Yamaha B-1 - Rare VFET "Monster" Amplifier With VU Meter Module

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Whenever we get a piece of gear featured on thevintageknob.com, we *immediately* know it's something special.

That was the case with this rare Yamaha B-1 amplifier.

Here's a bit from their page:
Awe-inspiring, unbelievable sound, magnificent design - a true landmark.

Filled with 4 of Yamaha's 1st generation V-FET power devices : 2SK77, enclosed in bigger-than-TO3 cases.

Unlike the later [Yamaha] B-2 or Sony's units, the B-1 doesn't use complementary pairs of devices, giving a more complex pre-driver circuit but making it easier to find matching devices.

[This was] Also available very briefly at the very end of the production run for a couple of markets in very very low numbers in silver color.

Complemented by the optional UC-1 controller which ads some fairly non-useful features like the ability to switch five pairs of loudspeakers at a distance or huge VU meters.

Never mind the meters - just plug the amp and enjoy!

This rare Yamaha B-1 will ship to you with a power cord, meter bridge, and a second smaller silver faceplate which allows use of the amp without the meter bridge (see our later photos).

Each "faceplate module" securely plugs into the front of the amplifier which is pretty unique by itself for any HiFi gear, let alone vintage.

*Note the Yamaha RU-I cord shown in the manual is not included as this was not provided to us originally and looks to have been an optional accessory originally. This cord  is *not* required for operation. 

Click below to add our recommended matching cables from Kimber Kable, all brand new as SkyFi is an official Kimber dealer.

Kimber Kable - RCA Interconnects

Kimber Kable - Speaker Cables

Kimber Kable - Power Cords

Click on the following links or see our last photos for full specs:

Yamaha B-1 Amplifier + UC-I Module - Original Sales Brochure

Yamaha B-1 Amplifier + UC-I Module - Owner's Manual

(The Following Description borrowed from Stereonet):
The B-1 was Yamahas foray into cost-no-object concept building and remains the most powerful Vfet amp commercially made. Rated at 160 watts per channel but independently tested in the 70's by Bascom King to deliver somewhere near 220. Considering this is a solid state triode amp, thats some serious power!
 
Comes with the small face plate for "basic" operation as well, meaning only one set of output terminals are active rather than the 5 you get with the UC-1 controller in play. Inbuilt defeatable rumble filter as well which may be a handy feature.  

The SkyFi Testing Process for Solid State Amplifiers:
We start with a visual inspection of all internal components to make sure there are no signs of stress or aging. Capacitors are checked for telltale sings of bulging or leaking, resistors are checked for signs of overheating or cracking, and transistors are checked for signs of stress or damage.

We then power up the unit carefully and run a simple 1k sine wave while monitoring the output on an oscilloscope for signs of distortion or noise. Finally, we run the amplifier to its full rated power into the appropriate resistive load provided by our Sencore amplifier tester. If there is an issue, it will usually be noticeable at this point. If everything reads clean, we will often test for THD (Total Harmonic Distortion) measured by our Keithley distortion meter, and compare it against the original manufacturers specifications. The amplifier then remains powered on to "burn in" on our test bench for a few hours to make sure there are no heat related issues. If there are balanced inputs available they will be also be tested.

Final testing involves pushing actual music thorough the amplifier. We've learned over time that some issues are only noticeable to a trained ear while listening to familiar source material. Our test bench has reference vintage KEF speakers that we're very familiar with which quickly reveal any discrepancies. Some amplifiers will then move into our listening room where they are tested with our in-house reference speakers of choice.