Coherent Systems
Not your average hi-fi retailer would be an understated way to describe Coherent Systems in Gerrards Cross just outside the M25 in Buckinghamshire. Owner Tony Sallis has to be the most technically capable engineer selling audio equipment in the country, his workshop contains more test and measurement equipment than many electronics manufacturers in this business. But this is because Tony not only repairs all manner of high end gear but upgrades it in to a far more comprehensive degree than most. He also builds power supplies and cables for to suit all manner of systems, these are sold under the brands MC Audio, END and RTZ while cables come under the Coherent Systems banner.
However, Tony’s favourite audio brand appears to be Wadia, the American company that made some of the most convincing CD players of the nineties and whose DACs he considers to be among the best ever made. Because they haven’t been in production for nearly 20 years many are in need of refurbishment and repair and this is something Tony clearly enjoys. He has a large collection of products from the brand, those in the listening room are just the tip of the iceberg as far as can be told, and anyone looking for a pristine example of Wadia’s art could do a lot worse than contacting Coherent.
Tony is a enthusiastic advocate of TAD loudspeakers and electronics from Japan, once the high end wing of Pioneer and now an independent entity that has a predilection for concentric drivers and extreme build quality. His demonstration system on the day of my visit was fronted by a pair of TAD Grand Evolution One loudspeakers, the only pair in the country I’m told. These stand on hydraulically isolating Track spikes and are driven by the TAD M700 (350W) stereo power amplifier that sits between them.
The source in this system starts with an Aurender N30-SA streamer with music files stored on an internal Samsung 870 SSD, from here an AES cable hooks up to the first in a pair of Mutec MC3+ USB reclockers connected in series, an unusual arrangement that is further refined by converting the reclockers to DC power operation and the use of a twin output MC Audio Quiet Power 5V power supply which can be seen on the left. Clocking precision is enhanced with a Mutec Ref 10 SEW-120 10MHz word clock. Tony naturally upgrades the MC3+ USB units as well as removing the first stage of the power supply and fitting a DC input.
The DAC in the system is a Wadia 25 from 1997 that has been completely overhauled and upgraded, with 250 components replaced in the process. Pricing for these DACs starts at £5,000 depending on customer requirements, they are good for PCM up to 24/352.8kHz but do not decode DSD which was not around when they were created. So the Wadia DACs may not be as highly specced as contemporary converters but are capable of giving even the most ambitious a run for their money, I am told. Tony has an Ideon Absolute Meta converter in the Creaktiv rack which is apparently pretty good but not as much to his liking as the Wadia 25. The preamplifier is a ground up Coherent Systems creation call the Liquid Music One, a digitally controlled analogue design that has huge bandwidth and 120dB signal to noise, it goes large in all respects except physical size.
All the cables are bespoke and made to order by MC Audio as are the grounding devices, there is also an END (Earth Noise Dissipation) unit that minimises any noise on the mains. The large transparent acrylic box marked Oracle is a mains power distributor while the RTZ units (Return to Zero) are grounding devices that weigh a daunting 80 kilos apiece. Tony is very keen on keeping all forms of noise to a minimum and that is understandable. Noise whether it be on the mains supply, the network or microphonic within components is the enemy of good sound, and nowhere less than in digital components.
He is also keen to clarify the difference between ground and earth, ground is the 0 volt reference point for electrical circuits, or the point used to measure a voltage in such circuits. A car battery does not have a positive and an earth connection it has positive and ground, this allows it to swing +/- 12V, by contrast a DAC or preamplifier runs on +/- 16V. An earth is a protection system that connects specific parts of an electric power system with the ground, usually via the earth in the ground outside a property. British electrical installations have an earth wire beside the positive and negative conductors for 240V AC and this is connected to ground for safety reasons.
The Coherent demonstration system is in a fairly normal British living room, not particularly large albeit with a bit of room treatment and more electronics than most. Listening to it was a very pleasant experience, the system has exceptionally low noise and sounded effortlessly transparent yet also managed to be musically fluent. There was no audible distortion just clean, calm and inspiring music thanks to the fact that it is totally devoid of the sharp edges, glare, grain, call it what you like typically found with digital systems. This system proves that if you can get on top of sources of noise in all forms you are left with a purity of sound that is rare regardless of original format.
You might be able to see various shiny Creaktiv ci2p devices on the components and under cables in this system. These aren’t damping the casework or raising cables to avoid vibration but RF noise absorbers which apparently reduce noise ingress in the various parts of the system.
Tony has a challenge for customers who spend time listening to his systems, essentially if he can’t get it to sound the way that they like he will buy them lunch at a swanky restaurant. If he succeeds they get sandwiches, but I imagine that they get something better if they buy the whole system.
Tony has a lot of tips for getting better sound out of streaming systems. These include using BubbleUPnP (Android) as a control app, the Amazon HD music streaming service and, most controversially, using a 4G/5G router rather than a regular wired router connected to a landline for streaming from the likes of Amazon or Qobuz. He is the first person to suggest this approach that I have met but given that a SIM card 5G router is galvanically isolated from the noise that comes from wired networks it clearly warrants investigation. Tony does use one metre Audioquest Diamond ethernet to connect the router to the Aurender but that is a very simple streaming back end compared to many. He appreciates that the wired approach can deliver great results however and recommends the Silent Angel Bonn 8 Pro switch because it can be used with an upgraded power supply and external reference clock.
Jason Kennedy