Why you need the Electrodyne 511 500 Series Equalizer:

The Electrodyne 511 is a classic two-band, discrete transistor, reciprocal, active inductor-based equalizer using late-’60s/early-’70s design technology.  As with the 501, the 511’s custom inductors and output transformer are made by Electrodyne’s original provider to strict factory tolerances as small as two percent.  This affords a consistent EQ performance and repeatability from channel to channel that was simply not possible in the 1960s.  Smooth performance and EQ response from minimum to maximum gain at all frequencies provides unusually broad sonic and tonal options not experienced since the 1970s. 

The module’s faceplate sports twin large rotary EQ controls each offering ±12dB of boost and cut with four selectable frequencies per band (LF: 40, 100, 250 and 500Hz / HF: 1.5, 3, 5 and 10kHz).  Shelving is available on all frequencies, with peaking offered at 250 and 500Hz in the LF band and 1.5, 3 and 5kHz in the HF band. An EQ in/out switch with accompanying LED rounds out the front panel feature set.

Specifications:

• Input: active balanced discrete transistor impedance converter.
• Output impedance: 150 ohms
• +/-12 db gain range: equalize or attenuate
• 4 frequencies selectable per band. LF: 40, 100, 250, 500hz. HF: 1.5k, 3k, 5k, 10k.
• Peak/shelf function on each band. Shelving at all frequencies, peaking at 250, 500, 1.5k, 3k and 5k.
• Distortion: 0.03%typical.
• Maximum output: +30db at less than 0.8%thd. (+29.5db at 0.06%thd)
• Frequency response: +/- 0.25db, 10hz to 70khz typical.
• Signal to noise: -85db typ.