Harrison GP-215
A pro-audio graphic EQ that turns up so rarely that most collectors only know it from a line in a 1987 classified page.
Overview
The Harrison GP-215 is a dual graphic equalizer. The scattered documentation calls it a "Dual Graphic Eq," and the one seller who described it in detail calls it a "professional 15-channel stereo graphic equalizer." That's fifteen bands per channel, two channels. "Professional" at the time meant something about build and intended installation, not just marketing gloss. The Harrison name carries weight in studio circles, and a dual 15-band graphic with that badge is the kind of box that gets pulled out of a rack and photographed before it gets listed.
The evidence for this one is thin. Nearly everything known about the GP-215 comes from classified listings - a pair of Bulgarian ads and a French one - plus a single line in a 1987 issue of Studio Sound, where the unit appears as "HARRISON GP215, 2 x 15 Graphic" in a price-listing block. That's it. No brochure, no manual, no service literature surfaced in the archive's search. What follows is assembled from a handful of fragments, and the gaps are genuine gaps, not things this equalizer lacks.
The fragments do establish a stereo unit with fifteen bands a side. The "2 x 15" of the magazine listing and the "15 канален стерео" of the Bulgarian description are the same fact in two languages. For a graphic EQ that's a serious band count: enough sliders per channel to shape a mix or ring out a room with real precision, and the dual-channel layout suits stereo program material or a pair of monitor paths. Harrison built its reputation on console work, and a dual graphic from that lineage reads as an outboard tool meant to sit in a rack alongside the console, not as a hi-fi toy.
One owner's setup note places the GP-215 in company. It was listed as part of an outboard processors rack that also held a Warm Audio EQP-WA, a pair of Urei 537 graphic equalizers, and a Urei LA-22 dual multiband compressor. That's a working studio's outboard bay, not a collector's shelf, and it suggests the GP-215 was used as a peer of those units. Whether it earned the spot on sound or on availability is impossible to say from the record.
Key Features
2 x 15 Graphic Layout
The headline is the band count: fifteen graphic bands per channel across two channels, which is what the Studio Sound listing means by "2 x 15 Graphic." That's a fine enough grid to chase problem frequencies without the broad-stroke smearing of a ten-band unit, and the dual-channel format gives stereo material matched treatment on both sides. The fact sheet records no center frequencies, no Q, and no gain range. Anyone who wants the exact filter spacing before buying is out of luck, because that data isn't in the surviving record.
Dual Graphic Equalizer Architecture
Documentation describes the GP-215 as a "Dual Graphic Eq," which is the plainest statement of what it is: two graphic equalizers in one chassis, sharing a front panel and a power supply. For studio use that's the sensible configuration - one box, two channels, matched settings visible at a glance. The "professional" designation in the seller's description points to installed and studio work rather than consumer hi-fi. The archive has found no input/output details, no connector information, and no confirmation of balanced versus unbalanced operation.
Rarity as a Feature
Scarcity is an odd thing to list as a feature, but the seller's own words make it one. The GP-215 is described as "доста рядък и труден за намиране" - quite rare and hard to find. That's a market observation, not an engineering one. A graphic EQ that turns up once every few years in classifieds is a different proposition from one you can buy any week of the month.
Collectibility & Value
Pricing evidence is a single data point dressed as two. A GP-215 has been listed at 320 € on Bazar.bg, from a seller in Sofia, and the same 320 € figure appears on alo.bg. The two listings are likely the same unit cross-posted, so read that as one asking price, not two corroborating sales. A separate example has surfaced on leboncoin in Pontarlier, France, described simply as an "Égaliseur graphique Harrison GP215," with no price attached in the available record. There is no original list price, no completed-sale data, and no auction history to check the 320 € figure against.
Condition reporting is thin, but positive where it exists. The Bulgarian seller describes the unit as "в много добро състояние - работи без забележки" - in very good condition and working without issues. That's an owner's claim, not an inspection, and the archive has found no common-failure information, no service notes, and no spare-parts availability for the GP-215. A buyer should assume the unit is unverified and budget for a technician's once-over, since there is no published repair lore to lean on. It's rare, priced in the low hundreds of euros when it appears at all, and trades almost entirely on the Harrison name and the scarcity of the model.
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