Pioneer SPEC-1 Vintage Full Featured Preamp with Phono - Serviced

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An amazing vintage preamp from Pioneer.  

We love the look of this LARGE unit, in particular the size of the knobs and brushed aluminum faceplate. It screams late 1970's!

This is a feature rich preamp packing functions not commonly found on other units. 

There are two tone controls for bass and treble and a switch to bypass them completely. There are a total of five inputs, with an additional gain control for the 2nd turntable input, plus two tape inputs. 

That's right, two phono inputs while many preamps don't even offer one! There's a handy attenuator switch that adjusts the overall gain allowing you to get the most resolution from the volume control. The independent low and high pass filters allow you to tailor your specific setup to protect your amplifier and speakers.

Lastly, this unit features a unique setting giving you the option to feed amplifier speaker outputs though this preamp, and then control them via the front panel selector.  

This unit was carefully reviewed and fully tested by our expert technician. Every function, switch, knob, and connector works as it should. All controls were cleaned and lubricated, and the knobs were removed for a thorough cleaning.  

On our test bench this preamp passed with flying colors and is super quiet. 

Cosmetically it is very clean for its age and looks super sharp. There are a few scratches here and there but nothing substantial and it presents beautifully.

More from Pioneer:

The SPEC-1 has differential amplifier circuitry incorporated in the equalization and tone control amplifiers.

This is complemented by a dual positive and negative power supply system for all amplifier sections, which provides improved DC balance and stability, while eliminating click noises due to switching.

An electronic muting circuit, employing a reed relay, blocks surge noise associated with power switch operation.

SPEC 1 Specifications
Frequency Response:
10 Hz to 70,000 Hz

THD:
0.03%

Input Sensitivity:
2.5mV (mic)
2.5mV (MM)
150mV (line)

Signal to Noise Ratio:
70dB (MM)
90dB (line)

Output:
150mV (line)
2V (Pre out)

Dimensions:
18.90" x 7.34" x 14.37"
(480 x 186.5 x 365mm)

Weight:
24.70 lbs / 11.2kg

Approximate Year:
1976

Click here for a PDF copy of the Owner's Manual

Recommended Cables:

Kimber Kable - RCA Interconnects - Better

Kimber Kable - RCA Interconnects - Best 

Kimber Kable - Phono Interconnects - Better

Kimber Kable - Flagship Tonearm Interconnects - Best

The SkyFi Testing Process for Preamplifiers:

We start with a visual inspection of all internal components to make sure that there are no signs of heat stress or damage. Capacitors are checked for telltale signs of predictive failure including bulging, shrunken wrappers, or physical leakage. We also inspect the PCB’s for discoloration from resistors or transistors that may have been running hot. On vintage units we often spot check select capacitors for value and ESR.

When we first power on a preamplifier we connect its RCA output to a Sencore PA81 Power Analyzer which simulates real world loading conditions and gives us an oscilloscope interface. The first order of business is checking that the volume control works smoothly throughout its entire range with acceptable channel balance. This is accomplished by feeding a 1KHz sine wave into one of the preamp’s line level inputs while monitoring the preamp’s output on an oscilloscope. We then switch to a 1KHz square wave to test the tone controls, loudness function, and filters where applicable. During this step we are watching for equal alteration of the test signal by both channels. This also helps us identify dirty controls that will need treatment. Once the basic line stage functions are verified, we test each input individually. This is especially important for devices that use relays to select their sources. If the preamp is equipped with a phono stage we test that as well. We use an inverse RIAA filter which allows us to feed a reference test signal into the phono input with the proper RIAA equalization and level. A square wave or sine sweep is used to verify that the device’s phono stage is faithfully reproducing the RIAA curve. If the preamp under test has balanced inputs and/or outputs these are tested as well.

We finish up our bench testing with a listening test with our bench amplifier and reference speakers. During this test we check for hum or hiss that may not have shown up in earlier testing. We also check that all of the tone controls and filters perform as expected. If the preamplifier has remote control functions these are also tested. Preamps with tube circuits or complicated power supply topologies are connected at our long term test rig for extended stress testing under real world conditions.