Solid State Amplifiers

We are involved in an extensive listening programme to re-evaluate some of our amplification brands. Having had many years of supporting well known manufacturers such as Spectral Audio, Nagra, Accuphase, Karan Acoustics, Leben and conrad-johnson, we are now looking for an equally excellent sound and better value for money. What we do not like is bright and forward presentation of which there are, sadly, many examples. Whatever we choose to represent will be a natural, more realistic presentation of music reproduction.

One of the best amplification systems we have heard over the years is from Spectral Audio. This was, and to a large extent still is, our reference sound. Unfortunately this brand is no longer represented here in the UK but it remains the sound to measure others by. We have encountered some that are close to their philosophy of tonal accuracy, speed and 3-dimensional, holographic sound stages. We will represent more as we find them.

From our first stages of evaluation, Norma Audio, a little known brand from Italy, and the low profile Edge Electronics from the USA, have astonished us by how good a sound their products can achieve for a modest investment. They offer a true high-end sound at medium level prices with their entry level products. For once, their value-for-money options compare very favourably to some of the eye-watering priced offerings from the more obvious, heavily marketed brands. See below for more details.

At their Reference level, Edge Electronics is on a par with our favourite Spectral Audio in terms of speed, dynamics, tonal accuracy and probably exceeds it in terms of sound stage scale and depth. 

We have listened to Pass Labs, Luxman, Vitus and Jeff Rowland Design. The first 3 brands have not really come up to what we are looking for in terms of sound stage and tonal correctness. Jeff Rowland Design offers probably the best execution of Class D designs that is on the market today, more like the sound we are after and has been added to our portfolio. We will be evaluating samples from PS Audio, Hegel and some new OTL valve designs from the German manufacturer Eternal Arts.  If anyone has other suggestions to go with our speaker references of Avalon, German Physiks and  ProAc loudspeakers, please email us.

We have evaluated the new Pure AA designs from this long established Italian company. In particular, the heavily re-designed Puccini Anniversary integrated amplifier is a very impressive product, quite an advance in sound over its original version. The tonal balance is very natural, but very dynamic when called for. A large and deep soundstage which is always something that appeals to us. Dual mono in its layout, with inputs separated left and right, and handed. One very large toroidal transformer and a power supply giving 25 amps current. Audiophile grade components abound including the high quality RCA inputs and winged speaker terminals. It delivers an understated 80 wpc into 8 ohms, which is more like 100 wpc and 185 wpc into 4 ohms. More than capable of keeping most speakers under control. The most important thing is the sound: very elegant and smooth but not euphonic or lacking in detail. Even played loud it retains its composure. Quite a different refined presentation setting it apart from the more usual competitive brands in this price point.

The Maestro Anniversary integrated amplifier takes this design philosophy to a higher level with the dual mono, fully balanced design that includes two transformers. Output jumps to 150 wpc into 8 ohms and 300 wpc into 4 ohms, probably conservative ratings. Both the Maestro and the Puccini employ zero global feedback technology.

There is an entry level integrated amplifier in the AA range called AACento which is not dual mono in design and is built to slightly lower specification but offering superb value at its price point.

AACento integrated amplifier – 100 wpc/8 ohms£2999.00
Puccini Anniversary integrated amplifier – 80 wpc/8 ohms£3749.00
Maestro Anniversary integrated amplifier – 150 wpc/8 ohms £6999.00
All models available in black or silver.

Audio Analogue website

AACento integrated amplifier
AACento integrated amplifier
Puccini Anniversary integrated amplifier
Puccini Anniversary integrated amplifier
Maestro Anniversary integrated amplifier
Maestro Anniversary integrated amplifier

Once in a while comes along a product that is so different in sound from the rest of the pack that you start to have few doubts about what you are hearing. Why is this so good to listen to, you ask yourself? The answer isn’t so obvious to determine just by looking at the specification sheets but these electronics distance themselves from the sound of others in the already crowded high-end market.

We have evaluated samples from both the reference NL series pre and power amplifier range and from the more affordable G series. The sound is so natural, so neutral without any obvious colouration, emulating the feelings one gets from listening to the very best pure Class A valve amplifiers but with the authority that comes with ample power. This is a remarkable achievement particularly when considering that this is from what is a very powerful solid state design which is not Class A. Huge power supplies, massive current delivery and, in the NL range, pure and highly symmetrical dual mono design in one chassis clearly show exceptional attention to good design philosophy. Transparency, some call this clarity, is of the highest order with an exceptionally low noise floor. Probably the best we have ever heard. The soundstage is wonderfully holographic both on the macro and micro scales emulating that normally heard with Class A amplification. Notes are presented at correct timbres; harmonics and decay are delivered so realistically giving a real sense of a presence to the instrument or voice being listened to. High current delivery when required results in dynamics being extremely fast; effortless and powerful at the same time. Power with elegance. Edge engineers say ‘that’s low level linearity’. The NL range is now our reference point amplification system.

The G Series, whilst not at the NL Series level, does offer much of the house sound and philosophy at more affordable prices. It even comes through in the G3 integrated amplifier. An exceptional achievement when one considered the sound quality against the asking price. Small chassis that are easy to accommodate in most equipment supports. An initial impression of the style of the chassis would indicate a slightly fussy and retro appearance. On closer examination, it is clear that the engineers have built this in an unconventional way, constructed from separate sections of metal strategically bolted together rather than a chassis made from the usual bent, relatively thin sheets of aluminium. This results in a chassis that is very stiff with thicker than average metal work, which is less prone to the degradation effects from unwanted resonance feedback, a very common problem with many, even expensive, amplifier brands.

We strongly urge you to audition this amplification design. It is likely to change your perception of what musical reproduction is capable of.

G Series

G3 integrated amplifier – 115 watts, 6 amps (pictured) £9900
G2 pre-amplifier – battery & AC powered £8500 
G6 power amplifier – 135 watts, 14 amps £7000 
G8 power amplifier – 175 watts, 18 amps £10900
G10 mono amplifiers – 200 watts, 26 amps £19500 pair

NL Series

NL Signature 1.2 SE pre-amplifier – battery & AC powered (pictured) £19900
NL 10.2 power amplifier – 225 watts, 28 amps  £24000 
NL 12.2 power amplifier – 300 watts, 56 amps (pictured) £32000
NL Signature 1.2 mono power amplifier – 400 watts, 83 amps £58000 pair

Please note the power rating quoted above is watts per channel into 8 ohms load.
The current rating quoted is constant, not peak. Peak current would be approximately 4 times the figure quoted.

Edge Electronics website

G3 integrated amplifier
G3 integrated amplifier
NL Signature 1.2 preamplifier
NL Signature 1.2 preamplifier
NL10.2 amplifier
NL12.2 power amplifier

Continuum S2

We have not been totally convinced by Class D amplification designs over the years but listening to a few samples from the Jeff Rowland Design portfolio has convinced us that, with careful and proper execution, Class D can deliver in musical terms that appeal to the refined audiophile. The new Rowland Continuum Series 2 integrated amplifier offers perhaps the best value for money with a high level of performance from a one box solution that rivals many pre-power combinations from some other famous brands. It delivers stunning dynamic realism and expressive refinement using advanced topologies. It incorporates the new Capri S2 pre-amplification circuit, input/output, and control features with an innovative 400 watt Class D power amplification stage into a single chassis.

The amplifier delivers the trademark Rowland musicality, resolution, and unfailing authority to the most refined audio environments. The Continuum S2 is very capable with the extreme dynamics of high-resolution digital sources as well as the power requirements of large bi-wired speakers. It is equally happy with the complex loads of electrostatic panels in high performance 2-channel systems or in a sophisticated multi-media system.

The elegance of Continuum S2’s trade mark sculpted fascia panel, machined from a solid block of aircraft-grade aluminum, coupled with the high build quality of the chassis adds to the pride of ownership. There is an impressive complement of standard input/output interfaces, utilising Cardas made connectors throughout, and with the option of a DAC card, or a Rowland fully redesigned phono stage board, it makes this one box solution totally flexible.

Continuum S2 integrated amplifier – 400 wpc/8 ohms £7999
Continuum S2 with DAC board £8500
Continuum S2 with phono board £8500

other models:
Capri S2 pre-amplifier £3500
Model 125 stereo power amplifier – 125 wpc/8 ohms £2300
can be bridged to mono amp delivering 500 watts/8 ohms
Model 525 stereo power amplifier – 250 wpc/8 ohms £3995
can be bridged to mono amp delivering 960 watts/8ohms

Jeff Rowland Design website

Continuum S2
Capri S2 pre-amplifier
Capri S2
Capri S2
525 amplifier
Model 525 stereo power amplifier

Norma Audio Electronics

This is a superb sounding amplifier and electronics manufacturer from Italy. Little known in the UK but well established throughout Europe as a worthy partner with many speakers but work very well with German Physiks, ProAc and Elac loudspeakers. Well built on genuine dual mono design including two transformers -the exception being the IPA-70B integrated amplifier. High quality component count, high capacitance power reserve capable of delivering high current resulting in a very fast sound. An elegant Italian designed chassis rivalling the quality from the best from more famous high end manufacturers. Refined and elegant tonal balance with a natural presentation of a deep soundstage. A true high end sound quality at moderate prices.

There are no bargains in audio, but this is an amplifier that can go up against amps costing £12,000-£16,000 despite costing the right side of £5,500 in its all up top spec guise. The hifi market can be fickle, but the IPA140 has some real staying power. I think for many, to try it will be to love it.
Alan Sircom, HiFi+

REVO IPA70B integrated amplifier 70wpc/8ohms 24A constant current, 100A peak
Silver £2895
Black £3095

REVO IPA140 integrated amplifier (pictured) 140wpc/8ohms 36A contant current, 150A peak
Silver £4725 
Black £4975

PH1-REVO phono board for IPA70B £175
PH2-REVO phono board for IPA140 £305 
USB1-REVO USB 196kHz/24bit board for IPA-70B £440
USB2-REVO USB 196kHz/24bit board fro IPA-140 £440

REVO SC-2LN line stereo pre-amplifier
Silver £4425
Black £4975

PH3-REVO phono board for SC2LN £305 
DAC1-REVO DAC board for SC-2LN; 5 digital inputs 4 x SPDIF,USB, 192kHz/24bit. £1575
MCH6-REVO Multichannel Option, 2 sets of 6 channel inputs. £1150 

REVO PA150 stereo amplifier 150wpc/8ohms 48A constant current. 200A peak 
Silver £4650
Black £4895

Norma Audio Electronics website

REVO IPA70B integrated amplifier
REVO IPA140 integrated amplifier

PS Audio 

PS Audio has launched a new range of amplification called Stellar. They offer exceptional audiophile sound quality at truly affordable pricing in a market where spiraling cost-no-object equipment abound. The amplifiers combine discrete Class A analogue stages for the all-important input stages with ultra linear Class D technology for the output stages. The Gain Cell DAC/pre-amplifier is also a unique design combining a state of the art DAC with a Class A pre-amplifier and analogue volume control. The sonic results are more than the sum of these parts, offering a sound of a high level of elegance higher than you would expect from the price point.

PS Audio Stellar Gain Cell DAC

The heart of the system is the Gain Cell pre-amplifier, a pure Class A pre-amplifier combined with a refined and improved version of their NuWave DSD capable DAC. There is no better way of sending a DAC signal to a power amplifier than via a good analogue pre-amplifier where the output is controlled by an analogue volume control. PS Audio has put both into one chassis and all you need to do is add your sources, digital or analogue. A full complement of inputs to cater for computer sourced files, pure DSD and asynchronous USB, as well as I2S for CDs from a transport or vinyl via the analogue inputs from a phono stage; a complete pre-amp and DAC in one chassis.

The PS Audio Gain Cell relies on a different technology known as a variable gain amplifier (Gilbert Cell). This topology was invented in the 1960’s by Howard Jones and Barry Gilbert and widely adopted by recording and mastering studios in their analog heyday—later abandoned when these same studios went digital. The idea behind the Variable Gain Cell is simple. Instead of adding additional circuitry to the signal path to vary loudness, the preamplifier’s actual amplifier stage varies its gain in response to the user’s front panel volume control. This method requires zero additional circuitry in the signal path, offers more than 80dB of attenuation

Fully balanced circuitry used throughout for those that prefer this principle although 3 non-balanced analogue inputs are included. Build quality and case work design are also excellent with a very solid feel to it. All Stellar products are hand built in Boulder Colorado, USA.
A long burn-in time is required, as is the case with many designs featuring high quality components, and once complete the sound is exceptional for the price asked. A rich sound without being too warm and powerful dynamically. Good holography and sound stage which pleased us as it is not often the case with many competitors at this level.

Stellar S300 Stereo Power Amplifier

This stereo power amplifier is a dual mono amplifier design in one chassis capable of effortlessly driving demanding loudspeaker loads to concert levels. The S300 combines an ultra linear, high-current, Class D technology for the output stage with a discrete Class A MOSFET based Analog Cell for the all-important input stage. The S300’s rich and engaging sonic character comes from the Analog Cell design. Its powerful, authoritative control over the loudspeaker stems from its high current, ultra-low impedance Class D output stage. Effortless dynamics with a spacious 3-dimensional stage, no hint of aggression or forwardness which can be common with Class D designs.

Stellar M700 Mono Power Amplifiers

The M700 mono amplifiers are a more powerful design taking the principle of the S300 stereo amplifier to a higher level. Two chassis with two completely independent power supplies provide more power and more current to give increased headroom on dynamic music. The M700 uses unique topology in the Analog Cell to preserve the fine details found in quality recordings. The Analog Cell is zero feedback Class A, balanced MOSFET input stage which closely mirrors the sonic characteristics of a vacuum tube.

Loud and complex musical passages are effortlessly rendered but even the tiniest nuances in the music are easily perceived from a transparent background. Overtones from plucked instruments, subtle cues that define stage placement, the depth as well as width of the soundstage, transient decays which are often lost in the very powerful amplifiers. The Stellar mono amplifiers surprised us with their ability to capture the rich full-bodied essence of recorded music and present it with authority and grace. A very natural presentation, never forward and lacking in glare common at this price level.

Stellar Gain Cell DAC£1700.00
Stellar S300 Stereo Power Amplifier – 140 wpc/8 ohms; 300 wpc 8 ohms. £1500.00
Stellar M700 Mono Power Amplifiers – 350 wpc/8 ohms; 700 wpc/4 ohms. £3000.00 the pair

PS Audio website

Stellar Gain Cell DAC
Stellar Gain Cell DAC
Stellar S300 Stereo Power Amplifier
Stellar S300 Stereo Power Amplifier
Stellar M700 Mono Power Amplifiers
Stellar M700 Mono Power Amplifiers

Valve Amplifiers

We like valve amplifiers, and have considerable experience of the different types that are, and have been, available.

Designs of valve amplifiers fall into three basic principles: single-ended, push-pull and output transformerless (OTL). Push-pull designs are the most common as they can be designed easily to give as much power as required dependent on the number of push-pull pairs of valves utilised. Because of this, this design works well with most real world loudspeakers on the market. Single-ended designs inevitably mean low power output, but can produce superb results with appropriately sensitive speakers, but good examples of these are hard to find. OTL designs can combine the transparency of single-ended with the dynamics of push-pull, but there are only a few designs based on this principle.

There are many valve amplifiers on the market but not many that sound truly excellent. Those that do tend to be very expensive, possibly too highly price for what they offer. We continue to evaluate brands as they appear and will only select from those that satisfy our criteria on sound, value and reliability.

At present we are considering two OTL designs classic designs with completely modern interpretations. One brand from Germany called Eternal Arts with amplifiers delivering extremely wide bandwidth, powerful, but with a low noise floor. The other is from Italy called Alieno LTD 250: a Class A. OTL and OCL design generating 250 wpc from just two 300B valves. Seems unbelievable on paper but, from hearing a pre-production sample in a very high quality system, the sound was truly excellent substantiating the claims.