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.

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

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, pushpull and output transformerless (OTL). We mostly favour pushpull because this type of design works well with most of the 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 pushpull, and there are very 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.

Tsakiridis Devices is a Greek company that specialises in valve amplifier designs, built in Europe to a high standard, that do not cost a fortune. Whilst they have 7 power amps 2 pre-amplifiers and a phono stage on their list, the integrated amplifier the Aeolos is the unit that stands out as offering superb value for money. It has a sweet, liquid midrange that extends to the upper frequencies too with a very open and transparent sound. Elegant and civilised in its presentation. Whilst obviously a valve sound, it is not overly warm and has a dynamic approach that will fit with many real world loudspeakers. The improved version of the Super Plus has made a small but significant improvement in bass definition and depth with a little more dynamic range.

The amplifier is Class AB in output and can be switched from pentode to triode mode with the obvious loss of output watts. There are two versions available, the Aeolos Plus and the Aeolos Super Plus. The difference is one of output valves: 4 x 6550 for the Plus version and 4 x KT120 for the Super Plus – both offering 45 wpc.

The chassis is basic in design. A little retro in appearance but well built and comes with a remote for volume and input selection.

Aeolos Plus integrated amplifier (6550 output tubes) 45 wpc £1590.00

Aeolos Super Plus integrated amplifier (KT120 output tubes) 45 wpc (pictured) £1745.00

Tsakiridis Devices Aeolos Super Plus integrated amplifier review by Alan Sircom, Hi-Fi+ Tsakiridis Devices Aeolos Super Plus integrated amplifier review by Alan Sircom, Hi-Fi+ (229 KB)

Tsakiridis Aeolos Super Plus review by Alan Sircom, Hi-Fi+ Tsakiridis Aeolos Super Plus review by Alan Sircom, Hi-Fi+ (166 KB)

Tsakaridis Devices website

Aeolos Plus integrated amplifier
Aeolos Super Plus