Shelford 5051 – Inductor EQ / Compressor

The 5051 combines a classic three band EQ based on Rupert’s vintage designs with the power and flexibility of the Portico II compressor. Utilizing a fully-discrete, class-A signal path and high performance input and output transformers, the 5051 delivers the performance and musicality expected from a Rupert Neve Design.



The EQ design on the 5051 evokes sonic similarities with some of Rupert’s classic EQs. The 5051 uses a custom tapped inductor with selected capacitors to form the mid range equalizer band, and the shelf curves are based on Rupert’s vintage modules, including very similar frequency choices. Each EQ section also uses low feedback class-A discrete electronics to prevent low level artifacts and harshness from detracting from the tonal shaping. The EQ, however, is a modern design with advantages offered by techniques that were not possible 35 years ago along with improvements in electronic components currently available, and should not be considered a clone. Let’s just say it has heritage.

Frequency Response:
Main Output, no load, –3 dB @ 2.5 Hz
–3 dB @ 125 kHz

Measured at Main Output, unweighted, 22Hz-22kHz, Terminated 40 Ohms, With gain at unity
better than –102 dBu

Maximum input:
from 20 Hz to 20 kHz, +25 dBu.

Maximum output:
from 20 Hz to 20 kHz is +25 dBu. Total Harmonic Distortion and Noise: from <10 Hz to 80 kHz, @ 1kHz, +20 dBu output: Better than 0.002% @ 20Hz, +20 dBu out Better than 0.120% 13 @ 20kHz, +20 dBu out Better than 0.010%