Blenda PLP502

Parallel Loop Processor Module


Specs and Operating Characteristics:

Rear Connector:
• Line input and Line output on card edge (xlr i/o on standard "500" racks)
• Send output and Return input on card edge (TRS 1/4" i/o on Purple Audio Sweet Ten racks)

Front Connector:
• Send output and Return input on TRS 1/4" jacks

Nominal Gain figures: (actual gain can be somewhat dependent on source and load impedances)
• Line input to Line output ("direct" path): 0dB with blend knob fully CCW and trim knob centered.
• Send output to Return input: 0dB regardless of operating mode.
• Return input to Line output ("return" path): 0dB with blend knob fully CW and trim knob centered.
• Line output +/-12dB according to Trim knob.

Max Input Levels:
• +28dBu at Line input and Return input in "line" mode
• +18dBu at Return input in "synth" mode
• +8dBu at Return input in "pedal" mode

Input Impedance:
• 20,000 Ohms Line input and Return input in "line" mode
• 300,000 Ohms Return input ("synth" and "pedal" modes)

Output Impedance:
130 Ohms Line output
• 1,300 Ohms Send output in "synth" mode
• 2,700 Ohms Send output in "pedal" mode
• Send output in "line" mode carries the impedance of source device (see explanation below)

Clip Level:
• +34dBu at Line output (+28dBm into a 600 Ohm load)
• +18dBu at Send output in "synth" mode
• +7dBu at Send output in "pedal" mode
• Send output in "line" mode carries the clip level of source device (see explanation below)

Power Consumption:
• +/-15Vdc 60mA


Blenda (PLP502) blend-O-matic null-O-matic parallel loop processor module:

Blenda provides a parallel insert loop with three selectable loop operating levels/impedances for optimal utilization of a wide range of external signal processors, and continuously variable blend and output level trim controls to optimize the balance between the un-effected direct and effected loop return signals and output level.

Three loop modes accommodate balanced or unbalanced signals, matching the operating level and impedance to a variety of different equipment, including effects pedals and electronic instruments, as well as traditional outboard gear. A polarity reversal switch (“phase”) inverts the return signal for creative nulling and cancellation effects, such as turning an EQ into a bandpass filter, or turning a compressor into an expander/gate.

Blenda enables classic parallel processing (parallel compression, for instance), while occupying only one slot of any standard “500” Series enclosure. Parallel inserts have traditionally required that one splits signal to two mixer inputs to create direct and effected channels. Blenda provides the functionality and signal path of a premium analog studio mixer and adds optimization of level and impedance of the effects insert loop to match to pedals, synth and hi-fi devices... a feature that no studio console we know of incorporates.

additional applications:

Blenda opens up new territory in effects processing that a typical mixing console can not optimally achieve, by turning efx pedals, electronic instruments, and related specialized processors into studio "+4" line-level effects for use in recording or mixdown of any preamplified source.

Blenda's flexible gain structure, impedance-converting loop, and lo-Z transformer-balanced output lend themselves to a variety of useful tasks in addition to parallel processing and reblending...

• Use the Send output in "synth" or "pedal" modes for re-amping.
• Use the Return input in "synth" or "pedal" modes as a Hi-Z D.I., with the Blend and Trim knobs affecting gain and output levels.
• Use the Line input and/or Return input (in "line" mode) to attenuate loud signals, boost quiet signals, sum two signals into one, and cleanly drive heavy loads (such as 600 Ohm vintage outboard gear) at optimal level.
• Deliberately induce or avoid analog overloading, using Blenda's "blend" and "trim" knobs as "gain" and "master volume" controls.
• Use Blenda to balance and level-shift the unbalanced consumer-level insert loop of certain mixing consoles, for better integration of professional-level outboard equipment.

Front Panel Controls - top down:

Blend Knob:

The Blend control is a continuously variable crossfader. At counterclockwise rotation the "direct" signal is unity gain (0dB) through the module while the "return" signal is fully attenuated (off). At center each signal is attenuated by half for equal volume summing (where signals are in phase) or nulling (where signals are out of phase). At clockwise rotation the "direct" signal is fully attenuated (off) while the "return" signal is at 0dB.

Phase Switch:

The Phase switch invokes an electronic polarity reverse that affects only the loop "return" signal

Trim Knob:

The Trim control is a continuously variable output level adjust providing -12dB at counterclockwise rotation, 0dB unity gain at center, and +12dB at clockwise rotation.

IN Switch:

The IN switch is a master bypass control. In the up position Blenda signal path is engaged and an orange LED illuminates. In the down position, a relay sends line input directly to line output to create a straight wire system bypass. Useful for making before-and-after processing comparisons.

Loop Mode Switch:

This is a 3-position toggle for selecting Send/Return loop operating level and impedance. Toggle left for Lo-Z high level balanced "line" mode. Toggle center for medium-Z unbalanced "synth" mode operating at -10dB. Toggle right for hi-Z unbalanced "pedal" mode operating at -20dB.

Send and Return Jacks:

Standard 1/4" TRS connectors provide a front panel insert loop. These are normalling jacks which break the connection to rear panel loop connections (i.e. the optional input and output jacks found on Purple Audio Sweet Ten racks) when a plug is inserted.



$625 per module when purchasing 1 to 3 modules
$600 per module when purchasing 4 to 7 modules
$575 per module when purchasing 8 or more modules


multiple unit discount valid only as a single order, paid for and shipped together



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