These Op Amps Labs G9s are 9-band inductor based passive equalizers with the option of two different discrete operational amplifiers (DOAs) on the outputs.
They come with their original Op Amp Labs 325 EQ amplifiers, as well as a pair of Wolfgang Michael Sound (WMS) EQ Amplifiers which use an upgraded Sphere SPA62 circuit - the same op amp used in our Sphere Eclipse Type III console. This amplifier has high headroom, incredible depth and clarity and is one of the most musical amps I've ever heard.
These EQs have been fully serviced by Wolfgang Michael Sound and come with their original socketed power supplies as well as a brand new custom +/- 24V PSU that powers both units. They also come complete with output cables and PSU cables.
When used with the WMS EQ Amplifiers, these EQs sound almost exactly like the famous Sphere 900 Series Graphic EQ, which makes sense since Op Amp Labs, Altec, Langevin, Electrodyne (and eventually Sphere) were all from the same golden-era, the same geographical location, and all shared similar designs and parts.
Just like the Sphere 900, The G9 EQ operates at +/- 24 V, has 12 dB of boost and cut per frequency, and has same nine frequency bands: the thunderous 50 followed by 100, 200, 400, 800, 1.6K, 3.2K, 6.8K, and the heavenly 12K. The biggest difference between the G9 and 900 series EQ is that the G9 uses sliding potentiometers in place of rotary switches, which allows for infinitely variable adjustments between -12 and 12 dB versus 2 and 3 dB steps with the 900. The G9 offers more fine-tuning whereas the 900 offers exact recall-ability.
The G9 is an unbalanced EQ (also like the 900), and sounds fantastic this way. But if you are interested in adding output transformers, we can provide a pair of original Reibenbach 7393 output transformers (used for all of the outputs on all Sphere consoles), and may be able to rack them up so that they can be patched (or switched) in or out of the signal path. The transformers alone would be $120, or $250 racked up.
