I have three 1/3-octave AudioControl C-131 equalizers for sale. This is a rare opportunity to buy an extra unit for the center channel without the expense of a second bundled stereo pair. This is hands down one of the finest equalizers ever offered for home audio systems. Original list price was $525 in the early 90s. I’m the original owner and have had these equalizers since 1996 and have been very pleased with them. Extremely quiet, no S/N penalty to your system. Absolutely clean and transparent with no audible coloration until you adjust a slider. I once did a head-to-head comparison with a comparably-priced professional-grade Ashly 1/3-octave EQ, and the AudioControl C-131 annihilated it – much quieter, more accurate dB markings on the faceplate. Two of the equalizers will come with an original owner’s manual. A photocopy of the original owners manual is included for the third unit. Asking $200 firm for each one. Will separate. I’ve been tracking these equalizers on eBay for the past several months, and they typically sell in the $200-250 range. I intend to put them up on eBay in the Spring, when prices are best, but thought I’d list them here in the interim. Expect shipping to be in the $30 range for each one. I don’t have a box bid enough to ship them all together. I can e-mail larger jpg pictures if you like. Buy with confidence, see my 100% eBay feedback, user name wpflugha. The owner’s manual gives the specifications as: Noise –112 dB (A-weighted, all controls set at 0 dB boost/cut) Total Harmonic Distortion - 0.002% Frequency Response - 10-100 kHz +/-0.2 dB (All sliders set to 0 dB boost/cut) Thirty 1/3-octave filters from 25 Hz – 20 kHz, range +/-15dB Input impedance, unbalanced - 47k ohms Input impedance, balanced - 10k ohms, differential mode Output impedance, unbalanced - 100 ohms Output impedance, balanced - 50 ohms Dimensions – 3.65" H x 17" W x 11" D Weight - 10.5 lbs.