Echoplex pre and a modded Mr Black Eterna

[Boba7]

Hi everyone!

So I made myself an Echoplex preamp in a 1590lb (always on), following Aion's schematics. For the switch I used 22n-off-10n instead of 22n-off-47u, cause I don't need that much boost, and 10n is a really nice in between (my favorite position)




Now the Eterna story... if you wanna skip it, pics are at the end!

A few months ago I bought a Mr Black Eterna Gold, and I loved it so much I decided to void the warranty and mod it.
I wanted to:
- get rid of the 3pdt! I HATE their loud clicks during acoutic gigs
- have a shimmer on/off footswitch
- not spend too much (the pedal wasn't cheap to begin with)

The shimmer on/off  seemed easy : disconnect lug2 from the pcb, put a switch to connect them back or short the pad on the pcb to ground. (can't just shunt lug2 to ground, cause when the pot is maxed you'd shunt the power supply to ground...)

But then I thought it'd be even better if I could also switch the settings of the 2 other pots on the shimmer channel...

Since the pots are 50ks, I put 2x 100k in parallel for each function, and then just needed to switch the wipers. I added resistors from the wipers to lug1 or lug3 to perfect the taper, and now it's better than stock, in my opinion.

For all this and an led I needed to switch 4 poles and of course did not want to use a 4pdt. A bit of searching, and I came accross Mictester's relay schematics which uses a latching switch, has an led and is cheap. So I was able to use a dpdt footswitch to switch the shimmer and the relay circuit with the led!

And now I have my dual channel Eterna Gold!

It was stressful, quite a bit of work, and definitely not fun as building a new pedal! The wiring is terrible and I had to hide my lousy job at desoldering the 3pdt with some tape. Also the black mix pot is too low and the right led too high... oh well...

But it works flawlessly, and I couldn't be happier!

Forgot to add that the pcb layout (not shown in the pics) is absolutely beautiful!

[cajone5]

You do some incredible work boba7

[Boba7]

You do some incredible work boba7

Hey thanks mate! Means a lot coming from you!

Forgot to say that by some kind of miracle, the ground spring coming off the pcb now touches the bypass footswitch, effectively grounding the enclosure (I used isolated jacks)! I didn't plan that at all.

[zombie_rock123]

Awesome looking work! Yet to try an echoplex pre but have had it on my build list for years.

Do you have any shots of the Mr Black PCB? I've always wondered what the insides of his pedals looked like.

[Boba7]

Awesome looking work! Yet to try an echoplex pre but have had it on my build list for years.

Do you have any shots of the Mr Black PCB? I've always wondered what the insides of his pedals looked like.

Thanks! No I didn't take pictures of the Mr Black pcb, I really like his pedals and didn't feel like showing their guts to the world... Sorry!

[zombie_rock123]

Nay worries at all, I respect that

[nzCdog]

That EP is quite an impressive little guy!  Great job, and a great circuit
Eterna looks beautiful.  2 great builds, congrats

[Boba7]

That EP is quite an impressive little guy!  Great job, and a great circuit

Thanks! Yeah the circuit is great. I drew a layout for it that I shared on the tagboard forums (I modified it slightly for my mini build)

I measured the Idss and Vp values of a bunch of transistors until I had values close to Aion's ones, and to my ears it really makes a difference.

[Coda-effects]

Very impressive !
I really like the rehouse of the Mr Black pedal!

[oip]

that preamp is so cute!  they both look fantastic

i made the aion sd3000 preamp recently and it's like adding extra flavour to everything, i'd imagine the echoplex is similar

[Boba7]

Thanks a lot!

The more I look at the wiring of the Etrerna the more ashamed I am but oh well! ahah

I've never heard the SD3000 preamp, I'd be curious to. I haven't played my single coil guitars without an Echoplex preamp for years now... 

[wgc]

awesome!

[verr76]

1590LBs.... I can´t get myself to try 1590B and you cram all that in there
Well done Sr., well done.

[culturejam]

That's a heck of a mod/rehouse job. Well done!

[Boba7]

Thanks guys!
I keep playing the Eterna, it's such a beautiful reverb.

1590LBs.... I can´t get myself to try 1590B and you cram all that in there
Well done Sr., well done.

Ahah I dont think I'll build another 1590lb in a while to be honest...