Tom Evans Audio Design Groove+ SRX Mk3 phono stage
I have been using a MkII Groove+ SRX since this phono stage was launched in 2017 and I have found very few alternatives that could deliver more of the signal with less distortion, and virtually none that do so at the asking price of that design. Which at the time of my original review was £5,000, so how on earth is Tom Evans making a Groove+ SRX Mk3 for only 10% more seven years later? He says that he wants to maintain its bargain status in the context of a range that goes up to nearly five times the price. At a time when most in this business are charging at least 30% more than they were pre-pandemic this is quite an achievement.
The Groove+ SRX Mk3 has not changed in appearance, it still inhabits a shiny black acrylic case chosen for sonic rather than aesthetic reasons, and has high quality in- and outputs on RCA phono sockets. There have been a number of key upgrades under the glossy cover for the Mk3 version, not least a new layout for the signal PCB, a new version of the local regulator PCB and a new version of the large regulator PCB that is said to provide 20dB lower noise than its predecessor. As well as these new boards the external power supply has a larger mains transformer and a further stage of regulation that also drops noise by 20dB.
As you can tell from this Tom Evans has identified electronic noise as the enemy of sound quality, something that those in the digital field have been talking about for many years yet which is also crucial in analogue electronics. Not least phono stages where the incoming signal is measured in single digit millivolts while the output needs to be several thousand times higher. Any noise that gets into the signal at low level will be amplified along with it so it’s critical to keep the circuitry as quiet as possible. Tom uses ICs to do this but has to be extremely selective when choosing devices, testing every one he gets to find those with the best measurements which are then used in the Groove+ SRX Mk3.
This is a method used by most audio manufacturers, Rega for instance saves the best bearings it gets for the best arms it makes and uses those with less fine tolerance for the more affordable options. I would imagine that Tom does the same across a range that spans £600 to £25,000, using the closest tolerance ICs in the best preamplifiers will make them the quietest and thus best sounding.
He uses pro series tantalum capacitors for power supply decoupling because they are so much more reliable than the electrolytic alternatives, quoting the fact that the Michell Iso phono stages that he built in the nineties and which also use tantalums are still working today. You can see from the internal shot that the circuit boards are not devoid of protection from EMI/RFI but have insulated copper shields top and bottom. Tom also avoids capacitors in the signal path, the circuits are fully DC coupled, this is an established means of increasing sound quality in audio electronics.
The power supply for the Groove+ SRX Mk3 is not quite so elaborately cased as its predecessor which had a black acrylic top cap and a few fancy nuts, maybe some savings have been made here, but as such things need not be on display that’s hardly a deal breaker. The new PSU is actually bigger than its predecessor and inhabits a silver anodised aluminium case with a long umbilical that leads to the four pin connector for the phono stage. It would have been nicer if the lead was in the same end of the PSU as the IEC socket and power switch but it probably makes for a more economical build this way.
While the Groove+ SRX Mk3 is limited to moving coil cartridges and doesn’t offer variable gain, it does provide a range of capacitance and impedance settings. The two banks of dip switches on the rear allow impedances between 112 ohms and 1 kohm in nine stages, the banks of four switches provide five levels of capacitance from 100pF to 500pF. Tom can build his phono stages with custom impedance and capacitance settings if something more extreme is required.
Sound quality
As the Groove+ SRX Mk3 supplied for review was a new unit I used it for a few days prior to getting down to some serious listening, the process was rather pleasant to say the least. Connected to the Rega Naia with Aphelion 2 moving coil cartridge (output 0.35mV, impedance set to 112 ohms) the results were positively vivid with all manner of recordings, tone seemed to be particularly well resolved on Jeff Parker’s The Way Out of Easy which is a relaxed West Coast jazz release, captured live on an analogue tape recorder. The nature of the recording was abundantly obvious with the Groove+ SRX Mk3 because the whole thing has so much space in it and the instruments sound so real. With the guitar and fiddle dirge of Lumen Drones you can hear right into the mix and appreciate that what often sounds like a wall of noise actually has dynamic range which separates out the various instruments and makes the whole thing more accessible.
Another highlight of the Groove+ SRX Mk3’s capabilities is in the frequency extremes, both bass and treble are very well defined, many phono preamps deliver great midrange but smooth off the highs and fail to find the power in the bass. This does the opposite, revealing shining highs from pianos, electric guitars and voices while extracting seriously solid bottom end from all manner of vinyl pressings. With a favourite test record, River, the Joni Letters both Leonard Cohen’s vocal and Herbie Hancock’s piano have an incredible three dimensionality on The Jungle Line. Frequently the vocal on this is overblown, but here the deep gravelly tones are clear and precise, there is weight to them but also focus, I usually listen to the piano on this piece but here the spoken words were equally inspiring thanks in no small part to the quality of songwriting.
Contrasting the Groove+ SRX Mk3 with its Mk2 predecessor the most marked difference was an increase in perceived volume level when switching to the new model, it sounded as if the volume had been turned up and only by reducing it by eight points on the Townshend Allegri Reference preamplifier did it have approximately the same level. This impression was created by the fact that the new Groove+ SRX Mk3 has so much more dynamic range than the Mk2. With another track from the Hancock album it sounded as if there was more gain such was the increase in energy, the sound was vivid with life, so much so that I could have been listening to a higher resolution format (if such were available to the music buying public).
It was interesting to listen to a record that I have previously only had in the digital library, Liv Andrea Hauge Trio’s Døgnville (piano, bass drums), this tended to engage me when the groove was strong but was less interesting when things get slower and more experimental. With the Groove+ SRX Mk3 opening up the spaces between the musicians and clarifying the dynamic differences between them these more abstract tracks became significantly more entertaining. The vinyl provided something not far from a live experience thanks to the dynamic range exposed, something achieved solely by the noise floor in the phono preamplifier being pushed down so much lower than is usually the case.
The flip side of this is that recordings that have been compressed are not disguised to the same extent as with less revealing stages. I love the acoustic guitar picking of Gwenifer Raymond but was disappointed to find that her latest release is has had the full production works and sounds thick and constrained as a result of this. The music is still fabulous and I am enjoying it but a little more openness would have been nice.
It’s worth noting that the Groove+ SRX Mk2 is no slouch, I have contrasted it with a fair few alternatives over the years and some have been considerably more expensive, but few have managed to show it a clean pair of heels in all respects. I have also used it with a wide variety of cartridges and it served them all exceptionally well. The Groove+ SRX Mk3 is markedly better, it resolves finer details and expands the depth and spaciousness of any recording that has this information in its groove. I will be very surprised if there is a better MC phono stage available at the price.
Conclusion
The difference between the Groove+ SRX Mk3 and its Mk2 predecessor (there has been a Mk2.5 between them) is so great that most manufacturers would have changed the name and added another 30% to the price. The fact that Tom Evans has managed to keep the rise in price so low whilst delivering such a stonking phono preamp gives one faith in humanity, it really does.
His pursuit of an ever lower noise floor in this most competitive of Grooves has resulted in a phono stage that is only likely to be excelled by the most ambitiously priced alternatives, and presumably those in his range. The advantages conferred by the acrylic casing and the evolution of the circuitry make the Groove+ SRX Mk3 a giant slayer in its class, anyone who wants to know exactly what their turntable is extracting from the grooves on their favourite records should put it at the top of their must hear list.