Sunn SPL-4120 Graphic Equalizer

in good working condition. 

From Sunn:

The SUNN SPL 4120 is an advanced solid state equalizer containing features which can be appreciated by the professional musician as well as the discriminating audiophile. Low noise, low distortion, high slew rate devices have been used throughout the SPL 4120 to insure state-of-the-art performance. 15 db cut and boost is provided at ten octave intervals with an overall level control capable of a full #20 db. Level sensing is employed at two critical nodes in the circuit to provide distortion free performance while maintaining an excellent signal to noise ratio. All inputs and outputs allow balanced or unbalanced line operation to insure compatability and flexibility. These features are all contained in a rack mountable steel chassis to provide you with a rugged, high performance audio tool that will fulfill your equalization requirements for years to come.