Wyndsor
PHONO PRE-AMPLIFIER
Instruction Manual
Thank you for purchasing Creek’s Wyndsor phono pre-amplifier.
To enable a signal from a turntable's pick-up cartridge to be heard through a modern hi-fi stereo system, it is first necessary to boost its level. In addition, since vinyl discs are recorded with a form of compression to squeeze all the dynamic information onto the disc, it is necessary to expand it again before it can be listened to. This frequency compression is known as RIAA equalisation. RIAA stands for Recording Industry Association of America and was formed in 1952. Although an American administration, it created a world technical standard that regulated the way in which vinyl discs were made. Frequency curves were devised to reduce the excursion of low frequencies and increase those of high frequencies, to enable all the information to be squeezed onto a microgroove recording and to reduce the inherent noise generated by the vinyl itself.
To correct the frequency levels to the original pre-recorded ones, the Phono pre-amp incorporates filters that are the opposite of those used in the recording studio, to flatten the frequency response.
The Wyndsor Phono Pre-amp is Creek Audio's finest quality Phono pre-amp, incorporating user selectable gain and cartridge matching capabilities. It is housed in an attractive new case with a simple control interface and display enabling everything from the front panel, without degrading the performance.
To power the Wyndsor Phono Pre-amp, Creek developed a new power supply, with +/-20V and +12V outputs to power both the critical analogue and digital circuitry. The Wyndsor Power Supply contains two separate, over rated, mains transformers and separate high quality regulators to maintain maximum isolation from the analogue and digital supplies.
It is connected to the pre-amp via a custom 5 pin power plug and socket, enabling the pre-amp to operate with low levels of 50/60Hz interference, since the noisy power supply transformer is situated in another case, which can be located up to its cable length apart.
Left and right channels are on completely separate multi-layer printed circuit boards fitted with solid high-grade RCA sockets for the input and output, and a 3-way connector as an alternative input. For the more adventurous, there is also a balanced input capability. Both styles of input connector can be used, however it must be noted that both sets of connectors CANNOT be used at the same time. When using balanced mode this requires the pick-up cartridge not to be grounded.
This semiconductor circuit is split into 3 separate stages, with precision RIAA equalisation, in each stage. A gain selectable balanced to unbalanced conversion stage precedes a passive 75us de-emphasis filter; active 318us and 3180us EQ is performed in a high grade op-amp and passive IEC low frequency roll-off follows. Finally another op- amp gain stage drives the output with 50 Ohm output impedance, so long interconnects to the main amplifier are not a problem. In addition, the pre-amp is completely DC coupled to eliminate sonically detrimental capacitors in the signal path and is monitored and controlled, in case of unwanted offsets, by a DC servo circuit. If a DC condition exceeds the servo’s ability to correct an offset, a muting relay will stop any harmful DC from exiting the pre-amp. A dual voltage power supply allows the pre-amp to output up to 10 Volts RMS before clipping.
Moving coil and moving magnet cartridges from low to high output are catered for, together with the more unusual high gain moving coil types, which have characteristics similar to a low output moving magnet type. Matching of cartridges is an often overlooked fact in retrieving the best performance from your system. The pre- amp can select a wide range of values to better match your chosen cartridge.
The vacuum fluorescent user interface clearly indicates the gain, matching and other options - displayed in English. The display has 4 adjustable levels of brightness and can be completely turned off for minimum noise.
