What were these modified EQ's used by Boston, before the Rockman EQ was born? On this picture from the 1987 tour, we can see that Boston used Boss 10 bands EQ's: these were the modified units.
The first Rockman EQ prototypes were certainly reproductions of these modified 10 band EQ's, housed in a Rockmodule enclosure to match the existing Sustainor and Chorus/Delay. The following picture, grabbed from a 1987 guitar magazine, shows this un-issued 10 bands Rockman EQ, the draft of the 12 bands model we all know:
Bob Cedro, now MXR's chief-engineer, was in charge of the development of this 12 bands Rockman Instrument EQ. The first models, made in 1987 had the same blue logo as the Sustainor 100 and the Chorus/delay, as on this ad published in December 1987:
Then the white face series was issued, with the Stereo Echo and the Stereo Chorus: the Instrument EQ was finally a white-face too, and these blue-face models must be extremely rare now.
Inside the Module
The first thing that a tech will see inside the Instrument EQ is... no 4053/4066 chips! These J-FET IC's are everywhere in the other modules, and were not used in the EQ. As a matter of fact, SR&D designed it for the best signal-to-noise ratio, and selected a +/-12V power supply - instead of +/-8V - that prevented from using the integrated switches (the bypass circuit is therefore based on discrete J-FET's).
The higher the power-supply voltage is, the stronger the signal can be, and the better is the S/N ratio: with a total amplitude of 24V, the immediate improvement is 4dB compared to a 9V powered stompbox. The Rockman EQ can thus be used both with guitar level signals, as required by Tom Scholz, and strong line-level signals (up to 14dB): there is a switch on the Rockman EQ that selects the operating signal level (Normal: line level or Hot: instrument level).
Back to the features of the unit. The real difference between a classical EQ and the Rockman Instrument EQ is the presence of 3 additional bands in the mid-frequencies:
The range of each band is +/-12dB: all in all, the Instrument EQ is extremely precise and efficient, and allows the best sound sculpture for the most demanding musicians.
This is not instrument gear any longer: the Instrument EQ is a genuine studio-quality device.
Usage and limitations
The Rockman EQ is truly mandatory for anyone who really wants to create and tweak his own sounds. When one starts building a Rockman rig with a Sustainor, it becomes rapidly obvious that two EQ's are necessary: one placed in the loop as a pre-distortion EQ, the second one being placed after the Sustainor.
The possibilities provided by a pair of EQ's are both subtle and endless. Changing a few dB's on a frequency band can alter significantly the sound and the position of the guitar in a mix, and using radical settings can also deliver specific sounds: fuzzy or metallish, fixed-wah effects, etc...
As a matter of fact, EQ'ing can become very complex, and can turn into a real nightmare. Finding the perfect sound is impossible, and the situation was perfectly summarized by UseHerName on the boards of Gonnahitcharide.com:
Collectibility and conclusion
The Rockman EQ is a sort of perfect tool, and is becoming quite hard to find: people always want more EQ's and don't sell them easily.
The problem is that there are 21000 Sustainors and 15000 DG's to equip, while only 5500 Rockman EQ's were manufactured! Rarity makes the price, and it is not uncommon to see EQ's selling above $200.
Copyright Rockman.fr 2008