Building the tap tempo tremolo

[Taylor]

That's not relevant. You can tap twice to set a tempo, then immediately tap twice again to set a new tempo. The time between second and third taps can be short or long, doesn't matter.

Also, say you tap three time by accident. The tempo will be set by the first two taps. The third tap puts the chip in "listen" mode, but after a certain period of time (check the datasheet on electricdruid.net for the time - it's something like 5 seconds) the chip stops listening for the fourth tap and exits listen mode. This is good because if it didn't do this, you'd tap three times, then 10 minutes later you'd tap twice trying to reset the tempo, but you'd actually be setting the tempo for a 10 minute cycle.

It seems complicated when I describe it this way, but it's actually very simple when you get the hang of it.

[Moonibopper]

Very informative. Thanks again.

Do any of the pots (I've installed all 6 as external pots) have to be set to a certain level for the tap function to work well? Particularly the speed or multiplier knob?

Also, do either of the trimmers (between the TAPLFO and OpAMP) effect the tap function depending on their setting?

That's not relevant. You can tap twice to set a tempo, then immediately tap twice again to set a new tempo. The time between second and third taps can be short or long, doesn't matter.

Also, say you tap three time by accident. The tempo will be set by the first two taps. The third tap puts the chip in "listen" mode, but after a certain period of time (check the datasheet on electricdruid.net for the time - it's something like 5 seconds) the chip stops listening for the fourth tap and exits listen mode. This is good because if it didn't do this, you'd tap three times, then 10 minutes later you'd tap twice trying to reset the tempo, but you'd actually be setting the tempo for a 10 minute cycle.

It seems complicated when I describe it this way, but it's actually very simple when you get the hang of it.

[Taylor]

No, the pots don't effect the function of the tap. The speed knob is totally overruled when you tap in a tempo. When you adjust the speed knob it overrules the tapped tempo.

The trimpots also don't effect the tap. They are to be tweaked according to the manual to get the proper functioning in the audio section.

You might need a debounce cap on your switch as Chris says, but my guess is that (like me when I first built it) you just need to get the hang of tapping.

[lwatford]

I just wanted to say how great this board looks! I got it in the other day and just started populating it, I'm going to end up building one for myself! Great job putting this together, and I can't wait to finish it up.

[Moonibopper]

After all your help and fiddling around with the board things are working great:

1) Ticking - replaced the 330pf capacitor with a 2.2nf capacitor and the tick is completely gone.
2) Tap tempo - putting a 10nf capacitor across the SPST improved its responsiveness. I realized that if I press it fairly rapidly (rather than a slower press) it works better.

[Poste]

Got started on my build finally, Christmas was quite hectic and so on goes the story...

I have soldered in a few resistors, and have started to notice that the flux doesnt want to do what I would like, could someone please tell me if the flux is fine to be left as is, or should I clean it off? and if cleaning is required how would I go about it, I have acetone but have been reading that Iso Alcohol is the best way to remove it?

And could someone please tell me if my soldering is up to the mark?

Thanks in advance for any advice

[calpolyengineer]

It should be alright to leave it. Only at very high voltages does flux residue become an issue.

But if you did want to clean it off, iso alcohol and an old toothbrush works well. My personal preference is to use an xacto knife and chip off the flux. I find that dissolving it just leaves a thin layer of flux residue on the entire board.

--Joe

[Taylor]

Flux: if you've been using that same solder and flux with success, then you should be fine. I once bought a kind of Kester solder that - unbeknownst to me at first, had conductive  flux. Be sure you don't have that.

Your soldering looks ok, but I would clip the leads much shorter than that.

[lwatford]

I've got a quick question about board mounted pots...what would be the preferred orientation?

Like this:


Or like this (which seems like it might be the "right" way):


I liked the first one I built for a friend so much, I had to build a second one for myself!

[Taylor]

I don't know, actually, because I'm not sure what the convention is for depth.

The first way, you get deeper trem towards clockwise. That might be the way people expect it to work, not sure. 

[lwatford]

I don't know, actually, because I'm not sure what the convention is for depth.

The first way, you get deeper trem towards clockwise. That might be the way people expect it to work, not sure. 

I think you're right, the first way would also let it fit into a vertical 1590BB...if I measured right.

[Poste]

Here is a quick question,
I got this working today, however I am a little confused about the trimpots.
I brought the "gain" trimpot out to the front of the box, and I am guessing that one of the remaining two trims sets the amount of light from the led and the other brings the tick down.
But if I crank the brightness one all the way and the other all the opposite way, is this going to affect the performance of the pedal?
Thanks in advance for any info and thankyou for a great product.

[.Mike]

I brought the "gain" trimpot out to the front of the box, and I am guessing that one of the remaining two trims sets the amount of light from the led and the other brings the tick down.
But if I crank the brightness one all the way and the other all the opposite way, is this going to affect the performance of the pedal?

One of the trimpots controls the brightness of the LED contained within the photocoupler, and the other controls the brightness of the LED that is visible on the outside of the enclosure. You want to set both to be as bright as possible without inducing ticking.

From the build doc:

4. Setting the trimpots
The 2 trimpots in between the TAPLFO chip and the TL072 are for limiting current to the LEDs. The one directly next
to the TAPLFO limits the current to the optocoupler, and the other one limits the visible LED. Carefully setting these 2
trims will prevent ticking and give the ideal optocoupler performance as well as a tolerable LED brightness. Set them
to the position that eliminates ticking.

I would think it is more important to have the optocoupler as bright as possible, while still allowing a usable LED brightness. You just have to strike a balance between brightness and ticking.

Mike

[Poste]

Thanks mike,
At present I have the visible LED set to the brightest setting, all the way clockwise (I am guessing the trimpot is at "zero" resistance) and the trimpot for the LED in the OPTO is set to the dimmest setting, all the way anticlockwise (I am thinking full resistance)

Is this a problem, the tremolo still works, but I am wondering if I can not get more out of it.

[Taylor]

Thanks Mike, good advice.

Basically, the brightness of the opto controls the max depth of the tremming action. If you're happy with the depth you have, it's good. If you want more depth, increase the brightness of the opto and trim back the gain to keep levels equal in effect and bypass.

[Poste]

Alright now I have another problem,
Hopefully the last one, I seem to be getting a quieter overall sound when using this pedal as opposed to bypass.
Can anyone give me an idea why this would be?
Thanks.

[Taylor]

It would be because you have the opto trimpot and/or the gain too low. You've read this, right?

http://musicpcb.com/wp-content/uploads/2010/09/Tap-Tempo-Tremolo-build-PDF-updated.pdf

[Poste]

Thanks for the fast reply, Taylor.

This is what I guess I was asking a couple posts back about the "performance" of the pedal relating to the trimpot settings. Nowhere in your PDF does it say that a low opto trim setting will effect the output of the pedal, just thought you might want to know to maybe update it.

Or at least it is now here, so people reading this thread now has a little bit more info on setting this pedal up.

Thanks again for a quality product and the help during the build, this is my first build and I was expecting more difficult problems then this, I am wrapped with how it turned out. I will post pictures of my completed, yet ugly pedal soon.

[Poste]

I just reread this whole thread and found the info was already there, so sorry for reasking the same questions. I think I will have to up the 330pf to something higher I am thinking possibly the 1nf and failing that the 2.2nf.

So again sorry to keep bringing up problems that have been remedied.

[Taylor]

No problem, these long threads are tough to navigate. Glad you got it sorted.