Engl e570 tube midi preamp

This unit is missing the little grey button for "FX Loop Active", it switches the FX loop on/off.  I never needed it so never bothered to get it replaced but ESP Guitars is the US distributor for Engl and should have some extras.  Other than that one button the unit is in very good condition operationally and cosmetically (aside from some rack rash, especially on the bottom, see photos).

The grey button cover that is missing isn't really necessary to switch the FX Loop, you can see the real button more clearly in the last image. You can easily switch it on/off with a pencil or something similar (use something non-conductive like a pencil or piece of plastic so you don't short something out).  I've never tried but according to the p10 of the E570 manual I found online you can also use midi or the Engl Z-9 footswitch to control it. "The red LED above the button lights up to indicate FX Loop is activated. You can also switch the on and off via MIDI program change or Custom Z-9 Footswitch." Whether the FX Loop is on or off will be stored with the MIDI preset.

ENGL E570 Features
ENGL E570 features 4 channels “Clean“, “Crunch“, “Lead I” and “Lead II” with separate gain, treble and volume controls.

You have also a preamp defeat function that bypasses the circuit and allows you to combine E570 with other preamps or multi-effect processors.

Global Modern/Classic switch determines the voicing of all four channels and provides you with a huge amount of variants of guitar tones.

For “Clean & Crunch” and “Lead I & Lead II“, you have 2 gain variants respectively “Gain Boost” and “Hi-Gain“.

On top of this, you have additional sound-shaping buttons called “Bright” and “Ultra Bright” for “Clean & Crunch“, “Countour” and “Mid Edge” for Lead I & Lead II channels.

Another cool feature of E570 is the programmable stereo effect loop that allows you to insert stereo effect processors into your signal chain.

E570 comes with a pair of balanced and a single stereo unbalanced frequency compensated outputs for DI recording and sending your signal to a mixer or a monitor (simulates a 4x12 cabinet).

As it’s a MIDI programmable preamp, it has 128 MIDI presets via 16 channels and also has MIDI IN and MIDI THRU ports for integration into other MIDI systems.

In terms of footswitches and controllers, E570 never ceases to amaze us with three different remote controller interface ports!

First, we have S.A.C. (Serial Amp Control Port) that accepts a custom footswitch such as ENGL Z-9. This option allows you to select channels and also use two sound-shaping functions.

You can also use MIDI IN for ENGL Z-9, Z-12 and Z-15 or 3rd party MIDI foot controllers. Lastly, it’s also possible to a simple footswitch with a stereo jack that only allows you to switch four channels.

Last but not least, it features a programmable noise gate for only Crunch, Lead I & Lead II.

As E570 is a very sophisticated yet easy-to-use all-tube preamp, it’s recommended to go through every feature to better understand its capabilities. There are fine details to know before one really understands it, so let’s get started with the front panel going from left to right