ADC SS-115 (1980s)

A no-nonsense, ten-band analog equalizer that treats your signal with surgical precision - when it's not crackling from 40 years of dust.

Overview

Flick the power switch on an ADC SS-115 and you learn most of what you need to know. The illuminated logo lights up like a tiny neon sign, the sliders click into place with a mechanical thud, and if the unit has been serviced lately, a clean, neutral hum settles in. No buzz, no hiss. This isn't a warm, colored box designed to flatter your records. It's a tool, built for people who wanted to tweak, tune, and sometimes totally twist their sound with surgical control. ADC Professional Group of Japan released it in the early 1980s, into a market flooded with flashy, gimmicky EQs promising sonic miracles. ADC skipped the theatrics. You got ten bands per channel, from 31.5 Hz to 16 kHz, ±15 dB of cut or boost, and a build quality that suggests it was meant to survive both basement studios and touring racks.

It's easy to overlook the SS-115 in favor of more famous names like the Rane or Drawmer units that followed. But it was quietly competent: solid-state, discrete design, no digital trickery, and a signal path that stayed out of its own way. It wasn't trying to sound "vintage" because it *was* vintage the moment it rolled off the line. The sliders use stepped potentiometers, which feel deliberate and precise. They're also the unit's Achilles' heel. Decades of oxidation and dust mean most un-restored units crackle like a campfire when you move the faders. The glowing ADC logo is powered by a small incandescent bulb, now almost certainly burned out or fragile as a soap bubble.

Despite its pro-grade DNA, the SS-115 found a home in high-end home systems too, often slotted between a preamp and power amp to fine-tune room acoustics or tame harsh recordings. It has dual tape loops, labeled "Dub 1" and "Dub 2", so you could EQ while copying tapes. That made it a quiet favorite among audiophiles who still believed in the mixtape as art form. It shares DNA with the SS-115X, a nearly identical sibling with cosmetic tweaks and minor circuit revisions. The original SS-115 has a slightly cleaner front panel layout and, some argue, a marginally more transparent sound.

Specifications

Key Features

Ten-Band Surgical Control

The SS-115 doesn't mess around with broad strokes. Its ten bands sit at ISO-standard frequencies, which gives you enough resolution to target problem areas without the overkill of a 31-band EQ. The ±15 dB range is generous, more than many modern digital EQs allow, and it's applied with a flat, uncolored hand. Some graphic EQs add their own sonic signature, usually a softening of transients or a low-mid murk. The SS-115 stays transparent when flat. That makes it good for corrective work: taming a boomy room, reducing sibilance on a vocal track, or smoothing out a bright speaker. When you boost or cut, you hear the change in frequency balance, not the EQ itself. That was rare for a unit at this price point in its day.

Discrete Analog Design

Inside, the SS-115 relies on discrete circuitry centered around the JRC4559D op-amp, a workhorse IC known for decent performance and wide availability. It's not as revered as the 5532 or discrete transistor designs in high-end units, but the 4559D holds up well when properly maintained. The power supply uses electrolytic capacitors, which, like all components of their era, degrade over time. Many unrecapped units suffer from hum or channel imbalance. A full capacitor overhaul, especially on the power supply and signal path, can restore near-original performance. Some owners have upgraded to higher-grade capacitors for even better clarity, though purists argue the original-spec parts deliver the intended neutrality.

Dubbing Loops and Signal Routing

The two tape loops are a functional feature, not just a relic of the cassette age. They let you insert the EQ at multiple points in your chain. You could, for example, leave your main signal path clean while applying EQ only during tape dubbing, preserving the original recording while experimenting with tonal shaping. The routing is switched manually with front-panel buttons, with clear labeling and positive tactile feedback. It's a simple system, and it avoids the complexity of microprocessor-controlled signal paths that could fail or drift over time.

Historical Context

The early 1980s were a transitional moment for audio gear. Analog was still king, but digital was creeping in, first in test equipment, then in effects and eventually full digital mixing. The ADC SS-115 arrived when graphic equalizers were shifting from live sound applications into home and project studios. Competitors like Sony, Technics, and Pioneer were releasing their own EQs, often with flashier designs or built-in meters, but few matched the SS-115's straightforward utility. ADC, while not a household name like Denon or Yamaha, had a reputation in pro audio circles for building reliable, no-frills gear. The SS-115 fit that mold: not glamorous, but dependable.

It also arrived just before the home audio boom of the mid-80s, when audiophiles began obsessing over room correction and system matching. True parametric EQs offered more precision, but they were expensive and complex. The SS-115 sat in a sweet spot, with enough control for serious tuning and simple enough for non-engineers to use. It never achieved cult status, but it was widely used in small studios, broadcast booths, and high-end living rooms where someone cared enough about sound to want to adjust it, but not so much that they needed a Neve console.

Collectibility & Value

Today, the SS-115 is a sleeper in the vintage gear market, respected by those who've used one but largely overlooked by collectors chasing flashier names. A working, cleaned, and recapped unit typically sells for between $80 and $150, depending on condition and whether it includes original packaging or manuals. Unrestored units often go for under $60, but that's a false economy. Most need at least slider cleaning and capacitor replacement to perform reliably. The electrolytic caps in the power supply are particularly prone to leakage, and if left unchecked, they can corrode the PCB and damage other components.

The biggest issue is the slider potentiometers. Decades of dust, oxidation, and wear mean most uncleaned units crackle when adjusted. Some people try contact cleaner, but experienced techs warn that repeated spraying can create conductive sludge inside the pots, which makes the problem worse. The best fix is disassembly and ultrasonic cleaning. In severe cases, the answer is replacement with modern conductive plastic sliders, which give up some originality but restore function.

If you're buying, test every slider across its full range. Listen for crackles, dropouts, or channel imbalance. Check the LED bar graph: if it's dim or flickering, the AN6877 driver ICs may be failing. The power cord is another red flag. The original two-core ungrounded cables are a fire hazard by modern standards. Many owners retrofit a three-core grounded cord and add a proper earth connection to the chassis, a must for safety if you're using it regularly.

For what it offers - a full-featured, pro-grade analog EQ with wide frequency coverage and solid build - the SS-115 is a bargain when properly restored. It won't add "warmth" or "vibe," but it will let you shape your sound with precision, just like it did in 1983.

eBay Listings

ADC Sound Shaper SS-115X 10 Band Frequency Equalizer,TESTED!

$95.00

​Vintage ADC Sound Shaper SS-115 Stereo Graphic Equalizer -

$125

ADC Stereo Frequency Sound Shaper Equalizer SS-115X - H

$130

ADC Sound Shaper SS-115X Analog Stereo Equalizer Black RCA L

$85.00

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