Ideon Audio Sigma Wave USB Isolator
REFERENCE AUDIO – WITHAM ESSEX
BOB’s Review Series - No 84 – IDEON AUDIO SIGMA WAVE USB AUDIO ISOLATOR
INTRODUCTION
Ideon Audio are based in Athens and are probably best known for their DACs streamers and USB reclockers, and I have been using their Absolute Time USB reclocker in my home system for some time. At Munich High-end in 2024 they showcased for the first time their Sigma Wave USB Isolator and their Alpha Wave LAN to USB Isolator. I already use an optical converter to form an electrical break in my ethernet supply to the streamer and for this reason I haven’t tried the Alpha Wave LAN to USB Isolator yet, but maybe I’ll give it a listen soon. Instead, I have been listening to the new Sigma Wave USB Isolator. Is it a worthwhile upgrade or is it just another box taking up shelf space and requiring yet more expensive connection and mains leads? I wanted to find out but didn’t really know what to expect and even after reading the instructions and their lengthy website information I’m still not clear exactly what it does. But here is an abridged version of what Ideon have to say about the Sigma Wave USB Isolator:
“The Sigma Wave is a part of our new Innovator Series and gives full USB isolation designed to eliminate noise from the USB stream by isolating the ground, data signal and power lines for a cleaner distortion free analogue signal. It includes a high quality Femto level timing platform and is designed to be used between a streamer or computer and your DAC of choice. If you already have a USB reclocker then it can be used between your streamer and your reclocker which then connects to your DAC”. It has, by definition of purpose I guess, only a single USB in and USB out connection on the rear panel which also has an on/off toggle switch and a switch to turn on or off the 5v power supply that many DACs still need for their USB connection, but not so Ideon DACs. I used it with the 5v supply in the off position as my Gryphon DAC doesn’t appear to need it switched on. The front panel has a small central pale blue LED showing it is powered up and a long thin linear LED bar that lights up in an orange yellow colour when it is receiving and processing a USB signal. I know from experience that anything with Femto clocks inside can take up to three days to fully warm up, so I left it constantly powered up for the duration of this review.
Its looks, shape and finish have more in common with their EOS range of DACs, streamers and clocks than to their Absolute range. They come with either a silver or black finish and measure 460mm wide, 295mm deep and just 70mm high and weigh in at 10kg. That width may not fit on older style audio racks which were designed to accommodate standard 430mm wide equipment.
CONNECTIONS
I inserted the Sigma Wave into my home system between my Innuos Statement streamer and my Ideon Absolute Time USB reclocker. USB overkill perhaps but it’s one of the ways that Ideon recommend using it. Using this device requires another mains lead unless you use the one included in the box and of course another USB lead, which isn’t supplied. I chose ones from Jorma to keep the wiring loom as consistent as possible with the rest of my system.
LISTENING
This is one of those products that doesn’t sell itself quickly on first listen but soon starts to show its merits as it warms up. It’s also one of those devices that you appreciate most when you remove it from your system at which point everything just sounds a little flatter and less exciting and engaging than before. Colin Chapman famously said upgrades to his Formula One cars were designed to add lightness and the audio equivalent to that seems to be to add silence. Sounds like a daft concept for a music making device but what this means is that it reduces distortion and noise in the signal path to give darker and quieter backgrounds and this lets more of the music’s fine detail through. It has the effect of heightening dynamics, giving greater clarity and definition and in my experience increases pleasure and enjoyment. The Sigma Wave USB does this by reducing the noise you probably didn’t know you had, and it does it stealthily. It kind of creeps up on you until everything just sound better, which is why you will miss it so much if you disconnect it. This is one of those easier devices to accommodate easy A/B comparisons because it can simply be bypassed by rerouting your USB cables and just take a minute to do so. This means your music memory remains largely intact when doing A/B listening.
I found it also added to the power, definition and lushness of vocals and instruments alike, giving access to those fine details that were previously a little harder to separate and define. Listen to ‘No Future In The Past’ by The Alan Parsons Project from ‘Time’ and the track is underpinned by what sounds like a tapping beat but with the Sigma Wave in circuit it now defines it as probably a snare drum rather than something less defined. It could be my imagination of course but I don’t think it was. The Sophie Zelmani track ‘My Soul Remembers’ from the album ‘Soul’ has a repeated bass note near the start that with the Sigma Wave in circuit clearly has an echo sound behind it that I wasn’t aware of before. I’m not saying these sounds weren’t there before, it’s just that with the Sigma Wave USB in circuit they have better definition and are easier to pull out of the overall mix. That added detail is what we are all seeking with new devices and equipment and it’s what keeps us audiophiles coming back for more.
I listened to lots of tracks and was never disappointed in the overall musical engagement brought to play by the Sigma Wave USB Isolator. ‘Just ‘Cos You Got The Power’ by Baba Blues from ‘Glimmer Of Gold’ had greater placement of vocals and instruments with the Sigma Wave. The piano on ‘Down The Years I Travelled’ by Allan Taylor was just more piano like which is always a struggle for any audio system, but the Sigma Wave proved its merit here. I also played ‘Two Tribes (Annihilation Mix)’ from Frankie Goes To Hollywood and just kept wanting to turn it up, luckily it was the extended mix.
CONCLUSION
As I explained earlier the improvements gained by adding a Sigma Wave USB Isolator to your system will not be a night and day first impression update, but it will be one that grows and grows on you the longer you listen, and you will miss it if you take it out of circuit as I did when it returned to the showroom. It enhanced everything I played and kept me listening for longer, and probably louder. Digital audio has never sounded better. Ideon are masters of digital replay from their entry level Ayazi DAC and matching clock right up to their Absolute range where it’s possible to get really spendy. If you purchase an Ideon Sigma Wave USB Isolator don’t compromise on USB cables because they make a very real difference and fortunately Ideon make those as well.
FINALLY
A couple of our staff, me included and many customers like to use their Gryphon Essence power amp in ‘green’ Class A/B mode rather than the pure Class A ‘red’ mode. It seems daft when this amp is designed for that pure Class A experience. Nonetheless many of us prefer it in Green mode where it often sounds more dynamic and engaging. When I had the Ideon Sigma Wave USB in circuit however the Gryphon clearly sounded better in Class A red mode. Don’t know why, it just did, so I guess the cleaner signal presented by the Sigma Wave was allowing the amplifier to deliver at its very best. Interesting ha.
February 2025
Bob – Team Reference Audio