B. K. Butler Tube Works MosValve MV - 962 MV-962

The Mosvalve MV962 is a stereo solid state power amp made in the late '80s/early '90s to offer a more realistic take on the tube power section in a solid state power section. Tube power amps are great, but are subject to the consistency issue of the air around you and how your ears hear them, whereas solid state gear tends to sound more consistent. They can also be quite heavy when mounted in a rack, which is another selling point for something like this Mosvalve. It's a stereo rig that puts out about 80 watts of power per side. Each side (A and B) has volume and presence controls available. I believe it runs at 8 ohms impedance.

UTILIZATION

Getting a good sound out of this power amp isn't difficult. I'm definitely a fan of the Tube Works gear, and this is no exception. Granted, I do prefer a real tube rig, but for what the MV962 is, it sounds decent. When I had mine I tended to run it about flat as far as the volume and EQ went, and just did my tweaking from my Mesa preamp as far as master volume or tone. One nice selling point for the Tube Works is that it definitely did have a bit of that tubelike compression that you really don't hear often in simulated attempts at tube tones. I hear it in their amps as well which is cool.

SOUNDS

This power amp sounds decent overall. I used it with a Mesa Boogie Studio Preamp (basically Boogie's famed Mark IIC+ head in a preamp) and a cheaper Ibanez Tone Blaster TB412A angled cab with generic Ibanez "Power Jam" speakers. I got the rack rig as a package deal because I wanted to try out rackmount gear and compare it to the nicer heads I'd owned. I was definitely happy enough with the Mosvalve power amp for what it was. It certainly doesn't have the fully tubelike sound that one would get out of something like a VHT/Fryette or Mesa Boogie tube power amp, but for what it was it sounded good. I used it in a band setting for gigs and recordings and it held up really well for reproducing my glassy cleans and thick smooth drive tones accurately

MosValve 962

Operation Notes

This amplifier was designed primarily for musical instrument amplification. It is an addition to your audio rig which will add warmth and definition to your sound.

• Use Mos Valve with any preamp capable of producing 450 MV into a 50K load (Virtually any preamp in existence.)
• Use with speakers or cabinets capable of at least 80 watts RMS continuous power. Re-member that MosValve can typically produce in excess of 100 Watts/channel under typical conditions common on stage today. At least 100 Watt speakers or cabinets are therefore highly recommended if you intend to use the amp at high power output.

This is a stereo power amp. Mono operation is switchable (both channels. input bridged) with the use of single input plugged into Channel A. Stereo operation is automatic when an additional input is plugged into Channel B.

• It is often advisable to use only one channel for mono (for example, if you have only one speaker cabinet), as the Mos Valve can produce over 100 Watts with only one channel driven. Use Channel A and set Channel B controls to "O." NOTE: It will not damage Channel B to have no speaker plugged into it while using only Channel A.
• NEVER attempt to power bridge the two speaker output channels together. NEVER parallel or series them into one speaker or cabinet. If power from both channels is used, ALWAYS use at least two separate speakers (one per channel) or separate speaker cabinets per channel.
• A certain amount of heat during operation is normal. The Mos Valve amplifier is biased in a manner in which even when idling there is some heat present. It is best to keep the ampli-fier towards the bottom of the rack (coolest air) and avoid obstructions to the vents in the case.

Never load the speaker outputs with less than 4 ohm loads. These can be single speake abinets per output or a combination of two cabinets per output.

Examples of cabinet com binations:

Per Channel: One 4 Ohm (or higher) or Two & Ohm (or higher)

TECHNICAL SPECS

OUTPUT POWER — 160 Watts RMS at 4 Ohms (80 watts per channel, both channels driven)

S/N RATIO - Better than 95 dB at 8 Ohms

HUM & NOISE - Better than -65 dBv at 8 Ohms (No input with controls at maximum)

SENSITIVITY - (For Rated Output): 450 MV (-5 dBv)

INPUT IMPEDANCE — 50 K Ohms

PRESENCE CONTROL — +/- 8 dB at 10 KHZ (I 6 dB range)

MAX POWER CONSUMPTION - 120 VAC, 400

Watts (220-240 VAC, 50/60 HZ: 200 Watts)

COOLING SYSTEM — Constant-turbulence internal fan

SHORT-CIRCUIT PROTECTION - Inherent to the design, thermal runaway-proof

SIZE — 3 1/2" H x 19" W x 7" D (Standard 2-space rackmount format)

(D = behind front panel)

OVERALL DEPTH — 8 1/2"

WEIGHT - 13 Lbs.