.

F.M. response: O.K. but isn’t there ‘current sharing’ going on and reducing signal to the other amp that’s sharing it, or something like that?

My thoughts concerning equal output are just due to the practical considerations of stereo power amplifiers - in a simple 2-channel, 2-loudspeaker setup, a balance control will suffice for adjustment (assuming the amplifiers don't have their own level controls).

With a 2-channel, 4-loudspeaker system, you'll be asking two distinct (although identical model) power amps to have exactly the same response in all four channels. With a *six* speaker system...well, you see where I'm going with this.

Response: Lost me there. I need help to think, I’m not

very knowledgeable electronically. I was many years ago, lost it by '82. My mind scatters when speaking of electronic theory. Cannot compute, must have help.

The Dynaco 400 amps had individual level controls for each channel, so I was able to carefully adjust all four AR-3a speakers to what seemed to be a balanced configuration.

For certain, the slight difference in the distance of each loudspeaker from the listener's ear required these fine adjustments for a baseline setting...once adjusted in this manner, the preamp's balance control then provided the normal L+R compensation for different recordings.

Response: O.K. I understand that, I wish I had such facility with my amps.

The Dyna 400 was rated at 200 watts/channel, and was a contemporary of your Phase Linear super-amplifiers, although I don't think that it was anywhere near as reliable as the PL.

Response: Golly, I’d been thinking all along and popular public word was that the PL’s were more prone to failure than any Dynaco could ever be, except my freak’in turd ST-120. Oh, the problems I had with that weak-ass piece of crap. And I really believed so strongly in it too, like a jerk. But hey it was ’71 and this was assumed to be one of the best out there. In theory it was, and the Dyna Company, hey most ‘in the know’ knew they were ‘cool’! Especially compared to Fisher’s and Scott’s and etc. etc.

The stacked AR-3a set-up definitely sounded more open with the woofers centered, with excellent LF response - superior to a single pair of the LSTs in this one regard, but not on par with the LST's stereo imaging characteristics.

In a large room, I would prefer the double-3a system to anything but an AR-9, or the LST.

Response: I could understand that!

In a very large room, I'd imagine that a triple AR-3a system would be pretty impressive, although I doubt that you'd give up your stacked LST system.

Response: You’re 100 percent correct about all of that too! But, I wonder.

Your stacked LST system with an AR-9 woofer section might be an interesting experiment!

Response: Good God man !! Are you insane? Have you lost your mind? Where do you get these ideas from? Are you obsessed with these mere pieces of wood and metal? Repent! Repent and shed these bonds of ‘AR’ mania and wrong feelings! You; my poor soul, are a victim of all that’s evil and great about being an ‘AR’ fanatic! You are a surviving breed that are few.

Welcome to my world! Embrace all that is musical and AR. Be the few, be the strong!

Frank Marsi, friend of all, foe of none!

Loving you, just joking!

7-3-08

P.S. Ah.. the listed time I posted this bull is wrong, it's 12:20A.M., EST officially the fourth of July.

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