Timmy not working

[Senile Implant]

Hi guys.  Long time no see.  I've gotten back into the pedal building thing recently with a Timmy clone from the layout at http://tagboardeffects.blogspot.com/2012/03/paul-cochrane-timmy.html but it's frustrating me so far.  I measured the voltages at the Op Amp, maybe some of you guys can tell me what I've done wrong.

using a 9v adapter, I have 9.4v coming into the pedal.

1= 9.1
2= .71
3= .67
4= 1.32
5= 0.0
6= .38
7= 7.08
8= 7.86

[GibsonGM]

Hey Senile, welcome back.

Somethin' ain't wired right. Your IC should read 0 (ground) on pin 4.  Pin 8 should be your supply voltage of 9+ volts.  I'd expect the inputs to read near 1/2 the supply voltage, 4.5V-ish. 

Since 'tagboard' or vero is really just placing stuff in a paint by numbers way, it's hard to see where you might have made the error.  But go back over each step, and see if a trace didn't get cut, or something like that.   I suspect either a mis-placed part, or one of the wrong value was put somewhere....so, check check and re-check! 

[Senile Implant]

It's really driving me nuts.  I've been over it a couple of times and can't find anything wrong for the life of me.  May just have to start all over and be extra extra careful (which I thought I was the first time).  Sure don't know what else to do though.   

[GibsonGM]

What are you using for an opamp?  You're sure it's not in backwards?  Sure it's GOOD?  What version did you build - sure you didn't go back and forth while building by accident?

Usually with something like this, it's a part placement error, a track that is cut and not supposed to be (or supposed to be and is not), or a solder bridge between tracks, which you have to look for with a magnifying glass. 

Having the 9V on pin 1 tells me something is shorting that pin to power...or you are thinking pin 8 is pin 1...(?)

Do you have an audio probe yet?  If not, I'd make one.   http://www.diystompboxes.com/pedals/debug.html   
Might show you where to look.

[Tony Forestiere]

Pictures (front and back) couldn't hurt.

[bluebunny]

I'm scrolling down gently and thinking: "Pictures, gimme pictures".  And now I see Tony got there waaaaay before me.

Yeah, pictures please.   

[duck_arse]

what? are there pictures I can't see already?

[GibsonGM]

what? are there pictures I can't see already?

Not yet, buddy, we're still waiting...maybe he's making an audio probe?

[LightSoundGeometry]

I just built this using GFX vero layout and a tl072. it sounds great but not a lot of db output like some pedals have. not owning an original, is the Timmy just like this?

it has a great sounding low gain amp like crunch which to me seems primed to be boosted with a another pedal and stacked. I think Alex or Miro in the comment mentions this and goes on to say timmy plus zen is one of the best combos.

I am going to leave the volume knob off, make it a three nobber, and stick it on my pedal board.

[GibsonGM]

Umm, mine is PLENTY loud, dude.  You sure something isn't messed up?  Feedback resistors or something?

[LightSoundGeometry]

Umm, mine is PLENTY loud, dude.  You sure something isn't messed up?  Feedback resistors or something?

yeah its working now, I had a 50K and the 500K switched..I am using a 500K as I do not have a 1M. I always dime out my volume so I do not add volume pots anymore lol

these sound fantastic!

I didnt have a 39nF , so I used a 47nF in its place.

[GibsonGM]

Umm, mine is PLENTY loud, dude.  You sure something isn't messed up?  Feedback resistors or something?

yeah its working now, I had a 50K and the 500K switched..I am using a 500K as I do not have a 1M. I always dime out my volume so I do not add volume pots anymore lol

these sound fantastic!

I didnt have a 39nF , so I used a 47nF in its place.

LOL, yeah, that was probably it - glad it is ok now!    The 1M will bring it up more (might simply result in more clipping tho).

The 47 is probably cool if it suits your taste! 

[LightSoundGeometry]

Umm, mine is PLENTY loud, dude.  You sure something isn't messed up?  Feedback resistors or something?

yeah its working now, I had a 50K and the 500K switched..I am using a 500K as I do not have a 1M. I always dime out my volume so I do not add volume pots anymore lol

these sound fantastic!

I didnt have a 39nF , so I used a 47nF in its place.

LOL, yeah, that was probably it - glad it is ok now!    The 1M will bring it up more (might simply result in more clipping tho).

The 47 is probably cool if it suits your taste!

well..the cut filters are working a bit strange, I know all the way down to zero its like a semi clean then it gets pretty insane saturation as gain goes up..but the filters really dont do too much ..maybe the 47k or the 50k pots? do you think 25K pots would be better for the dials? and its hard for me to trace a vero but I am thinking the 39nF works to form the frequency range of the eq cut?

looks like a 39 and 1nf are parallel ( or series?)on the 50k bass pot creating a low pass filter ..I forgot how to do all of this ..would I look for cut off frequency to find where the bass filter is sitting and start to cut off Highs? I am guessing it starts to cut the highs and change the FC via the variable R?

Ct= 1n + 47 = 48nF

fc=1/2(3.14)(50K)(48nF)

66Hz?
or is it the 3k3 in the pass filter? and can a R be after the C and still be a pass filter or does it have to go R then C ?

has anyone tried the layout from revolutiondeux, he has a schematic along with a strip on his site and has it laid out for the dip switches

are those caps parallel since they tie to vref ? I forgot everything I learned since taking 3 months off..my notes are sloppy since the instructor moves so fast ..I need to take speed writing classes

[nocentelli]

The bass control is a high pass filter that boosts everything above the (low-ish) frequency set by the 3k3+39n cap in conjunction with whatever resistance is set by the gain pot. The 50k/47k bass pot is connected to an additional 1uF (1 MICROfarad, not 1nF aka 1 NANOfarad) of capacitance in parallel with (i.e. added to) the 39n "minimum bass" cap. Since the 1uF cap is 1000n and therefore twenty-five times bigger than the 39n, the pot allows the high pass filter to pass much lower frequencies as the resistance is decreased so acts as a bass control.

[Cozybuilder]

This is my tracing of the Timmy circuit:

[LightSoundGeometry]

The bass control is a high pass filter that boosts everything above the (low-ish) frequency set by the 3k3+39n cap in conjunction with whatever resistance is set by the gain pot. The 50k/47k bass pot is connected to an additional 1uF (1 microfarad, not 1nF or 1 nanofarad) of capacitance in parallel with (i.e. added to) the 39n "minimum bass" cap. Since the 1uF cap is 1000n and therefore twenty five times bigger than the 39n, the pot allows the high pass filter to pass much lower frequencies as the resistance is decreased so acts as a bass control.

okay, if you flip it upside down its c4 into r3 , and yeah I see it going into the 3k3 and 1m gain pot ..I bet the 500K is messing with the filter. ahhh yes youre right lol ! its an electro 1uF there , doesnt look like GFX has that in the vero layout ? Looks they have a 47uF and only one electro in the power stage?

hey thanks for replying and helping Nocentelli

thanks Cozy. I will have to make a order for some different values and redo with the right values. Im going to get some 39nf and a 1M pot..also get a 4559 instead of the tl072 and put a volume on it

[nocentelli]

This is my tracing of the Timmy circuit:

Treble control comes from pin1 (opamp output) not pin 2 (inverting input)?

[Cozybuilder]

You are correct! Sorry for any confusion.