Building the tap tempo tremolo

[Poste]

So, I have tried a couple of things, and still havent gotten rid of the tick.

The visible LED trim is set to full, the OPTO trim is set at about half way, there is ticking from about 1/4 turn on, and it seems that I can get the required volume at about 1/2 turn.
I have replaced the 330p with a 1n and that hasnt fixed the problem, I have replaced the OPTO, still ticks, so is there anything else anybody can provide?

I have used the alternate 3pdt wiring schematic and have also wired in the extra cable off of the 10K resistor as I thought that might help too.

Still confused, I love this pedal, but the tick has to go...

[Poste]

Here a really quick thought, as I dont truely understand electronics just yet, but could I just up the Gain pot to a larger figure giving me more "range" does the volume increase with the pots increased resistance or is it the other way around?

Thanks in advance for any insight

[Taylor]

Yes, in this case, larger value equals more volume this is because the gain pot is the feedback resistor in a non-inverting amplifier (r2 in the drawing there).

You can't take it as a rule in electronics that bigger pot value=more volume, because often a volume knob is a voltage divider, in which case the volume is proportional to the ratio between the 2 sides of the pot. I know you didn't ask this, but I wanted to prevent you from getting that rule in your head when it won't work most of the time.

So, if the problem is just volume, you can make the gain pot a 50k or 100k and you should have plenty of volume available. The only problem with this approach is that you're limiting the maximum depth possible, because you're amplifying not just the loud part (LED lit) but also the quiet part (which is not silent). But otherwise it's ok, and if you don't need very deep trem you should be fine.

[Poste]

Thanks Taylor,

I have rewired a 100K pot instead of the 20K, and am now getting the required volume, as for depth, I am pretty sure I am getting quite a bit, however I think there is more to be had, but I am a happy camper with the obtained amount,

once again thanks for all your hard work and effort in putting this together, I have had a blast building it up, I still need to get the enclosure screen printed in the near future, but everything is working great.

[lwatford]

just a couple of quick pics of my second tremolo...the board mounted pots work great, but they made it a pain drilling the enclosure. It seemed easier to tune this one in than the last one, very little ticking. Thanks again for an awesome project!

[Taylor]

Nice!

[turunturun]

So the question was asked before but I searched everywhere and can't find the post, so I will ask it again at the risk of making my first post a flame-magnet....<shame>...sorry....</shame>

Is there a way to add a Control Voltage OUTPUT to this pedal that will reflect/mirror the tremolo wave-shape activity?

Or maybe stated another way, is there a way to construct this pedal so that it modulates a +5V signal instead of the incoming audio? AKA no longer a tremolo pedal but a control voltage generator with the same functionality?

Either way, my boards are in the mail and I can't wait to build it!!! (got one for a build-per-spec and one for devious experimentation.... hehehe)

Thanks!

[Taylor]

Typically for CV you'd want to build a real filter to filter the PWM signal into an analog voltage as in the datasheet at electricdruid.com. This board relies on the optocoupler to do the filtering.

So I guess the way to do this would be to remove all the caps from the signal path, and remove the anti-pop resistors. I haven't done this so I can't say anything about how well it works.

[turunturun]

OK, wow - got it. Upon closer inspection of the TAPFLO data sheet, "Application Notes: Modular Synth LFO with Tap Tempo and Ext Sync" is what I am looking for, just like you said. That will produce a 0-+5V CV generator with exactly the functionality I am looking for. COOL!
I will post some documentation on my build!!!
Thanks again!

[Valoosj]

The paint of the enclosure is drying as we speak, so here are the guts 




Big thanks to everyone who contributed to this!

[Valoosj]

I just plugged this in and R17 (the 10 ohm resistor at the 9V input) burned up. Should I increase this value or just leave it out? My onespot runs at 9.4V.

[.Mike]

You can just use a jumper.

It just lowers the corner frequency of the filter on the power supply, so unless you are experiencing power-supply induced humming, it's not necessary at all.

Mike

[Valoosj]

And it works! I don't know why the resistor burned out though. Replaced it with 100ohm.

This trem is really awesome, safe to say that it will never leave my pedalboard 

Once I redo the decal I'll post some pics.

[spargo]

Question:

This has happened on a much smaller scale before, but not as big as last night.

After the tremolo is on for a while (maybe an hour or so) I get to hearing some clicking from it.  If I engage it, there is a small pop.  Then I turn it off again and the clicking seems to have been "drained" out of the pedal.  Well, I did this the other night and there was a HUGE pop that went through the system.  Almost like there was no pulldown resistor at all and there was a huge current stored up.  Naturally, the tremolo was behind my delay set to a very high feedback so I unexpectedly got the pop numerous times...

Any idea what to look into for this?

[Taylor]

I have seen this kind of issue with a lot of different circuits. Some info:

http://www.diystompboxes.com/smfforum/index.php?topic=68210.0
http://www.diystompboxes.com/smfforum/index.php?topic=23743.0
http://www.diystompboxes.com/smfforum/index.php?topic=69693.0

[thedrivel]

Really excited, just finished up soldering. Plugged it in and it worked right away, haven't noticed any issues yet. No ticking, but I haven't messed with the trimpots yet. Hopefully tomorrow I'll have time to drill out the enclosure. This is my second pedal, my first was a Big Muff clone kit from GGG which worked right off the bat too luckily. Thanks Taylor for providing the board!

Here are a couple pictures, let me know if you all see anything that needs correcting.

[Taylor]

If it works and you have no ticking, then it's good. Nice job for a second project! My second was way uglier, but I didn't have such nice PCBs to work on back then. 

I would say that wrapping your LED wire around the in and out could potentially be a serious cause of ticking, but again if you're without it, then nothing to worry about.

[Taylor]

I was desoldering the wave distort on my tap tempo board and goofed up kinda bad I think. I couldn't get that old wire to come out, it was really stuck. I finally got it out, but now the eyelets are missing for that contact. Is it repairable or is the board toast?  It's the contact labeled "1" for the wave distort feature. Really pissed at myself grrrr 

That pad just connects to ground, so you can run that wire to any other ground point in the pedal and it'll work the same.

[EDLK]

 
I am about to hard wire the led direct on the board and do the rewire switching Mod per Taylor's diagram to get rid of ticking in the bypass position.
I would also like to add an  on/off led.  Is there a way to have both mods at the same time.  Does any one have a diagram or a pic of the best way to wire this.

Also i will be replacing the 330p cap to hopefully eliminate the ticking in the first 3 wave forms.
I have read about several different values from 1u to 5u to use.  Does one value work better than another.
Is bigger better?

Thanks all.

[Taylor]

With that wiring diagram, the flashing LED will turn off when you bypass the effect. So it acts as both bypass indication and speed indication, so you don't need a separate on/off LED.

Take note to use a cap between 1N and 10N, not 1u or 5u, which would be way too big. The bigger you make that cap, the more high end you will roll off, but also less chance of ticking. If you want to preserve your high end perfectly, I would recommend putting a socket in that spot and trying out caps starting at 1n and going up until you find the best compromise between ticking and high-end roll off.

The best way to avoid ticking, though, is to use board-mounted pots and keep all wires as short as possible. If you have spaghetti wiring, it will tick and all the cap stuff is just a bandaid.