Description: Tubed/JFET, two-chassis phono preamplifier. Tube complement: one 6922, two 7044.
Dimensions: 19" W x 4.125"H x 18"D (allow an additional 6" depth for PSU umbilical cord projecting out in the center) (Steelhead); 13.5"W x 4.625"H x 12.5"D (allow an additional 6" depth for PSU umbilical cord projecting out in the left) (power supply). Weight: 19 lbs (Steelhead); 18 lbs (power supply).
Price: $7300. Approximate number of dealers: 25.
Manufacturer: Manley Laboratories, Inc., 13880 Magnolia Ave., Chino, CA 91719. Tel: (909) 627-4256. Fax: (909…
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Sidebar 1: Specifications
Not only does the venerable vacuum tube refuse to lie down and die, as everyone predicted when audio went solid-state; it continues to deliver better performance than anyone had imagined it could. Only a few years ago, we could characterize "the tube sound" as being sweet but soft at the high end, rich but loose in the midbass, deficient in deep bass, and bright and forward, usually with excellent reproduction of depth. Since then, we've seen the introduction of what might almost be called a new generation of tube amplifiers, which rival solid-state units in those areas where tubes used to…
The output transformer is claimed to be an Ultralinear type, à la Hafler and Keroes, but it isn't really. The original patent for the Ultralinear circuit specified that the screen tap be at a point on the transformer primary 43% of the distance from the center tap to the anode end. VTL found that a somewhat different tap-off point worked better with their tubes under their operating conditions, and used that (proprietary) value instead, but in view of the change, the transformer should perhaps be called, simply, a tapped-primary type. Nit-picking, to be sure, but that's what high-end audio…
Sound
So, what does the 300 sound like? Not much. It seems to have very little sound of its own, which is (or should be) what we're all looking for in an amplifier, so its sound is very hard to describe. Adjectives like "sweet" and "open" and "detailed" and "solid" lose a lot of their meaning when applied to sound that is just as musically right as that from the VTLs.
So, what does the 300 sound like? Not much. It seems to have very little sound of its own, which is (or should be) what we're all looking for in an amplifier, so its sound is very hard to describe. Adjectives like "sweet" and "open" and "detailed" and "solid" lose a lot of their meaning when applied to sound that is just as musically right as that from the VTLs.
I've explained before in these pages why it is impossible to determine how neutral or uncolored a power amplifier is, so I won't repeat myself here. Suffice it to say that bypass or Hafler-style cancellation tests have…
Russ Novak wrote about the MB300 in its MB450 incarnation in July 1996 (Vol.19 No.7):
The tubed VTL MB300 monoblocks mated so well with the Acarian Alón V loudspeaker that I wanted to reacquaint Stereophile readers with them, and comment on developments since J. Gordon Holt first reviewed the amplifier in October 1988 (Vol.11 No.10).
Though the sweet, liquid, holographic quality of triode tube operation has often been written about, it remains difficult to describe unless you've lived with it in your own system. It's...seductive. Detail is presented in a casual, graceful manner…
Michael Fremer compared the VTL with the Conrad-Johnson Premier Twelve in February 1999 (Vol.22 No.2):
Whenever I switched to the Conrad-Johnson Premier Twelves from the far more powerful VTL MB450s, I never felt as if I was losing dynamics, authority, or control. In fact, the C-Js sounded faster, tighter, and punchier overall, particularly on the bottom—like bouncing a quarter on a bed made with hospital corners instead of one whose sheets have merely been tucked in. The Twelves elicited the best bass I've gotten from the Audio Physic Virgo speakers.
The VTLs created a bigger…
The sheet-metal rear panel is no longer flat, but angled up to make hookup more convenient. VTL still uses odd, 3/8" hex-capped binding posts, which means you can't attach the speaker cables using either Dynaclear's safe and convenient Postman or AudioQuest's knockoff of same.
While setting the bias is less convenient without the built-in meter, it's still relatively easy (once you remove the cage) using an inexpensive RadioShack digital meter, a plastic-shafted or insulated flat-blade screwdriver, and the well-written instructions. During the year or so I had the 450s in and out of my…
Chip Stern wrote about the MB450 Signature in October 2002 (Vol.25 No.10):
This Signature update of Vacuum Tube Logic's MB450 monoblock features a fully balanced input stage, remote voltage turn-on trigger, revised bias points and trim pots, new ground-loop circuitry, and a hair-trigger, fast-blow fuse for the B+ power rail, which (as I can attest to from several blown fuses) prevents a bad tube or a serious power anomaly from frying your circuits. Topping things off are a set of sophisticated new Multicaps in the signal path and to come, a pair of external-current inrush limiters, each…
Paul Bolin wrote about the MB-450 Signature in April 2004 (Vol.27 No.4):
Since Chip Stern's update on VTL's second-generation MB-450 Signature back in October 2002, the amplifier has undergone further changes and improvements. It now features a completely redesigned input stage that incorporates advances made during the development of VTL's mighty Siegfried monoblocks. The '450 now has a true balanced input stage, the asserted benefit being superior common-mode noise rejection without the use of an input coupling transformer. Despite these improvements, the MB-450's price remains unchanged…
Sidebar: Specifications
Description: Tubed monoblock power amplifier. Rated power: 300W (no load specified). Power bandwidth: not specified. Frequency response: not specified. Sensitivity: 775mV RMS. Source impedance: 0.1 ohm.
Dimensions: 19" W by 10" H by 10" D. Weight: 75 lbs each.
Price: $4900/pair (1988); $6990/pair (1996); $9000/pair (2002).
Manufacturer: Vacuum Tube Logic of America, 4774 Murietta Street, Suite 10, Chino, CA 91710. Tel: (909) 627-5944. Fax: (909) 627-6988. Web: www.vtl.com.