Tremulus Lune questions

[robbiemcm]

Just a few questions regarding the Tremulus Lune, I've done some searching and I didn't see much relating to this so I suppose I'll just ask.

Recommended reading:
http://www.commonsound.com/kits/doku.php?id=commonsound:tremulus
http://www.tonepad.com/project.asp?id=42

The schematic at commonsound appears to be different to the one at tonepad, are there many significant changes that will greatly alter the sound of the tremolo or is it just a bit of tweaking? One thing I noticed is that the commonsound schematic seems to require the use of part of the 3PDT switch to turn the LED on/off whereas the tonepad one has some weird disconnections around the LED but doesn't appear to be a switch, nor can I see any switches for the LED on the tonepad layout. Using a 3PDT represents a bit of a problem for me as they're not easy to come by where I am and are a bit big for my needs. I don't think the IC's turn the LED on/off so I'm going to guess that the one in the tonepad layout is always on, if I have that wrong however, please tell me.

Also I would like to cut out the number of potentiometers. I know that I can do away with the fine control, but I'm not exactly sure as to what "spacing" and "smooth" do, so I'd appreciate it if someone was able to tell me. If they're not anything that I need quick access to, I suppose I can just substitute trimpots for those two. And finally, comparing the two schematics I would guess that the trimpot on the version at tonepad is gain - is that correct?

Thanks,
Robbie.

[petemoore]

  Take a look at GEO, view the Millenium bypass articles, see if there's not one of these switching the led via output sensing and DPDT sw. on the layout which uses that type of switch.
  The tremulous gets just as Lune-y with or without the indicator LED.
  I'm not sure what the other differences are, but the TL from is a widely adjustable and full featured tremolo.

[robbiemcm]

I'm guessing it's not a millenium bypass because it doesn't have any transistors and the two ICs seem to be more part of the circuit than I would expect for a bypass. The schematic from commonsound definitely shows a 3PDT being used (well unless you planned to use multiple switches and press them at the same time). The schematic from tonepad has the bypass "route" permanently connected to the output jack, so it's actually only disconnected from one side. I suppose this is another way of doing true bypass and it would just leave one leg on a DPDT switch free. Not sure if there's any difference between them, maybe this one helps to eliminate popping - it would be useful if someone can answer that too. I'm not really that fussed about the LED indicator but it would be rather nice to have it.

[SonicVI]

The Tremulus has an LED that blinks at the speed of the LFO.  The Tonepad and Commonsound schematics have them working the same way except the tonepad version has it always on and the commonsound version shows how to use the third pole of a 3PDT to turn it of when the effect is bypassed.  You can do it either way with either version.  I used two LED's in my build, one for LFO rate and one for status.  If you can only get a DPDT then you can just leave the blinking LED always on and use Millennium bypass for a staus LED, or not have a status LED.  You don't even have to use the blinking LED if you don't want to.

The 4M's website explains what all the controls do. I'd read their description to decide what controls you want to use. All of the knobs are useful, but if I were doing a stripped down version I'd definitely keep at least the smoothing control. It morphs the wave between square and triangular for smoother or choppier effect.

[robbiemcm]

The Tonepad and Commonsound schematics have them working the same way except the tonepad version has it always on and the commonsound version shows how to use the third pole of a 3PDT to turn it of when the effect is bypassed.

I thought so, I just wasn't sure about the odd disconnection near the LED on the tonepad schematic. It doesn't look like a switch, maybe it's an "insert switch here, if you want".

The smoothing control does sound quite useful, I'm going to build this on breadboard first and I'll decide then which controls I will keep, but a maximum of 3. If I'm not that impressed with smooth or spacing (I might not build it entirely correctly, I read that someone had trouble getting one to do anything) it would still be nicer to only have two pots. Does anyone know much about the differences between the schematics, I think the one at commonsound is a revision but it might not make that much difference. Do people have much success with an LED/LDR combination rather than using a single component like it has listed in the parts list? I'd like to use a single component but I can't seem to find one.

[snoof]

the smooth pot is very useful.  i used homebrew LED/LDR's for mine and it worked great.  i'd use the schem at commonsound, it's there design after all.

[mr_fender]

I built the Tremulous Lune and love it.  It is a great sounding trem.  I slimmed mine down a bit too.  While it is useful and adds flexibility, I made the Spacing pot an internal trimmer instead of a regular pot.  The Smooth knob (I call it Shape) is great - goes from square wave stutter to smooth "traditional" triangle/sine wave trem sounds.  Depth is a must too.  After using it a bunch though, I find that the two speed pots are not necessary.  I usually only use the Fine pot and leave the coarse pot somewhere in the middle.  This thing has a huge speed range, going from supper fast to almost stopped.  I personally don't need all that range, so I would suggest using one speed pot and replacing the Coarse speed pot with a fixed resistor or internal trimmer to give a useful range of speeds on one knob.  That would turn 5 knobs into 3: Depth, Speed, and Smooth (Shape) on the outside, and Spacing and Coarse speed as either fixed resistors or internal trimmers.  I used the project from Tonepad.com and used a 3PDT so my blinking LED does turn off when I bypass.  If you can't use a 3PDT, I'd just leave the blinking LED going all the time.  It looks really cool.  BTW, the LED also shows the depth too:  High depth settings cause the LED to blink bright to dark and low depth settings cause the LED to just barely dim a bit.  Very cool!

[SonicVI]

Yeah, the LED is a great visual indicator of everything, speed, depth, shape, spacing, and symmetry. You can dial the sound you want before you even turn the pedal on.   

[snoof]

i built mine with all 6 pots, but as stated above, you can get by with 3.  If I did it again, i would prolly go with 4; either spacing or gain, smooth, depth, coarse speed.  the fine, and spacing/gain i could do without if i had to.  basically, the only trem you will ever need, unless you want the brownface trem/vibe thang, then the vibra-tone is a must build.

Yeah, the LED is a great visual indicator of everything, speed, depth, shape, spacing, and symmetry. You can dial the sound you want before you even turn the pedal on.   

very true, i should add the external LED to my build, just lazy i guess

[caress]

you can always change the spacing, smoothing, etc. to switches as well, if you want less controls but the extra flexibility....

[robbiemcm]

Thanks for the help everyone. I've been searching for the parts and can find all except the VTL5C2, I would just substitute this for an LED/LDR combination but the only LDR I have access to has a resistance of 10M when dark. I can't think of any tricks to lower the dark value to what it's meant to be (suggested is 500k). The only thing I can think that might help is swapping the depth pot for something larger and trying to make the LED stay between about 90% and 100% brightness, which I doubt would result in a nice sounding tremolo as the difference isn't enough for any sort of precision. Any suggestions would be appreciated.

[Edit]
I managed to find a 500k one at another store which happens to be close to the one I'm getting all the other parts from. It was quite lucky considering they only had two, a 10M and a 500k.