Amp Shootout: S-30, Ref 9 V2 SE, Raven, DAD-M100

Category: Amplifiers

Thanks to the ever-accomodating Koby of HiFi Logic in NJ, from whom I had purchased my Druids 2 years ago, I had a very interesting amp audition at my house today. First, let's start with my system:

Zero One Mercury CD/HD
Supratek Chenin preamp
Flying Mole DAD-M100 amps (modified)
Zu Druid speakers
Zu Mini-Method Subwoofer (turned off for this audition)
Zu Varial interconnects
Zu Julian speaker cables
PS Audio Power Plant Premier
Homemade Belden/Wattgate power cords
Real Traps Mini-Traps room treatments

I have had the Flying Moles in my system for 2 years, during which time I have upgraded them with a HexFRED rectifier, Black Gate input coupling cap, Multicap output cap, Cree SiC switching diodes, better binding posts and RCA jacks. These amps produce some pretty good sounds, but still I was feeling that my system had not reached the levels it was capable of with these little overachievers. I had been researching a new amp for the last 4 months or so, and was very interested in the Atma-sphere S-30 (which was said to be a killer match for the Druids), the Gilmore Raven (not too much press on these but what there was was pretty positive), and the NuForce Ref 9 V2 SE (latest iteration, supposedly with the RF issues greatly reduced). It turns out Koby is a dealer for all three of these amps, so a simple phone call arranged an audition of all three, back to back to back.

Here was our playlist for the audition:

Aubrey Hilliard - Turkish Rondo (classical piano)
Bob Dylan - Don't Think Twice It's Alright
Counting Crows - Raining in Baltimore
CSN - See the Changes (harmonies to die for - hopefully)
Bob Dylan - Everything is Broken (great for testing bass tightness)
Gary Moore - Still got the Blues (my next amp MUST make me cry on this one)
Nine Inch Nails - Down in it (to check general punchiness and bass handling)
Matchbox 20 - How Far We've Come (one of my wife's favorites, and the one that drives the Moles into clipping on a regular basis)

Let's start with the Flying Moles, my reference system. They are truly overachievers, and held their own aganst all three of these much more expensive amps. Their bass control is very good for such a small package, and they have the power to drive the Druids to ear-splitting levels. There were a few fairly obvious shortcomings for the Moles, however. First, they have a bit of glare in the upper frequencies, especially on piano recordings played somewhat loudly, that can make extended listening fatiguing on the ears. The midrange is nice, but a little flat, missing some of the magic in this crucial region. Finally, when I have them really cranked, I can sometimes cause them to clip quite badly, leading me to believe that their 100WPC power rating is probably overstated by 30-40 watts or so for continuous use.

NuForce: On to the highly touted NuForce Ref 9 V2 SE. What a disaster in this system! First off, the RF issue is still there - I had a constant humming/buzzing in my speakers during the (abbreviated) audition. I'm sure the cause was my Chenin preamp acting as an antenna and picking up the RF. I cannot have a cell phone in my listening room because the Chenin is so sensitive to RF, but please!! No modern piece of high-end equipment (or low-end for that matter) should be spewing radiation out like that. Even ignoring the RF issue, the Nuforce did not impress. The highs were very sharp, almost painful, especially on the piano piece, and the midrange was unspectacular, about the equal of the 10X less expensive Flying Moles. The Ref 9s did show good bass control and more than enough power, but that was not enough. No Deal!

Atma-sphere: The S-30 is a beautiful amp to my eyes, in an industrial retro-chic kind of way. I had the one without the polished reflector behind the tubes, and I liked the look very much. Since my interconnects are all single-ended, we ran the S-30 with jumpers in the XLR inputs. On powerup, no noise, no humming, just silence - a very good start! On to the music! Well, no complaints there; the S-30 is a great-sounding amp. The harmonies on CSN were just spectacular, and the Gary Moore blues guitar brought forth the requisite tears of joy. Midrange was excellent, and the highs shimmered with delicate, extended decay. The bass was also nice, but just ever so slightly warm and fuzzy - I didn't mind it too much but the wife was less impressed in that area. The bass performance is not surprising given the high output impedance (and thus low damping factor) of the S-30, and OTLs in general. The Druids' 12 Ohm nominal impedance should be a good match for a OTL, but the fact remains that the bass could have been tighter. Maybe a Speltz Zero autoformer might help a little, but we didn't have one on hand to test, and I wonder if that might not take away a little of the S-30s magic as well. Overall, an excellent performance bordering on spectacular, and one that would be very hard to beat. If your tastes run more to vocal harmonies, strings, female voice, etc. than to rock and blues, this may be just the amp for you.

Gilmore Raven: First off, the Raven is one impressive chunk of metal; it feels like a solid piece of steel! Gilmore is not lying on their website when they say you could drive your car over it - the Army ought to blast-proof the Humvees in Iraq this well! So, let's cut to the chase - we did not let Koby take this amp home! It combined almost all of the best attributes of the S-30, with the absolute best bass slam and punchiness I have ever heard from my system. The highs were extended and smooth, cymbals had very nice shimmer and decay (perhaps a little less decay than the S-30, but close). The mids were the best I have ever heard from a class D amp and maybe from any solid state amp. But the real trump card for this amp is the bass - WOW is all I can say. Kick drums feel like a punch in the chest, synth bass lines are deep and defined, bass guitar runs take you happily along for the ride. Perhaps the harmonies of CSN come across a little sweeter on the S-30, and maybe the S-30 made me cry a little harder during Gary Moore's solo, but the Raven's overall performance was superior to that of the Atma-sphere in my system. Take into account that my amp needs to do double duty as the amp for the front channels of my home theater (meaning it is on a LOT) and the maintenance-free, electricity-sipping Gilmore pulls further ahead. If this is the future of class D, I'm all for it!

So there you have it - the Gilmore Raven is my new amp, and I couldn't be happier about it! Once more, thanks to Koby for his excellent customer service; to anyone who is looking for an outstanding audio dealer in in the NJ/NY area, I highly recommend Koby at HiFi Logic in Maplewood.