I'm copying this across from the teardown thread - The 1980's was a dire time for the UK mid-market, as the far eastern amps with superb build and measurements were dismissed for 'not sounding good' and home grown products with seriously iffy performance were raved about by the then new wave of subjectivists led by reviewer/engineer/consultant/guru Martin Colloms, who was amongst the first to claim that measurements said little about perceived sound quality while recommending all manner of US made valve confections with diabolical bench performance (I could say loads more looking back but older members here will understand I think). Mr Colloms in print mentioned in speaker tests how much 'better' digital recordings were, yet to my old pal and colleague in the dealer's main store he worked at, he said a Rega 2 turntable 'sounded better' than any digital (this after we were lent a Sony 1610 AD/D-A unit wired in A-D-A mode which sounded identical on its output via a tape loop to the bypassed signal (I was later told any issues with early digital were in the workstations used back then in the days before 10 bit plus mastering, but I'm digressing again.
'Just to refresh our younger readers as to what was thought acceptable forty years ago - an early 80's HiFi Choice test on the UK-revered Naim 32/250 (could have been the small SNAPS preamp supply) had distortion at rated power into 8 ohms as -80dB, and -63dB at 20kHz. IMD (19 + 20kHz) was a mere -69dB. Just think what fun Amir would have tearing into one of these sets fully restored? Modern Naims are around 10 to 15dB better (and in my opinion, 'sound' a bit cleaner for it) according to Stereophile, but still....
Restorer John may remember this, but the same 'Choice book' tested a Pioneer [edit A-44] which measured well with claimed poor sound quality and in another issue, the two Sony ES integrateds (a 500 and 700 I think) sounded poor apparently (loose bass was one criticism). I'm starting to wonder if even by this time, reviewer ego and personal tastes were starting to heavily creep in to the judgements, unless some measurements were being left out. the followup test book left the IMD distortion figures off the reprinted Naim review for example. While I have the HFC 'Issue 50' here, the Io's distant ancestor Naim Nait (15 - 20WPC and now a quite valuable used collector's item) measured distortion at rated power as - 20Hz = -66dB, 1kHz = -72dB and 20kHz = -51dB. IMD at rated power 19/20kHz was -70dB and -52dB at '0dBW' on the phono input (RIAA was all over the place, but intentional I think and worked with the crap cartridges we used to sell back then, all with lf lift and presence suck-outs).
A Creek 4040 which in price is where the Io would be if made back then, was worse. THD ranged from -60dB, -69dB (1kHz) and -51dB at 20kHz and IMD as mentioned above was -57dB and -27dB on the phono stage, not that the latter figure mattered overmuch with the cartridges used as said above.
So, with that kind of UK spiritual ancestry, I honestly think the Io isn't 'bad' at all
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