EH - Attack Equalizer ( Knockout , KO , EQ )

Discussion regarding early stompbox technology: 1960-1975 Please keep discussion focused and contribute what info you have...
analogguru
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Post by analogguru »

Here:
http://electroharmonix.ronsound.com/art ... ttack.html

I could read:
The KO Attack EQ operates on a single 9 volt battery which supplies power to the LM324 quad op-amp that is the sole chip in the effect.
....
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."
...
The main (only) disadvantage to this model is that the circuitry was changed to accomodate 2 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.
Someone has more info about this unit or even a schematic ?

thanks in advance,
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Post by soulsonic »

I was reading Art Thompson's book on stompboxes and I saw an old E-H Attack Equalizer in one of the pictures. Apparently it's not a new box, so maybe there's a schematic of the old one somewhere.

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Post by analogguru »

Is this what your looking for?
In principle yes... but I was looking for a schematic or inside-pictures of the described (older or newer) unit. (outside-pictures I have from 7 different units)

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Post by DiscoFreq »

I don't have the EH Attack EQ, but I do have the 3 Polish Attack EQ's by PUE, Kod and Koda, I suppose they're copies (the knobs have the same functions), but I'm not sure :)

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Post by soulsonic »

That TESLA Attack Equalizer looks really cool!

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Post by analogguru »

I don't have the EH Attack EQ, but I do have the 3 Polish Attack EQ's by PUE, Kod and Koda, I suppose they're copies (the knobs have the same functions), but I'm not sure
yes......then let´s have a look inside to verify this :wink: :roll: :lol:

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Post by tuemmueh »

Great topic! I'm heavily interested in this circuit, also!

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Post by modman »

"Makes your Gibson style guitar sound like a Fender Strat" - that's at least how they were trying to sell it.

http://hammer.ampage.org/files/1981_E-H_pricelist.gif
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Post by DWBH »

tuemmueh wrote:Great topic! I'm heavily interested in this circuit, also!
ditto.

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Post by DiscoFreq »

tuemmueh wrote:Great topic! I'm heavily interested in this circuit, also!
I'm not, I have at least 8 of those Polish versions :D

(2 PUE's, 2 or 3 Koda's and I have A LOT of doubles of all Kod pedals :))

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Post by ech0es »

please the schematci of your attack eq polish clones

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Post by modman »

Discofreq,

Couldn't you give us a gutshot of an EQ Attack clone? Quite confusing if you say you bought eight and you're not interested in them :scratch:

thanks
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Post by modman »

https://cgi.ebay.com/NEW-ELECTRO-HARMONI ... dZViewItem

$67 only, maybe the Polish ones even beat the Behringen bottom stompbox prices record of 29EUR
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Post by analogguru »

The big price-fight:

"Can polish workers beat the price-dumping of chinese made pedals ?"

IMHO the new EH-pedals are also made in china, maybe in the same factory as MXR ?

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Post by DiscoFreq »

modman wrote:Discofreq,

Couldn't you give us a gutshot of an EQ Attack clone? Quite confusing if you say you bought eight and you're not interested in them :scratch:

thanks
I'm not interested in schematics to build this type of effect as I already have these clones ;)

I like the effects a lot :)

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Post by analogguru »

There´s a sucker born every minute - and too many of them end up in the bootweak pedal biz.

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Post by bajaman »

since nobody seems to be willing to help me out, I decided to do a new search and I found this
You are just too efficient AG :lol: :wink:
bajaman

ps: have you got the KLON yet?????

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analogguru
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Post by analogguru »

:shock: :shock: :shock:

I believe much, but I can´t believe that this hand-painted pcb has been manufactured by Tesla Vrable, even when components look like old czech/russian production.

maybe somebody exchanged the PCB ?
It is different than the EH schematic above.
We´ll see, maybe it´s the single supply version (LM 324) made with single op-amps.

analogguru
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