Building the tap tempo tremolo

[Helloimjohn1234]

Basically, I didn't have the jacks properly grounded to the enclosure which was causing some crazy sounds. It worked fine but was really noisy. I did a few tweaks and it wouldn't work at all, a ground wire had broken loose and I didn't see it.. Now I've got it up and running and can't get rid of the tick

[Johnny B]

I finished my tap tempo build the weekend before last and am still discovering all the things I can do with it. I had no problem with the build other than that I had a dud NSL-32 which I had to replace. I used a 1590BB and with 6 pots, 3 switches and an external tap input. It fitted perfectly. Here are a few pictures of the pedal

[Helloimjohn1234]

Did you have a ticking problem before you replaced your opto?

[Johnny B]

Did you have a ticking problem before you replaced your opto?

I built the circuit with C9 at 1nF rather than 330pF and had absolutely no problem with ticking.

[.Mike]

Very nice pedal Johnny, inside and out.

[vassil]

Hi all,
Sorry that my next post is not about succeses .

I finished today tremolo.
In the begining everything was ok (testing out of enclosure). No ticking.
But after some time somefing goes wrong and now tremolo have very loud ticking when waveform is ramp up ,ramp up or square position.
Even if trimpots R13 and R14 is max value (22k), ticking is very loud.
In another positions no ticking but is very very quite "sirene alarm type" whisteling (mayby becose the PCB is not in enclosure). 

With 3 difrent type power supply (Boss PSA-120, Harley Benton PowerPlant and one another) is the same symptom.
Capacitor C9 is 1nF. Optocoupler is NSL-32

When i touch TAPLFO pin 3 with a tester or if i replase C2 with biger cap then 22pF, the ticking disapere but waveform sound to (just clean sound).

I replaced C1 and C2 (22pF) caps with a newer same value. But this useless.

I will try next things:
1. Replace optocoupler
2. Replace crystal
3. Is the possible that TAPLFO is some way was damaged?

Any another recomendation.
Tnx.

[Johnny B]

Very nice pedal Johnny, inside and out.

Thanks, Mike, for the compliment. You probably can't make it out on the photos, but on the front edge of the pedal is a South African flag and the words "In Suid Afrika vervaardig met bloudraad en tang", which is a 'tongue-in-cheek' Afrikaans quote for Made in South Africa with blue wire and pliers". Unless you know something of South African cultural history this may seen strange. The Afrikaner population of South Africa were mainly farmers, or "boers".  Due to a lack of technological resources, people here had to use their ingenuity and "make a plan" if anything needed to be fixed or made. ( A bit like McGyver!). "Boer sal n plan maak" (the farmer will make a plan) is a commonly quoted SA phase when in a tricky situation. So the legend goes that no matter what the problem, as long as you had a piece of Blue (read fence) wire and a pair of pliers, you could fix anything. Hence the quote.         

[Giz]

Hi everyone, I've just finished the build of my Tap Trem.
I wanted to post some pictures for those who are interested about wiring a rotary switch for waveform select. I've simply soldered resistors between the legs of the switch and I've connected the switch to the board like a classic pot with 3 wires. (Sorry for my poor English, I hope I'm clear enough)

[monkeyssj1]

Hey there I was wondering if any of you know whether or not these smallbear trimpots would fit. SKU number is 1015AB. I'm probably gonna order from small bear hopefully if I can get all of the components there. Unless there are other recommendations... I'm really sorry if this question has already been asked, but I am at work and am in a rush so I haven't been able to read the whole thread yet. Thanks again for any help/advice           

[engineelite]

So I just built the tap tempo trem successfully. I used the 330pf cap and have zero ticking. I need more depth on my depth knob though. I need some extreme chop going on sometimes. any suggestions?

Thanks.

[.Mike]

Hmm.

The depth of the effect is determined by the 10k that is in parallel with the 330p, the second half of the opamp, and, the LDR side of the NSL-32. The NSL-32, unfortunately, does not have very tight specs.

If you give it 20mA of current, it'll hit its minimum of 500-Ohms or less. Give it 16mA and it'll hit about two-thirds of the minimum in 3.5 milliseconds. That's pretty fast. Going the other way is a different story. The maximum off resistance is at least 500k. If you feed it 16mA, and then remove the current, it will take up to a half a second to reach 100k. That's pretty slow.

Of course, we're going nowhere near 20mA of current, I don't think, at least not without ticking. The slowness is actually a good thing. The Taplfo chip puts out PWM, and the idea was that the slowness of the LDR would make filtering the PWM unnecessary.

Anyway, back to how to go deeper. When the LED is dark, the LDR resistance goes up to say 100k (optimistic), the gain would be 0.1 (10k/100k). When the LED is lit, the LDR drops to something like 1k, so the gain would be 10 (10k/1k). The faster you go, the less time there is for the resistance to rise during the dark periods, and the less deep it gets.

So, it stands to reason that in order to get a deeper effect at low speed, you need an LDR that has a higher off resistance than the NSL-32. In order to get a deeper effect at high speed, you need an LDR that takes less time to transition from on to off.

Or, if you only need it to be deeper at high speed, you can create the illusion of a deeper effect. Set the wave distort so that there is more off time than on time, allowing more time for the LDR to recover to a deeper (and quieter) level. Turn up the gain to compensate for volume loss.

Mike

[engineelite]

thanks Mike. So, Could I still replace that 330pf with something higher and it make an effect or could I replace the 10k depth pot with a greater value and it have any effect?

I've got other nsl-32's that I could try but this one works without noise. I've like to keep it in there if possible.

Thanks.

[.Mike]

The capacitor is just there to kill the tick. Changing it will have little impact on depth.

Changing the depth control (or any of the controls besides gain) with a higher or lower value will make no difference at all. They are all setup as voltage dividers that vary between 0 and 5v. They feed into the Taplfo chip, which uses software to make the waveforms. Exceeding 5v is not recommended, and I believe that anything over 5v is treated as 5v by the software.

You can use pots of practically any value for most of the controls-- they don't even have to match-- and there would be absolutely no difference in how the controls function.

Unless anyone else has any ideas, trying different vactrols (even of different brand/model) is the best bet, I would think.

Mike

[Taylor]

In my experience, it should be possible to get quite a large dynamic range between on and off in square wave mode. The optocoupler trimmer is highly important here. If you decrease the series resistance you should be able to get pretty much completely off at moderate speeds. As Mike notes, decreasing pulse width (wave distort) will help on really fast speeds, but unfortunately getting a tickless, very fast, completely on-off trem with an optocoupler seems to be a bit of a holy grail. I haven't ever seen/heard one.

[engineelite]

Thanks for the help guys. I've got a few other opto's which I will swap and then listen. I'll report back soon. Thanks.

[vassil]

Hi all,
Sorry that my next post is not about succeses .

I finished today tremolo.
In the begining everything was ok (testing out of enclosure). No ticking.
But after some time somefing goes wrong and now tremolo have very loud ticking when waveform is ramp up ,ramp up or square position.
Even if trimpots R13 and R14 is max value (22k), ticking is very loud.
In another positions no ticking but is very very quite "sirene alarm type" whisteling (mayby becose the PCB is not in enclosure). 

With 3 difrent type power supply (Boss PSA-120, Harley Benton PowerPlant and one another) is the same symptom.
Capacitor C9 is 1nF. Optocoupler is NSL-32

When i touch TAPLFO pin 3 with a tester or if i replase C2 with biger cap then 22pF, the ticking disapere but waveform sound to (just clean sound).

I replaced C1 and C2 (22pF) caps with a newer same value. But this useless.

I will try next things:
1. Replace optocoupler
2. Replace crystal
3. Is the possible that TAPLFO is some way was damaged?

Any another recomendation.
Tnx.

1, 2, 3 not help.
I found solution for remove ticking. Maybe its crazy but it works.
I solder together  R4 and R5 pins (red mark on pic.).Those that are closer to TAPLFO ICs.
Any explanation for that?

[.Mike]

I found solution for remove ticking. Maybe its crazy but it works.
I solder together  R4 and R5 pins (red mark on pic.).Those that are closer to TAPLFO ICs.
Any explanation for that?

Looks to me like those two resistors connect to pin 12 (waveform) and pin 13 (tempo).

I can't imagine that your waveform and/or tempo knobs are functioning properly after that.

Mike

[vassil]

I found solution for remove ticking. Maybe its crazy but it works.
I solder together  R4 and R5 pins (red mark on pic.).Those that are closer to TAPLFO ICs.
Any explanation for that?

Looks to me like those two resistors connect to pin 12 (waveform) and pin 13 (tempo).

I can't imagine that your waveform and/or tempo knobs are functioning properly after that.

Mike

I will do some video demo and i post here. But it takes some time.
Then you can evaluate, do my tremolo work properly or not.

[vassil]

Mike you was right. Waveform and tempo func. not work properly on some positions.
When i change waveform, then its impacts also tempo. 

[engineelite]

So I'm reporting back after trying out different photocells and the NSL-32sr3 solved my depth problem completely and didn't add any ticking BUT when the signal flows through it  there is slight buzz/hum that comes in and out with the pulse of the trem. while playing the buzz isn't very noticeable but without playing its very noticeable. any ideas to fix that issue. If I can get that buzz out then it'll be perfect!

Thanks.