Mooer Elec-Lady/E-Lady Feedback Mod

Big Monk

Big Monk

Well-known member
So, @Guardians of the analog and I were discussing flangers and I brought up how I wanted to tweak and calibrate the feedback trimmer on mine to try and get more useful range out of the Color (Feedback) knob. Turns out there is no Feedback trim.

As some of you may know, the Elec-Lady/E-Lady are more or less straight clones of the V6 Electric Mistress, with accommodations made for space and to adapt the MN3207 chip.

One of these space accommodations was to remove the Feedback trimmer in the resistive network off of the input lug to the Color pot.

So I opened mine up last night and decided to do some surgery:

03AB6A46-CA51-4BEB-A374-A69E32F47E6E.jpeg
6F0F2206-D026-4A9F-A742-1CEC91EF7A4F.jpeg
So, after reviewing the schematic I have for the E-Lady, Chris located the 5.1k fixed SMD Feedback resistor on the schematic but after tracing I found it was underneath the Daughter board:

39ED52B2-AF69-4E9F-AFA9-30951E7698CE.jpeg

In order to get at the resistor I had very carefully desolder and remove the top Daughter board.

I then tacked in two wires and ran them to the backside, the side which faces up when the enclosure it open (my thought being that the Feedback trimmer is the only control adjustable by ear), and attached them to the nominal 10k trimmer value attached to a PedalPCB Trimit!

B841144E-FDD4-4800-9AD8-04B7E0AB2D74.jpeg

The result is fantastic: Increased range across the Color Knob before oscillation happens and much lighter, less intense modulation at lower Color settings.

I remember Bjorn from Gilmourish stating how you can’t get the Color knob up much higher that 12:00 with it starting to oscillated badly and I think that comes from the value for feedback being fixed at too high a value.

This mod completely fixes this issue. I can successfully run the Color knob all the way up with no oscillation.
 
Last edited:
Big Monk said:
In order to get at the resistor I had very carefully desolder and remove the top Daughter board.
Click to expand...
I have a dead E-Lady where I think the problem is a blown 3207, which didn't appreciate 18 volts. I happen to have a spare 3207 so it's easily replaced, except that I need to desolder the daughter board.

So, questions: Do you just have to desolder the 10 spacer things at the sides? Or is there anything else that's attached?

I'm assuming that some or all of those spacers are electrical connections between the two boards, so they need to be treated with care. Luckily(?) I have experience with unsoldering things.
 
DAJE said:
I have a dead E-Lady where I think the problem is a blown 3207, which didn't appreciate 18 volts. I happen to have a spare 3207 so it's easily replaced, except that I need to desolder the daughter board.

So, questions: Do you just have to desolder the 10 spacer things at the sides? Or is there anything else that's attached?

I'm assuming that some or all of those spacers are electrical connections between the two boards, so they need to be treated with care. Luckily(?) I have experience with unsoldering things.
Click to expand...

Yes, all ten connections need to be desolder and the daughter board carefully pried up.

I came close, in my haste, to lifting two of the stand-off traces. Go slow and steady.

Also, full disclosure: I lifted an SMD pad clean off the board when preparing the fixed feedback resistor pads for wires.

Again, do as I say, not as I do.

I had temporarily tacked the new feedback trimmer in place with a piece of sticky tack and now that I’m confident things are working as advertised, I’ll hot glue it in place.
 
After some investigation, fixing the unity gain issue is very easy.

Since the bypass switch is on standoffs and board mounted, if you remove the switch, and remove the standoff that interfaces wit( the effect output, you can then patch in a simple BMP recovery gain stage between the main board and switch board.

I’ll use Bugg’s small buffer board that I have some spares of that I think I’ll use. I’ll mount the gain stage and a volume Trimit! to the back of the switchboard.
 
I change 3207 with 3007 (just for test ) so careful with nice and clean soldering , but after that the pedal has no "flanger effect" sound, i wonder that it has signal drop as usual but no "flanger effect " tone was heard from the pedal, i put 3207 again on pedal but unfortunately still no flanger effect sound ftom pedal.would you please help me about this problem.thanks
 
Last edited:
The two chips are not compatible.
If you look at build manuals for DIY versions of this circuit you’ll see that IF the board can take both 3007 and 3207 that it’s only possible with some tinkering, usually in the form of jumpers.

To reiterate, the chips are NOT drop-in replacements for one-another.

They also need a compatible clock chip. Search the Internet for which chip goes with what ( on my phone or I’d be able to give you the info off my computer). Cabintech sells ‘m, should have the info needed for pairing chips up.

cabintechglobal.com

Cabintech Global LLC

Specialty analog and digital audio semiconductors, synthesizer, and guitar effects modules from Coolaudio, Xvive, Alfa Rpar, and others
cabintechglobal.com

ElectroSmash - Bucket Brigade Devices: MN3007

Functionality, BBD Internal Circuit Topologies, Basic Topology, Tetrode Isolation Topology, Complementary Output Topology, Dual Topology, Tapped Output Topology, BBD Chips Comparison, Bucket Brigade Device Clock Drivers, BBD Clock Limitations, BBD Circui
www.electrosmash.com www.electrosmash.com

I don’t know enough to tell you whether or not you pooched your pedal, hopefully not and someone will be able to walk you through fixing it.
 
I think it would be helpfull to take a video of this process.
I couldn't quite understand which resistor you're mentioning and also the trimmer adjustment is a big question mark on my side.
 
dchero said:
I think it would be helpfull to take a video of this process.
I couldn't quite understand which resistor you're mentioning and also the trimmer adjustment is a big question mark on my side.
Click to expand...

I no longer have the pedal or the full schematics but it's simply a matter of locating R28 as i show in my pictures and replacing it with a variable resistor (trimmer):

1701264127712.png
 
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