Focusrite ISA 115-HD
A studio-grade Focusrite equalizer that turns up in the racks of the people who make records, and in the used-gear classifieds of everyone trying to sound like them.
Overview
The ISA 115-HD is a piece you learn about sideways. There was no glossy launch. You spot it in a photo of somebody's outboard rack in a magazine. Focusrite outboard keeps showing up in the same breath as vintage Neumanns and Pultecs, and that says what the market thought of it long before any spec sheet did. Contemporary users were vocal about Focusrite gear of the era: Mix (August 1987, p.23) ran a testimonial section in which engineers from Larrabee Sound and Electric Lady Studios praised the company's equipment in glowing terms.
The clearest picture of what the 115-HD is comes from a working engineer's road case. Electronic Musician (undated excerpt, p.108) documented the three racks Chuck Ainlay hauled to sessions. In the third rack the unit is listed plainly as the "Focusrite ISA 115HD equalizer," sitting directly above the Focusrite ISA 215 dual-mono mic preamp and equalizer. So it is an EQ, and in Ainlay's rig it was the Focusrite EQ he reached for, paired with the ISA 215 when he needed mic preamplification. The same article notes he used roughly three-quarters of the gear in those racks on the Toby Keith track under discussion, so the 115-HD wasn't there for decoration.
What the 115-HD did in practice is documented in unusually specific terms. Electronic Musician (undated excerpt, p.108) walked through Ainlay's drum-processing chain, and the Focusrite ISA 115HD is named as the unit he used on the hi-hat. He engaged a low-cut filter at 105 Hz and added a little boost around 12 kHz. A hi-hat is where a harsh or grainy EQ shows itself instantly, and this was the box chosen for the job. The same account describes broad moves across the kit: shelving boosts at 10 kHz, cuts around 450 Hz on kick, and presence lifts in the 4.5 to 5.6 kHz range.
Collectors should read the dealer listings carefully, because the naming is a mess. The same unit turns up as "ISA-115HD," "ISA 115 HD," and "ISA 115HD" depending on who typed the ad. At least one 1991 price sheet (Studio Sound, November 1991, p.79) lists it as "FOCUSRITE ISA 115 HD WITH PSU," and the "with PSU" is the important part. The external power supply is part of the package, and a used example missing its supply is a project, not a bargain. That same sheet also shows the model listed twice with what appear to be garbled figures, so period price lists shouldn't be treated as firm market values.
The record leaves out the boring stuff a buyer wants. There are no confirmed production years, no original retail price, no frequency-response or distortion figures, and no weight or rack-depth. The 115-HD's reputation rests on where it turns up: in the racks of engineers cutting major-label records, and on the short lists of brokers who dealt in the most desirable vintage outboard on the East Coast.
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