Pioneer did not traditionally build separate power amps, choosing instead to build a great line of integrated amps.  But when Pioneer did build power amps, they were among the best in the world.  There were four amps of note: the very rare M-22 and M-25, and the long-lived SPEC-2 and SPEC-4.

SPEC-2 Power Amp

The SPEC-2 Power Amplifier was introduced by Pioneer in 1975.  It was an unprecedented assault against the great names of Marantz, Phase Linear, and others who manufactured audiophile quality amplifiers which could serve double duty in the recording studio.  And the SPEC-2 had the power to do the job.  It was rated at 250 watts per channel.  It was ruggedly built for mounting in equipment racks with massive handles to assist in installation.  It could also be left right out in the open on top of a table or other piece of furniture. 

The big twin VU meters allowed listeners to see the power output per channel in watts.  The level for left and right channel could be adjusted separately with the knobs on the front.  All these features, not to mention the build quality and subsequent sound, made the SPEC-2 a popular choice with recording studios as well as home audiophiles with an unquenchable desire for power--stereo power, that is. 

 In fact, this amplifier was so successful in the market, it remained in production for six years, right through 1980.  And this despite the fact it was the most expensive component in Pioneer's entire line of stereo equipment.  In 1975 it had a list price of $900.00, but rose to $995.00 in 1979.  It was designed for rack mounting in 19-inch equipment racks, and measured 7.25 inches high and 17.50 inches deep.  It weighed 54 pounds.  These amps are still highly sought after today, which speaks volumes about how well they were engineered and built.

SPEC-4 Power Amp

Pioneer introduced the SPEC-4 power amplifier in 1977.  It had less power output per channel than the SPEC-2, but 150 watts per channel was usually sufficient for practically any home audio requirement.  With this came a lower price tag of $700.00.  The SPEC-4 actually had lower total harmonic distortion and lower intermodulation distortion than its more expensive brother.  The dimensions and weight were identical to the SPEC-2.  Pioneer chose to lay out the front panel of the SPEC-4 differently from the SPEC-2 to avoid confusion with buyers.

On the SPEC-4, the level control knobs were next to each VU power meter.  The power switch was in the identical location, and this amp also had the hefty rack handles to help move its 54 pounds of weight.  The SPEC-4, like the SPEC-2, was an example of the finest audio engineering Pioneer was capable of.  They were so well designed that Pioneer saw no need to make any changes or "improvements."  There was no need; in fact, there was little Pioneer could do to improve upon them.  That being the case, this popular amplifier remained in production through 1980, and is sought after by audiophiles and Pioneer component collectors today.