The Mode Machines KRP-1 is a phaser, and a distinctive one: the maker describes it as a 100% true discrete analog phaser with photo-couplers, built to produce an authentic vintage sound of the 70s. It takes one mono input and generates stereo effects from it, and its design is based on the legendary Compact Phasing A from Gerd Schulte Audio Electronik1. The first run was made in 1999, when Mode Machines presented it at the NAMM show in Los Angeles, and it has since been redesigned and improved with more practical features and modifications1.
The KRP-1 is discontinued. Mode Machines lists it on its discontinued products pages, and describes the phaser as being in its final production stage1.
Controls and how it works
The KRP-1 puts four effect parameters on big knobs: Phasing, Oscillator Period, Feedback and Modulation1. A heavy-duty bypass push button switches the effect on and off, and there are two status LEDs and a Bypass knob on the panel1. The circuit uses photocouplers, the light-dependent method behind classic phase-shifting designs, and the maker says the design follows the Compact Phasing A while adding practical features the original lacked1.
For players exploring other phasers, from compact pedals to stereo designs, the site's Phaser Pedals page gathers the type as a whole.
Power and connections
All connections are on the rear plate, using 6.3mm jacks1:
- Mono In, L/R Out on 1/4" jacks
- Amount and Rate inputs for CV pedals, so the amplitude can optionally be controlled by two external CV pedals
- External power supply, 18V AC 1000mA, PSU included
All connections are on the rear plate, using 6.3mm jacks: mono in, L/R out, and Amount- and Rate inputs for CV-pedals1.
Build and size
The KRP-1 sits in a road-ready metal chassis with vintage style knobs, and wooden side panels were optional1. It measures 23.5 x 17.6 x 7.5 cm (9.25" x 6.93" x 2.95") and weighs 1.9 kg (4.19 lb); with packaging it is 36.5 x 23 x 10 cm (14.37" x 9.06" x 3.94") and 2.9 kg (6.39 lb)1. A PDF manual is available as a support file from the maker1.
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Questions
Is the Mode Machines KRP-1 still made?
No. Mode Machines lists the KRP-1 among its discontinued products, and the maker describes the phaser as being in its final production stage. The first run was built in 1999, when Mode Machines presented it at the NAMM show in Los Angeles, and the design has since been through redesigns. Anyone looking for one now is shopping the used market.
What is the Mode Machines KRP-1 based on?
Mode Machines says the KRP-1's design is based on the legendary Compact Phasing A from Gerd Schulte Audio Electronik. The maker describes it as more than a sound-wise 1:1 copy of the original: it has been redesigned and improved with more practical features and modifications, aiming for an authentic vintage sound of the 70s.
Is the KRP-1 stereo?
Yes. The KRP-1 takes a single mono audio signal at its input and generates stereo effects at its left and right outputs, which Mode Machines describes as very unique stereo effects. It also has an Audio/Manual mode. All connections sit on the rear plate on 6.3mm jacks.
Can you control the KRP-1 with expression pedals?
Yes, but not with standard expression pedals. The KRP-1's amplitude can optionally be controlled using two external CV pedals, connected to the Amount and Rate inputs on the rear plate. Players using CV gear can therefore automate the effect's intensity and speed from outside the unit.
What power supply does the KRP-1 use?
The KRP-1 runs on an external power supply at 18V AC 1000mA, and a PSU is included with the machine. That is an AC supply rather than the 9V DC center-negative standard most pedalboards use, so it will not share a daisy chain with ordinary pedals.
Is the KRP-1 analog?
Yes. Mode Machines describes the KRP-1 as a 100% analogue discrete hand built phaser using photocouplers, and as a 100% true discrete analogue phaser with photo-couplers. The photocoupler approach is the same light-dependent method associated with vintage phase-shifting designs.
Sources (1)
- KRP-1 | MODE MACHINES, Mode Machines, 2014-06-04
