Tremulus Lune problems

[elpucho]

Hi everyone,

I wondered if anyone could help out with a few problems I've had building the Tremulus Lune (Fuzz Central with Mods).

I'll try and explain as best I can.......

1)  I've finished the build, but when I plug it in I get no sound through it at all, however I noticed when I push the resistor side of the photocoupler in (I used the NSL 32) I do get a sound coming through, without any of the tremolo effect.  I'm not sure if this is done to a dodgy coupler, or maybe when I touch both sides of the coupler I make the connection?  I tried replacing the resistor side with a 10k resistor, as advised on another thread, and I do get sound, with no effect.  The way I hooked the NSL 32 up was to assume the two long legs were the resistor side of the unit, and the two short legs were the LED, I also assumed the dot on the LED side was the negative leg.

2)  I decided to leave off the Fine pot from this build, is it as easy as just omitting the pot, or do I need to compensate by making some new connections?  As it stands I just left the pot off the build.

3)  I don't have the ramp switch, or status LED hooked up yet, so I just left the two wires that will connect the LED unconnected and connected the two wired that will run off to ramp switch.  Is this correct?

If anyone can help at all I'd be really grateful.  I'm not entirely sure what reading will help to resolve this problem, but I do have a DMM and can take any readings that will help.

Thanks

[petemoore]

  I'm not entirely sure what reading will help to resolve this problem, but I do have a DMM and can take any readings that will help.
  This helps "What to do when it doesn't Work" sticky @ top of threads page.
  There are links from here and there that may be of help too, but the WTDWIDW page shows effective debugging techniques that you, and/or we, will need to do to effeciently locate the problem.
 

[Unbeliever]

If you leave off the 'fine' pot, you need to connect the two wires that would otherwise be attached to the pot, otherwise the LFO won't work. Also, with the ramp switch, *don't* make any connections at all. This will leave the LFO in it's 'original' state and we can get that working first before doing any mods.

See if that gets you going..... ... if not, report back with what is happening....

Mike

PS The 4ms site has tremulus-specific debug pages, run through those also!

[elpucho]

Thanks for the suggestions.

I'll make the changes Unbeliever suggested (where the fine pot should be), and also spend tonight measuring what I need to measure, as Pete suggested.

If anyone has any idea how I can test the NSL-32 I have is working OK I'd be grateful, I ran the audio probe on the board and I get a signal going into the Non-LED side of the photocoupler, but nothing coming out the other side of it.

Thanks again, I'll report back after I have taken the measurements I need.

[Unbeliever]

Any progress?

[wademalorgan]

Hello,
I don't know if this will apply but:  When I built my first lune (fuzzcentral layout also), the tremolo would only work if I had the led connected properly.  If I didn't have the led hooked up (to both the led+ and switch for led on/off pads) I would only get a clean signal without the tremelo.
Don't despair, you'll figure it out!
wademalorgan

[elpucho]

Success!

I had missed one of the connections on the board  , and hadn't noticed it when I done my initial checkover.  I was convinced I had checked them all, I'll start double, and triple checking in future.

The pedal sounds great, and I'm currently just tinkering around with it at the moment.  I'll try and get some samples uploaded after I box it.

One thing I did notice was that the 25k pot I originally used for a gain control (in place of the 25k trim on the original) was barely turned at all before I had unity gain, I have replaced this with a 5k and it seems a lot more balanced to my bypassed volume.

The other odd thing (maybe) was that when I measure the voltages on the 2nd Opamp (4558) the voltages "flutter" (not set voltages like Opamp 1 which measures about half the battery voltage on 6 legs - 0v on leg 4, and full battery voltage on leg , but I've no idea if they should do that.

Any advice again is very welcome.

Thanks again everyone, I appreciate the help, and would be lost without this place.

[petemoore]

The other odd thing (maybe) was that when I measure the voltages on the 2nd Opamp (4558) the voltages "flutter"
  Does this opamp drive the LED to 'flutter', if ti's working I think the voltages are ok.

[Unbeliever]

Cool ... good work. The 4558 is the opamp used in the LFO, right? You might get a little variation on the 9V line I guess, but certainly you'll get changing voltages elsewhere as that's what needed to drive the LED. Also, if sounds like it's working, with almost all pedals .... it *is* working. 

Nice work on changing the trimpot for one with a smaller range too...