DeadEndFX Lovetone Enigma ? Flanger issues

[danielzink]

I did finally get mine working..

After audio probing the dang thing for...hours....

I stuck my probe on pin 8 of the 3207 and just started turning the trimpot on the daughterboard....and turning....and turning....

When...all of a sudden...from the backgroud came some noise...

Then as I continued turning the pot slower - full signal came in..

It was the pesky 25 turn trimpot the whole time...

Once I got my signal dialed in I went about the caibration procedure and now I'm happily making spaceship noises

Dan

[ElectricDruid]

It was the pesky 25 turn trimpot the whole time...

There's an important lesson here for both circuit debuggers and circuit designers!!

Every trimmer a designer puts in a circuit is an opportunity for someone to consider it broken (because it doesn't work) when actually it just needs some heavy trimming. And for circuit debuggers, every trimmer is a potential problem solved, if only you can find out what the "correct" value is supposed to be - for older circuits, often not at all simple.

Honestly, the damn things are a minefield. Avoid at all costs.

[Invertiguy]

I did finally get mine working..

After audio probing the dang thing for...hours....

I stuck my probe on pin 8 of the 3207 and just started turning the trimpot on the daughterboard....and turning....and turning....

When...all of a sudden...from the backgroud came some noise...

Then as I continued turning the pot slower - full signal came in..

It was the pesky 25 turn trimpot the whole time...

Once I got my signal dialed in I went about the caibration procedure and now I'm happily making spaceship noises

Dan

Sounds just like the first startup of my build! When I went to check the bias I got a very nice sine wave that didn't change much until the trimmer reached the extremes of travel, so I left it alone and moved on and went I went to plug it in I got nothing. I even tried swapping out ICs to no avail! Turns out I forgot the ICs were facing in opposite directions and I had my scope lead on pin 3 (the input) instead of pin 7 (the output), and actually properly setting the bias solved all my issues. Felt like a real idiot when I finally figured it out, although at the same time it was a huge relief knowing that I didn't actually fry anything or solder anything in the wrong spot. Long story short, if you're not getting any signal out of any BBD based project, your first place to check should be the bias.

[Josemitejam]

Hmm ok all good info to know! I'm still debugging, and still not getting Any signal at pin 3 of the 3207. I was wondering tonight, instead of using the normal diffused green, yellow and red LEDs, I used the "high brightness" LEDs from smallbear....could this be an issue??

[Govmnt_Lacky]

Hmm ok all good info to know! I'm still debugging, and still not getting Any signal at pin 3 of the 3207. I was wondering tonight, instead of using the normal diffused green, yellow and red LEDs, I used the "high brightness" LEDs from smallbear....could this be an issue??

It is OK to use the high brightness LEDs for the Loopage, Time, and Space PANEL lights. You really want to use diffused green for the LDRs in the circuit.

Since you are not getting clean guitar signal at Pin 3 of the 3207 then you need to audio probe backwards from there and find out where the signal is being lost.

Start at Pin 6 of the daughter board. If no signal there then you need to trace backwards onto the main board. If you do have signal at Pin 6, then you need to check R8, C7, R9, R10 and even play with the Bias again. If you have signal at the junction of C7 and R9.... then you need to pull the 3207 and verify that the IC is not killing the signal.

This is ALL assuming that you only have the "Time" function activated.

[Josemitejam]

So here's what I found. I highlighted the spots in pink that I'm getting no guitar signal at and the spots in yellow I'm getting a guitar signal. There are areas that I think are just really quiet though. For instance, if I have the "time" switch on then the r30 branch of the schematic works very very quietly it seems. If the "time" switch is off it works at a solid volume. I wonder if some the areas highlighted in pink are passing signal just at a very low volume that I can't hear...and maybe that's even correct.

I'm not getting any guitar signal on the daughter board.

3 more questions:

1. I put the socket for the 3207 in backwards, the chip itself is in the correct orientation though. That shouldn't matter, right?

2. When you say pin 6, do you mean pin 6 of the 3207?

3. How do I check to see if the 3207 is killing the signal? I replaced it with another one a while back with the same results.

Thanks again! I hope I'm giving good readings, I have cranky crying 5 month old baby that's asking for my attention so time to stop for tonight!

Best,

Joe

[Josemitejam]

Two more things:

I plan on a lot more trim pot work tomorrow night, but no luck yet as I follow the directions on calibrating.

And in those crucial areas where no guitar signal is heard I haven't found a wrong component yet. Perhaps the there's one further upstream that is weakening the signal more noticeably in these certain areas?

[Govmnt_Lacky]

So here's what I found. I highlighted the spots in pink that I'm getting no guitar signal at and the spots in yellow I'm getting a guitar signal. There are areas that I think are just really quiet though. For instance, if I have the "time" switch on then the r30 branch of the schematic works very very quietly it seems. If the "time" switch is off it works at a solid volume. I wonder if some the areas highlighted in pink are passing signal just at a very low volume that I can't hear...and maybe that's even correct.

I'm not getting any guitar signal on the daughter board.

3 more questions:

1. I put the socket for the 3207 in backwards, the chip itself is in the correct orientation though. That shouldn't matter, right? As long as the chip is oriented correctly you should be fine.

2. When you say pin 6, do you mean pin 6 of the 3207? No. I mean Pin 6 of the PCB as in the schematic in the build diagram. It is the shielded cable that runs from the daughter board to the main PCB. That is where your guitar signal is coming into the daughter board from the main board.

3. How do I check to see if the 3207 is killing the signal? I replaced it with another one a while back with the same results. If you are getting guitar signal at the PCB Pin 6 (as in question #2) then you would simply remove the 3207 from the socket and see if you have a guitar signal at Pin 3 of the 3207 socket. If you are not getting good guitar signal at the PCB Pin 6 then you do not need to do this.

Thanks again! I hope I'm giving good readings, I have cranky crying 5 month old baby that's asking for my attention so time to stop for tonight!

Best,

Joe

Unfortunately, I cannot see the pics on this CPU. Will have to look later.

As for the questions... see my answers in RED above.

[Josemitejam]

Ok ya definitely no signal at pin 6. So this could still be a biasing problem it sounds like, even though there is no signal getting to the daughter board?

As of now that'll be my next step, playing more with the trimpots. If you get a chance to check out those pictures, let me know what you think. No pressure though! I appreciate all the time and help you've given me.

[Govmnt_Lacky]

Ok ya definitely no signal at pin 6. So this could still be a biasing problem it sounds like, even though there is no signal getting to the daughter board?

As of now that'll be my next step, playing more with the trimpots. If you get a chance to check out those pictures, let me know what you think. No pressure though! I appreciate all the time and help you've given me.

Ugg... it appears that I have had my tracing bass-ackwards. My apologies!

The signal comes on to the daughter board by the single wire that is on the RIGHT side of the board (to the right of the LED/LDR combo). The shielded wire is the signal LEAVING the board 

Check to see if you have clean guitar signal at either side of R8 on the daughter board. If you do, then follow it through the circuit on the daughter board to see where it gets lost (and possibly mess around with the Bias trim some more)

If there is no signal on R8, then you need to trace back to the main board via the Loopage stomp according to sheet 15 of the build doc.

So sorry for my confusion until now.

[Josemitejam]

No worries!

Ok I just made a leap forward...when I plug another pedal into the send and return fx loop jacks, and that pedal is turned on, and the loopage switch is turned off, then I suddenly get guitar signal on All of the daughter board! I'm still missing a lot of guitar signal, especially on pg 16 (the second  page of the schematic) of the build guide.

I read in the original lovetone manual that you sometimes need to plug a jack in and out a few times in order to "exercise" the contacts if they haven't been used for a while. I did this to all the jacks to see if it made a difference and nothing so far. Also, this might be the reason why Ry's pedal started working (see page 1 in the thread).

I'm going to keep audio probing around, but is it possible that I'm using the wrong jacks?

Here's a picture:

[Govmnt_Lacky]

No worries!

Good to hear that you are making progress.

I stated it before BUT, I will say it again... Be SURE that all of your jacks are wired to their proper place on the PCB. As well, make sure that all the poles on the Loopage stomp are wired correctly to the PCB.

With nothing installed in the effects loop, you should have continuity/short between the Send jack TIP and Return jack TIP. Do you have that? Make sure you are reading the TIP contacts and not the Tip SWITCH contacts.

Those appear to be the correct jacks for the build. If they have phenolic/plastic threading on them then they will work in all positions. If they have metal threading then you need to make sure to isolate the Time Out jack SLEEVE from the enclosure.

Everything sounds like you have either your Effects Loop jacks wired wrong -OR- your Loopage stomp wired wrong.

[Govmnt_Lacky]

I'm still missing a lot of guitar signal, especially on pg 16 (the second  page of the schematic) of the build guide.

Most of what is on that page is the generation, control, and distribution of the LFO and VCO waveforms. You probably won't see "guitar signal" there.

[Josemitejam]

So I checked over the fx loop send and return I can't find anything wrong, I also resoldered the wiring just in case. Same with the loopage stomp, nothing seems off. I do get Connectivity between the send and return tips. Here's a few more things I'm wondering about:

1. R22 gives a signal, but then it stops there. I can't find a signal at any of the pads to the loopage switch Which it goes directly to. That seems a little strange. I've checked that resistor many times and even replaced it, to no avail. Could the signal somehow be blocked between those two points? There's nothing there that I know of.

2. I'm getting connectivity between the sleeve and the tip on the send and return jacks....that doesn't seem right, since the sleeves always tend to go to ground. I don't know How they would be touching though.

3. In my last post when I noticed that if I have a pedal plugged into the fx loop and that pedal is turned on, and the loopage switch is turned off then I suddenly get a signal where I didn't have it before....why would the pedal need to be turned on in order to give that result?

I agree, I feel like the issue is right there at the jacks or the loopage switch, but I just can't see it. I'll send more pics ASAP too.

Thanks again for all your time!

[Govmnt_Lacky]

1. R22 gives a signal, but then it stops there.

If I were to guess, it is because of this:

2. I'm getting connectivity between the sleeve and the tip on the send and return jacks....that doesn't seem right, since the sleeves always tend to go to ground. I don't know How they would be touching though.

You are correct. That is NOT right. I am guessing you are seeing signal at R22 on only one side and that side is the same that connects to the R19/C7 junction.

My best guess is that there is a short on the main PCB at the solder points for the Send jack, Return jack, or both. Check the PCB where you solder the lead wires for the two jacks and see if there is a solder bridge between the Tips(s) and Sleeve(s) solder points.

[Josemitejam]

Got it! That was it, imperceptible solder bridge between the sleeve and tip pads for the return jack. I gave it a quick scrape Between pads and had it going within 30 seconds from when I sat down to work. The calibration was straight forward from there, this things up and running beautifully!

Thanks a ton again! I owe you one for sticking with me on this!

[ElectricDruid]

Nice work, both.

[Josemitejam]

Now that I've been fully flanged out for the last month or so, I'm wondering about the fair amount of static I get when I turn up the Manual knob. If it's all the way Up I get the most Static and it fades as I reach the 12 o'clock position.  The action knob will also back the static off as I turn it to its middle position (which makes sense). I'm calibrating this with a voltage generator and my ears...no oscilloscope or pitch generator. I just can't find a sweet spot where there is no clicking, no static and the flange is existent. I also have the 50k trimpot in for the R47 mod, but no changes in static are noticed when I adjust it.

When I check out demos online of other people's builds I think I can hear some static. GovmntLackey I saw yours on there from 7 years ago! Pretty cool to run across a familiar name elsewhere online. Your manual knob stuck around the 1 o'clock zone so I couldn't get a read on if you where getting static or not.

Btw, I built another for a friend (which came out with no flaws right off the bat!!! ) and I have the exact same calibration outcomes.

Should this static be there? Does anyone know, was there static in the original Lovetone pedals?

[Josemitejam]

...and just for fun here's a pic...

[Govmnt_Lacky]

Now that I've been fully flanged out for the last month or so, I'm wondering about the fair amount of static I get when I turn up the Manual knob. If it's all the way Up I get the most Static and it fades as I reach the 12 o'clock position.  The action knob will also back the static off as I turn it to its middle position (which makes sense). I'm calibrating this with a voltage generator and my ears...no oscilloscope or pitch generator. I just can't find a sweet spot where there is no clicking, no static and the flange is existent. I also have the 50k trimpot in for the R47 mod, but no changes in static are noticed when I adjust it.

When I check out demos online of other people's builds I think I can hear some static. GovmntLackey I saw yours on there from 7 years ago! Pretty cool to run across a familiar name elsewhere online. Your manual knob stuck around the 1 o'clock zone so I couldn't get a read on if you where getting static or not.

Btw, I built another for a friend (which came out with no flaws right off the bat!!! ) and I have the exact same calibration outcomes.

Should this static be there? Does anyone know, was there static in the original Lovetone pedals?

My memory is hazy but... if I remember correctly.....

The static you are hearing is from "overdriving" the circuit. The Manual and Depth controls actually control the brightness of the LED on the daughter board. If you look at the circuit in operation (under dim lighting of course) you will notice that changing both the Manual and Depth will change the brightness and 'evenness' of the LED.

I do vaguely remember that if the Manual control is cranked along with the Depth that you will get static at the ends of the sweep. I always found that the best "sweet spot" for the Manual control was around the 1 O'Clock position for good flanging.

As for the Action and Reaction, they are center Zero controls. Actually turning one of them past the 3 or 9 O'clock position is where you should get the crazy "police siren" noises. I believe this info is in the build doc.