Slo Gear almost working !

Started by Samy, June 29, 2006, 03:55:46 PM

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Samy

It´s the first time that i have a pedal not working at 100%, the others were just minor details but nothing serious ...
This pedal it´s almost working, almost because the pots turned at min. there is a a delay and a crescendo in the notes , i believe it´s the Fx working, but when i  tur the pots a little, it´s like a bypass, nothing happens. I´ve turned the trimpot several times, sometimes better others not ! I´ve checked everything and it seems ok .
My build uses k30A fet ( i beleive it´s SK30A), C549B transistors ( i believe they are BC549) and i´ve used a W20K pot on the "attack" and TL061.
I´ve used the topopiccione pcb and schem., my voltages are:
IC:
1- 0V
2- 4.35V
3- 3.78V
4- 0V
5- 0V
6- 4.68V
7- 9.18V
8- 0V

K30A :  D=5.52V , G=2.7V , S=5.52V

Here´s the topopiccione layout with the caps polarity placed by me and other info :


Any tip it´s very very very very welcome !

Thanks.

Samy

Any tweaks to improve this ? Pots seems to be almost useless ... after 40% it´s like a bypass, no fx ...
I´ve used a 0.47µF film cap not an electrolytic, that´s not important ... i think !
I´ll try to use matches transistors too see the differences and place here a sound sample.

Yun

Do you mean that you're getting no sound, or just that the effect is not what it should be eh?

Make sure that the trasistors are "the right way around".  Meaning: make sure you got the pin-out correct.  Same thing for the IC . 

Also, check and make sure that all your grounds are connected together and grounded properly....

"It's Better to live a lie, and forget the past, then to Forget a lie, and live the past"

Yun

what's the pot values stock-wise, and what pot values are you using?  Are you using linear or audio?  Sometimes linear and audio taper pots can be essential.  But i've never built this circuit, so........
"It's Better to live a lie, and forget the past, then to Forget a lie, and live the past"

Samy

I have sound, i have some effects working but i don´t know if it´s working like it should be. I have one 20KW on the "attack", and a 100KA on the "sens.", my transistors and IC are ok, i´ve already triple checked everything and it seems to be all ok.
Pots seems a little useless if they are turned more than 40%, the effect it´s very audible if the "sens" button it´s turned to the min, it´s a little tricky !
I will post some sounds later this day.

Yun

Quote from: Samy on June 30, 2006, 03:46:29 AM
I have sound, i have some effects working but i don´t know if it´s working like it should be. I have one 20KW on the "attack", and a 100KA on the "sens.", my transistors and IC are ok, i´ve already triple checked everything and it seems to be all ok.
Pots seems a little useless if they are turned more than 40%, the effect it´s very audible if the "sens" button it´s turned to the min, it´s a little tricky !
I will post some sounds later this day.

Have you tried 100K Linear eh?  It's worth a try, no?
"It's Better to live a lie, and forget the past, then to Forget a lie, and live the past"

Samy

Here´s the link to hear a sample : http://media.putfile.com/SG1---Test .
I´ve connected the stompbox to my Voodu Valve and then to a PC SBLive soundcard, the quality sucks but you´ll get the point !
I can´t move around the knobs alot, i just wish to have a little more versatility on them to increase or decrease the effect, like this, it´s just a "set and forget" FX ... :icon_confused:
The pots are all turned to min. .

Yun

Quote from: Samy on June 30, 2006, 11:31:56 AM
Here´s the link to hear a sample : http://media.putfile.com/SG1---Test .
I´ve connected the stompbox to my Voodu Valve and then to a PC SBLive soundcard, the quality sucks but you´ll get the point !
I can´t move around the knobs alot, i just wish to have a little more versatility on them to increase or decrease the effect, like this, it´s just a "set and forget" FX ... :icon_confused:
The pots are all turned to min. .

Man, that's strange.  Sounds like you need to lower the value of the pots if that's at minimum.  Try 50K as aposed to 100K .  That should make it a bit more versatile....
"It's Better to live a lie, and forget the past, then to Forget a lie, and live the past"