The Creek Sequel 54 mk2 MM Phono Pre-Amp is suited for medium output moving coil cartridges, with an output between 0.5 to 1 mV and a matching impedance of < 120 ohm. The Sequel 54 mk2 is not suitable for high output MC cartridges, which require lower gain and a higher input impedance.
The Sequel mk2 has two gain stages using low-noise op-amps. RIAA correction is performed both active and passively. The first gain stage matches the MM cartridge's < 120 ohm impedance and adds gain, without changing the frequency response.
The first stage of RIAA de-emphasis is performed passively between the two gain stages. The mk2 circuit uses a low impedance filter circuit for improved noise performance. The second gain stage boosts the level further and uses active filtering in its feedback for the RIAA de-emphasis, For improved RIAA accuracy and improved sonic quality, the Sequel mk2 is made with E96 1% tolerance metal film resistors and 1% tolerance polypropylene WIMA capacitors.
To eliminate coupling capacitors that can negatively affect the sound, a DC servo circuit is used to block DC from input to output and roll-off low frequencies sensibly below 10 Hz. There is no rumble filter in this design.
The Sequel mk2 is powered by a dedicated voltage from the integrated amplifier, via its PCB connection pins. Locally, it uses low noise voltage regulators, whose function is to stabilize the voltage and filter noise from the main power supply. The Sequel mk2 has optimal overload margin for a given gain.