The big, bad hi-fi audio post

Posted on 25 March 2008


(part one of a series, I’m sure…)

Image: Magneplanar 20.1 by Magnepan of White Bear Lake, Minnesota from

…yes, it would be sweet. It’s too bad that the stereo rig above would cost about as much as a new (and loaded) 5 series; add the room treatments and you’re talking more in the range of an M5.

Maybe someday. Until then, I’ve got a big old Harman/Kardon solid state amp driving a nice little set of MMGs that approximate (okay, “very very loosely approximate”) the sound of the setup above–it’s more than enough SPL for the room I’ve got it in, and the room is easily the weakest link in the chain. More on home acoustics in a future post.

Anyway, I’ve never gotten around to building a tube amp for my stereo, but I’d really like to do it someday. I play guitar through either a Pod 2.0 or a Fender Deluxe Reverb reissue that I modified five or six years ago (with NOS RCA 6v6 power tubes, some new Sprague Orange Drop caps and new resistors). It’s no Matchless or Dr. Z, but cranked up above “7,” and run through a 2×12″ cabinet loaded with a Weber Blue Dog and a Silver Bell, it makes power chords kind of sound like three-pack-a-day angels singing the Lacrimosa the morning after an all-night bender.

It’s fantastic, and I want that same vibe with my stereo. Modifying old point-to-point wired tube amps is super easy–all you need is a soldering iron and a solder sucker. Soldering is great fun to do with friends, too, because you never have enough hands to hold all of the caps/resistors/wires, etc. out of the way.

(A brief aside: ever seen Threadless? I’m going to make a t-shirt design of a soldering Shiva playing with vacuum tubes. I hereby declare that idea my own information property. It’s mine!)

Anyway, back to the topic at hand:

  1. Big, quiet, and clean power is a must for Magnepans because of their low efficiency.
  2. Single-ended triode tube power amp designs are an important achievement by our species, akin to high-resolution photography. It shows that we can still value beauty over economy. It’s like the Saturn V or the integrated circuit: Man, sometimes, when we really try, we’re just really good.

So where will I find a potential solution to this problem? With two SET monoblocks, I could live with only 25 watts. Not loud or bassy, but the speakers don’t really do that anyway. For now, I just want the most perfect midrange I can get; I’ve been told that really good bass and treble is expensive. Plus, tubes are pretty. Very pretty.

Enter the 845 power triode:

Yes, the date does read April 15, 1940–apparently we were building glorious-sounding audio devices in 1940. (We were also making beautiful paintings in 1440 and we were composing beautiful oration in 940. We were philosophizing on an epic level in 140 BC. We’re not smarter than the people who came before us, ok? Everyone should be taught in grade school to value things that are old; newer does not always equal better, even in technology.)

Apparently, some people got this lesson. Andrea Ciuffoli must have been one of them; he has designed a single-ended class A 845 schematic and put it online for all to see. It’s way over my head and he uses pricey components, but one day I hope to build something like this. Find more information about his designs here.

For now, I should probably start small by putting together a tube headphone amp better suited for those high-impedance Sennheiser cans that opened my eyes (ears?) when I heard them a couple of years ago. I wish I knew more about electronics so I could just order this stuff and put it together in one night! If I ever get around to starting this project, I will post in detail about it. Promises!

Posted in: Design, Music, Ramblings