Home/Amplifier /Audio Innovations Series 700

Amplifier Audio Innovations Series 700 review

Archaic valve amplifiers have long been partnered with modern digital gear to good effect. This works particularly well as, on the whole, glowing bottles are better able to deal with the RF interference generated by CD players than their transistorised counterparts. So what, in this day and age, could be more appropriate than a line-only valve amp?

In practice the Series 700 is a derivative of the Series 500, sharing the same wacko styling of enclosed mains and output transformers with a semi-circle of valves exposed to the front. Therefore, handle with care and store well away from inquisitive little fingers.

The Series 700 also matches the 500’s pricetag but has sacrificed the vinyl disc stage to concentrate on improvements in the execution of the power amp. Separate ECC83 drivers and phase-splitters are employed, just as the two ‘phases’ are level-matched, in order to keep distortion in hand.

Add to this an ECC82 double-triode and EL34 pentode output stage (in the classic ultralinear configuration) and you’ve got the measure of this intriguing amp.

Sound quality

An understated and graceful sounding amplifier ‘oozing both pedigree and class’, according to our panel. A wealth of atmospheric detail now surrounded the jazz sax, just as the accompanying cymbals stood out clearly without appearing bright. Furthermore, during the bass solo the pianist could now be heard ‘twiddling his thumbs and striking the odd key in the background’.

Subtle and ambient distractions of this nature ensured the Series 700was consistently entertaining. Tonally it was judged neutral, indeed the piano from Prokofiev’s Romeo and Juliet sounded as rich, vivid and natural as we could have wished. More importantly these complex recordings were now mercifully free of the congestion that had plagued lesser amps.

Our listeners’ applause continued in a similar vein through the Jennifer Warnes track where the resonance of her bass guitar acquired an almost ‘elastic’ quality. Switching from the 4ohm to the 8ohm tap brought about a general softening, however, whereupon both the bass line and male harmonies were described as ‘splodgy’.


Midnight oil still needs to be burned on technical and safety grounds, yet Audio Innovations has succeeded in maintaining its reputation for fine sound quality. Just stick with very sensitive, easy going loudspeakers and the Series 700 will provide rich rewards with music that’s clean, nimble and utterly charming.

Copyright © 2013-2022 audio-reviews.com