Mooer E-Lady and several other Chinese Flanger clone schematics

[bushidov]

Hi Guys,

So, after a few tear downs, I discovered the Stagg BX-Flanger, Donner Jet Convolution, Rowin LEF-612, and Mooer E-Lady are all copies of the THOMEEQUE's EM3207 MN3207 based EHZ Electric Mistress (9V) clone with only some very slight modifications. Obviously, they are all surface mount, as they crammed them into a 1590A enclosure. Here is the tear down of the Stagg BX-Flanger:

























So I did some desoldering with my desoldering station and broke the PCBs down into their Foot Switch, Main PCB and Daughter PCB.
Footswitch:





Main Board:





Daughter Board:







After desoldering the larger components so I could visually trace as well as multimeter trace and then further desolder the SMD capacitors so my capacitor meter would get their values, I made the following 3 schematics:







The pots are:
Color 10K Linear
Range 100K Linear
Rate 1M Reverse Log

In conclusion, the differences are the use of SMD components, using 100uF caps instead of the 220uF caps typically called out, a hard set voltage divider for the Color pot (R22 and R28) instead of a trim pot and the bias resistor values for the LM324 being lower resistance. Basically though, a lot of similarities. What I really thought was odd was that Mooer, Stagg, Rowin, and Donner all used the same layout and even named the silk-screened parts the same.

However, I will say, I got a lot good sounds out of them, so the schematic is a legit Flanger schematic. I will say that I wasn't a fan of the filter switch. I preferred Normal. I'm going to redraw it in Eagle as one single board that uses through hole, just for kicks.

I am curious what everyone else thinks? How is Mooer, Stagg, Rowin, and Donner all able to get away with this? Are they all really the same company?

[bushidov]

I will say, I am pretty impressed on how they stacked up the 3 boards to make it fit without wiring.

Sadly, though, the tolerance rules of their vias, spacing between traces, and such would not be something I'd do. Way too small and too easy to have a board house screw up.

[FlyingWild]

Thanks for taking the time to do the strip down and produce the schematic, I'm on the verge of buying one, either a Donner or Mooer but also scouting around to see how feasible it would be to build one, unfortunate I can't help thinking I'd be lucky to build one for less than twice the price of the Mooer, possibly not as good, and most likely three times the size!

[bushidov]

Well, if you are looking on Amazon, it appears that the Skagg ones are the cheapest at the moment for prime members. Same exact circuit and PCB. I could see how they would get manufacturing defects easily based on how close to the edge traces and vias are, as well as how close some vias are to other traces. There is a via for 9V and Ground that are not touching, but so close that a tin wire could happen and then, zap.

I just like tearing down just to see what makes it tick. I want to build one without the filter switch and see if I can replace the clock with a micro to shrink the parts count down.

[ElectricDruid]

Replacing the clock with a microcontroller is easier when the BBD is running on 5V rather than 9V. Having to put a level-shifter in-between kind of spoils the point of the component reduction! Aside from that, it works fine, go for it!

T.

[bushidov]

Thanks Electric Druid, you just ruined my fun! LOL

[bushidov]

Oops, corrected a small part for the filter switch. Now it is correct to how the Mooer/Skagg/Rowin/Donner folks do it.

[Ben N]

I have a Mooer, that sounded great for about three weeks, then stopped sounding at all. I haven't the least inkling how to go about troubleshooting such a thing, and doubt it is worth it. The Donner is $25.75 on Aliexpress, but at this point I think I may just have to build one, although it would be the hardest project I have undertaken to date by a long shot--life is just not the same without a mistress, and my real one (a DEM reissue) is too big and awkward to power to go on my board.

BTW, I have long assumed that all the seemingly interchangeable mini pedals from China are in fact generic and interchangeable. I imagine the brands belong to companies that are essentially jobbers or marketers, who order products off the stock menus of anonymous manufacturers with customized silk screening. Of course, brands like Mooer and NU-X also have quite a few unique and seemingly proprietary offerings, so those may work differently.