Tube Power Amp Reviews

Aside from the changes detailed above, the new Panor/Dynaco amp is clearly a Stereo 70 clone; the two pairs of EL34 output tubes driven in Ultralinear mode, centrally mounted power transformer flanked by the two smaller output transformers, and front-mounted input RCA jacks all duplicate the classic Dyna look. Located on the rear of the 70 II are four single 5-way binding posts per channel for ground, plus 4-, 8-, and 16-ohm output transformer taps. Potential modifiers take note: while the original Dyna's entire audio circuit was exposed on the top of the chassis for easy access, the Panor amp's PC board is hidden inside, making it very difficult to shuttle parts in and out, as with the original. Modkateers looking to play around with a 70 should try to find one of the older amps; the new Stereo 70 II doesn't lend itself to modifications as easily as its forebear.

Build quality overall is very good, with better caps and resistors than the original Dynas but not quite on the level of the Wima and Rel caps and Resista metal-film resistors found in many modern high-end amps. Panor sent me both the $995 flat-black and $1095 chrome-plated chassis versions, and I strongly advise you to spring the extra 100 clams for the chrome; not only does it more closely resemble the Dynacos of old, but the flat-black version looks like something the A-V geeks used to wheel into your classroom whenever it was time for another lights-out viewing of The Dung Beetle: Nature's Unsung Hero.

Sound
I remember well my first taste of tube sound. It was a pair of restored Dynaco Mk.III KT88 monoblocks, 60W apiece and sweet as you please, and they made what I thought was a pretty decent solid-state amp I'd enjoyed for years sound like a bad trip. The restored Dynacos were a revelation, and I've been hooked on tubes ever since—so much so that I bought a vintage Stereo 70 from Angela Instruments (footnote 1) and rebuilt it with good caps, resistors, and a beefier power supply with 1N4007 rectifier diodes and larger high-voltage caps. Seeing as how I had the "new" Stereo 70 for review, I hauled out my restored Dyna and retubed it with a quartet of the excellent Czechoslovakian "Tesla" brand EL34s distributed by VTL so I could compare Panor's new version to an original, albeit redesigned Dyna.

The original Stereo 70's sound was "classic tube": mellow on top with almost no definition in the bass, but with a midrange clarity that's kept it a popular amp 30 years after its birth (footnote 2). Larry "Ramone" Archibald calls amps like the 70 "low-resolution" designs, but while the classic Dyna can't quite deliver the finesse and honesty of the best modern tube amps, it still sounds musical and enjoyable. And that's just what I got from the new Dynaco Stereo 70 II. An ultimate high-end amplifier I wouldn't call it, but the new Dyna offered up a good chunk of the classic Dynaco tube sound: not really in the league of the best modern tube amps from Audio Research, VTL, etc., but plenty pleasing nonetheless.

Comparing the new Dyna with my rebuilt "original," I heard two immediate differences. First, the Stereo 70 II sounded much thinner than the oldster, with a weaker bottom end. Tommy Shannon's E-flat-tuned Fender Jazz bass on Stevie Ray Vaughan's "Tin Pan Alley" (Couldn't Stand the Weather, Epic LP FE-39304) lacked the full, pulsing weight that usually drives the minor-chord changes. This wasn't a case of a better-controlled low end than the older 70; the new Dyna's low end wasn't as rich in either quality or quantity as my 70, but splitting hairs over the bass performance of two 35W tube amps is like arguing over which of the Golden Girls has the best gams; if you're looking for tight, powerful bass, a low-power tube amp isn't your ticket to Happyville.

The second major difference I heard was the 70 II's slightly reduced sense of speed from the lower midrange on up. It sounded somewhat slower and less transparent than the other amps I had to hand, with less of a sense of ambient space, depth in particular. The acoustic ensemble on Lyle Lovett's cover of the Dead's "Friend of the Devil" (Deadicated, Arista ARCD 8669) sounded as though the musicians were bunched closer together in a smaller room. The distinction between Lyle's voice and the slap echo off the studio wall wasn't as clear as with the older Dyna, or with a modern tube amp like the VTL Deluxe 225. I wasn't sure what to pin this on, but I have a hunch it might be the 0.018µF coupling caps on the 70 II's inputs; while these were better than the low-rent caps in the original Dynacos, they didn't look like they had the stuff of the typical Wima, Rel, and Wonder caps used in most modern high-end gear. It's also probable that with a low-frequency -3dB corner of just 19Hz, these teensy coupling caps were also responsible for the reduced bass weight.

The new Dynaco Stereo 70 II is a nice, musical little amplifier, but a "giant-killer" it isn't; showdowns with the VTL 225s were not very favorable, in any possible dimension. What the new Dyna is is a very good reissue of a classic tube amp, with excellent build quality and pleasant, easy sonics. The new 70 isn't exactly the kilobuck best-buy I was looking for, but it's nice to see a bona fide audio classic reproduced with care and quality.

Conclusion
In spite of my criticisms of the Panor/Dynaco, I should point out that this amp will kill most of the sub-$1000 mid-fi solid-state dreck out there; it's not the greatest amp for the money, but it is a well-designed tube amp, and that alone will ensure more long-term listening pleasure than a lot of the budget solid-state amps.

That said, I can't really recommend the Panor. You can find good-working vintage Stereo 70s on the used market for $200, and the new 70 II just doesn't offer a grand's worth of sonic improvement. There's enough excellent gear for a cool thou, both tube and solid-state, that the 70 II doesn't keep pace with. If this amp sold for $600, I'd say buy it even if you don't need it, but while the 70 II is a nice little amp, your $1000-$1100 can ultimately buy better sound.

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Footnote 1: Angela Instruments, 8600 Foundry St., Savage, MD 20763, (301) 725-0451. The self-described "bad motor scooter" of used Dyna gear, Angela's Steve Melkisethian usually has around 30 working, rebuilt Stereo 70s on hand, with prices hinging on how much toiling Steve has to do to get them back in good working shape. Five clams gets you Angela's infamous catalog, a treasure trove of old hi-fi and music gear and a bona fide piece of American subfolklore.—Corey Greenberg

Footnote 2: When I visited Reference Recordings' Jan Mancuso and her husband Ric of Monster Cable in San Francisco after The Case of the Raging Tweeters (see Stereophile Vol.15 No.3, March 1992, p.156), I heard some mighty nice sounds coming out of their reference system: an old Stereo 70 driving LS3/5as. Loud it wasn't, but it delivered the goods. And how.—Corey Greenberg