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Line 6 Echo Pro

Modelling Effects Processor By Paul White
Published February 2002

Line 6's acclaimed Delay Modeler pedal gets a rackmount makeover.

Line 6 Echo Pro front panel.In SOS March 2000, I reviewed the Line 6 Delay Modeler stomp box which uses physical modelling to very effectively recreate the sound of vintage tape, magnetic disk, analogue delay and digital delay boxes. The new Echo Pro rackmount model offers virtually all the features of the pedal version, but with a better user interface, 99 programs, stereo balanced ins and outs and MIDI, including MIDI control over the unit's loop record/playback functions. MIDI may also be used to change programs and parameters, as well as for controlling tempo. Echo Pro programs can be mapped to specific MIDI Program Change messages and virtually any Echo Pro parameter can be mapped to any available MIDI Continuous Controller. Tempo sync is achieved by setting a note value, after which the delay can be locked to MIDI Clock.

To create the Echo Pro, the designers analysed original hardware echo boxes, then attempted to recreate such factors as wow and flutter, distortion and high‑end loss to get their models to sound like the real thing, but without the hiss. In addition to the delay programs, there's a loop sampler capable of up to 60 seconds of loop time. Using the front‑panel buttons or external MIDI controllers, a loop can be recorded, replayed, overdubbed, doubled or halved in speed, or even played in reverse. The loop can be started and stopped at any time and a separate echo/delay function can add delays of up to 800mS to the material being looped, with or without adjustable pitch modulation. On top of all that, the Reverse program lets you play genuine reversed guitar parts in (almost) real time. Actually, you have to play a bar ahead of the sound, but the effect is fantastic! The only downside of the rack format is that you can't control the looping from footswitches unless you have a suitable MIDI controller or a set of MIDI bass pedals.

Line 6 Echo Pro

The 1U package is mains powered, with the rear‑panel stereo ins and outs on both balanced jacks and XLRs, though you can use the unit in mono if you prefer. There's also a jack input for an expression pedal, as well as MIDI In and Out/Thru sockets.

User Interface

One look at the bright‑green sculpted aluminium front panel reveals a rather more comprehensive user interface than on the pedal version, with proper input level metering, status LEDs around the model select knob, and further status LEDs next to the Tweak and Tweez knobs so that you are always aware of what parameters these are controlling. The main delay parameters — Delay Time, Repeats and Mix — have dedicated functions, while Tweak and Tweez vary their function depending on the model selected. A two‑digit readout shows the current patch number as well as some cryptic two‑character clues when in some of the setup modes. A further four‑digit display can be switched to read the delay time in seconds or bpm. The note values are shown beneath the digits in this display, and the buttons directly below the display double as time/note/tempo display selectors and as controllers for the loop sampler (Record/Overdub, Play/Stop and Play Once). A Global button allows the tempos or times stored along with a patch to be overridden by the currently set value, which can be set up using the Tap Tempo button or the Time knob. Other buttons allow for saving edited programs, bypassing the unit and getting into the MIDI setup mode.

Most of the models are based on specific commercial echo boxes, though the rhythmic delay of the stomp box version has been replaced by a 'platter'‑type echo algorithm designed to sound like the old Binson echo units that used a rotating disc coated with magnetic oxide rather than a tape. Non‑emulative effects include Sweep Echo, which combines delay with a swept wah‑wah‑like filter, and a marvellously effective low‑resolution digital reverb, where the user can adjust just how much the decays deteriorate as they recirculate.

I won't go into each model in too much detail, but the main difference between these delays and regular digital delays is the way in which the tone or resolution of the recycled signal can be made to degenerate as it did on the original machines, creating a very musical effect as well as a sense of distance. Model types include Maestro's EP1 tube tape echo, the Roland RE101 Space Echo (with head switching for the four heads), the Boss DM2 and the Electro Harmonix Deluxe Memory Man analogue delay. There's also Auto Volume Echo, where a slow‑attack enveloper is combined with echo.

Programming the unit is very easy. For the echo models, you dial in a model type, then adjust the Delay Time, Repeats, Tweak and Tweez parameters, and set the wet/dry mix. Saving a patch can be done to the current location or to any other memory location, and the display will show FACT or USER to inform you what type of patch you are overwriting — factory patches can always be restored. Normally, when you call up a new model, it loads with a set of default settings, but you can replace these defaults with your own preferred settings if you wish.

An optional expression pedal can be used to move between two different front‑panel control settings, provided that they are based on the same model. A simple procedure is used to memorise the two lots of settings, then this information is saved as part of the patch. A practical use of this facility would be to change delay time, feedback, modulation rate or modulation depth in real time, though you could arrange to change the Delay, Feedback, Tweak and Tweez values simultaneously if you needed to.


I'm already an owner and big fan of the pedal unit, and in some ways it seems perverse that you have to pay twice as much in the UK for the rack version. Although it has a much longer loop delay time than the 14 seconds of the pedal, it has no integral footswitches to control the loop recorder functions. However, you do get stereo balanced ins and outs, much better metering and a clearer user interface than the pedal version, as well as the 99 user memories. Soundwise, there's little to choose between the pedal and the rack version — both are excellent and produce what must be the best digital emulations of tape echo currently available. The wow and flutter that you can add to the models, along with the progressive breakup of the repeats comes very close to the sound of the real thing, but without the noise. I'm not sure that they've quite captured all the nuances of the old valve/tape‑loop echo sound, but they've got pretty close. However, for Shadows purists, the ability to set up individual head timings is perhaps too limited.

If you're into looping, the loop function is great fun and quite easy to use, as is the reverse effect, which is simply the best thing of its kind I've come across. This kind of attention to detail shows up best on guitars, as those were the main instruments which used these effects originally, but great results can also be achieved from vocals and electronic instruments. If delay is an important effect to you, then the Line 6 Echo Pro is one of the most advanced and flexible units of its kind that you can buy.


  • Excellent user interface.
  • Convincing emulations of classic delay boxes.


  • No optional loop control footswitch other than a full MIDI controller.


A more professional version of the Delay Modeler stomp box, with more loop memory and a better user interface, but at the expense of those useful loop footswitches.


£459 including VAT.