tfpro P38 Strereo Mastering Compressor

P38 Strereo Mastering Compressor description:

The TFPRO P38 is a stereo mastering and record production compressor with advanced optical compression, in a substantial 2U rack mounting format, with balanced line inputs and outputs operating at line levels.

The TFPro P38 is built to last; from its heavy gauge front panel to the steel chassis; the construction is ‘substantial’. Terminations are via both XLR connectors and conventional 1/4 inch jack sockets, and the power supply is built in.As with all top-end TFPRO equipment, the inputs are transformer coupled using double wound audio current transformers giving transparent performance, total isolation and freedom from hum and buzz.

The stereo input gain control is a feedback type with extremely low self noise, and incorporates a ‘+14dB’ switch to allow for lower level inputs. To maintain perfection in stereo imaging, the stereo signal is processed into ‘sum’ and ‘difference’ signals and these signals are compressed separately. Immediately before the output, the sum and difference are reprocessed into left and right signals. The compressor retains the optical concept that gives such an amazing sound, but Ted has incorporated novel and original design features giving extreme control of compression, with selectable ratios from 1.2:1 up to 100:1 so that the P38 is like having all the historic compressors at once! To achieve these different ‘flavours’ there is a ‘model’ switch to select four distinct compression types (detailed in the handbook).

Some of the model types incorporate an element of automatic release so that programme material influences compression; this facility is modified by the TR REL button (Transient Release). Immediately following the compressor there is another innovation; this is the ‘soft clip’ option where transient overloads can be ‘clipped’ without audible distortion. An LED indicator shows when these transients are being affected.

The TFPRO P38 has a pair of meters that read final output level. A meter change-over switch alters the status so that the left meter reads ‘mono input’ while the right meter reads ‘GR’ (gain reduction). While the M/S matrix system takes care of the stability of the stereo image, and provides the ability to go from mono, right through to full stereo and beyond to an enhanced stereo (150% stereo), there are often times when there are slight gain differences and imbalances between left and right. The P38 provides for this with a balance adjustment capable of plus and minus 6dB on each side.

TFPRO P38 tech specs:

• Line input to line output max gain 25db plus additional 14dB with the '14dB' button pressed. So absolute max system gain is 39dB.
• Input Overload Margin: Maximum input level +28dBu (balanced 20K load impedance)
• Output Level: Normal output level 0dBu, Max output level +22dBu (balanced <30ohm source impedance)
• Amplitude Frequency Response: 20Hz to 20KHz +0 -0.1 dB, 6Hz to 60KHz +0 -2dB
• Harmonic Distortion without compression 200Hz 0.001% 1KHz 0.0008% 10KHz 0.003% measured at normal level. Measurements at +10dB are similar. Distortion is predominantly 2nd order.
• Harmonic Distortion with 10dB compression 1KHz 0.03% predominantly 2nd order, Low frequency distortion is dependent upon release settings.
• Noise 20Hz to 20KHz approx -88dB unweighted, Noise effectively -96dBu; dynamic range 118dB
• Compression: Servo driven optical compression with 4 compressor emulation ranges
• Model 1 emulates conventional VCA compression.
• Model 2 emulates 1176 type FET compressors.
• Model 3 emulates LA2A optical types.
• Model 4 emulates Ted Fletcher's own design historic optical compressors.
• Ratio is variable from 1.5 to 1 up to 100 to 1 (limit).
• Attack and release ranges are nominal (markings are approximately correct for model 3 setting) actual attack range is approx 150 microseconds to 10 milliseconds for model 2, up to 0.5 milliseconds to 20 milliseconds for range 4. Release is similarly faster for models 1 and 2.
• Transient Release: disengages the auto transient release function so that the compressor treats transients as normal signal.
• Power Supply: Internal, 115/230VAC switchable. Power requirement 10 watts.