The Electrodyne 2501 is a two stage discrete transistor, transformer coupled preamp with active DI, using classic 1969 / 1970 design technology. Each amp stage is individually optimized for peak performance using Electrodyne factory engineering notes and selected high performance components identical to the originals. The transformers are made by Electrodyne’s original manufacturer to exacting factory specifications. The active DI circuit presents an almost immeasurable load to sensitive musical instrument outputs allowing incredibly accurate capture of the instruments true tone. The output of the DI circuit is designed to directly connect and interact with the mic input transformer to allow maximum tone options.

Features:

• Maximum Gain: 68db. Adjustable over 50db in 2db steps with two ranges using 20db pad.
• Output level control: Infinitely adjustable from 0 (off) to +6db over unity.
• Input impedance: Microphone, 50 / 200 ohms selectable. DI, over 7 megohms.
• Output impedance: 150 ohms
• Distortion: 0.02%typical over entire gain range.
• Maximum output: +30db at less than 0.8%thd. (+29.5db at 0.06%thd)
• Frequency response: +/- 0.25db, 10hz to 60khz.
• Signal to noise: -80db typ, -60db at absolute maximum gain.
• Clip indicator: Monitors all three amp stages and illuminates when any stage is 3db from clip.

The Electrodyne 2511 is a classic two-band discrete transistor reciprocal active inductor equalizer using 1969/1970 design technology. The custom inductors and output transformer are made by Electrodyne’s original maker, to strict factory manufacturing tolerances as small as 2%. This allows consistent eq performance and repeatability from channel to channel that was not possible in the 60s. 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.

Features:

• 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

The Electrodyne 501 is a two-stage, discrete transistor, transformer-coupled preamp with active DI based primarily on the modules found in the classic 1608 console.  Each amp stage is individually optimized for peak performance using detailed Electrodyne factory engineering notes and select high performance components identical to the originals. In fact, the 501’s transformers are made by Electrodyne’s original supplier to exacting factory specifications.

The new preamp’s active DI circuit presents an almost immeasurable load (over six megohms) to sensitive musical instrument outputs allowing incredibly accurate capture of the instrument’s true tone.  Furthermore, the output of the DI circuit is designed to directly connect and interact with the mic input transformer to permit an extremely broad spectrum of tonal options. 

The faceplate of the Electrodyne 501 features a large rotary gain control offering up to 68dB of gain – adjustable over 50dB in 2dB steps with two ranges via a 20dB pad switch – and a smaller output level pot infinitely adjustable from 0 (off) to +6dB over unity.  Additional switches for impedance selection (50 or 200 ohms), phase reverse, +48V phantom power and DI (with 1/4" input jack) are also present, as well as a clip LED that monitors all three amp stages and illuminates when any stage is 3dB from clipping.



Specifications:


• Maximum Gain: 68db – adjustable over 50db in 2db steps with two ranges using 20db pad
• Output level control: Infinitely adjustable from 0 (off) to +6db over unity
• Input impedance: Microphone, 50 / 200 ohms selectable. DI, over 7 megohms
• Output impedance: 150 ohms
• Distortion: 0.02% typical over entire gain range
• Maximum output: +30db at less than 0.8%thd. (+29.5db at 0.06%thd)
• Frequency response: +/- 0.25db, 10hz to 60khz
• Signal to noise: -80db typ, -60db at absolute maximum gain
• Clip indicator: Monitors all three amp stages and illuminates when any stage is 3db from clip

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.

Complete True Large-Format Analog Summing Bus with Stereo Insert
Essential Studio Control Room Monitor Features
Artist Cue/Talkback
High Power Headphone Amp

Classic Electrodyne 1970's Large-Format Console Summing and Stereo Mix bus:

• 16 channel active summing network and stereo bus with fully balanced stereo insert path.
• Transformer balanced analog outputs. Transformer control for "tight" vs. "warm" mix bus sonics.
• Precision Detented Master Bus Level Pot with Stereo Bus Calibration Trimmers.
• Original Electrodyne design transformers and discrete transistor op-amps throughout.
• Studio Quality Control Room Monitor Section:
• Stereo Mix, Artist Cue, XLR and 1/8" Mobile Device Inputs.
• Precision Detented Control Room Level Pot.
• Mono, Dim and Mute Controls.
• Main/Alt Monitor Selector with Precision Level Trimmers for Alternate Speakers.
• Extremely Low Distortion Balanced Signal Path for Quality and Accuracy of Monitoring.
• High Power, Low Distortion Headphone Amplifier.
• Artist Cue and Talkback:
• Cue Input Talkback Loop for Artist Headphone / Studio Monitor Mix.
• Integrated Talkback Microphone with Control Room Monitor Dim function and Remote Talkback Jack.
• "Control Room Listen" Function Allows Artists in Studio to Hear Control Room Sources (Playback,
• Rehearsal, etc.)

FRONT PANEL:
SUMMING SECTION:

• MONO 1-2, MONO 3-4 buttons: Changes stereo pairs 1-2 and 3-4 to two mono channels each.  This allows two or four mono sources 
      (eq: Kick, Snare, Lead Vocal, Bass, etc…) Avoids using up a stereo pair for mono tracks.
• MIX level knob: 31-step detented Master Stereo bus level for accurate recall. “0” setting is unity gain.  +6db of gain above unity is available for boosting mix levels. 

INSERT button: Engages a fully balanced Stereo bus insert for mix mastering and stereo processing gear.
• BUS trimpots: Allows trimming +1.5db/-3db for exact stereo bus levels to your stereo master recorder (DAW, Stereo tape machine, etc...)
• TRANSFORMER button:Changes mix bus tones by switching mix amps and output transformers to two different configurations. 
     “WARM”, classic 1970’s full transformer harmonics. 
     “TIGHT”, smooth and silky with controlled harmonics.

CUE / TALKBACK SECTION:

• TALKBACK button: Mutes incoming CUE or CR LISTEN audio and sends Talkback Mic to CUE bus outputs.
• TALKBACK level knob: Adjusts level of Talkback microphone to CUE bus outputs.
• Talkback Mic.
• CR LISTEN button: Switches CUE output from CUE input, to audio selected on CONTROL ROOM source selector buttons.
• CR LISTEN level knob: Adjusts level of audio from CONTROL ROOM source selector to CUE outputs, when CR LISTEN is engaged.

CONTROL ROOM SECTION:

• EXT-1 button: Selects Control Room input from 1/8” front panel jack. For SmartPhone, MP3 player and other portable audio devices.
•  EXT-1 front 1/8" jack: For personal/mobile electronics (Smartphone, MP3 player, etc..) Standard 1/8” stereo  audio input jack, over-rides rear 1/4”
         TRS jack when plugged in.  (-6db nominal level)
• EXT-2 button: Selects Control Room input from rear panel balanced XLR connectors.
• CUE button: Selects Control Room input from CUE input xlr's.
• MIX button: Selects Control Room input from Summing section Stereo mix bus.
• CONTROL ROOM knob: Controls level of studio monitor speakers.
• MONO button: Folds stereo signal to mono (for phase checking, mono compatibility, etc..)
• DIM button: Reduces CONTROL ROOM level by approximately 20db.
• MUTE button: Mutes studio monitors.
• MONITORS button: Selects MAIN or ALT monitor speaker sets.
• ALT trimpots: Adjusts level of ALT speakers for matching MAIN speaker levels.
        Factory default setting is no attenuation (equal to MAIN).  Adjustments should be made by setting level controls on your ALT speakers louder than
         Main, and turning down ALT trimpots to match MAIN speaker levels.
• HEADPHONE level knob: Adjusts level of HEADPHONE amplifier. (NOTE: Headphone amp can be set Pre or Post Control Room level. (see internal
         jumper settings).
• HEADPHONE jack: 1/4” TRS jack for professional headphones.