April
2023

Country of Origin

Korea

iSO-CAT7

Reviewer: Srajan Ebaen
Financial interests: click here
Main system: Sources: Retina 5K 27" iMac late 2020 with Ventura 13.3, 40GB RAM, Audirvana Origin, Qobuz Sublime, Singxer SU-6 USB bridge, LHY Audio SW-8 network switch, Sonnet Pasithea DAC; Active filter: icOn Gradient Box at 80Hz/4th-order hi/lo-pass; Power amplifiers: Kinki Studio EX-B7 monos, Goldmund Job 225; Headamp: Cen.Grand Silver Fox; Phones: HifiMan Susvara; Loudspeakers: Qualio Audio IQ w. sound|kaos DSUB 15 on Carbide Audio footers, Audio Physic Codex, Cube Audio Nenuphar Cables: Complete loom of Allnic Audio ZL; Power delivery: Vibex Granada/Alhambra on all source components, Vibex One 11R on amps, Furutech DPS-4.1 between wall and conditioners; Equipment rack: Artesanía Audio Exoteryc double-wide 3-tier with optional glass shelves, Exoteryc Krion and glass amp stands; Sundry accessories: Acoustic System resonators, LessLoss Firewall for loudspeakers, Furutech NCF Signal Boosters; Room: 6 x 8m with open door behind listening seat
2nd system: Source: Shanling M3 Ultra, Soundaware D300Ref; DAC: Cen.Grand DSDAC 1.0 Deluxe; Preamp/filter: Vinnie Rossi Signature L2 + icOn 4Pro + 4th-order/40Hz hi-low pass; Amplifier: Enleum AMP-23R; Loudspeakers: MonAcoustic SuperMon Mini, Dynaudio S18 sub; Power delivery: Furutech GTO 2D NCF + Akiko Audio Corelli; Equipment rack: Hifistay Mythology Transform X-Frame [on extended loan]; Sundry accessories: Audioquest Fog Lifters; Furutech NFC Clear Lines; Room: ~3.5 x 8m
Desktop system: Source: HP Z230 work station Win10/64; USB bridge: Singxer SU-2; Headamp/DAC: iFi iDSD Pro Signature;  Headphones: Final D-8000; Active speakers: DMAX SC5
Upstairs headfi/speaker system: Source: smsl Dp5 transport; DAC: Auralic Vega; Integrated amplifier: Schiit Jotunheim R; Phones: Raal-Requisite SR1a
2-channel video system: Source: Oppo BDP-105; All-in-One: Gold Note IS-1000 Deluxe; Loudspeakers: Zu Soul VI; Subwoofer: Zu Submission; Power delivery: Furutech eTP-8, Room: ~6x4m

Review component retail: $450

SOtM offer three different CAT7 links identified by color to tune our sonics. Such things always cause the monkeys in the peanut galleries to engage in obscene behavior.

In SOtM's world of the Soul Of the Music, premium streaming demands complexities. Below is the wiring diagram for their Axpona 2023 system. Go count the number of network switches in series, linear power supplies, 10MHz clock generators, USB regenerators, CAT7 wiring and inline digital isolation transformers. If you can't be that serious, you might already have a made-for-audio network switch like my $594 Lhy Audio SW-8. That overhauls a Cisco with linear power supply, high-grade regulators and a quality oscillator. Now SOtM's May Park might suggest starting us out with today's iSO-CAT7. Make no mistake, she doesn't consider me truly serious about cloud streaming. And she's not half wrong. 99% of all my listening is to local files. I hit up the cloud only to scout for new talent. Then I buy what I want to listen to without the evil eye in the sky watching. That means remaining off-line.

Local files process through Audirvana Origin in extreme mode; Qobuz Sublime outputs straight to Singxer USB bridge.

I recently massaged my main system's digital front end as explained here and here. Now May was fine with me testing their updated inline digital isolator right in front of my new 27" iMac's RJ45 port. That's preceded by the Lhy. So my cloud-based signal path would be far simpler than theirs: a wired fiber-optic connection from the mast in front of my office to our local provider's matching router/modem, then a 20m CAT8a along the floor board across the entry hall into my music room into the SW-8 switch into SOtM's bonbon into the iMac. Running Qobuz Sublime, the signal would then exit USB, hit a Singxer SU-6 ultra-cap powered USB bridge then travel via AES/EBU to Sonnet's Pasithea DAC.

Aside from with/out, my other comparator would be a 4TB Thunderbolt 3 drive hosting my local library through Audirvana Origin. To date my cloud streaming doesn't yet fully equal the fine sound quality I get from my local library. Given how rarely I make it rain, you appreciate why I'd never follow SOtM's above lead. If that's what it takes to get cloud streaming up to par with local files—if that's how much is wrong with the Net to mandate these many fixes—I frankly couldn't bother. But I still would inject this lozenge gizmo if it made a noticeable improvement. We all have our limits. I know mine. That'll be today's tale.

iFi Audio's Thorsten Loesch recently designed a similar gizmo called the LAN iSilencer below. At $89 it aims at a different audience. Its integral male RJ45 plug then eliminates SOtM's extra pig-tail cable. For the basics on the 'RJ45' standard, Telegärtner have a good page. This Renhotec page talks about the type of digital isolation transformers which are used in the Ethernet protocol and its connectors. It's important to say that we don't worry about dropped bits unless our Internet connection is iffy or we suffer a bad cable or connector. Devices like these are about lowering the UHF noise which hitches a free ride along our CAT5-8 wiring antennae to then make the job of our D/A converter harder which can lead to a hit on its performance. This noise is oodles beyond the audible band. Its reduction or cancellation is not ascertained by putting our ear to a tweeter. It's not that kind of power-supply or ground-loop hum. It's noise whose interfering action we're entirely unconscious of until it diminishes. The same applies to power-line noise filters though AC line harmonics above 50/60Hz very much fall into the audible band. It's again the ultrasonic spectrum populated by WiFi, Bluetooth, radar and other transmissions which we can't hear per se but whose presence intermodulates or otherwise disturbs the optimal functioning of our kit. In those terms SOtM's iSO-CAT7 is a basic Ethernet line-noise filter. If we install just one, we obviously put it as close as possible on the receiving end to also capture whatever our own Ethernet cable run picks up beyond the router or switch. Ivette's computer for example sits at the tail end of a 30m stretch of CAT8a. That's a lot of surface to pick up stray radiation.

In SOtM's above wiring schematic for a show system we saw two each iSO-CAT6 and iSO-CAT7. They act like old-fashioned toll booths on a bridge. You want to cross, pay the fee in noise or don't pass. We should probably also say that our overall system resolution including how well our speakers play the room ought to limit how much of an improvement such gizmos can make. These are low-order effects very far down the list of room treatments, room EQ, speakers, subwoofers, amps, power delivery and primary resonance attenuation.