Rupert Neve Designs - 517 500 Series Mic Pre/DI/Compressor

Classic tone & control for your mic AND instrument.
The 517 provides a world-class mic preamp, one-knob compression, DI circuitry with Vari-phase, Silk saturation and DI + mic blending capabilities - all in a single module.

GAIN
A 12-way precision rotary switch covering from Line (0) and Mic from 0 to 66 dB in 6 dB steps.

+48V
Engages phantom power on the microphone input, as supplied by the 500 series rack.

POLARITY
Push button inverts the polarity of the signal path. The symbol "O" is often used to denote opposite polarity.

COMPRESSOR
Based around a new LDR (light dependent resister) design, the 517's opto-coupler compressor has been simplified to a single threshold control with auto make up gain. By default, the compressor is set to a fixed 2:1 ratio with fixed attack and release. To set the compressor, simply dial the threshold control down until the desired amount of compression is achieved. An LED light indicates when the compressor is active.

BLEND
The 517 can be used to combine and compress a direct signal and an amplified signal. To achieve this, use the DI for an instruments direct signal and the mic preamp for either the mic'd speaker cabinet signal or an entirely separate source (like a vocal microphone). The blend control allows you to achieve the desired tonal balance between the two sources.

SILK
Pushing the Silk button engages the Silk circuit, which enhances the source's harmonic content in a manner very reminiscent of many of Rupert's class-A vintage designs.

VARI-PHASE
The VARI-PHASE control rotates the phase incrementally, allowing two signals with the same source to be phase aligned. This control is most apparent when the signals being combined are at roughly equal levels, and is generally used when blending an instrument's direct signal with its amplified signal, as captured by a microphone.

INSTRUMENT GAIN
Front panel TRS Input and passive through for hi-z sources. Continuous gain control from 0dB to 30dB.

THRU & INST 1/4" PHONE JACKS
These 2 jacks are used for instrument direct input and a THRU output to an amp, and are paralleled and wired together, as it is a passive design. Inserting a plug into either jack breaks the normal MIC input and the user has the full range of MIC GAIN and TRIM. These jacks have a 3 mega Ohm input impedance that will provide less loading (i.e. better highs) than most DI boxes, and the sheer amount of gain that is available makes this input extremely versatile.

Specifications
FREQUENCY RESPONSE

Mic Pre, Main Output, no load.
-0.1 dB @ 10 Hz
-1 dB @ 120 kHz

DI Input, Main Output, no load.
-0.1 dB @ 10 Hz
-1 dB @ 120 kHz

NOISE
Measured at Main Output, unweighted, 22Hz - 22kHz, Terminated 150 Ohm.
With gain at unity: better than -100 dBu
With gain at 66 dB: better than -60.5 dBu
Equivalent Input Noise: better than -125 dBu

DI
With Gain @ Unity: Typically better than -100 dBu
With Gain @ +30 dB: Typically better than -75 dBu

HIGH PASS FILTER
Frequency: 80 Hz
Slope: 12 dB/Octave Bessel

Microphone Input Impedance
10,000 Ohm

Instrument Input Impedance
1.6 Meg Ohm (3.3 Meg Ohm balanced)

Maximum Output Level
Maximum output from 20 Hz to 40 kHz is +23 dBu.

GAIN
Mic Pre: Unity to +66 dB in 6 dB steps
DI: Unity to +30 dB continuous

Total Harmonic Distortion and Noise
- @ 1 kHz, +20 dBu output: Main Output: Better than 0.001%
- @ 20 Hz, +20 dBu output: Main Output: Better than 0.002%
- Silk Engaged: Better than 0.2% Second harmonic

VARI-PHASE
- @ 100 Hz: 2.9 degrees to 57.4 degrees
- @ 1 kHz: 33.5 degrees to 156 degrees
- @ 10 kHz: 149 degrees to -175 degrees

PHANTOM POWER
+48 Volts DC +/- 1% (provided by 500 Series Rack)

POWER REQUIREMENTS
Supplied by 500 series rack with 110-125 mA @ +/- 16V

COMPRESSOR

THRESHOLD
Continuously Variable from -20 dBu to +10 dBu

RATIO
Fixed at 2:1

ATTACK & RELEASE
- Fast Mode: Attack 5ms, Release 50ms
- Slow Mode: Attack 250ms, Release 500ms

TOTAL HARMONIC DISTORTION
Measured @ Main Output.

MIC PREAMP AND DI
- @ 1 kHz, +20 dBu output: Better than 0.002%
- @ 20 Hz-20 kHz, +4 dBu output: Better than 0.02%

SILK
- @ 20 Hz, +4 dBu output: Better than 0.5%
- @ 50 Hz, +4 dBu output: Better than 0.1%