Pre/Power Amplifiers

Class A operation has a noble history. Thanks to the always-on nature of the topology and the removal of an entire type of distortion, allied to sound that excels in low-level detail, superb dynamics and transparency, its devotees are more than happy to put up with low efficiency and heat. From Sugden to Levinson to Krell, and here to Belles, it’s a choice for connoisseurs.
   Should the escape of all that heat come to the attention of Brussels, the EU might then outlaw Class A amps as they have light bulbs. But if you’re not feeling so green that it affects your hi-fi purchases, the Belles SA-30 could be an ideal guilty pleasure. It is an absolutely perfect example of the genre, able to remind crusties like me of the sweetness of the Levinson ML2, the bass and slam of a Krell KSA-50 and the delicacy of the Sugden A21. What Class A always seemed to offer above everything else was valve-like sound without the maintenance of tubes. Nice irony: you still got the heat.
   Belles admits that the SA-30 ‘has been purely designed as a genuine alternative to quality valve designs.’ It certainly has the natural bass of valves without the ridiculous vice-like damping (only suitable for synth music) of most tranny amps, the treble is silky and sweet, it’s open and transparent, and – for those so inclined – it has no internal glassware.
   Belles amps adhere to a couple of rules: the company eschews op-amps and balanced operation, the latter because it feels that the technology adds too much to costs, complexity and size, while bringing nothing to the performance unless you’re talking pro sector and huge cable runs. The amp is shorn of frills, other than special pointed feet, nice gold phonos and decent speaker binding posts at the back, and an on/off switch on the front with pilot light. Its perceived value comes from the stunning styling and finish.
   Packed into the beautifully-sculpted, chunky 432x133x342mm (whd), 22kg chassis is a new circuit with a complementary differential input stage. It employs bipolar transistors instead of JFET transistors, while the output stage uses MOSFETs.
   It may be rated at only 30W into 8ohm, but in practice it’s far beefier [see Lab Report]. It certainly had no trouble driving my resident Wilson Sophias.

VALVE PREAMP
Despite the all-transistor nature of the SA-30, Dave Belles employed four 12AU7 valves in the VT-01 hybrid preamp. It’s a line level unit with motorised volume control and remote, tiny toggle switches choosing power on/off, monitor and source. The back features a soldierly row of phonos, and its purposefulness plus Bauhaus hygiene reminded me of other non-showy, superbly-constructed high-end classics like Klyne phono stages and Sutherland preamps.
   Sharing real estate with the 12AU7 valve differential amplifier is a solid-state gain stage, while the output is a dual-cathode follower. Belles employs global feedback to improve stability and lower noise, and I can confirm that the VT-01 is remarkably quiet and free of spits or crackles. Still, it possessed more than a hint of valve lushness, as I found when comparing it with the all-valve Quad QC-twentyfour and McIntosh’s C2200.
   Measuring 432x88.9x330mm (whd), it accepts four sources. A weight of 12.5kg attests to its robust cabinet work, and the unit is simply a joy to use – once you get used to its extended warm up period. The remote does all it should, but I wish the remote’s on/off button was less prominent. That, and viscious heatsinks on the SA-30, are my only complaints about their physical presence. Other than that, they’re nigh on perfect: compact, luxurious, aesthetically faultless and totally free of the shabbiness that marks too much audio equipment.

TASTE OF BASS
With absolutely no qualms about power, I fed the system with Kimber cables to the aforementioned Sophias; sources wired via Yter included the Marantz CD12/DA12 and Musical Fidelity kW25 CD players. Quite why I was drawn to a bass-busting first taste I don’t know, but Hall & Oates’ Looking Back was already in the player, and I just stabbed ‘3’ randomly. ‘Rich Girl’s percussive kicks 22 seconds in threw out such mass, such musical weight that the tambourine and vocals floated over a foundation which suggested 300W, not 30.
   Something was afoot. The last track, ‘Starting All Over Again’, was one of the best cover versions H&O ever delivered, and it, too, had a rich lower sector, some tasteful strings and truly powerful percussion. Majesty? If the wee Belles could fill the room with this track, then I knew I was on to something special.
   And it did, with only one teensy proviso. Speed, transient attack, dynamic swings – the Belles pair behaved precisely as one would expect of a pre/power combination with a combined price tag of £8500. That is no small sum, and a reviewer is forced to consider what else is out there for the money. Now the world isn’t awash with pure Class A power amps, but you could fill a 40ft container with £4000-5000 preamps – valve, tranny or hybrid. Mixing and matching with Quad, GRAAF and McIntosh preamps and Quad, McIntosh power amps allowed me to isolate the sound of the two from each other.
   Voiced so closely and in so truly complementary a manner, the two Belles pieces form a natural pair. For a listener who owned one but not the other, matching either with a product from another brand would reveal immediately a change in character. Returning to an all-Belles system would restore the whole. So, if pressed, I would say that the SA-30 provides the command, the presence and the scale. This is one rock-solid performer. The VT-01 is neutral, erring toward the dry despite its tube complement, but less revealing of its presence, which is as it should be.
   But back to the listening... After swapping components, I could isolate only one characteristic where the Belles pair offered less than my preferred reference: absolute soundstage width. That’s it. And for some, that’s no sacrifice at all, when you consider that the rest is stunningly good. All I could think of was the circa-1980s Krell
KSA-50, as wonderful an amp as I have ever let slip though my fingers. And what showed me how good this is was Mel & Tim’s superior original version of ‘Starting All Over Again’.

TIME TO BOOGIE
From the album of the same name, it possesses some of the most liquid, rhythmic, lush bass Donald ‘Duck’ Dunn ever produced. It is proof-positive that he is the finest electric bass player God ever allowed us to savour, and the album itself is the best record that Sam & Dave didn’t record. As I played it to death when my system consisted of Sonus faber Extremas driven by Krell Class-A monoblocks, I knew how that music could flow. I knew how the two voices had to mesh – Mel & Tim really were ‘Sam & Dave Lite’, but in a good way – and the guitar picking was a note-perfect facsimile of Steve Cropper.
   To the Belles, it was an invitation to, well, boogie. After the slow, embracing angst of the title track, the album delivers high-octane Stax funk, including a righteous cover of ‘Wrap It Up’. The Belles’ sound perfectly placed a brass section in the room, punching the air above snapping bass lines and kicking percussion. Then I was floored by the whucka-whucka guitar and rolling organ/bass of ‘I’m Your Puppet’.
   ‘Majestic’ is the word that keeps popping into my head. From the Pixies indie crunch via MoFi CDs to the saccharine (but admittedly delicious) sweetness of Billy Joel’s ‘Just The Way You Are’ to the woody, unplugged acoustic satin of early Peter, Paul and Mary, the Belles did something that the manufacturer may not take as a compliment, but which is intended that way: it transported me back to 1985. For which I am grateful beyond words.

VERDICT
   While the VT-01’s superb build, perfect ergonomics and clean, detailed sound reveal a winner, there are too many less-costly rivals. It has so much to recommend it, but it’s not alone. The SA-30, however, is a little gem that reminded this listener of the Krell KSA-50 – as high as praise can get. Its astonishing bass and dynamics belie its power rating; the freedom from grain marks it a thoroughbred. As a pair? Truly magical.

Originally published in the August 2009 issue