DeadEndFX Lovetone Enigma ? Flanger issues

[danielzink]

Hey All,

Just finished up an Enigma Flanger build...and no joy....

Well....50% joy...

Here's whats up.

The first thing I noticed upon completion - was that when I started the "biasing" procedure outlined in the build doc that the trimpots were having absolutely no effect.

One thing that is curious to me is the operation of the trimpots....I used the recommended trimpot p/n from the build doc...they seems to be "infinite turn" trimpots ?

I'm used to trimpots that have a positive start end end stop...these just turn and turn.

I get bypass signal from the "out" jack and when I engage the "space" footswitch I get the vibrato portion of the signal.

All the proper pots affect that signal as well.

The 4 position switch affects the shape of the vibrato as well.

But....I have zero flanger output.

My tests so far (everything done at 9V):

Apply a steady input signal...

Using "out" jack I get a good bypass sound.

Engage the "Space" footswitch and I get the tremolo effect (no flange)

Knobs: Manual (no affect on sound), Depth (no affect), Rate (does slow down or speed up tremelo), IP Gain (does affect output), Reaction (no affect), Action (no affect), 4 position switch does vary shape of tremelo waveform, mono/stereo (no affect), Time or Loopage footswitches (no affect).

Plug into the "time out" jack ("Space" f/s still engaged and "space" LED still pulsing):

Get bypass sound ok.

Engage "Time" f/s and lose all signal.

Time and Space LED's flashing.

Manual knob: affects intensity of "Time" LED

Depth knob: affects intensity of "Time" LED

Rate knob: affects intensity of both "Time" and "Space" LEDs

IP-Gain knob: affects nothing as I have (zero) sound output

Reaction knob: affects nothing

Action Knob: affects nothing

Disengage "Space" f/s has no effect on anything.

Voltages:

TL074:
1: varying 3.7 to 5V
2: 4.4V
3: 4.4V
4: 8.8V
5: varying 3.5 to 5V
6: 4.4V
7: varying 1.4 to 8V
8: 4.4V
9: 4.4V
10: 4.2V
11: 0V
12: 4.4V
13: 4.4V
14: varying 3.2 to 6.1V


MN3102:
1: 8V
2: varying 3.4 to 3.8V
3: 0V
4: varying 3.5 to 3.8V
5: 3.9V
6: 4V
7: 4V
8: varying 7.1 to 7.5V

MN3207
1: 0V
2: varying 3.5 to 3.8V
3: 8V
4: varying 7.1 to 7.4V
5: varying 7.5 to 7.8V
6: varying 3.5 to 3.7V
7: varying 6.5 to 6.7V
8: varying 6.5 to 6.8V

I've also been through the thing with my trusty audio probe with no luck.....

Thanks for any and all help/ideas/thoughts !

Dan

[PRR]

Link to build doc?

Where did you get those trimmers?

[danielzink]

Build doc: https://drive.google.com/file/d/1kqEvRodTRtgS7zFl3puy6qp6RXRRoSle/view

and - Mouser

Thanks, Dan

[Ry]

You aren't alone.  This is the one build that is still sitting on a shelf waiting to get tuned.  I get all of the modulation, but no flange.  I've traced the signal to the MN3207, but nothing comes out of it.  I've swapped it out and worked through the other side of it to see it anything is pulling the signal to ground...nothing.  I spent a good bit of time on it over the holidays and couldn't figure it out...it's actually next on my list now that I've finished the Pompei.

[Invertiguy]

Yeah, I had that issue with my build initially as well. In my case it turned out that the bias was totally out of whack because I was taking the oscilloscope signal from the wrong pin! In any case, 8V is way too high for the bias on pin 3 of the 3207- it should be somewhere around 4.5V, so I'd start there.

As for the 'infinite turn' trimpot, yeah that was a little annoying to get centered since the wiper idles rather than reaching a hard stop. You can't really feel it, but you will hear it click when you reach the end of travel. I ended up counting the turns from end to end and then dividing that number in half to find the halfway point since the number listed on the datasheet is a nominal value rather than exact.

[Ry]

Ok, I got my build working after hours of fiddling with it this weekend.  I honestly don't understand why the flange started behaving, but I'll list out what I did to finally get it going and maybe it will help someone (although I don't promise anything).

I had been running a Panasonic MN3207 with a 12V supply. I decided to try a V3207 at 9v instead.  This initially didn't change anything.  Then I noticed that the delay path can come from the Return jack tip if the Loopage switch is engaged.  I figued I'd try plugging a guitar straight in to the Return jack just to see if it made any difference...immediate flange was my reward!  I was able to tune in the oscillations quickly and everyting worked great.  Then I unplugged from the Retun jack and plugged back into the Input jack, ready to debug whatever was going on, confident that all the blocks worked...and it was still working great.  I don't understand what gremlins I had to scare away, but I cannot tell you how many hours I've spend on this pedal since November.

Time to box!

[danielzink]

Ok, I got my build working after hours of fiddling with it this weekend.  I honestly don't understand why the flange started behaving, but I'll list out what I did to finally get it going and maybe it will help someone (although I don't promise anything).

I had been running a Panasonic MN3207 with a 12V supply. I decided to try a V3207 at 9v instead.  This initially didn't change anything.  Then I noticed that the delay path can come from the Return jack tip if the Loopage switch is engaged.  I figued I'd try plugging a guitar straight in to the Return jack just to see if it made any difference...immediate flange was my reward!  I was able to tune in the oscillations quickly and everyting worked great.  Then I unplugged from the Retun jack and plugged back into the Input jack, ready to debug whatever was going on, confident that all the blocks worked...and it was still working great.  I don't understand what gremlins I had to scare away, but I cannot tell you how many hours I've spend on this pedal since November.

Time to box!

Thanks for the hints - unfortunately - still nada for me.

I'm going to order a Cool Audio 3207 and a new 3102 (from wherever I can get one) and go from there.

Thanks, Dan

[ElectricDruid]

I had been running a Panasonic MN3207 with a 12V supply.

This is not a good idea. The MN3207 datasheet gives 4-10V as the supply range for this chip, so 12V is toasting it.

I decided to try a V3207 at 9v instead.

Much better idea! And lo and behold, it worked!

[danielzink]

This is not a good idea. The MN3207 datasheet gives 4-10V as the supply range for this chip, so 12V is toasting it.

Unfortunately the build doc says you can run the pedal up to 12V for more headroom....

Additionally - the "Bias Trim Calibration (Daughter Board)" in the build doc instructs you to do the biasing on 12V....

EDIT: Even the original Lovetone owners manual states you can run the pedal on 12V

Dan

[ElectricDruid]

Unfortunately the build doc says you can run the pedal up to 12V for more headroom....

Additionally - the "Bias Trim Calibration (Daughter Board)" in the build doc instructs you to do the biasing on 12V....

EDIT: Even the original Lovetone owners manual states you can run the pedal on 12V

Dan

Unfortunate indeed.

The datasheet is clear in the "Absolute Maximum ratings" that the *absolute maximum* allowed on a power pin is 11V. That's usually the "it's toast from here on in" point. 4-10V is given as the typical supply voltage. For that one volt from 10-11V, the chip should work, but other datasheet parameters can't be guaranteed since you're outside the specified range.

[Josemitejam]

Ok, I got my build working after hours of fiddling with it this weekend.  I honestly don't understand why the flange started behaving, but I'll list out what I did to finally get it going and maybe it will help someone (although I don't promise anything).

I had been running a Panasonic MN3207 with a 12V supply. I decided to try a V3207 at 9v instead.  This initially didn't change anything.  Then I noticed that the delay path can come from the Return jack tip if the Loopage switch is engaged.  I figued I'd try plugging a guitar straight in to the Return jack just to see if it made any difference...immediate flange was my reward!  I was able to tune in the oscillations quickly and everyting worked great.  Then I unplugged from the Retun jack and plugged back into the Input jack, ready to debug whatever was going on, confident that all the blocks worked...and it was still working great.  I don't understand what gremlins I had to scare away, but I cannot tell you how many hours I've spend on this pedal since November.

Time to box!

Thanks for the hints - unfortunately - still nada for me.

I'm going to order a Cool Audio 3207 and a new 3102 (from wherever I can get one) and go from there.

Thanks, Dan

Hey Dan, any success with those Cool Audio chips? I'm having the same issue as you guys, I started with the V3207 and V3102 though, so I'm not sure why it isn't clearing up. I'll be doing some more debugging in the coming nights but it sure looks like I'm having an identical issue - no flange at all. My IC pin readings look good. I haven't spotted anything with my probe.

I'd love to know if it ended up working for you with those new chips!

Best,


Joe

[Govmnt_Lacky]

Couple of things:

- With the trimmers, I believe they are 25-turn trimmers. If you listen closely, you will hear a slight "click" when the trimmer has reached its maximum or minimum point. Its best to set the trimmers to the point where you hear the "click" and then rotate back 12 turns to get them centered. Then, go from there.

- TRIPLE CHECK that you have all of the jacks wired correctly. It is crucial that the proper wires are going to the correct lugs. (i.e. TIP, RING, TIP SWITCH, RING SWITCH, etc.)

- The Time (Flange) signal goes directly to the TIME OUT TIP. If you are not getting Flange from that jack then the issue is coming from the PCB. If you are getting Flange from the TIME OUT jack but, not from the Mono Space Out jack then the issue is with the wiring between the two.

- The only pot that functions in Space mode is the Rate pot. ALL of the other pots are for Flange (Time) mode. Set Manual to 12, Depth to 3, Rate to 9, IP Gain to 12,  Reaction to 9, and Action to 3 (all clock references). Remember that Action and Reaction are center zero pots. If they are both at 12 then you will get nothing.

- I have always run these at 9V. Never saw any real benefit to running them at 12V.

- If you still do not get Flange from the Time Out jack, then look for a signal (with audio probe) at Collector of Q6. If you get it there then the issue may be with the transformer.

- Did you do the Ring Lift mod?

[Josemitejam]

Thanks for the quick reply!

- trimmers are in the correct spot, 12 turns in

-BI've checked the jack wirings over and over, I can't find anything wrong there

- no signal from the TIME OUT jack

- all pots have been set to what you recommended

- Running at 9v on my regulated power supply

- I probed Q6 and I didn't get anything at all

- I do get a flange "background sound" from pin 6 of the 3207, but no guitar signal

- I did do the ring lift mod

Here's a few pictures as well:

[Josemitejam]

One of those pictures came in upside down, here's the upside right version:

[Govmnt_Lacky]

Set all knobs like I mentioned in my last post. Set rotary switch to get both Sine waves. Loopage and Space OFF. Time ON.

- Do you get clean guitar signal on Pin 3 of the 3207?
- Do you get a Flange output on Pins 7 & 8 of the 3207?
- Double check that all of your stomp switches are wired according to the build doc.

Pins 2 and 6 of the 3207 are the clock inputs. You should not be checking for Flange or guitar signal on these pins.

[Josemitejam]

I'm about to rush out the door for work - but here's the pin readings I got last night. My internet cut out on me so I couldn't send it then. I'll check everything in your last post tonight! Here's the readings:

V3207 cool audio

1 = 0
2 = 3.71
3 = 5.41
4 = 7.19
5 = 7.7
6 = 3.73
7 = 6.82
8 = 6.83

v3102 cool audio

1 = 7.7
2 = 3.71
3 = 0
4 = 3.73
5 = 3.79
6 = 3.86
7 = 3.81
8 = 7.19


TL074

1= 3.6 – 4.4
2 = 4.09
3 = 4.14
4 = 8.28
5 = varying 3.5 – 3.8
6 = 4.14
7 = varying 1.8 – 6.8
8= 4.14
9 = 4.15
10 = 3.95
11 = 0
12 = 4.15
13 = 4.16
14 = varying 3.42 – 5.5

[Josemitejam]

Everything is set, except the rotary switch, to what you asked for. Did you mean something other than Sine wave? I only see triangle and square options.

Here's what I got though:

1 - nothing
2 - flanger background, no guitar signal
3 - nothing
4 - nothing
5 - nothing
6 - flanger background, no guitar signal
7 - flanger background, no guitar signal
8 - flanger background, no guitar signal

That flanger background reading sounds like exactly that, a flanger effect that's small and quiet, no guitar signal at all. I can adjust it with the pots though!

I checked all the stomp switch wiring and it looks good there.

Thanks again!

[Govmnt_Lacky]

Everything is set, except the rotary switch, to what you asked for. Did you mean something other than Sine wave? I only see triangle and square options.

Here's what I got though:

1 - nothing
2 - flanger background, no guitar signal
3 - nothing
4 - nothing
5 - nothing
6 - flanger background, no guitar signal
7 - flanger background, no guitar signal
8 - flanger background, no guitar signal

That flanger background reading sounds like exactly that, a flanger effect that's small and quiet, no guitar signal at all. I can adjust it with the pots though!

I checked all the stomp switch wiring and it looks good there.

Thanks again!

I am assuming these are readings from the 3207 chip so.....

Pin 1 = GND (should be getting no audio signal)
Pin 2 = CLOCK (should be getting no audio signal)
Pin 3 = INPUT (this is where you should hear clean guitar signal with audio probe)
Pin 4 = VGG (should be no audio signal)
Pin 5 = VDD (should be no audio signal)
Pin 6 = CLOCK (should be no audio signal)

Pins 7 & 8 = EFFECTED OUTPUT (this is where you should hear delayed audio signal output)

Looks like you are getting NO guitar signal into Pin 3 of the 3207. You need to use the audio probe and schematic and trace backwards from Pin 3 and find out where you are losing it.

Good Luck!

[Josemitejam]

Awesome - Will do! I went a little ways last night, no luck yet, I'll keep going in that direction though. Thanks Govmnt_lacky!

[Govmnt_Lacky]

Awesome - Will do! I went a little ways last night, no luck yet, I'll keep going in that direction though. Thanks Govmnt_lacky!

Something quick....

- Double check that your 3102 and 3207 are in the proper spots on the daughter board. When looking at the PCB, the 3207 should be on the left and the 3102 on the right (next to the LED/LDR)
- Make sure your shielded cable going from the upper left of the daughter board to the top of the main PCB is connected correctly and properly. (I mistakenly wired it backwards on a build once and had the signal wire going to the GND  )
-Although there is a spot for it on each end, that shielded signal cable does not need to be grounded on BOTH ends. If you look on Sheet 5 of the build doc, you can see it in the lower pic. You really only have to ground the shield on one end. Grounding it on both ends could turn it into an RF antenna.

EDIT: Sorry.. I cannot see any pics right now. Going by what you tell me and the build doc info.