Purchased this cartridge on Audiogon a few months ago and have put a few hours on it. It is a superb sounding cartridge, among the best I have owned. But it's not a good fit for my present analog rig, just not enough output for my present phono preamplifier. And I have found it is very hard to setup. Don't buy this if your arm doesn't have a lot of adjustment, or if you're not experienced in twiddling and tweaking high-end cartridges. I am just being honest here, I have spent hours on fine adjustments on my JMW 12.7 to get it to sound its best. When you get it dialed in right, the dynamics and tonal balance are incredible.
I am guessing 500 hours of total usage. I am rating it as 7/10 only because I am the second owner and I don't know its history.
These notes from the Hifi News review sum up the A90 pretty well, in my opinion:
What it certainly doesn’t do is make dull sounding LPs sparkle, or gloss over coarse sounding recordings with a smooth, silky sheen. Fundamentally it sounds honest and matter-of-fact. So I could imagine it sounding sublime on an SME turntable, combined with sweetly balanced electronics, driving electrostatic speakers for example. And given its very high price it perhaps goes without saying that this is not a cartridge to use for playing tired old LPs.
Also, this from the Vinyl Asylum review:
The A90 is based on the generator/cantilever/stylus of the Ortofon Windfeld, but places this motor in a minimal body made by Selective Laser Melting (SLM). You can google this emerging construction technology - it's actually pretty interesting and I'm betting we'll see more of it in cartridge construction. Output is a lowish 0.27mV so you'll need about 60dB of gain - which works fine for me.
Perhaps because of it's superior performance, the A90 is very sensitive to micro setup adjustments in VTA/VTF/Azimuth/AS and is probably best used with a fully adjustable tonearm to extract it's best performance. I initially loaded the A90 at 100ohms - and it sounded great - but later dropped the phono loading to 47ohms which appears to work best in my system.