The guy is right, and the same still applies in 2014. I used to have one of his firm's AVI preamps, it cost £700 20 years ago but it was genuinely worth it because it had innovative circuitry, was genuinely 'state of the art' (overworked term) and sounded amazing with other good quality gear. And it was a lot cheaper than other similar units from other manufacturers.
But the level of bullsh*t in hi-fi is truly staggering ad there are always plenty of people with more money than sense.
The basic maxim ALWAYS applies in hi-fi: if you can hear a difference, is it an improvement? And if so, can you justify the extra cost of that improvement? The law of diminishing returns is true enough too, as you go 'up the scale' you have to spend more and more for smaller improvements. But if you can't hear if something is better, then it isn't.
bullsh*t is normally with cables and interconnects. I bought some very nice (and very expensive) ATC active studio monitors for my set up, at the time of the AVI unit. I spent ages listening to them and comparing them with other speakers, on different programme material, before I bought them.
I was bemused by the dazzling array of 'quality interconnects' to go from my pre-amp to the speakers, so I phoned up ATC to ask them what they thought. They guy on the other end was quite amused and told me to go to my local Maplin and buy plain Belden mic cable, just a simple twisted pair with a foil shield, and solder on some XLR plugs myself. Just out of interest, I borrowed some other interconnects from the shop where I bought the speakers, to compare. The leads I made up came to about £15 the pair, including professional XLR's (the cable was a fiver). The others from the shop were about £70 and £100. The £70 stuff sounded no different, but the £100 stuff was appalling because it had such a strange capacitance that it loaded the signal and took off loads of the HF.
PS - the firm is AVI
, not HFI