Leema Neutron & Graviton pre & power amplifiers
Leema Acoustics launched its Quantum range of entry level electronics late last year, the first to come our way are the Neutron, an analogue and digital preamplifier bristling with input options and boasting onboard DAC and MM/MC phono stage, and the matching Graviton is a 150 Watt power amplifier. Both borrow tech from the flagship Constellation series but rebuilt with affordability in mind. The products arrive as Leema celebrate their 25th anniversary and is the first all-new range from this marque in over a decade.
The company
Leema Acoustics was founded in 1998 by a pair of former BBC engineers, Lee Taylor and Mallory Nicholls; the spelling as such taking the first part of each name, rather than the standard lima. Lee started in the film sound department which became part of BBC post-production where he was firstly a dubbing mixer and then a sound supervisor.
The first project was a small loudspeaker designed to be a miniature monitor capable of outperforming one many times its size. Hampered because neither design principles nor mathematical models available at the time were capable of creating the product Lee and Mallory envisioned, they began four years intensive work. This culminated in the Leema Xen, initially made available only to the professional audio market.
Following the success of their first product, the pair decided to turn their expertise to audio electronics. Their first product, the Tucana integrated amplifier, was released early in 2006, followed shortly afterwards by the Antila CD player. Since then, Leema’s portfolio has expanded to include the Reference and Elements Ranges, and, more recently, the Essentials line. In 2007, joint operation began in association with a local Welsh manufacturer in order to meet the increasingly high demand for products.
Established in 1983, Davlec originally designed and manufactured electronics for the Dairy industry. Since then, they have expanded their business to cover a wide range of sub-contract areas such as automotive and metrology. After working together closely for a number of years, in 2014 the two companies made the decision to join forces. Now housed under the same roof, the production and design teams combine their decades of experience.
Quantum range
The long-awaited new range is called Quantum and, initially at least, features four products all entirely designed, engineered and built in the Welshpool factory in Powys, Wales. Quantum comprises the new Electron CD player, Positron streamer, Neutron DAC/preamp and Graviton power amp reviewed here. The new-look range has been painstakingly developed under the watchful eye of Leema Acoustics’ co-founder, Lee Taylor. He tells me that the product names have been chosen to reflect the designs’ characteristics.
Potentially the launch is exciting because the aim has been to make the technology in Leema’s flagship electronics available in a simplified form and at more affordable pricing. That has to be a good thing for the cost-conscious audiophile who’s looking to buy British.
An advantage of making their PCBs in-house, Leema has been able to simplify the layout as well as reducing outlay on casework, although we are still treated to machined aluminium facias. Inside, too, savings have been carefully considered with power supplies reduced to single transformer operation.
Leema explains that they’ve maintained as much commonality between the parts used in the upmarket Constellation products and this new range as they can. This helps keep parts costs down due to the economies of scale. This is aided by complete in-house manufacturing, including through-hole and surface-mount technologies, which allow tight control of quality.
Neutron preamp
A feature rich design, the Neutron packs a lot in to a £1,500 package based on OP275 op amps. Not least, 13 inputs including a switchable MM/MC phono stage which uses FZT753 transistors and has been cloned from the Essentials design; in-built DAC circuit using the highly-regarded ESS Sabre 9018 chip (limited to 192kHZ/24-bit); four line-inputs (on RCAs), plus a pair of XLR inputs. Digitally, there are three optical and three coaxial inputs available alongside a USB port. I also appreciated the inclusion of a front panel headphone socket (6.3mm) which is located adjacent to the IR receiver.
Rather than adopting the all-too-common approach of down-market electronics in a heavyweight case, Leema says it would rather put the customer’s investment in to the areas that really matter for sound quality and “not put cheap tat in a posh frock”. Sounds promising in that we have a well-engineered product rather than something driven by the marketing department.
There is, perhaps surprisingly, no digital output although if the Neutron is intended to partner the Graviton one is not needed. Leema explain that providing the option is not a problem, but implementing volume control is: “Just re-sending a digital stream is not volume controlled, so we would have to re-convert the analogue preamp output via an A-to-D, which is not desirable”, they say. “It also requires conversion of non S/PDIF formats for transmission via coaxial or optical, which is not cost-effective for the only two people in the real world who would want to do that.”
Despite this, the Neutron offers flexibility with output via a pair of XLR and two sets of RCAs, along with a tape-out and a stereo subwoofer output. A nice touch is the ability to rename inputs (via the user menu options) and one can be nominated as ‘fixed gain’ for AV use. A large, central display (OLED) dominates the front panel and can be switched off, although not dimmed. It can display volume levels either in dB or with a 0-120 range. To each side is a large rotary knob, one is the Burr-Brown analogue volume/mute control, the other for source selection/menu access.
Graviton power amp
A solid design in more ways than one, part of the weighty construction is down to the Noratel extra quiet 600VA toroid transformer in the centre of the casework. It probably wins the award for largest transformer in an amplifier of this class. Power is delivered from three pairs of Toshiba transistors in high-current Class A/B and provides 150W into 8 Ohms and 260W into 4 Ohm loads.
The Graviton’s inputs are on both RCAs and XLRs with loop-through RCAs to allow stacking of similar units for bi-amping. This is a super-easy upgrade. Using the 12V control sockets on each unit, both can be controlled from the same IR remote handset which worked well even though the on/off function was shared with my Sony TV.
Balanced or unbalanced?
The XLR connections on both products are truly balanced, with the return phase reversed in the receiving stage and summed. For a design created by a former BBC engineer, one expects nothing less. However, Leema do say that there is no inherent advantage with balanced cables at home, the cable runs are very short so induced noise is unlikely to occur. In a recording studio where the cable runs are often very long some form of noise cancellation is needed. “The additional phase reverse circuitry is likely to counterbalance any noise advantage”, I am told. “However, many people think it sounds better simply because the signal is hotter and therefore louder, a common misconception.”
Powerhouse
For east of installation, I initially left my Hegel H190 in situ (with its various inputs connected) and used it as a DAC/pre to drive the Graviton which fed a pair of Elipson XLS7 bookshelf speakers. Using its single ended RCA inputs, the power amp showed itself to be highly competent and able to handle dynamics in an impressive manner as evidenced by the Tom Jones’ comeback single Sexbomb, where that decisive drum beat punches through with richness and power. The noise floor was also deliciously quiet and signal to noise clearly superb. I would have expected nothing less, but was nonetheless reassured.
I left the system like this for almost a week, until the listening panel arrived, and enjoyed a range of material. My usual speech-rich running order produced nothing to unnerve the Graviton which also acquitted itself well with all manner of classical repertoire, both streamed and from internet radio recitals.
The sound was full of poise and finesse in a natural balance which allowed the acoustics of the venue and the recording engineer’s mix to be represented without adding any obvious character from the electronics. What goes in, comes out. Of particular note was fine stereo imaging and an output capable of decent levels of well-defined bass, along with lots of detail which is portrayed without harshness.
I particularly noted the levels of enjoyment experienced when streaming Mahler’s First (Bavarian RSO/Kubelik on DG from 1967) where the famous of seven-octave opening, sustained by string harmonics, was reproduced with a realism I had not expected at the price. The Graviton is clearly an amplifier that punches above its weight as confirmed by the work’s invigorating final triumph which brought a tingle to the hairs on the back of my neck.
Perfect partners?
Leema clearly see, and have designed the Graviton to partner the matching Neutron, and it wasn’t long before I married the two making use of the balanced XLR connections offered to drive my reference Revival’s Atalante 3 speakers. Digital sources were a satellite receiver and internet tuner, plus an Auralic Aries G1 streamer via coax, because the Neutron has no on-board streaming.
To make sure all was working as it should, I listened solo for a couple of days and was treated to a Radio 3 concert by the BBC SO (Martyn Brabbins) of Mussorgsky’s classic Pictures at an Exhibition. The electronics/speaker combo seemed an ideal paring to enjoy the piano cycle representation of ten drawings that inspired the composer. The entire work came over with sufficient realism and atmosphere as to transport me to The Barbican recording venue as we are taken to “view” each work to the concluding, and rather apposite, Great Gate of Kiev.
Rather than being overwhelmed by detail, we became immersed in Joni Mitchell’s live album, Miles of Aisles. The assured, decisive and emphatic delivery of this vocal tour de force is surely exemplified in Both Sides Now, and shows just how ‘at home’ the performer was in front of an audience. The recording may not be the greatest but it’s more than made up for by the performance which was reproduced with an immersive soundstage and natural tonal balance. The bass doesn’t have as much overall grip as bigger, more expensive amps but what it does is convey something that’s impressive and can go loud, neighbour-annoyingly loud.
The panel also selected Duffy’s Warwick Avenue to hear a Welsh singer through Welsh electronics. This great ballad highlighted how the Neutron doesn’t quite match the Hegel H600 when it comes to dynamics, but given that integrated Hegel is £9,000 more expensive, this can be forgiven. Timing is spot on and there’s plenty of lively energy to drive things along and get the feet tapping. Comments were also made about the naturalness of the vocals and how they retained their magic on this example of 21st century soul.
Personal audition
Just before packing the units away, I took the opportunity to try the headphone outlet. Sometimes an afterthought, especially at this price point, that doesn’t appear to be the case with Leema. The Neutron has a dedicated amp for cans and it did a decent job of driving the several pairs I tried, from high-impedance Sennheiser HD25s to the audiophile-inspired HEDDphone Twos which cost slightly more than the Neutron.
Leema say that headphones used must be over 32-ohms which, at 41-ohms, the HEDDphone Twos just scrape but the sound they produced was transparent, detailed and involving. Just as I found no use for the phono stage, many may not use the headphone output but it’s good to know it’s there, just in case one day you need it.
Conclusion
Listening to the Neutron and Graviton it’s not hard to hear why it has taken Leema so much longer to finalise the Quantum amplifiers than was expected when they were first shown in 2022. Making a highly featured preamplifier and a high power amplifier at these prices in the UK is quite a challenge. The costs have been kept down by using less substantial casework than is found on Leema’s more ambitious products but the quality of electronics within is clearly not compromised. Both components delivered excellent results for the money and you will be hard pressed to find this combination of features and power from a British built pre/power pairing elsewhere on the market. Add to this Leema’s reputation for making consistently good performing and reliable electronics and you have an offering that warrants close attention from anyone looking to make the step into separates amplification.