Tonepad's Maestro FSH-1 has a strong ticking

[gigimarga]

I've decoupled IC5 using a 100 ohms resistor and a 47uF capacitor, but no noticeable effect 
I will try to got some TL022, but it's almost mipossible here...

[flo]

Perhaps you can try a TL061 low power single opamp (although it has a high slew-rate). It has the same pinout as the 741.
http://www.datasheetcatalog.org/datasheet/SGSThomsonMicroelectronics/mXvwry.pdf
1 - Offset null 1
2 - Inverting input
3 - Non-inverting input
4 - VCC-
5 - Offset null 2
6 - Output
7 - VCC+
8 - N.C.

The +8V -8V power-supply of the "audio path", Q1 Q2 IC1 IC2, is already decoupled from the rest via R35 R36 C12 C14.
Just to check, you did try to decouple the "rest" by putting a 100ohm resistor, together with a 10uF to GND, between:
- C11 and anything that wants +9V
- C13 and anything that wants -9V
Like this:
+9V / -9V
|
>
> 100 ohm
>
|
|      10uF
|------||-------- GND
|
|
opamp pin7 / pin4



Just for "fun", although I do not have high hopes for this one, try to put a 1uF capacitor (not an elco) between:
- The + and - inputs of the 741 opamp
- The output of the opamp and GND.
Just try this by touching the opamp pins with the capacitor's legs while the circuit is on.

Also:
The opamp IC5 is used as a "relaxation oscillator" with an uneven duty-cycle so it outputs a pulse for the S&H circuit. You can try to reduce the pulse "slope" a bit by putting a 0.1nF up to 100nF capacitor between the gate of Q5 and GND or -9V. The problem is, the Sampe&Hold circuit wants a "sharp" pulse to sample the noise adequately so you can not make that C too large. Find a compromise.
http://en.wikipedia.org/wiki/Relaxation_oscillator

I one of these does not work on its own, try them all together!

[gigimarga]

Wooooow again...you're a very kind man...thx a lot again!!!

In the layout that i used (http://www.tonepad.com/getFile.asp?id=96) i replaced the jumper from the right upper side with a 100ohms resistor and i placed after it the 47uF capacitor...it's ok?

[flo]

I was referring to the single 741 opamp of the LFO (IC5) in:
http://www.freeinfosociety.com/electronics/schemview.php?id=1125
Sorry for the confusion, I should have been referencing LFO IC3b of Tonepad's version.
So in my previous posts: 741 and IC5 are the same a Tonepad's IC3b. Well, you'll figure it out...
The LFO opamp IC3b is part of a DUAL opamp. So a low power LM358, TL022, TL062 DUAL op-amp for IC3 will be fine NOT a 741 or TL061 SINGLE opamp!

> "i replaced the jumper from the right upper side with a 100ohms resistor and i placed after it the 47uF capacitor...it's ok?"
That's the red trace going to pin8 of IC3b, right? If the capacitor was placed:
- One leg on the 100 ohm resistor connected to IC3b pin8
and
- The other leg on GND,
then its ok.

Try the same with the yellow trace that goes to IC3b pin 4 to decouple the -9V of the LFO.

[gigimarga]

Thx again...there is any trick about how to set the 100K trimpot?
It must to be set to 0V on the "wiper"?

[flo]

I have no idea about the trimpot, sorry...

[frequencycentral]

Thx again...there is any trick about how to set the 100K trimpot?
It must to be set to 0V on the "wiper"?

Connect a meter set to 'voltage' to the wiper, trim the wiper until the meter reads 0 volts.

[gigimarga]

Thx a lot!

[returntable]

Oh wow, Thanks very much for your help FLO.
tried the LM358, but that didn't solve the ticking... I will work on it, when I find the time.

[gigimarga]

Thx again...there is any trick about how to set the 100K trimpot?
It must to be set to 0V on the "wiper"?

Connect a meter set to 'voltage' to the wiper, trim the wiper until the meter reads 0 volts.

I did it, but after i've set the voltage of the wiper to 0V i couldn't find any position of the another trimpot to work...

[returntable]

Try exchanging Q5 and Q6... I have had this problem and after changing the transistors it worked again. so maybe one or both of them are broken.

[gigimarga]

Thx returnable...my FSH works, but bot if i set the wiper of the 100K trimpot to 0V...that was your problem too?

[returntable]

yeah, I was turning the trimpots without the Sample&Hold effect becoming audible, no matter which setting. After exchanging the Transistors everythings fine. I set the 100K Trimpot to 0V and the other one was fairly easy to set up.

Did you manage to solve the ticking problem yet? I haven't had the time for experiments yet.

[gigimarga]

Thx a lot returnable...i will replace Q5 and Q6 as soon as i will have some time for that.
I've replaced IC3 with a TL062 and it seems that the ticking was serious lowered (thx a lot flo for the tip!), but i did it at 2AM and i coudn't test it at a fairy high volume.

[returntable]

I replaced IC3 with a TL022 and that lowered the ticking, so that it's okay at lower volumes, but at higher volumes, it's still audible.

[gigimarga]

Thx a lot returnable...i will replace Q5 and Q6 as soon as i will have some time for that.
I've replaced IC3 with a TL062 and it seems that the ticking was serious lowered (thx a lot flo for the tip!), but i did it at 2AM and i coudn't test it at a fairy high volume.

OK...thx TL062 solved the problem of ticking for me almost perfect...thx a lot all!!

[returntable]

Cool, then I'll get one as soon as possible too

[soggybag]

Great research, I will have to try a TL062. That seems like an easy fix to try.

[returntable]

damn, after exchanging IC3 with a TL062, the S/H doesn't really work anymore. The Filter is fine though, only in very high filter sounds you could hear a little ticking...
So now I will have to fix the S/H part. I wonder if I ever finish this project... 

[soggybag]

I just tried a TL062 in my FSH-1 and the ticking is still there. It seems a little more quiet, but it's still unacceptable.