Emerald Echo - possible mods

[jbm222]

I have somebody's "broken" emerald echo at the moment....  turns out it was just a battery connector problem.  He said he'll sell it to me pretty cheap, and i've wanted an analog echo to play around with.

Has anyone around here modded one before?

There's plenty of room on the board to add components & stuff.  I was hoping to increase the feedback level on the repeats so that I can get it to oscillate & all that fun stuff.

And perhaps slow down the clock for some longer lo-fi weird sounds.

[Mark Hammer]

I highly recommend the following mods:

1) Find the feedback path and the series cap that normally blocks DC (C6 in this case).  By cutting that cap value you can chop the bass so that each repeat has less and less bass.  This is similar to the kind of echo sound used frequently in dub music.  In this instance, the optimal way to change it is to stick a .1uf cap in series and use a toggle to shunt and unshunt that cap.

2) Stick a .0068-.01uf cap from the wiper of the repeat pot to ground.  This will roll off highs only for the repeat content.  The first echo will be as bright as the design permits but subsequent repeats will be progressively duller.  This sounds much more natural since reflected sound in the real world loses a lot of high frequency content the longer it is being bounced off surfaces (i.e., late reflections).

Both of these mods should be defeatable by toggle.

3) Input-kill is a wonderful thing on delays.  This cuts the input to the delay line, but retains whatever is recirculating for as long as it recirculates.  The value is that it lets you "move on" and play new stuff without having to create clutter by adding yet more delayed/echoed notes.  The "trails" function is a nice feature on Line 6 delays, though I like to use it in a more hands-on (well, toes-on) manner with different momentary switches.  So, for instance, enabling input to the BBD with a momentary connection lets you insert echo for as long as you press the switch, and instantly disable new input when you lift your foot.  This lets you use echo in a riff-wise manner if you want.  Conversely, a momentary switch that lets you defeat new input when you press, can insert non-echoed changes on a riff-wise basis if you want.
On the Emerald Echo, the optimal place to add an input kill is probably the junction of R5, R6, and C5, using a momentary switch of some kind.  How to do it is another thing, and here I'm scratching my head a bit.  If you simply break the connection from C5 to R5 with the switch, you'll likely get a pop when the connection is resumed.  If you simply ground the junction of C5/R5, there is a possibility that you'll monkey around with the level or high end.   I'm open to ideas and suggestions from folks how best to do this.

[jbm222]

I'll definately give those a shot.

Do you know off hand if there's an easy way to increase the level in the repeat path?   Because right now, the repeat knob basically varies the volume of the second repeat.  anything past that is barely audible. 

I still haven't really gotten into the data sheet of the compander, so I don't know how much room for adjustment there is there.  But I'm hoping to be able to make that mod without adding an extra transitor booster or something to the feedback path.

[Mark Hammer]

Many analog delays, flangers, and phasers use a trimpot to set the maximum regen/repeat level.  Setup typically involves turning the chassis-mount control full tilt, and adjusting the trimpot on the board to the point where the annoying oscillation stops.  That way, the panel control can never be set to anything "dangerous".  There is a good chance that the trimpot on your board is either bumped off the initially setting, or perhaps there is corrosion preventing the wiper of the trimpot from making contact with the resistive strip (which would likely result in the circuit treating it as set to maximum resistance, thereby severely attenuating regen signal).

So there doesn't necessarily need to be any change made to the pedal, other than maybe a "tune-up" of the trimpot in question.

[jbm222]

Tried the trimpot.  I maxed out the repeats using the trimpot & I'm still only getting a few echos.  It was making noticible adjustment, so I doubt it's corosion.  I don't know how it's supposed to behave, but it sounds good other than the lack of echos so i figured it was working right.