I met Dave Belles, owner and designer of Power Modules, earlier this year in at the 2011 AXPONA show in Atlanta. Mr. Belles is not exactly an unknown in the audiophile world: He has been designing amplifiers for over 30 years, beginning with the Belles ‘A’ Class A power amplifier. Today’s extensive line-up of Power Modules consists both of Class A and Class AB power amplifier designs, as well as solid-state and vacuum tube line stages.
Belles Power Modules, David Belles’ latest company, provided the horsepower to a sound room at AXPONA, co-shared with European Audio Lab and Legacy Audio. It was clear that this room’s mission was to present a well-balanced, musical system experience using equipment that provided lots of value for the buck. At the time of my initial visit, I commented to Mr. Belles that I thought the room sounded very well put together. I visited the room on several occasions throughout the weekend and as a result, Mr. Belles offered me an opportunity to review the Statement Series top-of-the-line VT-01 vacuum tube linestage and the Reference Series 350A V2 power amplifier; both of which were running at the show. Here now is the second of a two-part review of this pair of electronics. The Power Modules Reference Series 350A V2 power amplifier is the subject of this review.
Installation and Break-In
The Power Modules Reference Series 350A V2 stereo power amplifier arrived just a few weeks after active duty at AXPONA, as part of a paired review system along with the VT-01 vacuum tube linestage. Much like the preamplifier VT-01 sibling, the Reference Series 350A V2 is a fairly small but hefty and ruggedly built power amplifier. The chassis is flanked on either side with plenty of heat sinking, and the front panel contains a simple power switch. The 350A V2 is a solid-state dual mono design with a single common 2000 VA toroidal transformer. The 350A V2’s circuit design consists of three amplification stages, an input stage utilizing matched dual J-FETs in a cascaded differential pair, a voltage gain stage utilizing bi-polar transistors, and a final stage using a source follower with eight class B biased power MOSFET’s. The power rating is a generous 250 watts per channel into an 8-ohm load and doubling into a 4-ohm load. There is no 2-ohm rating. However, Mr. David Belles provided his assurances that the amplifier should have no problem handling the 1-ohm load presented by my Martin Logan CLS IIz.
Having already completed much of my listening evaluation of the companion Statement Series VT-01 linestage, I inserted the Power Modules Reference Series 350A V2 power amplifier into my system and played it for roughly 40 hours before conducting any critical listening. During this period, I noted that the amplifier did indeed seem operationally fine providing power to my full-range electrostatics. That said, it was producing prodigious amounts of heat; perhaps even more than the gigantic space heater otherwise known as the Pass Labs X350.5 stereo solid-state power amplifier.
My first group of listening sessions included the Martin Logan CLS IIz, Belles Power Modules Statement Series VT-01 linestage, ASR Mini Basis Exclusiv, Merrill Williams R.E.A.L 101 turntable/Ortofon TA-110 Rubber Injected Arm/assorted phono cartridges, Conrad Johnson/McCormack UDP-1 Deluxe universal player, TRS Audio Pure Note Designer’s Edition speaker cables, Aural Symphonics Chronos interconnects and Aural Symphonics MagicGem V2t power cords throughout.
The Sound
The Power Modules Reference Series 350A V2 requires several of hours of warm-up to sound its optimum. In fact, I felt it best to leave it powered up throughout the weekend since this is when I tend to do the most listening. Since there are no vacuum tubes to worry about, there doesn’t seem to be any reason why you would even want to power it down. My Sunfire Signature Series II amplifier basically stayed powered up for nearly 10 years with no detriment.
Overall, my impressions of the Belles PMR 350A V2 was positive. Indeed, this diminutive power amplifier delivered a punch that worked well with the electrostatics on most material, as long as it wasn’t exceedingly demanding from a dynamics standpoint. Reading back through my notes of the VT-01, I found that much of what I had written remained true. The 350A V2 was indeed a great pairing with the VT-01 linestage and added no significant signature of its own; meaning that overall balance, imaging, and definition remained true to the companion VT-01’s capabilities and had little to add or subtract to that performance level in the overall system.
Spicing things up a bit with material containing considerable dynamics proved to be a challenge for the 350A V2. I noted that when playing dynamic rock recordings such as In a Glass House by Gentle Giant, the more demanding the passage, the smaller and narrower the soundstage would become. This is an occurrence that is not new to me. The CLS IIz seems to react this way with many solid-state and vacuum tube amplifiers alike; undoubtedly due to their difficult sub-two-ohm impedance. Still, to its credit, at no time did the 350A v2 misbehave, blow fuses, or shut down as has been the case with other amplifiers. As I was in the process of breaking in a pair of superb Eficion F300 speakers in a second system, I decided to continue the evaluation of the 350A V2 driving the Eficions, once I was familiarized with their sound in my room.
A month later, for a final evaluation system, I managed to pull together the Belles PMR 350A V2, Pass Labs XP-10 preamplifier, Merrill Williams .R.E.A.L. 101 turntable/Ortofon TA-110 tonearm/Accuphase phono cartridges, Conrad Johnson/McCormack UDP-1 Deluxe universal player, TRS Audio Pure Note Designer’s Edition speaker cables, Aural Symphonics Chronos interconnects and Aural Symphonics MagicGem V2t power cords throughout.
The highly efficient Eficion came alive with the Power Modules amplifier in a way different than that with the Pass Labs. More about that experience in the forthcoming Eficion review. Released from the limitations of the stable mate VT-01 linestage , the Belles Power Modules 350A V2 paired with the Pass Labs XP-10 proved to be beneficial overall to the cohesiveness of the system. In fact, the Power Modules 350A V2 became fast, linear, uncolored in sound, and handily reproduced the broader range that the Pass XP-10 brought to the table. That said, the 350A V2 was still no match to the Pass Labs X 350.5. The Belles’ reproduction of subtle dynamic shadings, smoothness of midrange, deepest bass, size and specificity of images, and lower-level detail were certainly all very good and actually out-classed its stable mate VT-01 preamplifier’s performance, yet were no match for the Pass Labs XP-10/ 350.5. Still, this is darn good performance for an amplifier with an MSRP of under $4,000.
Summary
True to the overall Belles Power Modules mission, the 350A V2 power amplifier is a superb amplifier for its price point. When inserted in a properly matched system, the 350A V2 delivers faithful and clean performance with no significant errors of omission; not bad for $3,995. Better yet, doubling them up and running two amplifiers in mono would yield a sub-$8,000 pair of monoblocks that deliver 1000 watts each into 8 ohms. That’s what I call value.
In much the same way as the VT-01 linestage, the 350A V2 delivers excellent performance when used within its operating parameters. Its build quality and sheer ruggedness shone through in its ability to play the CLS’s despite their sub-2-ohm impedance. At $3,995 this amplifier handily earns a recommendation and is a must-audition in its price class.
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