Intg Amps: Hegel 590 vs NAD M33 Masters vs Gryphon Diablo 120

@bigtwin how much of a difference did going from the H590 to H30 make exactly? I see that you have them monoblock configuration in your picture?

I had H590 and downsized to H390, did not see a big difference in my space. The same formidable detailed sound. I would change your speakers though. I had great resutlts with Dynaudio and Stirling (Harbeth like). 

Aesthetix MIMAS anyone?

I’ve had the opportunity to audition all three of the great integrated amps that you’re considering, extensively, and here’s my assessment (I auditioned the Gryphon Diablo 300). The NAD M33 is great for the money, but system matching is critical with it. The NAD M33 isn’t in the same league as the other two. The Gryphon Diablo 300 outshines the Hegel H590 when it comes to build quality (although the Hegel H590’s build quality is outstanding as well), and aesthetics. But, that’s about as far as it goes. Firstly: The Hegel H590 should be compared to the Gryphon Diablo 300, along with all other best-in-class reference integrated amps currently on the market.  When comparing the Hegel H590 to the Gryphon Diablo 300, honestly, I could go either way. I use an outboard DAC, so I’m referring to the sound quality of the amp/preamp sections of each integrated, exclusively.  To my ears, the Hegel H590's awesome sound quality didn’t have to take a back-seat to any other high end integrated on the market, including the renowned Gryphon Diablo 300 (the Hegel H590 is pretty "renowned," too). I strongly believe that the H590 is a much better value than the Gryphon Diablo 300, as it’s very comparable to it in terms of sound quality (and I do mean "Comparable"). I’m not one of our more well-heeled audiophiles.  High end audio is expensive enough as it is. I definitely don’t have money to burn.  So, for my money, I'd undoubtedly go for the Hegel H590, save a bundle of dough, and just forget about the rest.  The Gryphon Diablo 300 is one of the best, but so is the Hegel H590 (for less). To be totally candid with you, I auditioned several other integrated amps as well, including the above mentioned, and I has prepared to spend more money for something like the Gryphon.  But, I was so blown away by the Hegel H590, I purchased it and never looked back.  Kudos to Hegel Music Systems for producing such an absolutely fabulous product.

Auditioned many integrateds including the 3 the OP is asking about, bought the 300, to my ears the best of the lot.

Here is my informal ranking of the integrateds:

Gryphon 300

Accuphase E-5000

Aesthetix Mimas

Mcintosh MA12000

Hegel 590 <-> Gryphon 120

Luxman 509

NAD M33

My system:

B&W 804 D4s

Lumin P1 streamer/DAC

Lampizator Baltic V4 DAC

Linn LP12 Selekt TT

Primaluna EVO 100 phono stage

Transparent and Audioquest cabling

Puritan power conditioner and ground system

The Accuphase I suspect for most ears is as good as the Gryphon, just not to my ears for my musical tastes which run the gamut from ambient electronica to jazz to chamber music to classic rock etc. Those with less broad musical tastes - vocals and acoustic instruments for example - might even prefer the Accuphase for its more refined tone/timbre. The gap between the 300 and the Accuphase and the rest of the amps on the list is large IMHO.