Yamaha C-1 Vfet preamplifier - fully restored

Offered for sale a very special Yamaha C-1 Vfet preamplifier that has been completely restored back to prime working condition. This is an opportunity to own one of the most unique preamplifiers without the concerns of repair and need for maintenance for years to come.

C-1 is the only Vfet preamplifier ever built, with specific transistors designed and only used for the C-1. Arguably, more R&D development went into the C-1 than most 99.99% of any preamplifiers ever built.

Finding these statement pieces is generally difficult. Finding one that is fully restored, it is nearly impossible. The restoration is difficult and not many people work on them. This was my realization when I started building my Vfet collection and that is why I am now specialized in restoring my own Vfet units. The "Vfet sound" can be quite addictive and I now have a large collection of Vfet units. I very rarely take on the restoration of other people’s units, but occasionally I might sale some of the duplicates in my collection, as it is the case with this beautiful C-1.

Once rebuilt, the C-1 is a solid and fantastic sounding performer. Yes it's many bells an whistles make it the antithesis of wire-with-gain, but the many options could come in quite handy if you need to tame a not so well prepared listening space, or a lacking source, all without the need of a DSP or other fancy digital equalization. The many analog bells and whistles can also be defeated for those who favor a straight through audio signal path, and I can tell you that the line stage of C-1 is superb and exceedingly difficult to mach.

This unit has some signs of use and some scratches, but otherwise the unit is in really good cosmetic condition and in perfect working condition. Please judge cosmetics based on the included photos and please ask for additional photos if needed.

As far as the restoration, this is not a typical recap and Deoxit cleaning of the pots and switches. The intent of the restoration is to reset the age clock and give this piece of audio history a new life. The associate effort required for this level of restoration far surpasses most of anything a typical corner shop would ever engage on.

Restoration summary below:

• Unit fully disassembled and cleaned throughout
• All PCBs old glue and flux cleaned; new flux cleaned after installing the new components.
• All switches and pots, fully disassembled, cleaned, re-lubed, individually bench tested.
• All ill-fated transistors replaced
• All components with tarnished legs replaced
• All electrolytic capacitors replaced with function appropriate replacements (i.e. audio caps for the audio boards, long life, high temp rated caps for the PSU, etc..)
• Any original board-scorching power resistors, replaced and lifted off the boards
• VU-meter lamps converted to LED. This yields substantial less heat than the original incandescent lamps.
• ALL PSU components replaced. The lifeline of the ultra rare transistors in this unit, is a rock solid PSU. This is why I replaced everything in the PSU with much better components than the original components (e.g. electrolytic caps rated @ 105deg replaced the old and tired caps rated at 85deg.; Metal film 1% @50ppm replaced the old 1/4w carbon film 10% resistors; aluminum heatsinks raised off the board, etc).
• ALL service bulletins implemented.
• Removed the factory power cord and installed a power plug to expend the choices for a power cord.
• Unit bench tested and fully adjusted to factory specifications
• Unit tested (all functions) for over 2-weeks in my personal listening space

All in all, a few hundred components replaced, all factory service bulletins implemented, and any potential points of failure mitigated. This C-1 is now bullet proof and has a new lease in life, without the need of maintenance for many years to come.

Specifications

Frequency response:
5Hz to 100kHz

Total harmonic
distortion: 0.02% (Actual THD of this unit after restoration is less than 0.01% - see attached photos)

Input sensitivity: 2mV
(mic), 2mV (MM), 150mV (line) ( NO MC option with C-1)

Signal to noise ratio:
60dB (mic), 70dB (MM), 90dB (line)

Output: 150mV (line),
0.775V (Pre out), 7.75V (Pre out Max)

Semiconductors: 110 x FET, 143 x transistors, 2 x zener diodes, 58 x diodes, 4 x IC, 6 x LED

Dimensions: 18 inches x 16 inches x 6 inches

Weight: 38 pounds

Year: 1976

This unit was originally sold in Japan and the rear panel showed 100v, but it is now internally converted to 117v (factory transformer primaries allow for 100v-117v conversion). The rear panel now reflects the 117v conversion.

Only the unit and a generic power cord are included in the sale.

CONUS shipping is included. International buyers would have to cover the full international shipping cost.

Local pickup is encouraged, and an audition / demo is available for your convenience if you come to pick-up in person.

Note: please see my other listing for a great matching amplifier. You can also view listings of my prior C-1 listing on this forum.

Best,

Peter