Here's what I posted on AA about these amps:
In addition to the Cary SLP-05 preamp, I have also had the opportunity to audition two of Carys recent solid state amplifier products the A-306 and the CAD 500-MBs.
Again, to save my lazy fingers, here the blurb on the A-306 This new CARY DESIGNER SERIES A 306 stereo power amplifier has the latest digital design circuits in it. It is conservatively rated at 600 watts per channel at 8 ohms and 1,100 watts per channel at 4 ohms. Each channel has a separate power supply complete with its own with power transformer. The power amplifiers control circuits have their own transformer and power supply. The all aluminum chassis has custom machined aluminum cone feet for system leveling. The speaker terminals are CARDAS designs. The A 306 power amplifier has one each balanced of an XLR and a single ended RCA input with an input selector switch for each channel. The back panel includes a remote turn on trigger input for system remote control. This power amplifier will be capable of running low impedance loads with ease, such as electrostatic designs. The chassis size is 18" w x 5" h x 15" d. The weight is 50 lb.
These amps have been my first extended listen to solid state amps in over ten years. Things have certainly changed in those ten years. For the better!
First the A-306. This is Carys first Class D amplifier. Class D is commonly referred to as a digital amp, but it is not. The input signal modulates the power supply through PWM (pulse width modulation). For more details, refer to http://www.ee.ucr.edu/~rlake/EE135/Class_D_amp_notes_AL.pdf
This amp outputs a whopping 600 watts per channel @ 8 Ohms, 1,100 watts per channel @ 4 Ohms and on up to over 2,000 watts per channel @ 2. Ohms. The A-306 got well over 150 hours play time and another 150 hours on standby. It takes quite a bit of break in to come in to its voice.
Grab your speakers and head for cover! Thats a lot of power to unleash. The most power my system has had is around 250 Watts with bi-amping. All I can say is power corrupts. I was completely blown away with the sound. Subterranean bass with complete control. Every musical impulse was imbued with energy. Every musical nuance had a voice, life. With orchestral recordings, it was easier to hear the resonance of the floor under the cello and double bass strings. Organ music was unreal, loud, deep, controlled. Piano recordings had the weight and heft in the lower octaves that only get conveyed with gobs of acoustic energy (fueled by gobs of electrical energy driving the speakers).
The A-306 had the exact same soundstage as my other amps, and as the CAD 500-MBs. The incredible thing to experience with all this available power was how the soundstage would not only fill to the upper extreme corners of the soundstage, it would fill with palpable sound.
As with the SLP-05, I mostly listened to the A-306 with balanced cables. On occasion I connected the phono stage with RCA cables. The RCA (single-ended) connection was smoother sounding and had more texture. This could be due to the phono stage, cables or other interactions.
Overall, I was impressed by the power. At times, the high frequencies had a little too much edge. This was ameliorated by switching to the RCA/single-ended interconnects.
The A-306 also maintains the Cary sound characterized by a sweet, palpable mid-range that goes right to the heart and soul of the music. Amazing that the sonic signature was so present in a Class D amp.
On to the CAD 500-MBs.
As with other Cary gear, these took well over 100 hours play time to come in to theur 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 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.
System: see post on Cary SLP-05.
Enjoy the music.