I've owned two Benz Cartridges in my life, the original Benz Glider HO, bought in '97, and the Ruby 3, bought in '07.
While I cannot recall the Glider sounding so thin, and horrid upon first fire-up, the Ruby 3 almost sounded like nails on a chaulk board.
So bad in fact, that the next day after installation, I was on the phone with both MusicDirect, the dealer, and Garth Leerer, at Musical Surroundings, the USA distributor, from where it was shipped to me from.
I actually thought the Cartridge was defective. The Glider that it replaced actually sounded much better, fuller.
I wondered "how can this be, a much more expensive offering sounding worse?"
Garth of course kindly offered help, and suggested if these issues continued, send it back, they will look at it, and go from there.
I even had bought a new Cardas Sweep&Burn LP, and ran the Ruby 3 on the 3 Burn in Tracks, a period of 20 minutes each, for a total of one hour. Absolutely no difference was noted. The cartridge was sounding truly horrid at about the 3-4 hour mark.
The other problem I was experiencing, was auto turn-on, and shut off with my Sutherland PhD Phono Stage, which up until that point had operated flawlessly for a period of a good year prior to the purchase of the Ruby 3.
The Sutherland, which should activate instantly upon Stylus contact, was taking 20-30 seconds to then come to life. And normal auto shutdown for the Sutherland is about 1/2 hour. With the Ruby, three hours later, the PhD was still on! Only unplugging the Phono Cable permitted the PhD to shut down.
Then, at about the 6-7 hour mark, when I went to try the Ruby 3 again, things were then coming around, and not subtly either. It was like a different cartridge. Like I literally threw a switch, the Ruby 3 began to sound lush, warm, clean, pure. Bass extension was getting deeper, and deeper by the track. Voices were beginning to have realism, and fullness.
I should note that Gain, and Loading all along on the PhD were set at 60db gain, and 1000 ohms.
I am unsure if this would be experienced with all higher tier Benz offerings, but I cannot honstly say if my Ruby 3 was a brand spanking new, never used cartridge, or one that was re-built/re-furbed by the Benz people in europe?
The ZYX Airy 3X that was thrown into the system shortly after, did not exhibit these wierd anomalies that the Ruby 3 did.
I would say at 10-20 hours, things should change with the sound, and the Benz at that point should start showing some promise. I hope this helps you. Mark