Is there a simple DIY optical trem?

[nbabmf]

Am I missing something?  I can't seem to find an optical tremolo with rate, depth, and a toggle for square/sine waveforms.

I just finished rehousing a Dano Tuna Melt trem for someone, and I'll be damned it it doesn't beat the pants off my Stereo Pulsar.

[smallbearelec]

http://www.smallbearelec.com/Projects/TremBear/TremBear.html

Gives square and triangle...

[Top Top]

I haven't seen one (optical one), but I don't have an encyclopedic knowledge of pedal designs... I have run through a few designs for it in my mind but haven't had a chance to try any yet. Seems like a good first thing to try designing if you've never designed anything before.

[candidate]

http://www.tonepad.com/project.asp?id=42

[nbabmf]

Tremulous Bear is a possibility, but I don't need all those controls.  The Tremulous Lune only does one type of wave so that won't work.

I'd be willing to forego the optical thing if I have to.  The simple rate, depth, and wave toggle are more important.

[Slade]

Tremulus Lune can go from triangle to square with the Smoothness control. And you can add the Symmetry mod to get sawtooth waveshapes. Look at mine here: http://www.youtube.com/watch?v=V4nIQ81ynyw

Cheers!

[CynicalMan]

www.tdd.lt/~antonas/guitar/gifs/andertontremolo.gif

[jkokura]

Not simple, but I fully endorse the Tap Tempo Trem project released by Taylor here on the forum. As far as I know, it's an optical trem. I could be wrong on that...

Jacob

[Scruffie]

Tremulous Bear is a possibility, but I don't need all those controls.  The Tremulous Lune only does one type of wave so that won't work.

I'd be willing to forego the optical thing if I have to.  The simple rate, depth, and wave toggle are more important.

I looked for ages for exactly the same thing but there isn't really a project about for such a project (Other than the EHX Pulsar but that has issues apparently)

Not that I ever got round to it but the best idea would probably be to just find an LFO that does what you want and go from there.

[deadastronaut]

if you want a simple optical , as in your title...

http://www.diystompboxes.com/smfforum/index.php?topic=87322.0

or a dual tremolo...simple too...

http://www.diystompboxes.com/smfforum/index.php?topic=87409.0

could use them as a starting block anyway. very simple indeed... ......rob.

[JKowalski]

Not simple, but I fully endorse the Tap Tempo Trem project released by Taylor here on the forum. As far as I know, it's an optical trem. I could be wrong on that...

Jacob

Yeah, it's optical. Its basically the exact same thing as the tremulus lune except that the LFO circuit is replaced by Tom's (ElectricDruid) TAPLFO chip.

I like the tremulus lune style of optical AM (amplitude modulation), it is small and simple to build. Just add in whatever LFO you can find to that, and you are set. The total circuit separation between LFO and AM circuit that optical gives you is real easy to modify.

You can get the XR2206 Monolithic Function Generator (very simple since all you need are a handful of external components for the IC) for around $2 I think, it gives you easy triangle, square, and sine wave outputs with constant amplitude (as opposed to many simple oscillator circuits with short ranges and frequency-dependant amplitudes). Plus it can be voltage controlled, so if you wanted to mess around with more complex stuff like frequency ramping and etc...

My go-to LFO circuit is now the TAPLFO chip, since I can program & modify them to my hearts content. If I were to have to choose another, though, that would probably be the XR2206. If I were confined to OP-Amp or transistor circuits with easily available parts, I would probably do a tri/square with adjustable duty cycle op amp oscillator. Simpler... - maybe just a tri-square.


Sine waves are lovely to have available but they aren't THAT much different in sound then triangle waves.

[nbabmf]

I saw the Anderton one... that's definitely an option.  I'm no stranger to his bipolar trickery because I built his ring modulator a while back, and have almost all the parts on hand.

I just have to stress simple because I have a very picky friend who says his trem must be analog, just 2 knobs and a toggle, etc.  I can't seem to swing him towards something with more flexibility, like the Tremulous Lune or the Tap Tempo Tremolo project that was born here.  He's really anti-EHX for some reason, otherwise I'd just have him use my Stereo Pulsar.

With respect to the sine/square thing, triangle/square would be fine too.  I'm still pretty n00bish when it comes to LFO's.  A friend turned me onto the XR2206 last night, but I'm still a little hung up on how to integrate that into an existing design.  I should spent more time experimenting and reading about this stuff.

[ckyvick]

If you want a warm analog trem build the ea. You can even add a toggle switch to use it as a boost as well.

[JKowalski]

I saw the Anderton one... that's definitely an option.  I'm no stranger to his bipolar trickery because I built his ring modulator a while back, and have almost all the parts on hand.

I just have to stress simple because I have a very picky friend who says his trem must be analog, just 2 knobs and a toggle, etc.  I can't seem to swing him towards something with more flexibility, like the Tremulous Lune or the Tap Tempo Tremolo project that was born here.  He's really anti-EHX for some reason, otherwise I'd just have him use my Stereo Pulsar.

With respect to the sine/square thing, triangle/square would be fine too.  I'm still pretty n00bish when it comes to LFO's.  A friend turned me onto the XR2206 last night, but I'm still a little hung up on how to integrate that into an existing design.  I should spent more time experimenting and reading about this stuff.

Check out the datasheet for the full XR2206 oscillator schematic. Page 8-9. Read up on the intro & pin functions to get a good sense of what they do, then adjust to suit. R and C on the schematic determine the frequency range, you'll want to use larger values to get down to LFO speeds.

The datasheet gives the frequency as a function of the resistor R and capacitor C: F = 1/RC, simple. Use a potentiometer connected as a variable resistor for the R in series with a resistor (limits R to a minimum value). If that limiting resistor is R2 and the potentiometer size is R1, then you can find each by determining your frequency limits F1 and F2....

F1 = 1/(R2)C, R2 = 1/F1*C

then,

F2 = 1/(R1+R2)C, R1 = (1/F2*C) - R2

There, you have the right resistors for your freq. range. The variable resistor on pin 3 apparently (datasheet tells you) sets the output amplitude of the sine and tri waves. However, you are using the square too probably so I would set this fixed and instead let the LED current limiting resistor be variable.

Stick an LED and the variable current limiting resistor (with a limiting resistor, of course!) on the output (switchable between the square, tri and sine outs), and you have your LFO.



The datasheets got all the answers!