Recording - May 2010 - 34

BY SCOTT DORSEY

Square State Solid State EQUALIZER
model one b
A new company offers classic eq sound at an unheard-of price—here’s how

The Square State Solid State EQUALIZER model one b is a singlechannel 3-band LCR-filter eq with 1/4" TRS balanced I/O. It’s the first product from Square State Solid State, a Colorado-based firm that designs and builds its products entirely at its Denver-area workshop. It’s a new take on an old classic design with some serious attempts made to keep the costs down. Engineers who have used old-style inductive equalizers will immediately find a familiar sound. Younger folks who grew up with inexpensive gyrator equalizers in lowend consoles will find it a pleasant step up at a reasonable price.

you would expect to hear if the opamp was running out of steam. The bypass button is not a true bypass; if you press it with the power disconnected, no audio passes through the device. (That is, the bypass button disconnects the filter networks from the feedback path of the op-amp without bypassing the op-amp itself.) This is not a huge concern since the unit is still very neutral-sounding in bypass mode, but it’s something to watch out for. Even with its steel case, you’ll want to be careful about hum pickup with this eq. Don’t put it right on top of a power amplifier. If you notice 60 Hz hum, move it If this box had been built around in your rack and try and allow for a little bit of rack Build: something old, something thirty years ago, it would be space between it and the new sources of the magnetic fields. selling on Ebay for $1000... For example, the power transWith respect to the general construction quality, Square State former on my HHB CD-R unit is if you could find one. Solid State did some good things on the lefthand side of the case and some less-good things. First of inside the box, the same side as all, the case is stamped from steel, the Square State eq’s inductors, which is a very important thing in so the HHB needs to be kept the case of an inductive device though, the unit is somewhat more sen- away from the Square State by a coubecause it helps to block hum from sitive to stray magnetic fields than it ple of rack spaces. On the other hand, being induced by outside magnetic otherwise would be. the power transformer on my Great fields. The case is solidly built and the The op-amp used in the circuit was River preamp is on the righthand side two PC boards are solid and well laid a rather standard type, and the good of the case, and there’s no problem out; there’s an external power supply, news is that they socketed it so that racking it next to the Square State eq. which can help a bit with hum issues you could try other op-amps if you The manual doesn’t warn you about and keeps costs down. were curious. In this case, though, the this, but it’s something you will In contrast to the case, the internal inductors probably affect the sound encounter with just about any induccarbon-element pots and rotary wafer more than the op-amp, and I expect tive equalizer to some extent. switches look like typical consumer- they selected the op-amp to make grade electronics parts from the sure this was the case. I didn’t hear Sound: (almost) like an old friend 1970s—the kind of stuff that you’d any slew limiting when I used exagNormally with a review unit, I spend expect to find in the blister packs at gerated equalization settings, like a lot of time listening before I pop open
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Lafayette. Still, for the price point you can’t complain; they operated reliably in my testing period and they don’t feel bad. Internally the unit uses inexpensive rod inductors that are designed for switching power supplies rather than a big multitap inductor. I was surprised when I saw this, because really the thing sounds better than I would expect from powdered iron rods, although the fairly wide filters may have something to do with that. Because of these inductors,

Recording - May 2010

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