Here's what I posted last month in this forum on the Cary 500-MB:
Here's an excerpt I wrote on Audio Asylum on the 500-MB:
As with other Cary gear, these amps took well over 100 hours play time to come in to their own. And come in to their own they did.
From the Cary write up 1 x 500 watts per channel @ 8 ohms, 1 x 1,000 watts per channel @ 4 ohms, Class A/B solid state design, Toroidal power transformer, remote turn-on trigger, RCA or FET discrete Pure Balanced Inputs, audiophile design mono power amplifier, silver anodized aluminum front panel standard, black front panel optional, black painted steel chassis. Dual WBT speaker terminals for bi-wire operation.
Again, this is serious power. Fortunately, the Ruarks soaked it up. My friends and I had loads of fun listening to The Vikings by Arthur Wills (Reference Recordings HDCD Sampler and Pomp & Pipes). The bass ports moved enough air to create a draught in the room. Ah organ music and a fresh breeze.
I never heard these amps run out of steam, never heard them get harsh, never heard anything but effortless sound. The dynamics were powerful, lots of bass slam, deep powerful bass with excellent control, orchestral swells that did not run out of steam, fully fleshed out soundstage with energy and palpability in all locations.
But the most amazing thing about the CAD 500-MB is how akin to the finest Cary tube amps they sound. The harmonic presentation and timbral character is so close to the 211 AEs that it is amazing. The 500-MBs do not have that last degree of burnished glow in each and every instrument or voice, but then again they cost less than half of what the 211s cost.
I really could not detect any soundstage difference between the CAD 500-MB, the 211AEs or the 1610s. They were that close.
Compared to the Cary A-306, the 500-MBs had a more musical sound, more refined high end (upper frequencies) and a more liquid ebb and swell with the music. They just got out of the way and sang. The A-306 always sounded like they had more power, more reserve, always raring to go. I preferred the more effortless sound of the 500-MBs.
Now to get my hands on some attenuators so I can bi-amp with the 500-MBs on the woofers. That should be something else. Tubes on top, outstanding solid state on the bottom.
Bottom line: the CAD 500-MBs are staying, the A-306 goes back.