Hum and noise problems in both live and recording environments can be maddening. Often mysterious in origin, these issues are usually sussed out as we are pressed for time, while artists, clients and/or audiences patiently wait (best-case scenario). Worst-case scenario, the show must go on with the problem left unsolved, and it’s not the venue, the amp, the instrument or the artist’s fault: It is ultimately ours.
Weighing approximately two ounces and pocket-sized, the Sescom IL-19 Extreme Hum Fighter sounds somewhat like a superhero. In many ways, it is; I was personally rescued in several scenarios as illustrated above, yet I was the one who came out looking extraordinary, despite the fact that I often had no idea what the original problem was, except that it was coming from a certain sound source.
PAR Bench Test: Sescom IL-19 Sescom’s IL-19 inline isolator is passive and transformer-based, in a nonconductive housing, with no common ground from input to output XLR connectors. The frequency response is relatively flat, within 0.8 dB from 100 Hz to 20 kHz and within 1.8 dB from 20 Hz to 20 kHz, the LF roll-off somewhat indicative of the physical limitations of a transformer that can fit inside even a slightly bloated inline shell.
THD+N vs Level, -30 dBu input swep
THD+N (Total Harmonic Distortion + Noise) performance at 1 kHz is a respectable .02 percent with a nominal +4 dBu input. LF distortion, again a factor of the transformer size, will be more noticeable. THD+N at 100 Hz with a +4 dBu input is .3 percent, and near 10 percent with a +22 dBu input. The square wave response is also decent.
Frequency response, +4 dBu input = 0 dBr.
In short, the Sescom IL-19 will perform as advertised, effectively isolating connected circuits and breaking ground loops. LF signals can be significantly colored (though some might say it adds that transformer “warmth”). For voice in particular, and with the proclivity for ground related issues in spoken-word sound reinforcement situations, the IL-19 could be an event-saving device. For musical applications, let your ears be your guide.
-- Frank Wells The IL-19 is an inline XLR-male to XLR-female matching transformer. “Three products in one,” touts Sescom, the IL-19 “removes ground loop hum, mode noise and differentially induced hum without the need for transformers, ground lifters or phase inverters.” As such, it also reduces noise from power supplies and over lengthy cable runs. It can be popped in nearly anywhere in the signal chain: equipment inputs or outputs (amps, preamps, DIs, various analog outboard, etc.), or via connecting two XLRs cables with the IL-19 between.
The IL-19 is a most valuable player in live-sound settings, especially in the harshest of environments: club-level gigging, where power is often dirty, and house gear (especially amplifiers) is borderline unusable. In my first application of the IL-19, I popped it in between a mono FOH mix output and an onstage (house) amplifier input, dramatically reducing a hum problem to a comparatively nonexistent level. In another live application, I inserted the IL-19 directly into a bass head’s XLR line output, which was headed for FOH (originally generating a certain pesky, low-frequency hum). Voilà — like that, it was almost gone.
At FOH, I also employed the IL-19 directly into the console’s microphone preamp inputs on several vocal microphones, all of which benefitted, at least slightly, with a lower noise floor and/or reduced hum, the cause of which was likely the very long cable (multichannel snake) run.
In recording applications, the IL-19 was also useful, if not as dramatic in its “clean up” jobs. In recording DI via an intermittently buzzy bass guitar (an early ‘80s U.S. Fender Bullet Deluxe, which has passive pickups) I inserted the IL-19 between the chain’s Radial Pro DI’s XLR output and a FMR Audio PBC-6A compressor, “to tape.” No joke, the signal went from “I can’t record that bass” to “that works.”
What was ultimately the problem? I’m still not sure, but the IL-19 was my solution. Further, any change in tone that the IL-19 presents is negligible, in my opinion; if it does affect the sound of the signal, it’s so slight that you’d have to be an audiophile-type user to care.
Granted, the IL-19 is more of a “Fighter” than an “Eliminator” — I applied it to a few hum/noise problems that it just couldn’t wrangle to an acceptable level. Yet considering its size, flexibility and cost, I was genuinely surprised by how often it was able to improve the lacking or even use the unusable. For that reason, the IL-19 is now my favorite little fighter.
Price: $49.95 list
Contact: Sescom | sescom.com
Strother Bullins is the reviews and features editor for Pro Audio Review.