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.
Ait how a ref 9 SE V2 not integrating in your system is interesting.

Lucky for me i am not having any problems with SE V2 connecting with my Tyler Linbrook Sigs and system. I am getting a full wide stage with all the air, resolution, power and might expected in a top end amp.

And none of the other issues you mention. Goes to show you it does make a difference what components are in your system. Its not an exact science for sure.

Thats very cool indeed to get a selection of gear to audition. Glad you have sound and gear that mate to give the musical presentation you are looking for.
I have the NuForce MCH-3SE (multi-channel equivalent to the Ref 9SE V2) and it replaced my Bel Canto Ref 1K for music, and now double-duty as my HT amp as well. After a few weeks of burn-in, the sound is just spectacular from all angles: sparkling, clean, high resolution and extended treble w/o edge, harshness or anything identifiably negative. Mid is extremely textured and nuanced w/ great articulation but not colored or sugar-coated like some tubes. Just neutral and natural. Bass is proundly strong, fast, palpable and well-controleld yet realistically rendered down to the lowest octave your speaker can dish out. Soundstaging is both the widest, deepest, most 3-D and coherent I've ever heard in my system. Also, dynamics of the micro and macro nature really adds to the realism of the musical performance. Imaging is solid as a rock and spot-on. In addition, there is no spot-lighting to any aspect of the sound spectrum but nothing is amissed.

Overall, I cannot ask for a better amp. However, it is very sensitive to cables and equipments that leans to the edgy, bright and overly detailed variety. I would recommend something ever slightly warmish (yin-yang balance)to bring out the best in the NuForce. Once this criteria is met, just be prepared to listen to music much longer and have more enjoyment. And, you'll yearn for more beautiful music when you're away.

Just my $.02

Too bad your setup wouldn't accommodate the NuForce after it's warmed up and ready to play music. Those who have know its the opposite of what you described.


The NuForce is not the opposite of what I described in my system - it is EXACTLY what I described. It was literally like fingernails on a blackboard, and it pumped out so much RF that I could hear it feeding back through my tube preamp. I appreciate that you guys like it in your systems; my review was not intended as a putdown of NuForce, it was intended as an honest assessment of all four amps IN MY SYSTEM.

I actually wanted to like the NuForce, but in fact it was terrible in my system. Perhaps the poor performance was all due to the RF issue, but that is not acceptable to me in a $500 amp, never mind a $5000 amp.

Now to look at the positive side, the Gilmore sounds better in my system, has a chassis built from 1/2" thick aircraft grade aluminum with EAR isolation feet, has far superior Cardas binding posts (miniature versions of the clamping binding posts on the Zu Druid speakers), has a high/low gain switch that allows it to be adapted to systems with both high and low gain preamps, doubles its output from 8 ohms to 4 ohms due to its overbuilt power supply, and costs $1500 less than the NuForce. Faced with those facts, the decision was a no-brainer.
Hi all,

I look at this review objectively...meaning that it could be a case of system synergy. I am using Nuforce 9SE V1, (just waiting the right time to upgrade to Version2) with following associated equipment/cables
Nuforce P8
Northstar 192 DAC
Escalante Fremont speakers
Gabriel Revelation Interconnects throughout
Satori speaker cables
VD Master Powercord on Preamp,DAC and Transport
(These cables were horrible on Nuforce amp)
Harmonic cables on Nuforce

I really like the sound from the nuforce amplifier. Relaxed, Clear and organic from the speaker. The only thing i am looking forward is to replace the preamp. I want to have a tube preamplifier. From the reviews here, I am considering either TD Horizons or Antique Sound Labs Flora. I am actually leaning more towards Antique Sound labs. Seems like this unit works very well with Pass Labs amplifier as well.

From your review, I would say if i have any of your components, guess i will not be looking at Nuforce amp and in the same vein, if i have nuforce amplifiers, i should not be looking at your type of components. With that I really thank you for this review. This is what i really look for in any reviews.


Can you confirm if the Raven is ICE-powered? If so, I have an idea of its sound as I have recently graduated from a pair of Bel Canto Ref 1K (500watts/ch 8ohm, double down into 8) to the Nuforce. Different sound signature from each for sure.

Again, the Nuforce has potential that was untapped in what appeard to be a mismatch in your system. Luckily, the vast majority of the folks out there aren't complaining as they're busy listening to great music. I would say that your experience is an anomaly for sure.

From what I understand, Gilmore uses a highly modified, very high sampling rate version of the ICE engine - not the standard off the shelf version, at least according to the linked review of the Raptor, the monoblock version of the stereo Raven. The power supply transformer is a large toroid - the linear supply no doubt contributes to its very low RF emissions for a class D design.
Hi Ait,

Thanks for the follow-up. Yes, I read the review and it definitely sounded impressive to say the least. Man, 1/2" aircraft aluminum chasis? This thing was probably taylor-made for the troops in Iraq.

Follow-up: I have replaced the Russian 6SN7GT tubes in my Supratek preamp with NOS RCA Gray-glass 6SN7GTs and all I can say is WOW. The warmth of the RCAs removes any trace of SS hardness from the system - it now sounds every bit as seductive as it did with the S-30 amp, but with way more power and slam. The Raven amp just passes the RCA warmth right through to the speakers - true transparency!
Update: I have traded in the Gilmore Raven for Gilmore Raptor monoblocks (500wpc into 4 ohms).

All I can say is they are the best of the Raven, plus more bass authority. I recently changed my main speakers to Infinity RSIIb's (2 10" woofs, 3 EMIM mids, 3 EMIT tweets) and they need a lot more power/current than most speakers. The Raptors really make a big difference over the Raven with these speakers. I'm highly impressed.
In having read all the listed posts, and also being familiar along with owning some of these ampifiers, I can say that they are all wonderful peices on their own that has wonderful merits. Just remember there's a sleeper out there, and they come under the name of Spectron, make no mistake, words really can't describe their virtues....