freestompboxes.org

first of all "hi" (since this is my first ehh 6th post on this great forum).

i am looking for some more informations on the emma db-1 discumbobulator.

got 2 gut shots some months ago from a guy selling it on ebay:

https://img406.imageshack.us/img406/595 ... ontln4.jpg
https://img406.imageshack.us/img406/377 ... idekz7.jpg
https://img406.imageshack.us/img406/502 ... euptz0.jpg

the 3 chips remind me of the mxr envelope filter,
so maybe a modded one?

greetings from germany,
slegdehammer

Hi,

does anyone know more about that pedal?

I´d like to built a clone, cause it sounds really cool...

Has anyone got the schematics, or even a pcb layout? Or at least a photo of the other side of the pcb?

http://www.emmaelectronic.com/v2/index. ... 1232232559

~roseblood~

i think you could probably build a good workalike using the tonepad mxr envelope filter layout with all the mods implemented. at least, that's what it looks like.

Hi,

I built the tonepad MXR envelope filter with all the mods. And I played around with the values of some caps.
It sounds nice but the discumbobulator sounds better. It´s more defined, more "hifi".

The main part of the pcb just looks like the mxr circuit (but I haven´t checked the resistor values yet...)
But I don´t understand what all the parts between the jacks do...
-It´s a 2pdt switch, so 1 transistor should be part of a millenium bypass
-power filtering and polarity protection...

But there are more parts than are needed for that, esp. the second transistor. Could it be part of a buffer?

Where would you add decay and resonance controls? Might be a neat mod if they can be done.

Hi,

The "emphasis"-mod on tonepad.com is a resonance control, but only for the first filter stage.

Maybe this will help:
https://www.diystompboxes.com/smfforum/ ... ic=55796.0

https://www.diystompboxes.com/smfforum/ ... ic=20811.0

regards, Sue

Oh yeah! DUH!

Thanks.

Schematic

Just traced this one. Nice sound. Pretty close to a MXR Envelope Filter.

IC's are sanded off pretty good. All caps are sanded off also........ pretty good as I can't read anything!

Bernardduur wrote:Schematic

Just traced this one. Nice sound. Pretty close to a MXR Envelope Filter.

IC's are sanded off pretty good. All caps are sanded off also........ pretty good as I can't read anything!

Btw, IC's are powered by Vb

so maybe the missing values match or very closely match the mxr unit?

chicago_mike wrote:so maybe the missing values match or very closely match the mxr unit?

Maybe....... I couldn't read the values

once I get some time, I think I can do a quick layout and try out mxr'ish values and see what I come up with.

Always did like this pedal.

Okay I built the npn sections and added it to the Tonepad MXR Filter.

I used a value of .022 for the input and output caps. So far seems to work fine.

Not sure if I notice a huge difference but its a cool pedal now!

I perfboarded the npn sections and used metal can 2n2222's.

Excuse me please, I'm a little late ...
But are your sure there is not another 100k between R25 and C14, like in the Original?

Tuemmueh's absolutely correct - there is another 100K in the original MXR schem - although I think is between R26 and C14 on Bernardduur's schematic. Not sure whether this was skipped in the tracing, or accidentally/intentionally omitted by Emma. Ideas anyone.

Anyone built this??

Just asking, cause other I was gonna put together a project based on the tonepad layout but incorporating the mods and input/output buffers to turn in into a Emma-ish pedal.

Was gonna base the cap values on the original MXR 70s schems - I've noticed that there is 1 or 2 errors on the tonepad layout e.g. C4 should be 0.01.

I've noted in the tonepad build reports that the circuir is picky with respect to the IC manufacturers. TI being unreliable for the CD4066. Some reports suggest that this can be fixed by manipulating the voltage divider around IC2 (100K/62K, vise versa or 2x 100K). I may put 2 trimmers in there to make sure I can deffo get it to work.

I assume the input/ouput buffers help with the impedance problems from the original and volume drop etc.

Anyhoo, Im gonna start this very soon. If anyone has any helpful hints - please contribute!

RyUK

I replaced the 62k resistor with a trimpot, if i remember correctly, this made the IC-manufacturer non-important. I read somewhere, that you could replace 62k+100k with a trimpot, that was, what i wanted to try next. Still looking for some spare time (must have lost it somewhere and can't find it anymore ...).
Also, i think, the pedal is worthless without a (switchable) booster in front of, especially, if you have low-output pickups.

tuemmueh wrote:Excuse me please, I'm a little late ...
But are your sure there is not another 100k between R25 and C14, like in the Original?

I'm sure!

tuemmueh wrote:Also, i think, the pedal is worthless without a (switchable) booster in front of, especially, if you have low-output pickups.

tuemmueh - are you talking about the MXR Envelope or the Discumbobulator? I understood the MXR had issues which necessitated a buffer (or booster), but the Emma has tranny input/output followers, which should alleviate any issues, no?

Anyone have a schematic of it ?

Found this online. Anyone know if it's correct and/or what the missing values are? guess the values from the MXR could be subbed in for the missing values.