Flo Rida Optical tap tempo Tremolo

[Kipper4]

Time to give something back.

I've had the new Stompflo chip from Electric Druid on the breadboard for a week or so.
For me it's an ideal replacement for my usual dual op amp schmitt trigger/integrator. Less parts, more waveforms and no non polarised caps to worry about.

I want to thank Tom and shamelessly promote this super little chip.
You can get your chips here and access the pdf data.
https://electricdruid.net/product/stomplfo/

Heres the schematic.




Thanks for all the help. You know who you all are.

[Kipper4]

And a dodgy demo

Forgot to demo the tap. Doh.

[EBK]

I was going to say that I'll wait until Steve carries that chip in his store before I buy one, but then I saw that he has already anticipated this plan of mine.   
http://www.smallbear-electronics.mybigcommerce.com/ic-electric-druid-stomplfo/

[duck_arse]

hmmmm, a few less parts now ...... but! how come/why have you buffered the indicator led, but not the vactrol led? that buffer will handle both, Shirley, parallel strings. perhaps Q1 collector to +9V?

[Kipper4]

Much less parts agreed.
Yes you're right Q1 and R3 are not needed the lfo output can handle both led's off of pin 3.
If you dont want a tap tempo feature just leave pin4 open.
If you want a tap tempo but no Rate pot tie pin7 to either +5v or Gnd through a series 10k.
If you dont want the depth (a must IMO) then tie pin7 to +5v via a series 10k.

Even less.

However If you want more parts I also have an op amp version.
Shout out if you want that.

[Mark Hammer]

Perhaps a silly little question, but I noticed that the runoffgroove version of the EA tremolo had a rate indicator LED, but it was opposite phase to the actual modulation, such that it got brighter during the softest parts of the sweep, and dimmer as the volume peaked.

So, does the indicator LED in your circuit get brighter with level or dimmer?

[Mark Hammer]

Funny.  Way back when, I etched and populated the board for this nugget from Elektor: http://hammer.ampage.org/files/SEWAR.PDF

So strange to think that most of it can now reside in an 8-pin DIP.

[anotherjim]

Presume the LED control is PWM?
So you maybe ought to fit an RC filter - or the RFI emissions police will be after you!
Only joking  - kind of, but for a commercial product requiring standards approval,  wouldn't have to deal with that?

[ElectricDruid]

Presume the LED control is PWM?
So you maybe ought to fit an RC filter - or the RFI emissions police will be after you!
Only joking  - kind of, but for a commercial product requiring standards approval,  wouldn't have to deal with that?

The output on the StompLFO is actually a Pulse Density Modulation output. It uses a lot of narrow pulses instead of fewer big fat ones. This helps with the averaging, because the base frequency can be much higher. On this chip it's at 2MHz.

RFI emissions would need to be dealt with anyway for a commercial unit because it's a microprocessor, whatever the output does (although that might well affect whether it actually produces RFI or not).

Tom

[Kipper4]

Perhaps a silly little question, but I noticed that the runoffgroove version of the EA tremolo had a rate indicator LED, but it was opposite phase to the actual modulation, such that it got brighter during the softest parts of the sweep, and dimmer as the volume peaked.

So, does the indicator LED in your circuit get brighter with level or dimmer?

I'll do a drawing of how I achieved this both ways Mark.
I looked into the possibility of using opposing leds in a project. Just haven't gotten round to ticking it off the list yet. I managed opposing leds.


This will make a great candidate for a dub siren too.

[ElectricDruid]

This will make a great candidate for a dub siren too.

Funny you should say that...have you seen this?

http://www.benidub.com/ds71/

(Actually this uses the Druid VCLFO10 not the STOMPLFO, but it's a similar idea!)

Tom

[Kipper4]

To answer your question Mark the trem goes louder when the led goes out.
The blue led in the video is wired the opposite way.

[duck_arse]

I've got a funnee feeling your opposed led should be opposite. the other way.

[Kipper4]

Yep you got it. My mistake I'll repost asap.

Rich

[ElectricDruid]

That's making me think of stereo phasers with one channel running opposite phase to the other. Or a panning trem. Hummm....

T.

[Kipper4]

The drawings have been updated thanks for picking that up.

[Danich_ivanov]

That's making me think of stereo phasers with one channel running opposite phase to the other. Or a panning trem. Hummm....

T.

Is sounds really close to what i'm working on right now. Think harmonic tremolo, but instead of having filters on each side, you have phase stages, then add dry on top, and things get even more interesting. Quite a lot of room for experimentation with this circut.

[Kipper4]

Heres an updated enveloped tremolo.

[Ben N]

Looks very cool. In envelope mode, is there no way to set  min or max speed? And why no depth in this version?

[Kipper4]

No not really it's more of an special effect.
I haven't really tried to hard with that because I've already done such a pedal called the Trikbox Tremvelope.

I would have liked to get it to do a fast to slow mod too. Instead of just the slow to fast.
So when in envelope mode the detector sends the speed right up and it decals to a slower speed.
I'll do a q&d demo. When I get time.