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Saturday, October 07, 2006

T.O.P. Endorses: PRIMALUNA PROLOGUE ONE

Right, it's not a photographic product, but you can leave it to me to deal with the splattering of e-mails I'll get informing me that the senders a) don't want my opinion on matters non-photographic, b) don't think I can write effectively about matters non-photographic, c) object to non-photographic articles from T.O.P. on their RSS feeds, blah, blah, blah. (I'll just reject and delete them all! MuAAAAhahahaha!)

The best things in life are free, it's said. Such as, say, getting clean with your squeeze, watching your children grow, a long walk on a spectacular Fall day, taking in a sunset while sniffing a rose (which would make me sneeze, but never mind)—that sort of thing. And of course we all have our own preferences. Pleasure for you might be spotting a rare teal-tipped warbeldehoo on a hike in the rain forests of Brazil, or feeling the endorphins let go at mile 20 of a marathon, or re-reading Hume. (Personally, I wish I spoke another language so I could read Hume in translation; for some reason I have real trouble understanding him in English.)

On the list of life's mundane or quotidian pleasures, those that are material are thought to exist on a lower level: a bottle of your favorite libation, a shopping expedition with a recently fattened credit card, an "endless" evening of Texas hold-'em. Doubtless, all of us who tend toward connoisseurship have our own custom-tailored short lists of the material pleasures we favor, too. For me, those include small, light, naturally-aspirated four-cylinder cars with manual transmissions, watching a black-and-white print (sorry, but yes) come up in the developer tray, books, and wierd, wonderful music late at night on a tube amp, at low volume.

I don't actually own a tube amp myself at the moment, and I don't actually recommend a tube amp as your only source of power for music. The crackling rhythmic propulsion and crisper bass of a small British transistor amp generally better serves the '50s jazz I've favored for the past half-dozen years or so (thanks, Scott). (I also decidedly prefer acoustic-suspension speakers, which are essentially not made any more. Most people just plain can't hear bass.) And throughout most of their history, the care and feeding of tube amps has been something akin to keeping a vintage Indian or Triumph running—you know, a process thing. (Ahem.) Not to mention that the little brutes have traditionally represented very poor value for the dollar, euro, or pound.

But those drawbacks have diminished, thanks to the world's newfound relationship with the emerging capitalism of red China. At this historical moment you can buy modernized replicas of classic tube circuits in splendidly solid casework for half to a third of what they go for when they aren't being put together by recently re-energized segments of the Chinese peasantry. Among several available choices, PrimaLuna is first amongst equals. The little ProLogue One, in particular, is both a great little tube amp (which not all cheap tube amps are) and a very inexpensive tube amp (which very few good tube amps are). Inevitable reviewer blather to the contrary, you'll have to choose your speakers carefully; something "tube friendly" (meaning approximately 90dB sensitivity and no less than 6 ohms impedance in the lower frequencies) is indicated.

The sound of tubes is simply glorious, pure, caressing, and uniquely alive; if I didn't know better I'd say it's as good for shedding stress as a back massage. It attenuates you, lifts you up and draws you in. Especially at lower levels, where transistor amps have trouble not sounding dead, distant, and mechanical, tubes let music bloom and breathe.

Unless you're one of those sorry souls consumed by your own mongering after status, in which case I have pity for you but no sympathy, you really don't need more than the little model One. I don't even think it should be your only amp—just an option you should have to switch into your setup when you feel like it. In fact, there is really no justification for owning a tube amp at all...except, of course, for the fact that music reproduced with one in the wee hours of the night is a material pleasure par excellence, one of the good life's little treats.

Posted by: MIKE JOHNSTON

Featured Comment by Mike Potter: Thanks for the post, Mike - I hadn't thought about tube amps in years. But don't leave us hangin'... :-) Now that T.O.P. has endorsed an integrated amp, what about a tuner and CD player to feed it, and speakers for it to drive? PrimLuna sounds like a pretty spiffy amp, particularly for the money.

Mike replies: For a source, I would warmly recommend this, which can be purchased here among (no doubt) other places, and fed from here. Despite being way too cheap for any sort of respect from "audiophools," it's really quite lively and musical and will give a lot of pleasure.

Speakers are quite another matter, as they all tend to do a few things right and many things wrong, and what one person finds charming will leave another cold. I would say I like about one out of every 50 pairs of speakers I hear, and that's knowing my own tastes, and what technical properties correlate to my tastes, quite well. The one thing I can say is that a speaker will sound better with the PrimaLuna if it is easier to drive (sort of analogous to that 1.8 liter 16-valve DOHC Toyota engine coming to life in the Lotus Elise whereas it's downright pedestrian in the much heavier cars Toyota puts it in). What you look for are two specs in particular—sensitivity, which will usually be given in decibels per watt at one meter (dB/w/m, although the notation isn't standardized as far as I can tell), and impedance. Generally speaking, a change of +/ 3 decibels in the sensitivity rating will correspond to a doubling or halving of amplifier power. Take a look at the specs for this speaker just as an example. It's rated at 91 dB/w/m, and the PrimaLuna is rated at 35 watts per channel. To get the same loudness with a speaker rated at 88 dB/w/m would require 70 wpc, and if your speaker has a sensitivity of 85 dB/w/m you would need 140 wpc. (This is why you can see very low-powered SET amps happily making music—they're paired, necessarily, with very high-sensitivity speakers, usually horns. A 5-wpc SET amp paired with a 106-dB/w/m speaker would have the same ability to play loudly as a 160-wpc amp and the 91-dB/w/m speaker linked above.) Complicating all this is the fact that power ratings and sensitivities are measured variously in non-standardized ways, and that other factors come into play in all specific amp/speaker pairings. But sensitivity is a good general indication of driveability.

The other is impedance. A tube amp likes to see a benign load , so look for a speaker with an impedance of 8 ohms. The problem here is that there's no such thing as an "8-ohm speaker" despite the sale lit—the load varies with frequency, and every plot of impedance looks like waves, with highs and lows. So what you want to see is a plot that doesn't dip below, say, 6 ohms in the lower frequencies (the left-hand side of the plot).

In the above plot, for example, note that the impedance dips way down (to 2.8 or so)...but only in the higher frequencies (around 2.2kHz). This particular speaker couldn't honestly be called an 8-ohm speaker, and yet it would be an easier load for an amp than many speakers advertised as 8-ohm that dipped to 5 ohms or less at 50 Hz or below.

An appropriate speaker for a medium-powered push-pull tube amp would have a sensitivity above 90 dB/w/m and an impedance that never drops below 6 ohms, and not below 8 ohms in the lowest frequencies. And, of course, you would have to like the way it sounds (g).

10 Comments:

Blogger Mike C. said...

Oh yes, on various counts. At the risk of starting a silly competitive thread, now all you need is a copy of Blues Dream by Bill Frisell (assuming you don't already; note the George Tice image on the sleeve). Or Angel Song by Kenny Wheeler (featuring, um, Bill Frisell).

4:07 PM  
Blogger stevierose said...

I went through college listening to music through a tube Dynaco amp that I built from a kit put through large Advent speakers. Alas, the Dynaco is long gone but the Advents still live. Sometime in the last decade I was actually able to obtain replacement original acoustic suspension woofers for them. At the moment they are sitting unused in my son's room having been displaced a mere 20 years ago by new speakers for my stereo. My kids all listen to their music on ipods.

5:40 PM  
Blogger Kevin said...

Photography and high-end audio seem to tickle the same funny bone. You get two groups of people having a life-and-death debate over things that make no difference whatsoever to the outside world. Coil or magnet? Xenar or Planar? You can't listen to music without oxygen-free copper cables. If you're not using a Leica, you're not taking pictures. And so forth.

A Telecaster through a good tube amp is still a fab combination. But you know what? The same Tele sounds awful good through a POD (not an iPod!).

I haven't been paying attention lately...is anyone doing software modeling of tube preamps in software? I quit reading the audio mags when they tried to convince me that I needed to spend a few hundred bucks on a power cord.

8:31 PM  
Blogger Mike Johnston said...

I agree, basically...the megabuck wires essentially ended my full participation in the audio hobby. I've had more or less the same stereo for over 10 years now, 5 years on the amp. I actually ditched my tube preamp (a c-j) because it hummed in the new house. Oh well....

--Mike

8:59 PM  
Blogger Dave New said...

Ah, yes, I know what you mean, MJ. I'm looking at a pair of honest-to-god Infinity studio monitors which form the main drivers for my current system. The suspension foam for the bass drivers were 'ate up' a few years ago, and I found a wonderful little shop in Detroit near Grand River and Six Mile that rebuilt the drivers for me for $50 a piece -- the guy rebuilds Peavey amps for the local musicians on the bar circuit. They sound every bit as wonderful as the day I bought them almost thirty years ago...

9:14 PM  
Blogger DP said...

Rave on MJ, rave on....
I just ordered a 100-400L IS and was in a contemplative mood awaiting its arrival mulling over the expense for what is, after all, only a pastime. This was done whilst listening to some 35 year old music through a once rather expensive power supplied pre amp driving some rather plain looking power amps, every note sounding clear, clean and glorious as every note does from a turntable that exists to drag a nude elliptical diamond through a groove in a piece of plastic. The thought crossed my mind that the nude piece of diamond and its associated cantilevers and coils would cost more to replace than any lens I'm ever likely to buy.
The reason that I can buy such lenses may be testimony to the fact that over 30 years the turntable that I agonised over and eventually bought and my old amps and speakers still satisfy, hugely. Hence the need or desire to upgrade does not exist.
Wish I could say the same about my photography!
Although maybe I'm being disingenuos in not attaching any blame for this state to deteriorating hearing and eyesight!!!!!
Rave on, MJ.....

4:56 AM  
Blogger Mike Johnston said...

"Hence the need or desire to upgrade does not exist.
Wish I could say the same about my photography!"

Well, DP, you probably could, if you were using a 35-year-old 8x10 camera and making contact prints....

--Mike

5:34 AM  
Blogger Impasse Lebouis said...

"Despite being way too cheap for any sort of respect from "audiophools"

Sorry Mike, but that's a cheap shot.

I hope that it wasn't meant as a preventive strike against those who might question your choice of a turntable.

BTW, poster Mike Potter asked a recommendation for a...CD player.

Have a nice day.

2:02 PM  
Blogger Mike Johnston said...

"...that's a cheap shot."

It's not my coinage. "Audiophool" (or -fool) is a term that refers to audiophiles who spend for status--that is, who are more comfortable spending more rather than less, and who assume that the more something costs, the better it has to be--regardless of how it sounds. I'm sure the term comes from the old saying "a fool and his money are soon parted."

--Mike

6:21 PM  
Blogger Roger said...

Went to a demo of various Focal speakers last Friday. They top out at about 91db efficiency. Not good enough for my 2 watt/channel SET amp.

So, now, it's all your fault, Mike. I went hit Upscale Audio's web site and ordered a Prologue Five. 36 watts of push-pull KT88 bliss.

Roger

7:48 PM  

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