The Morley Emerald Echo Box (they call it EEB for short) is one of the pedals from their late 90s “Jewel Box” pedal series: Emerald Echo, Diamond Distortion, Sapphire Flanger and Crystal Chorus .
It’s an anlog delay based on the MN3205 bucket-brigade and with the NE571 compander. It has only one BBD chip, so the delay time is limited to around 300 ms. The circuit is similar to the classic analog delays, for example Ibanez AD-9 and Boss DM-2. It’s a buffered bypass pedal, the signal always pass through the input opamp (TL072) buffer.
Looking at the schematic (which is provided by Morley on their web site, thank you!), I found a few things that are a different.
The dry and wet signals are mixed using a blend pot. So when you blend in the wet signal, the original signal is attenuated. So it’s possible to (almost) completely dial out the dry signal and only hear the wet delay signal. In most delay pedals, the wet signal is added to the dry signal, you can only add the delay, not remove the original signal. So, on the Morley pedal, mixing in the delay causes a volume drop on the first, original, signal. Not a big problem I think, you can dial in a good mix.
The feedback signal is fed back through a voltage divider and a trim pot to the NE571 compressor circuit. This is how it’s done in most delay pedals. In the Morley the signal is fed to pin 6, in other pedals to pin 5. Both pin 5 and 6 goes to the inverted input of an internal opamp, the difference is that pin 6 passes a 20k resistor. The number of repeats in the Morley pedal is quite limited and no “oscillating feedback” is possible. The signal passes both the 25k trimpot and the 20k internal resistor.I’ve tested to connect the feedback to pin 5 instead, and it becomes possible to get more repeats. This is a good mod I think, it’s still possible to use the trimpot to get almost the original behaviour.
A really nice sounding analog delay. Perhaps a little to big for your pedal board, but heavy and sturdy if you go old-style with pedals on the floor.