Music, Audio, and Other Illnesses

Hitting Bottom

Mark Malboeuf, alias badbeef, asked me to comment on a thread in the PS Audio forums about PS’ AN-series speakers in development, and as I thought about it, I realized I had too much to say for a comment. So…

First there was the mighty Ampeg SVT, one of the first two high-powered and very large bass amps — the SVT was tube, and the Acoustic 360, solid state. Both were equally interesting and equally unprecedented.

The 360 was, like the Les Paul Amplifier of the same era, a preamp and a powered cabinet. I have no idea where or why this idea came into being. People were trying things. It was a good idea, brought only partly into being. The 300-watt cabinet was huge, deep, and contained an 18” driver in a folder horn. So automatically it gave a deep but woofy sound.

The SVT was allegedly developed for the Rolling Stones’ fall 1969 tour of the US, famously documented on the incredible bootleg LiveR Than You’ll Ever Be and the subsequent “legitimate” release Get Your Ya-Yas Out! It…  was, to my mind, a 97-lb. fuzzbox. You can turn it up to 4 — or about 11 o’clock — cleanly, and from there on it would start to saturate, and rather than increasing volume, you would just be increasing distortion. No headroom. But: the speaker cabinet: THAT Ampeg got right.

The Ampeg SVT cabinet that they got right.

As Mark said in the discussion, it was an 8 by 10” configuration, arranged in 4 pairs, the boundaries of the cabinet only slightly larger than the speakers. Internally it’s baffled by pairs as well, so it’s sort of 4 cabs stacked one on top of the other. Initially it was a relatively shallow large box; later versions were a bit deeper and added upper handles and lower casters. And holy cow, did it work! (Within reason.) The smaller drivers (as opposed to the more common 15” or 12” drivers) gave better highs, and combing that many speakers gave a large front of oomph!

And this is where we connect with the high-end: the first time I sat in front of the IRS V, at Harry Pearson’s back in the Pleistocene era, and he played me a track by Yello, I felt the bass drum walloping me in the chest, though I was about 10 feet from the woofer towers. It was actually kind of incredible. And though he had the two columns of 6 12” inch drivers separated by some distance, I felt like I was sitting directly in front of the SVT of god. It’s hard to convey that sense of sheer wallop if you’ve never felt it. The SVT can likewise really punch you in the gut. It’s very definitely a feeling.

My own SVT is, first of all, only the cabinet — I don’t need an overly- heavy, medium-powered amp that distorts when you try to turn it up. And it’s the original, flat-back version (its road case is one of my favorite pieces of gear, a beautiful sea-foam green). I got it 35 years ago, but in 1989 George Cardas and I modified it. Though it always had a 4-pin XLR input, only two of the pins were used. Those wires went to a terminal strip which distributed the signal into one of the interior boxes, to the drivers therein, and then onto to another box, and so on to the other three boxes, each of which had its own terminal strip. George and I removed the internal wire and the terminal strips, and replaced it with his wire, all eight drivers wired directly to all four pins of the XLR.

The first album I did with the rewired cabinet was Jon Hassell’s City: Works of Fiction, so you can judge for yourself whether the resulting sound was good or not. On that album I drove it with my hot-rodded SWR SM-400 amp, a hybrid 500-watt amp that one person can carry.  If I were still using the cab, I would use it in an SVT-of-God configuration with the prototype of the Wolcott Presence amplifier, a 250-watt amp with a ton of overhead and intended for high-end audio usage, with eight EL-34 tubes in an auto-bias arrangement. I can select from a range of different preamps, but most often, I went with something built by my friend Bill Sundt, modeled on the SVT’s front end. I even have a Volvo V70 for driving it around. But it hasn’t been out of storage, cabinet or amp or stacks of preamps, in 15 years.

The mighty Wolcott Presence. Still made!

For medium sized gigs, I have a cabinet that gets quite a bit of usage and was, though briefly made, a really brilliant design. It’s called, stupidly, Henry the 8×8. But it really works (as long as the horn tweeter is shut off). Though capable of bottoming out, which the SVT isn’t, it also is capable of quite a bit more low-end and is a lot shorter (and a bit deeper). But again, quite a bit shorter, and I can wrangle it into the old Volvo by myself. It doesn’t have quite the crunch and wallop, but has a more natural low end.

It’s downside is the presence of that bullet-horn tweeter.  20-odd years ago, as SWR was getting off the ground, I took one of my Thiel 03As out to the SWR shop and played through it for Steve Rabe, whose company it was. “You hear the natural top end? I want that.”

I didn’t get that — I got a bullet tweeter, and now they’re hard to avoid. But fortunately, on the Henry cabinet, there’s a volume control for the tweeter, and it’s always turned down.

Best laid plans….

[Lest you wonder about the header pick…er, pic—a Crafsman adjustable wrench is Dan’s preferred pick for the bass—Ed.]