VPI Turntables is one of the most dependable brand names when it comes to high-end audio systems. For years the brand has been recognized by audiophiles throughout the world as equipment that delivers clear and consistent quality in music.

What are the specs for the PLC - Power Line Conditioner?

Nominal Speeds:
33 and 45 RPM
Distortion (115VAC output):
Pitch Control:
+/- 5Hz (33 RPM) +/- 7.5 Hz (45 RPM)
Output Imdedance:
143 Ohms (10W)
Reduced Voltage:
Rear Panel 100-60% (140VAC to 84VAC)
Turntable Connection:
NEMA 1-15 socket on back panel 120VAC
120VAC 1A input
9"W x 6"D x 2"H
6.25 lbs.

What else to know about the PLC - Power Line Conditioner?

**Overview**\ The VPI Power Line Conditioner (PLC) has two distinct models. The early version had continuously variable dials for each speed (33/45 RPM). The dials controlled a digital oscillator that produced the 60Hz or 81Hz square wave signal for the motor. The oscillator signal fed a 4049 inverter that created 2 out of phase square wave signals that drove a bipolar output amp connected to a step up transformer to create the high voltage supply for the motor. There is a front panel rocker switch to turn the unit on/off and a slide switch to select 33/45 RPM.\ \ The design is similar to the early power inverters that boosted a car battery up to 120VAC to power drills, soldering irons etc. One of the problems with this type of circuit is the output is a modified square wave rather than a sine wave so the motor will run hotter and noisier; if measured with an RMS voltmeter the 120VAC output actually reads closer to 140VAC.\ \ The PLC is powered by a 120VAC direct input and the PSU has one output for 120VAC motors. There is a rear adjustment for the output voltage on some of the newer units that allows for reduction of the output voltage by 40%; the control adjusts the output voltage for both speeds. The PLC does not work with 50Hz motors.\ \ **Circuit Description**\ The PLC uses a variable frequency oscillator to create the 60Hz/81Hz square wave signal. The signal is split into 2 phases by the 4049 inverter and drives the output transistors 2N3904/2N3055 in a quasi-darlington push-pull configuration. The output of the push pull amp is directly coupled to the low voltage windings of a 26VAC IE construction transformer. The output of the transformer is the HV windings and provides 120VAC to the output connector.\ \ **Measurements**\ The output frequency at 33.3 RPM (dial centered) measured 58.3 Hz and 83.6 Hz at 45 RPM (dial centered). Adjustment range of the speed was ~ +/- 5Hz for 33 RPM and +/- 7.5 Hz for 45 RPM. No load voltage at the 120VAC output was 143 VAC; the output dropped to 136 VAC at 5W, and 131 VAC at 10W. The output waveform is a ringing squarewave with severe distortion.

Brief History of VPI Turntables

Other VPI Turntables Products We Often Buy

Typically, StereoBuyers purchases mostly used amplifiers, especially the vintage amps and high-end VPI Turntables models.

StereoBuyers has purchased tens of thousands worth VPI Turntables brand equipment since 2014, with individual buys ranging from $100 to well over $50,000. If you are moving, ready to upgrade, or have VPI Turntables equipment you do not or will not be using, why not contact us today to find out if it is worth good money?

If you are interested in selling your used VPI Turntables equipment to us in the greater NYC area or Colorado, please click here to fill out a Free Quote Form and we will get back to you. If we agree on terms, we come to meet you where you want, and pay cash.

The following images show actual VPI Turntables equipment purchased by StereoBuyers.