What Amps Were Meadowlarks Voiced With?

[prime minister]

As the amp/speaker interface is one of the biggest challenges in getting a system to work and sound right, I'm always intrigued by what amp a designer uses when testing and voicing their speakers. Often, speakers are so demanding, or so of their time, that the choice seems easy. However, I really have no clue with the Shearwaters, or the Kestrels for that matter, because it seems that they would be gapha with nigh onto anything.

Pat, you willing to share what you were using, or what amp makes your speakers sound "right" to you?

 

[Pat McGinty]

A lab rig needs be three things:

It has to deliver enough detail to allow the designer to examine resolution issues, most of which arise from phase problems. That doesn't mean having extreme resolution since a speaker's resolution can be maxed out on merely good resolution signals.

It needs be tonally neutral; whatever that is. Truth be told, that's quite subjective but a designer's concept of neutrality is at the core of his competency. Enough said. At home I may like a little rosy glow. Not at work.

It also must be close to perfectly dynamic inside the band/amplitude envelope one wishes to explore. Of course you're gonna run out of power but the whole band should scale up evenly. This is critical since so many speaker problems come from dynamic nonlinearities. That's a pet issue.

Anyway, you can see how a ref rig might look like a pile of outdated, middling gear. Mine did. A Musical Design preamp, which I could toggle out for a simple ALPS pot, the pre was stripped down to the basic gain stages with trick oil output caps made for me by RTI, a Musical Design inverted CD transport built on the old Pioneer inverted transport, a Musical Design DAC that, again, was stripped all the way down. I forget the DAC chips. The owner of Musical Design and I went way back so he understood where I stood and worked as a friend on building my gear. Cardas Neutral Reference wire and cable. For a while I was using another brand of single crystal copper cables but when I recognized that they were choking on peaks I ditched them for Cardas. And a McIntosh MC7200 with direct coupled outs. (2x250W....which seems so tiny now I'd need four or five ;-))

The Mac had two key features: instant crowbar protection and a fast clip limiter. While developing filters, dead shorts happen from all sorts of boo-boos when the circuits are clip leaded across the floor, including frisky dogs. Most amps fry their output devices leaving them dead; the Mac just blinked and kept on. The clip limiter was nice for this heavy handed guy; saved a lot of tweeters. The tonality was dead-nuts flat. Hard, hard bass. Clean trebles. Midrange maybe a bit sterile, but that was good; when the system emoted it wasn't fake. The joy was actually coming through.

I did all of my measurements through that amp because it told no lies. That amp was turned on for 25 years and still runs great.

As a tube ref we used a Music Reference RM9. For a hybrid ref we inherited Mike Elliott of Counterpoint's monstrous ref amp following their demise in, I think, 1996. We also kept an Arcam around to see how things sounded on entry level stuff. We often showed with BAT and Rogue; the Rogue Zeus had enough guts to drive our Herons and Blue Herons nicely and the BAT CD player was sublime in the mids. Shows are a completely different problem: you have to get good sound in a bad room. So choices of tonality come in handy.

Funny story about amp voicing: during my hobby speaker builder phase I had a stack of Haflers upon which my mentor, George, frowned. Try after try my midrange was coming up muddy. George, a transcendent scientist with the personal lab to match, finally exasperated with me, swapped his MC240 for the Hafler and, I'll be damned, Winona Judd suddenly stepped forward of the band with a moist blush on her voice and a breathy female presence that swept away all doubt. Lesson learned. I bought lunch. Then the Mac.

 

[prime minister]

Fantastic post again, Pat. I'll have to reread and digest that some more.

It does lead one to wonder something though. If one were to randomly choose one of your speaker designs, like, oh, the Shearwater Hot Rod, for instance, used in a small room, of, let's say 11x9 feet, with a high cathedral ceiling, what amplification would you choose to make the Shearwaters sound "right" to you? And I get there are a million variables in any discussion like this, but I'm curious to hear what to you, the ideal combination would have sounded like.

 

[marantzfan]

Cheater.

 

[prime minister]

Cheater.

Moi?

 

[prime minister]

I guess there is an add on question to this too. I know in your newer designs, you have seemingly decided to ensure that your amps are not, ahem, underpowered. Is this a design choice you feel to be correct with your current speakers, or do you feel now that all of your earlier designs could also have benefited from this high power approach?

My present amplifier choice was very much influenced by my smallish listening room, and all of the low level listening that I do. While I have something like perhaps 16 watts of class A power (a monster amp around these parts ), a lot of that choice was driven by my experience with high powered amps and their seeming inability to really open up at low level/low power. A questionable first watt, in other words. Class A seemed a good way around it, and something like a Sugden A21se would have likely worked just as well as my current tube amp. I am not tribal, when it comes to audio!

I remember an old Bob Carver story of him trying to recreate the snip of a pair of scissors, and something like 2400 watts not being enough to reproduce it accurately on the scope. Bob sure is a great character with plenty of grist for the audio mill. One of my few audio regrets is selling my copy of his Sunfire amp. Great piece that was!

 

[StevenZ]

I really enjoy these Meadowlark threads and @Pat McGinty 's remarks. There's real value in these stories that I appreciate.

 

[mhardy6647]

At home I may like a little rosy glow. Not at work.

Words to live by there; very quotable (and admirable). I wonder how widely held this philosophy is in the biz?

Just musing.

 

[Pat McGinty]

Bob Carver's scissor snip story overlaps with my experience. Early on my buddy George, ever the clever tormentor, visited the lab and presented a child's toy; a small bomb shaped thing with fins that exploded a paper cap gun cap upon impact. He merely dropped it to the cement floor. POP. "Let's see you reproduce that." His 50 cent toy versus all of my technology. In 30 years, I haven't come close.

At issue is a very short yet very energetic burst of white noise. So the entire system must rise instantly at all frequencies to a peak of spectacular amplitude then settle instantly.

That this ability is fundamental to "realistic" audio reproduction goes without saying. I could go on for pages about the many avenues of difficulty involved. That's not the point. The point is that this problem sheds a narrow beam of "light" into the darkness at the frontier of the possible, showing us just how far from the ideal we really are.

Now, I've been critical of high end audio for spending that last twenty years fiddling around with vanishingly tiny technological increments. Beryllium tweeters are the big whoop? Really? Infinite variations of power cords? DAC after DAC? ZZZzzzzzz........if these are the real issues we must be getting close to that ideal, no?

No. High end audio has created a false sense that it is approaching optimization. Nothing could be further from the truth. Proof of that sillyness will cost you just 50 cents.

So, yep, stupid amounts of power is just for starters. It's a happy thing that FINALLY that barrier, which has always been an economic one, has fallen. My OEM cost for the 10x400W that goes into Nightingale is less than one kilobuck. 25 cents per Watt. So why hold back? Power should never the limiting factor. Even if you only need the full 4KW for a few milliseconds, you do need it. SNIP!

Now might begin an exposition of the many avenues by which that power can be applied with the magic of DSP, but let's leave that for another time. I'd be happy to go there with the caveat that things get very interesting very quickly.

As to the amp question: I apologize for a shortcoming, but my practical experience is hopelessly out of date plus, back in the day, I deferred that question to my retailers whose job it was (is) to spend the long hours between customers evaluating amps, wires and preamps and experimenting with various combinations in response to their customers' needs. They do get paid nicely to do that work.

In a smallish room, you'll be close to the speakers so a tight bottomed amp with a forgiving top would be about right.

Happy Days!

 

[Audionut]

I think I hear a suggestion to use a Mcintosh MC240!:

“Swapped in his MC240...well I’ll be dammed....I bought lunch then the Mac”
“A tight bottomed amp with a forgiving top would be about right”

 

[Pat McGinty]

That Mac is certainly nice to have. The Mac guys didn't skimp on the copper in the output transformers and it shows in the sonics.

In the classic tube amp category I'd not overlook the Music Reference RM9; easily the most beautiful sounding tube amp I've had in my pile. The last one I'll part with, too.

The point I was trying to make was that, back then in 1990, I was attempting to voice speakers with flawed amps. A fool's errand. The introduction of my pal's MC240 merely held the problem up in my face in a way that forced me to contend with it. That lesson stuck with me quite firmly. Over the years including recent experience, something like half of the amps that have come across my bench have had shortcomings. I think it's the cut-and-try 'cottage' nature of the business. It's important to seek out gear that is genuinely engineered.

 

[prime minister]

So, Pat, with something like the Shearwaters, would you go with your modern belief of as much power as possible? Say, off the top of my head, because I haven't been following big wattage amps of late, something like the Sunfire Signature 600? 600 watts into 8 ohms and doubling as the resistance drops, with something like 4000 watts into one channel at 1 ohm. Silly good fun!

Now, the Shearwater, as I understand it, is a pretty benign load, so I'd likely never make that Sunfire breathe hard, but is that kind of power an approach you'd recommend or at least favour?

 

[prime minister]

I think that company in Binghamton, NY (with the big blue meters) might still make some moderately powerful amplifiers.

I just don't anymore. I've been running with a crowd that looks on such things with derision and disdain. My choice of running a monstrous 16 watts aside likely makes me questionable company.

 

[mhardy6647]

There's a reason I deleted my post -- I exceeded even my own snark threshold.

This really wasn't the right thread for me to be knocking Big Blue -- or big power, for that matter. This is a good thread with real insight into the design process from a designer. And I really don't want to jeopardize that.

Maybe (in total seriousness) a high power/low power thread is in order.

 

[prime minister]

There's a reason I deleted my post -- I exceeded even my own snark threshold.

This really wasn't the right thread for me to be knocking Big Blue -- or big power, for that matter. This is a good thread with real insight into the design process from a designer. And I really don't want to jeopardize that.

Maybe (in total seriousness) a high power/low power thread is in order.

I like your idea, but around these parts, who'd fight for the high power side?

 

[mhardy6647]

I like your idea, but around these parts, who'd fight for the high power side?

Well - there's a GAS Ampzilla being rehabbed by a hifi colleague of mine... so I may have some data sometime later this spring.

"Spring" is a term that has become increasingly abstract in the northeastern US here of late.

 

[prime minister]

I think there is another part of this discussion that at least I've ignored so far. Apparently, it's not just the power, but also the speed, the response, of the amp that Pat has integrated into his new amps. N'est-ce pas?

 

[prime minister]

Well - there's a GAS Ampzilla being rehabbed by a hifi colleague of mine... so I may have some data sometime later this spring.

"Spring" is a term that has become increasingly abstract in the northeastern US here of late.

View attachment 5583

Spring in Toronto seems a moving target also. It's been darting around of late, showing its face briefly, and then vanishing again.

 

[Audionut]

Spring in Toronto seems a moving target also. It's been darting around of late, showing its face briefly, and then vanishing again.

It could be worse; we are in the 90’s and flirting with 100 degree temps! This is when most out here put away their tube amps and swap in solid state.
Great thread, loving the creative thought process POV.

 

[prime minister]

Just for my understanding, let's pretend, just for a moment, that I'm an idiot.

Pat, if I'm using my 89 db efficient Shearwaters, running at low level, with maybe 80 db peaks, how much power do I really need? Let's say I want to reproduce that scissor snip of Bob's, even at realistic leveks, how much power would the Shearwaters demand? A snip of a pair of scissors is not that loud. I'm guessing your 50¢ toy would be louder.

This is really interesting stuff!