Tonepad's Maestro FSH-1 has a strong ticking

[returntable]

I use a sharp knife and cut the trace several times at the location where I want it cut, then "scrape" the groove a bit wider to make sure the connection is completely cut.
Do not forget to "run the second wire to the common ground..." so that both parts of the trace are still connected to ground.
What you are trying to accomplish here is a "star-ground" (google it...), this should reduce the LFO having an impact on the audio-path in the filter circuit via the common ground trace.
Silly question perhaps but which schematics is being referred to when talking about C14? Tonepad's schematics uses no such indicators... I assume we are takling about the ground trace connected to IC3 pin4.

Okay, I will try star grounding this thing in the next days...
The trace cutting is a good idea, but the question from Flo is really appropriate: which track exactly is to be cut?
I think we should take the Tonepad schematic as a reference, since most of us built that.

[thedefog]

I've built one of these using a PCB layout supplied by General Guitar Gadgets. I have the same issue.

I'm hardly an expert on the matter. However, I did noticed that since my charge pump is offboard that the further away from the board I moved it, the less pronounced the ticking was. Maybe using some shielded wiring on the switches would help remedy this. 

[returntable]

All right, I have solved the ticking Problem for my build at least in the Filter Mode.

Like in the Echo Base Thread esplained, I soldered a 1uF Electrolytic Cap between Pins 7 and 3 of IC3(the S&H LFO). the ticking in Filter Mode is completely gone now.
The S&H doesn't work exactly how it should, but maybe I have to adjust the trimpot value again, but I wasn't able to test that yet. I will report about that tomorrow...

[gigimarga]

Woow...very good news!!!

[gigimarga]

Looking at the schematic it seems to me that you put the 1uF cap from the output of the LFO to the ground. Am I right?

[Cliff Schecht]

I'm not sure if this was mentioned earlier in the thread, but going to low power BiMOS-based op amps may help ticking problems. Since they usually draw a lot less current per amplifier than a normal BJT/FET based op amp, they won't pump the rails as hard and don't dump as much current into the grounds. This, in conjunction with proper decoupling, should help quite a bit. Also, if you run the LFO on a completely separate op amp, this can help to prevent bleedthrough problems.

[returntable]

Looking at the schematic it seems to me that you put the 1uF cap from the output of the LFO to the ground. Am I right?

exactly.

I'm not sure if this was mentioned earlier in the thread, but going to low power BiMOS-based op amps may help ticking problems. Since they usually draw a lot less current per amplifier than a normal BJT/FET based op amp, they won't pump the rails as hard and don't dump as much current into the grounds. This, in conjunction with proper decoupling, should help quite a bit. Also, if you run the LFO on a completely separate op amp, this can help to prevent bleedthrough problems.

Thanks for your ideas, but they have been mentioned before and didn't solve the problem completely.

[slacker]

The 1uf cap to ground off the output of the LFO will make the output pulses into a trapezoid shape rather than square, hopefully they should still switch the FET in the S/H section.

This might already of been mentioned, but adjusting the the value of the 3k3 resistor in the LFO will change the width of the pulses. Making it smaller will narrow the pulses which might reduce the ticking, of course if you make them too narrow the S/H won't work. Could be worth trying though.

[Cliff Schecht]

The 1uf cap to ground off the output of the LFO will make the output pulses into a trapezoid shape rather than square, hopefully they should still switch the FET in the S/H section.

This might already of been mentioned, but adjusting the the value of the 3k3 resistor in the LFO will change the width of the pulses. Making it smaller will narrow the pulses which might reduce the ticking, of course if you make them too narrow the S/H won't work. Could be worth trying though.

This also reduces the "error" seen by the sample and hold circuit. If you hold the "S&H pin" high too long, the capacitor will take the sample but also starts to allow some of your signals "wiggle" through. This can sound cool sometimes, other times it's undesirable. If you make the pulse-width wide enough, you can get a sort of track-and-hold type effect.

[flo]

track-and-hold

I like it!

[Cliff Schecht]

It isn't a true track-and-hold circuit, but you can get similar effects. If you make the sample capacitor really small, it will take the sample really fast but also allows a lot more "jitter" through because such a small capacitance can't easily block a lot of fast moving transients (less averaging is happening). So when you're in "sample" mode, the sample circuit grabs a value but also allows in some signal, which gives a cool addition to any filter. It will start to jump all over the place in conjunction with your signal transients and frequency (i.e. a low frequency gives a slow moving filter).

A true track-and-hold will take an input and reflect in on the output until the gate of the T&H circuit is pulled high, at which point it grabs a value based on where your signal is at in its swing. Korg implemented this on the MS-20 synth and it gives some really cool sounds!

[returntable]

This might already of been mentioned, but adjusting the the value of the 3k3 resistor in the LFO will change the width of the pulses. Making it smaller will narrow the pulses which might reduce the ticking, of course if you make them too narrow the S/H won't work. Could be worth trying though.

Sounds Interesting... I will try to put a Trimpot in that position al well...
Thanks Slacker

[returntable]

All right, re-adjusting the Trimpots worked, now both effects are working like they're supposed to
Finally... that was the hardest troubleshooting I ever had to do.
Thanks again for all the help.

[DimebuGG]

PS:

I had a problem before, mine's getting a severe volume drop when effect is on. This doesn't happened the first time I tested it. So I reviewed Tonepad's layout and compare it to the schematic and JD's layout.concerns the FET orientation. I was using Fairchild's BF245A then, and its pinout facing flat side is G S D. In the layout, it is oriented backwards.

Assuming  "G S D" is the standard pinout of BF245A. From the schematic, the SOURCE of Q2 was supposedly in junction with the 2 - 100K, 12K, and 3.3K resistors but in the layout they're connected to Drain. And the Source goes to +8V where Drain is supposedly the one to be connected. This has to be interchanged.

Now it's Q5, from the schematic, it's Drain goes to the 10K trimpot and Source goes to the Gate of Q6 together with the 0.05/0.047 cap. But in the layout the Source was connected to the trimpot while the Drain goes to the Gate of Q6. Again, this has to be interchanged.

JD's FET connections is the correct one.

After fixing, my unit returns to normal now..

[WormBoy]

I build an FSH-1 from the Tonepad layout last year for a friend of mine. I 'cured' the ticking by killing the LFO signal when its not needed (if I remember correctly, I did it by grounding one leg of the speed pot). This means that the ticking in bypass and in filter mode are gone, but it's still there in Sample & Hold mode. But, there it is not really that much of a nuisance (gives a nice kind of percussive noises). All in all, it seems that there is something wrong with the Tonepad layout. if I ever build an FSH again, I will attempt to make my own board, and isolate the LFO circuit as much as possible. I remember reading from someone on this forum who build a separate board for the LFO with good results ...

[DimebuGG]

All right, re-adjusting the Trimpots worked, now both effects are working like they're supposed to
Finally... that was the hardest troubleshooting I ever had to do.
Thanks again for all the help.

Really?..Are you sure? coz I tried it too and it doesn't even cures the ticking. Instead, it amplifies the pulses and destroyed the sample and hold mode. Yeah, I readjust the trimmers too with no
difference in the sound.!

[returntable]

All right, re-adjusting the Trimpots worked, now both effects are working like they're supposed to
Finally... that was the hardest troubleshooting I ever had to do.
Thanks again for all the help.

Really?..Are you sure? coz I tried it too and it doesn't even cures the ticking. Instead, it amplifies the pulses and destroyed the sample and hold mode. Yeah, I readjust the trimmers too with no
difference in the sound.!

really? but you added the Capacitor from the LFO Output to ground, right?

[DimebuGG]

really? but you added the Capacitor from the LFO Output to ground, right?

Yeah, a 1uF from pin 7 to ground(pin 3)..I used TL062 in the LFO..it really destroyed the S&H effect...


PS:
Ooops, to everyone BTW, does Xotic's version ticks too?

[returntable]

Okay, sorry DimebuGG and everyone else, the Pedal doesn't work correctly.
Last time, I tested it by running my WSG through it and into my Soundcard.
Today I tested it with guitar and bass through a loud amp, and the s&h doesn't work correctly with these instruments
(but it did work with my WSG)
plus at high volumes you could still hear the ticking in filter mode.

So, now I will try WormBoy's suggestion of killing the LFO when S&H is not needed and if that doesn't help I will build an extra board for the LFO.

Damn, this pedal sucks. I really start to hate it.

[DimebuGG]

Okay, sorry DimebuGG and everyone else, the Pedal doesn't work correctly.
Last time, I tested it by running my WSG through it and into my Soundcard.
Today I tested it with guitar and bass through a loud amp, and the s&h doesn't work correctly with these instruments
(but it did work with my WSG)
plus at high volumes you could still hear the ticking in filter mode.

So, now I will try WormBoy's suggestion of killing the LFO when S&H is not needed and if that doesn't help I will build an extra board for the LFO.

Damn, this pedal sucks. I really start to hate it.

maybe like this:


possible ground loops may occur..