Last Updated on Tuesday, 01 June 2010 13:48
I am the EH Man, Keeper of the Electro-Harmonix flame. In this column, We’ll be exploring the histories and purposes of those products we all know and some of us love. In this first column, I’ll be examining the EH Attack Equalizers.
First, the facts: The Attack EQ appeared very early in EH’s history. There are catalogs stating its availability as far back as the early 70’s, making it a triangle-knob model. There were no pics of this version in the catalog and so far, one hasn’t come to light. Perhaps it only existed in the ads and none were actually produced.
The Electro-Harmonix Knockout Attack EQ, model # EH-3004, made its appearance in or about 1974. Its first appearance in my literature collection is in Guitar Player’s “It’s New” column from Jan. 1975. It was housed in the standard 3 knob, Big Muff Pi style box and features a nifty boxing glove logo .
Controls for this edition consisted of (l-r): Volume, Blend, and Tone. According to the description from an EH catalog, the Knockout “takes the output signal from any guitar and amplifies the highs and lows while simultaneously allowing the guitar player to mix out the midrange.” Does it do this? Well, I plugged it in and played the trusty ol’ Guild Thunderbird (refinished, you guitar hounds) through it into a Mike Matthews Dirt Road Special and here’s what I found. Volume does just what it should and yes indeed, the Blend control does allow a blending of the straight signal with the EQ’d signal. I’m not certain that the Attack control does what the ad says, but it does have a wide range that takes you from a boomy bass to an annoyingly crisp treble. Different settings of the Tone and Blend knobs allow you to dial in (or out) that extra little touch of treble or bass you’ve been wanting. Try Blend on full and Tone on minimum. OUCH!!!
The KO Attack EQ operates on a single 9 volt battery which supplies power to the sole chip in the effect, the LM324 op-amp. An on/off switch on the back allows you to leave your guitar plugged in without running down the battery.
In April 1976, Guitar Player’s “It’s New” column announced a new Attack Equalizer. Same chassis, but now “Knockout” was deleted from the name and “Every guitar sound can be obtained from any guitar with the simple setting of a dial and flick of a switch.” was the bottom line here . The Attack Equalizer was designed to allow the guitarist to “convert his Les Paul into a Fender or vice versa.”
This is where the fiction comes in. In reality, the Attack Equalizer is a glorified 3-band rotary EQ. The controls are labeled as (l-r): Fundamental, Blend, and Attack but the schematic lists the controls as Bass, Mid, and Treble. After seeing the schematic, former EH engineer Howard Davis remarked:
“If I were to redo it, I’d certainly improve those PRIMITIVE low pass and high pass filters! Also, what is called the “midrange” control is actually a direct signal level control, not a bandpass, as a midrange control should be.”
Don’t get me wrong though, the Attack EQ is just as good as the KO. To me the sound is about the same, but I’m a bass player so what do I know?
The main (only) disadvantage to this model is that the circuitry was changed to accommodate two 4558P dual, internally compensated, high performance op-amps, which required positive and negative power supplies. This resulted in, yes, 2 nine volt batteries for operation which are switched on or off by a rear-mounted power switch.
The original Knockout Attack EQ carried a price tag of $69.95 as did the later Attack EQ. By the early 80’s though, the Attack EQ had increased its price to $89.95. The Attack EQs are not as popular with players as some other EH stuff, so you can probably pick them up for under $100 in working condition. Hey, it’s cheaper than buying an extra guitar! Pick one up, plug it in, and make a new guitar out of your old one.
Thanks to Kevin Macy and Al Pepiak for their help in getting this article put to paper.