Small Stone Inquiry

[Slowpoke101]

On FSB the board layout shows that 0.22uF capacitor as being a 22uf electrolytic and the photo of the original board shown on page 1 of that thread shows that it is. So go ahead and change the capacitor (use 16V or higher) despite what is shown on the mud-map (circuit diagram - for want of a better description). The rate pot should be an anti-log (C taper) type so that all your adjustment range doesn't pile up up in the last 20% of the pot's turning range.

You have chosen to build an unverified project so don't be surprised if some other problems come along to bite you. Have fun.

Edit: If you choose to use a polarised electrolytic capacitor to replace the 0.22uF capacitor, the positive lead connects to the track that also connects to pin 6 of the LM324.

[Baran Ismen]

I can call this confirmed with the below side notes...

1- I've tried several pots between 220k to 2m A and B types. With the current configuration, none seemed to act expectedly, on the fastest setting it was a real drone on all whereas the slowest wasn't slow enough for even B2M.

2- I've played with the 220n non-polar between W11-Z11, as it seemed to be responsible for the LFO speed, and I found the sweet spot with 22uf polar cap (positive side on W11), and used a 1m linear pot with it as it seemed to react better than A1M (I don't have any C taper and I can't find it in Turkey).

3- I used a 18k resistor between S5-S8 instead of 16k as I couldnt find it either. And for 15k's, I've used 8.2k + 6.8k resistors in series, which weren't in stock either. I'm not sure what that 18k resistor is responsible for, but 2k wouldn't be a big deal for any case, right?

4- I used 12v Zener, as I read somewhere that using 9.1v causes ticking or something like that, so I stayed on the safer side.

So, with the change of the mentioned cap to 22uf and using a Linear 1M pot, it sounds generally quite acceptable and this can be tagged as confirmed like this.

If there are any suggestions for arranging the LFO, please let me know.

[duck_arse]

I can call this confirmed with the below side notes...

4- I used 12v Zener, as I read somewhere that using 9.1v causes ticking or something like that, so I stayed on the safer side.

please tell us where you read this. the zener is in the voltage regulator, providing a reference of 9V for the transistor doing the work. there is NO WAY it could contribute to clicking, not even of my fingers. use 9V1 zener, because it is correct shown on circuit dia. there, now you've read that, too.

[Baran Ismen]

I can call this confirmed with the below side notes...

4- I used 12v Zener, as I read somewhere that using 9.1v causes ticking or something like that, so I stayed on the safer side.

please tell us where you read this. the zener is in the voltage regulator, providing a reference of 9V for the transistor doing the work. there is NO WAY it could contribute to clicking, not even of my fingers. use 9V1 zener, because it is correct shown on circuit dia. there, now you've read that, too.

I've read it here. I am aware this is a quite different approach for the circuit, tho. Ill change to 9.1v then.

http://tagboardeffects.blogspot.com/2016/05/electro-harmonix-small-stone.html?showComment=1514571634506&m=1#c4082304122066641207

update : changed the zener to 9.1v, no audible change but its safer I see.

One thing I may complain is the pot's response. Even tho I used a B taper, it acts like an A, nearly 1/4 of it seems not responsive at all (on the slower side of the rate) then it increases supposedly. I think there's some sort of resistance blocking it, or using a C taper is a must (even tho I tried A1M both straight & reverse, it's the same)

[Chillums]

One thing I may complain is the pot's response. Even tho I used a B taper, it acts like an A, nearly 1/4 of it seems not responsive at all (on the slower side of the rate) then it increases supposedly. I think there's some sort of resistance blocking it, or using a C taper is a must (even tho I tried A1M both straight & reverse, it's the same)

Nice job getting it up and going.  Just a thought.... So I have a schematic that I have verified myself but it is a little different as the LFO is done with a CA3080 instead of a LM324.  In that version the resistor coming off the LFO going to the Iabc inputs of the 3080's is indeed 100 ohms.  So if you used 100k instead of 100R maybe lowering it by say 25% and see if the control changes.  My schematic is attached.

[Baran Ismen]

One thing I may complain is the pot's response. Even tho I used a B taper, it acts like an A, nearly 1/4 of it seems not responsive at all (on the slower side of the rate) then it increases supposedly. I think there's some sort of resistance blocking it, or using a C taper is a must (even tho I tried A1M both straight & reverse, it's the same)

Nice job getting it up and going.  Just a thought.... So I have a schematic that I have verified myself but it is a little different as the LFO is done with a CA3080 instead of a LM324.  In that version the resistor coming off the LFO going to the Iabc inputs of the 3080's is indeed 100 ohms.  So if you used 100k instead of 100R maybe lowering it by say 25% and see if the control changes.  My schematic is attached.

I just went back to 100R for that part already.

The only difference is the 22uf for LFO speed, which is a typo on factory schematics.

Now I hassle with the potentiometer. Needs a c type, I got a B type..

Also, I have noticed that the rate LED makes a faint click noise when it goes on and off which can be heard on idle. I've used 2.2k resistor for Rate LED's CLR, tried with 6.8k afterwards, didn't help with the clicking. Its not hassling me much, but maybe can be fixed somehow.

[Chillums]

Could you use a C3M with a parallel resistor to get it down to 2M?  Tube depot have some.  Here is the link...

https://www.google.com/aclk?sa=l&ai=DChcSEwjrq9be3-2BAxVESEcBHXlMCtMYABALGgJxdQ&ase=2&gclid=Cj0KCQjwj5mpBhDJARIsAOVjBdos_ubaONdob-bReTgXNSXDA6J8Gn5ugFsgeq1_ltMwgf1wZMZUot8aApHQEALw_wcB&sig=AOD64_3bK7llu5QEIKwJ45OcSIhE4Ekg3A&ctype=5&q=&nis=4&ved=0ahUKEwi5_M7e3-2BAxUJm4kEHdJkBNUQww8I2w0&adurl=

[Baran Ismen]

Could you use a C3M with a parallel resistor to get it down to 2M?  Tube depot have some.  Here is the link...

https://www.google.com/aclk?sa=l&ai=DChcSEwjrq9be3-2BAxVESEcBHXlMCtMYABALGgJxdQ&ase=2&gclid=Cj0KCQjwj5mpBhDJARIsAOVjBdos_ubaONdob-bReTgXNSXDA6J8Gn5ugFsgeq1_ltMwgf1wZMZUot8aApHQEALw_wcB&sig=AOD64_3bK7llu5QEIKwJ45OcSIhE4Ekg3A&ctype=5&q=&nis=4&ved=0ahUKEwi5_M7e3-2BAxUJm4kEHdJkBNUQww8I2w0&adurl=

Supplying internationally is the last resort, I've already found on Tayda from 0.50$ each. I'm just trying to find if there's anything I can do with what I have at the moment, you know.

[Chillums]

I gotcha... Story of my life 

[Chillums]

The schematic I posted above is incorrect.  I decided to move the colour switch down by the LFO (instead of up top at the end of the phase stages, just like it is in the Tonepad schematic) but of course I managed to forget a trace (now in orange). Also moved the LFO over to take up some of the empty space.  I just triple checked it and it should be all good now. Serves me right to mess around with a verified schematic....  

[Baran Ismen]

I've had a chance to try this phaser on my pedal chain today (I'm going into analog from a processor), and I've put this guy after Mooer X2, which is a good stomp I'd say, but I saw that on both color settings, it tends to clip the sound, especially before ~ %50 of sweep rate.

Is it something intentional or expected from a phaser pedal? I've seen some posts around Google, and especially for MXR's phasers people complain about clipping on distorted signals.

Note that I don't have an amp and going into my PC, but without the phaser, my signal is just fine and doesn't clip at all, levels are all set not to clip, but whenever SS comes in, overall volume drops just a tad and tends to clip on each cycle.

Any ideas?

Can be disregarded, seems like the IR module on the mooer x2 was the problem, loaded ir was too loud, changing with another solved the problem.

[Baran Ismen]

Last night, I was dealing with this pedal; fixed its LFO bleed into bypass by grounding the input, then I noticed something.

1- It pops when on and off,
2- There's a tick/pop/thump sound at the bottom of the swirling effect where it starts to rise from zero, there's also one on top but it's just weak and can't be heard easily. I assume this is what's called LFO ticking?

Now, the project I've made is this. Even though it's the 2nd pedal I've made, I saw that I've done a pretty good job for a beginner but obviously missed this problem.

https://dirtboxlayouts.blogspot.com/2020/11/electro-harmonix-small-stone-v3.html

What I've done (and did not help) so far is;

1- Added 1M pulldown resistor between X3-Y3
2- Changed the 1uf on AA9-Y9 to 100uf(I don't know why, though, was messing around)
3- Changed the (assumingly) input cap at T6-T8 from 6.8n to 1uf NP
4- Disconnected the blinking LED(which is connected to 22uf LFO cap)

I'm pretty sure that these both are cap-related issues, yet I just could not figure out which one would be responsible for these.

Also as a side note; when I put an alligator clip to AB28 (Rate Led output, which I don't use, I get the rate led from LFO cap) and connect the other end to the ground, I'm getting a bit better swirl effect, its presence and highest peak increases noticeably.

[Baran Ismen]

I've noticed a difference here, and having a hard time to understand it.

On V1, 47n cap is connected between 5 and 7th pins of LM324, whereas on V2 (disregard the red arrows), its between 1st and 4th. What's that supposed to mean, do you think?

[ElectricDruid]

On V1, 47n cap is connected between 5 and 7th pins of LM324, whereas on V2 (disregard the red arrows), its between 1st and 4th. What's that supposed to mean, do you think?

You're looking at the wrong 47n. It's still there between 5 and 7. C9.

The hand-drawn schematic can't work out which side of the 27K it's connected exactly (notice it's been put in one position, then moved).

[Baran Ismen]

On V1, 47n cap is connected between 5 and 7th pins of LM324, whereas on V2 (disregard the red arrows), its between 1st and 4th. What's that supposed to mean, do you think?

You're looking at the wrong 47n. It's still there between 5 and 7. C9.

The hand-drawn schematic can't work out which side of the 27K it's connected exactly (notice it's been put in one position, then moved).

Seems about right, 1st one is connecting the Output 3 and - Out of it directly, 2nd one is connecting them via 27k and 4148. This is matching with the older one.

Oh wait, do you mean that it's removed? (just noticed its value is scratched)

So what's the deal with C10 on V2 that goes to +9V?

Geez, what a pandora box is this circuit..

[Baran Ismen]

Also, I have noticed that the rate LED makes a faint click noise when it goes on and off which can be heard on idle. I've used 2.2k resistor for Rate LED's CLR, tried with 6.8k afterwards, didn't help with the clicking. Its not hassling me much, but maybe can be fixed somehow.

This problem was there already, lol, even though it's not been a long time, I seem to have forgotten what I've done and made and faced what problems..
Thing is, its not related to LED at all.

[ElectricDruid]

Geez, what a pandora box is this circuit..

Between several different versions, EHX's somewhat-vague documentation and tendency to use whatever parts they had handy, plus many dodgy attempts at tracing the circuit over the years, I'd have to agree - a total pandora's box.

[Baran Ismen]

Solved..

Was messing around cluelessly with two alligator clips connected with a 1uf cap on them; 1 tip to gnd and other tip to 47n LFO cap fixed the issue. Correct value I've found is the 150nF. It's not series or in parallel with any other caps, tho, there's no caps going to gnd on LFO stage, so that's a bit weird, but end of the day, it fixed the problem and its just fine now. There's still a small popping when on and off, but its bearable.