Creek Audio has always been a fan of the vinyl disc. For those consumers who have an interest in enjoying this exciting source of high quality music there are few amplifiers equipped to deal with this format directly. It is not possible for a pick-up cartridge to connect directly to an amplifier without a Phono pre-amplifier in-between. A Phono pre-amplifier is designed to boost the signal level and change the frequency response in accordance with the RIAA standard.
All Creek integrated amplifiers built, from 1993, have been designed to accept a plug-in Phono module to enable vinyl disc reproduction.
The latest Creek plug-in Phono module is called Sequel mk2 and is designed to match a wide-range of MM and MC cartridges. It can be fitted to the latest integrated amps from Creek, and many of the earlier ones. See the list below for details.
The module must be fitted, inside the amp in a slot that will change the Auxiliary Line input into a Phono input. Either the supplying dealer, or the user, must fit the Phono pre-amp before the amp can be used to replay vinyl discs.
The circuit cannot be switched for MM or MC use, so the correct module must be chosen to match the cartridge fitted on the turntable. The EVOLUTION amp’s display will automatically show Phono, when the amp is fitted with the Plug-in module and selected for that input.
The Sequel 48 mk2 MM Phono pre-amp is the device specifically suited for high output Moving Coil cartridges, with an output between 0.9 to 2mV and a matching impedance of 47k Ohms.
The Sequel 48mk2 is not suitable for medium to low output MC cartridges, which require higher gain and a lower 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 47k Ohms 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 10Hz. 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 a low noise voltage regulators, whose function is to stabilise the voltage and filter noise from the main power supply. The Sequel mk2 has optimal overload margin for a given gain.