Building the tap tempo tremolo

[Taylor]

Maybe I misunderstand, but the waveforms are included in the PDF.

[roseblood11]

Sure. Some people placed them around the pot as a scale. Would be great to share that here, because it's not easy to recreate that if all you use is a simple software like photofiltre (that's what I use...)

btw: My pcb arrived last friday - after a long oddysey through german customs authorities. It's really a very high quality pcb. Many thanx for this project!

regards, Immo

[sholm14]

I didn't really get too involved with the forum, but I just thought I'd share a couple of my builds and get some feedback. The only thing I had to change was the 330p cap to a 1.5nf (I only had orange drops lying around, but it works!).

Here's mine and one that I built for a friend.


Here's another built for a friend.


And here's my guts!

[.Mike]

Sure. Some people placed them around the pot as a scale. Would be great to share that here, because it's not easy to recreate that if all you use is a simple software like photofiltre (that's what I use...)

Here's a 1200 dpi PDF of the wave shapes. You will have to put them in a circle on your own. If your image editing program doesn't open PDFs, let me know what common format would work for you, and I will generate the file. Link

I didn't really get too involved with the forum, but I just thought I'd share a couple of my builds and get some feedback.

Very nice!

I notice you didn't add the wave distort pot. Just curious-- did you try it and not like it? I think it's one of the best features of the LFO.

Mike

[sholm14]

Very nice!

I notice you didn't add the wave distort pot. Just curious-- did you try it and not like it? I think it's one of the best features of the LFO.

Mike

I guess I just never really thought of putting in the wave distort pot. My first problem is that I wanted to order the enclosures from PedalPartsPlus, and so that was the drilling that I chose. If I do build another, I will for sure try it out!

[Vince_b]

I have made a waveform labeling just for you roseblood 

https://www.box.com/s/31934e0eba281fb5458d

It will fit around a 3/4" knob. To make it fit around a bigger knob you just have to scale it to a bigger size before printing it. I made 3 different versions so it can be used either with a rotary switch, a 270° pot or a 300° pot.

[roseblood11]

many thanx!

but I hope that it's useful for more people...

@Taylor: Maybe in an updated version of the IC the switching could be simplified? What about this: Omit the waveshape and the multplier pot. Just use the momentary switch connected to "EXP" for both: If only this switch is pressed, it steps through the multiplier settings. If the tap tempo switch is continously pushed down, the switch steps through the wave shapes.
The values could be shown by different kinds of LED's:
http://www.reichelt.de/Flaechen-LEDs/FLED-10X22-GE/3/index.html?;ACTION=3;LA=2;ARTICLE=31470;GROUPID=3015;artnr=FLED+10X22+GE;SID=12T7F2-n8AAAIAAHU0RV4f416968deb1ca8516db9bbfa10a8c213
or nummerical:
http://www.reichelt.de/Siebensegment-Anzeigen/SA-39-11-GN/3/index.html?;ACTION=3;LA=2;ARTICLE=6920;GROUPID=3002;artnr=SA+39-11+GN;SID=12T7F2-n8AAAIAAHU0RV4f416968deb1ca8516db9bbfa10a8c213

[Taylor]

Definitely message Tom at Electricdruid.net about your suggestions. He is the designer of the chip, so even if my microcontroller skills were better than they are, I wouldn't have the right to modify the code. But he may be interested in a new version.

My personal preference is that I vastly prefer knobs over stepping through menus, though. I can't stand schemes where a single button controls multiple functions with long-presses, etc. Plus, having the multiplier as a pot control lets you sweep through it with expression control, which is pretty fun. But that's all just my own preference.

[roseblood11]

Plus, having the multiplier as a pot control lets you sweep through it with expression control, which is pretty fun.

That's a potent argument! ...and one more idea for my build

[teej212]

i just built mine and have a big problem with ticking, should i not have the jacks grounded on the pad that says 'ground'?

also for cv of the pots- do I just have a mono jack, tip connected to center lug and sleeve to ground?

[Taylor]

I recommend star grounding to the input jack sleeve. Also try upping the 330p cap to 1n.

If you want CV instead of a pot, connecting that way will work, assuming you have a CV source putting out 0v-5v. If you want both CV and pots active simultaneously, you'll need some resistive mixing. The CV source should have a 10k resistor in series, and the pot should have a 10k coming from its wiper. Then connect the two 10ks together and wire them to where the pot's wiper went previously.

[Radcon]

I am pleased to report that I now have the TTT working beautifully.  As encouragement (?) to other beginners, I offer the following list of problems which prevented the device from working, along with my thoughts on how to prevent similar problems on my next build:

1.  Transistor pinout different than expected - installed backwards (learned how to test).
2.  Gain trimpot was bad (test before installing)
3.  TAPLFO chip was bad (bad luck, I guess)
4.  Wrong value capacitor in the Xtal/ oscillator section of the circuit. (be skeptical of poorly marked items out of the parts bin.  Invest in a multimeter with a capacitor test feature)

Thanks again to everyone involved.  Great project.

[Hoffmann]

Hi!
I would like to use external tap in /out function also. Connector I plan on using is this :
It is something similar Cusac tap-a-whirl uses.
Should I connect sleeve pins to the ground of the board, or just TIP pin to the pin 7 of the uC?

[Hoffmann]

I would also like to know what is the max current pin 7 of the uC can handle?

[.Mike]

Hi!
I would like to use external tap in /out function also. Connector I plan on using is this :
It is something similar Cusac tap-a-whirl uses.
Should I connect sleeve pins to the ground of the board, or just TIP pin to the pin 7 of the uC?

I would also like to know what is the max current pin 7 of the uC can handle?

Pin 7 is a clock out. Pin 4 is the tap in. I don't see how an RCA jack is going to serve that dual function without extra supporting circuitry. If using that jack for either pin 7 or pin 4, though, you need the pulses to go between 0 and 5v, and for that you will need a reference-- ground.

Also, since pin 7 is a clock output, it isn't really meant to source current. It's meant to trigger some other circuitry, and that other circuitry should be designed to not need much current at all. Regardless, the max current that any output pin on the TapLFO (16f684) can source is 20mA, hence the transistor driver to protect the PIC on the off chance that the LEDs try to pull too much current.

Good luck!

Mike

[Hoffmann]

this is what I ment:

I am not sure I need to ground RCA ground pin?
This kind of arrangement can serve as TAP in and TAP out On the RCA connector, depending on the state of the toogle switch.Am I right?

[midwayfair]

Built mine a while ago and recently repainted the box. I did the rate LED mod that keeps it from ticking in bypass, but otherwise it's stock. This one's still on my board all the time:



No gut shots since I don't want to open it up ... it's finicky about the exact placement of the board. I probably ought to replace the jacks with low-profile plastic or enclosed jacks to avoid shorting. I wasn't as good at boxing things at the time I built this.

[Hoffmann]

Second version: I added the same driver to the TAP out ( to protect PIC if some external tap device trys to pull too much current from the PIC). review please!

[Hoffmann]

^bump 

[ElectricDruid]

Second version: I added the same driver to the TAP out ( to protect PIC if some external tap device trys to pull too much current from the PIC). review please!

Either look fine to me. The PICs outputs are pretty robust (20mA max) and I haven't managed to kill one by plugging things into it, so the second version seems a bit belt-and-braces. But if you want to be sure, go for it.

I would ask why include an expensive toggle switch to avoid the need for a second cheap RCA socket? Wouldn't it be easier and more flexible to have separate In and Out plugs? But again, I don't know the whole situation, so you've prob'ly got your reasons...

Tom