more information about ordering or installing the optional board into your P1 unit.
The enhanced RIAA curve: the unofficial Neumann time constant can be enabled by the user and is added to the RIAA equalization.
It is displayed on the unit's screen with the letter "e" preceding the standard filter: "eRIAA".
1.3 Voltage input impedance loading: helpful guidance from your P1
Manufacturers often specify a recommended loading value or range that best matches their cartridge. This is the optimal
impedance that should electrically load the cartridge.
If an impedance of that value is simply added in parallel to the phonostage input circuitry, sub-optimal result are often obtained.
The main reason is that the actual loading seen by the cartridge is the combination of the impedance of the cable, the input
impedance of the phono stage input and the variable loading that phono stage manufacturers usually provide. Moreover, some
cartridge/tonearm pairs can also exhibit resonance in the audio band, which can be seen as accidents (peaks or dips) in the
frequency response. Such ringing can also be slightly tamed by proper cartridge electrical loading.
In order to help our customer to optimally load their cartridge, the P1 phonostage comes with a 45 RPM test record. Side 1
contains a 250Hz-30kHz filtered pink noise track designed to be used in conjunction with a wizard available from the P1's menu.
The wizard allows to analyze the frequency response of the entire system (cartridge + tonearm + P1 input loading), while varying
the resistive loading of the P1's voltage input. Users can select to test the entire [20 Ohm – 100 kOhm] range that the P1
provides, or any subset of that range for finer tuning. The P1 automatically acquires 21 different frequency response curves
applying input loadings scattered across the range selected in the previous step.
In addition to the frequency response curve for each loading value, an average level and a measurement of the flatness of each
curve (standard deviation) is also a provided guidance.
As a general rule of thumb, user should start by analyzing the entire possible loading range when a step-up transformer is used, or
when no recommended loading is provided by the cartridge manufacturer. If only a minimal loading value is defined, users are
welcomed to analyze all values above this specification. In other cases, one can start around the recommended value, roughly
from half to twice this value. Iterative calls of the loading wizard, while refining the analyzed range is recommended to find
optimal loading.
Proper loading should meet the following criteria:
• Average level drop shouldn't exceed 2 to 3 dB compared with the 100 kOhm loading setup
• Most extended frequency response
• Maximum flatness of the frequency response (flatness value should be as low as possible)
Once a set of acquisitions is completed, users can browse through analyzed loading values both visually (seeing the corresponding
frequency response curves) and sonically (listening to the effect of each loading value while playing any record).
1.4 Careful metal work construction
The P1 phono stage chassis is made of high grade aluminum alloy with no visible screws on the front, top and side panels. First
class mechanical and chemical surface treatments provide the luxury finish of the P1. Pin assembly of all chassis elements enables
smooth joints between metal parts while screws every 6cm ensure protection against electromagnetic interferences.
Four stainless steel feet support the unit. Each foot is fitted with an elastomer ring to sit on delicate surfaces but is also equipped
with height adjustable hardened steel spikes to fine tune the unit position. Horizontal leveling is accomplished using the provided
screwdriver through the four adjustment shafts accessible from the top of the unit. Moreover, the steel spikes serve as vibration
evacuation channels in a stack of units. Special covers are provided to interface with the spikes of the unit above (see section 4.4).
Rev 1.1 P1 User Manual 7
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