Still can't figure this out (please help again)...

ftcl

Building effects is clearly a lot harder than I thought... Even after numerous efforts, I still cannot get any circuit I put together to work...

In this instance, I think it's the wiring rather than the actual circuit. Here are some pics (I'm hoping that it's an easy mistake to spot...)

Here's the layout I used:

http://tagboardeffects.blogspot.com/search/label/Devi%20Ever

I have checked the web for answers, notably the site mentioned above and Beavis Audio and Geofex, but I just can't seem to get this right...

deefstes

ftcl wrote

Your connections and cuts look to be accurate. I haven't bothered to check all of the wiring and seeing as I can't make out any detail on the capacitors or transistors, I'm going to have to assume that you used the correct components there. However, I do notice that your left most and right most resistors on the picture above are 2.2 KΩ whereas the diagram requires 2.2 MΩ resistors. Did you change these values for a reason or could this be the oversight that's causing you troubles?

ftcl

It appears to be an oversight on my part... :-[

Would that cause it not to work at all? Also, wouldn't the resistors get very hot? That does not happen.

bottledtone

Can't see where your circuit is grounded to the chassis? Both jack sockets only have one wire going to them?
When you turn your vol full are you getting any increase in noise or hiss?
And have you got your switch switching the correct points?

deefstes

ftcl wrote Would that cause it not to work at all?

I can't say because I don't know exactly what the circuit does and I'm a bit rusty on my electronics to go analyse it. It very likely cause it to act very differently from the way it was designed to. So, even if it works, it might not work anything like you expect it to. For example, the resistors in question could be components in some or other RC circuit in your board. RC circuits are usually employed as some sort of a low-pass or high-pass filter. By using the incorrect resistance the response of the filter could be WAY off and it filters out exactly the frequencies that you are interested in or something like that. Often times, two RC filters will be used together to form a band-pass filter. If that is the case here and you got the resistances wrong, you may conceivably have built a filter that filters out signals below frequency A while at the same time filter out signals above frequency B. If A>B, you don't have a band-pass filter anymore but a filter-out-everything filter.

ftcl wrote Also, wouldn't the resistors get very hot? That does not happen.

Not necessarily. The current through and the potential over those resistors will be so small that they would be very unlikely to display any significant heat energy. Like I said above, and I don't know what your circuit does, but the resistors and capacitors in circuits like these are usually used to serve as "variables" in an equation. You could use any resistor, it won't burn up or anything, it will simply affect the exponential decay time or the phase of the signal, or whatever the circuit is designed to do.

ftcl

bottledtone wrote Can't see where your circuit is grounded to the chassis? Both jack sockets only have one wire going to them?

Hmm. Well, the input has two wires attached, since I understood that the ground could go to the ground of the input? Also, because the jack is screwed directly to the box, it would ground it thus?

bottledtone wroteWhen you turn your vol full are you getting any increase in noise or hiss?

I'm not getting any sound.

bottledtone wroteAnd have you got your switch switching the correct points?

That I'm not sure of. I used the following diagram:

http://stompboxed.blogspot.com/2012/05/easy-3pdt-switch-wiring.html

The switch is labelled 123, so I assumed that 123 would be at the top, and wired it like that.

Btw, the circuit is a fuzz.

bottledtone

Sorry, it just looks like one wire to me on the pic. So the circuit is grounded then...okay.
When plugged into the amp, tap on the centre lug of the vol pot and turn it up. It should buzz when you touch. Otherwise the signal is not going out.
Have you got a multimeter? You must see that your footswitch is correctly wired. Maybe test circuit directly without switch.

Johnny-B

I think that you might have the 3PDT switch connected in the wrong orientation. In the on position, the input jack tip should connect to the input of the board and the output of the board shoul connect to the output jack tip. In the off position, the input jack tip should connect via the link wire on the switch to the output jack tip. It's probably easiest to check with a multimeter.

Johnny-B

Also. you seem to have the dc power connector connected in place of the LED (light emitting diode) shown on the switch wiring diagram.

psyx

Advice I can offer is to build on a breadboard first to make sure you have the layout figured out! Thats what I usually do. It helps you to fiddle around and get the right combination of components to suit your sound! Also I see you're using ceramic resistors. Maybe in the future you should get the blue metal film ones. They have a smaller error tolerance (1% as opposed to 5%) and apperently cause less noise on the circuit. Just my 5c

makepeace

i think bottledtone is right. your signal is grounded to the chassis, so thats fine - but the problem is - the circuit needs to be grounded to the signal ground. run a wire from your DC ground ground to the chassis.

secondly, your 3pdt wiring could well be wrong. reduce the number of potential errors. isolate different parts of the circuit and remove any that are irrelevant to the functionality of the actual circuit. what i used to do to check things like these (when i struggled to wire a 3pdt) is to remove the 3pdt from the story all together while you work out if the circuit is working or not. just wire eveything as if its on - ie positive rail connected to circuit, signal jacks connected to circuit in/outs.

you should also invest in a multimeter if you don't already have one. they're almost imperative to check for continuity at the least.

oh yeah, those 2m2 resistors in the layout diag are 2k2s on your circuit. so swap them out.

good luck!

makepeace

psyx wrote Also I see you're using ceramic resistors. Maybe in the future you should get the blue metal film ones. They have a smaller error tolerance (1% as opposed to 5%) and apperently cause less noise on the circuit. Just my 5c

can of worms there. those are carbon films - and there is nothing wrong with their presence in such a circuit.

psyx

makepeace wrote
psyx wrote Also I see you're using ceramic resistors. Maybe in the future you should get the blue metal film ones. They have a smaller error tolerance (1% as opposed to 5%) and apperently cause less noise on the circuit. Just my 5c
can of worms there. those are carbon films - and there is nothing wrong with their presence in such a circuit.

Oops, sorry!My mistake on the correct terminology. Ceramic resistors are something waay different! But still the 1% and 5% rules apply and on larger circuits I'm sure using carbon film resistors will contribute to more noise

DDR4LYF

I'm pretty sure it's the 3pdt switch! I seem to remember mine having the connection the other way around (rotate connections 90 degrees)! Can be confusing cause of it's square shape. I don't see an LED, so I would just run the DC input straight into the circuit board and connect the jack groundings to the circuit board ground (if you haven't done that already)

makepeace wrote
you should also invest in a multimeter if you don't already have one. they're almost imperative to check for continuity at the least.

+1

I used a little bread board circuit to test continuity at one point. LAME!!! Multimeter is way easier!

makepeace

psyx wrote
makepeace wrote
psyx wrote Also I see you're using ceramic resistors. Maybe in the future you should get the blue metal film ones. They have a smaller error tolerance (1% as opposed to 5%) and apperently cause less noise on the circuit. Just my 5c
can of worms there. those are carbon films - and there is nothing wrong with their presence in such a circuit.
Oops, sorry!My mistake on the correct terminology. Ceramic resistors are something waay different! But still the 1% and 5% rules apply and on larger circuits I'm sure using carbon film resistors will contribute to more noise

unfortunately its more complicated than that. 5% variation in components in a circuit like this will have hardly any measureable effect on the functionality of the circuit. there are circuits where it is critical to have the values as precise as possible (the dallas rangemaster for instance), but this isn't one. in fact, in some cases you might find the variation useful.

secondly, resistors have way more variables than you think, such as thermal coefficients, voltage coefficients, drift, physical size etc. this topic has been widely argued in numerous places that are googlable so i'm not trying to start it again - but there are noticeable differences in function and 'sound' of different resistor types in certain areas of certain circuits due to these qualities.

regarding hiss/noise, here's some information on the subject: http://www.aikenamps.com/ResistorNoise.htm. bear in mind that this was written with valve amps in mind, so the voltage and temperature considerations (mostly) will be a bit different from the usual 9V supply effect pedal - but its mostly applicable. the long and short of it is that its way more complicated than you think and a simple statement such as 'metal films are better than carbon films' is invalid. in such a small simple circuit like this, i would venture to say that most people would hear no difference in the noise between carbon film and metal film, and for those that would it will be negligible.

sorry if i might come across as rude - not intending to be - had a kak day and my written tone is reflecting that :/

ftcl

Thanks for the input guys! Lemme see if I can now get this right ?

psyx

makepeace wrote
psyx wrote
makepeace wrote
psyx wrote Also I see you're using ceramic resistors. Maybe in the future you should get the blue metal film ones. They have a smaller error tolerance (1% as opposed to 5%) and apperently cause less noise on the circuit. Just my 5c
can of worms there. those are carbon films - and there is nothing wrong with their presence in such a circuit.
Oops, sorry!My mistake on the correct terminology. Ceramic resistors are something waay different! But still the 1% and 5% rules apply and on larger circuits I'm sure using carbon film resistors will contribute to more noise
unfortunately its more complicated than that. 5% variation in components in a circuit like this will have hardly any measureable effect on the functionality of the circuit. there are circuits where it is critical to have the values as precise as possible (the dallas rangemaster for instance), but this isn't one. in fact, in some cases you might find the variation useful.

secondly, resistors have way more variables than you think, such as thermal coefficients, voltage coefficients, drift, physical size etc. this topic has been widely argued in numerous places that are googlable so i'm not trying to start it again - but there are noticeable differences in function and 'sound' of different resistor types in certain areas of certain circuits due to these qualities.

regarding hiss/noise, here's some information on the subject: http://www.aikenamps.com/ResistorNoise.htm. bear in mind that this was written with valve amps in mind, so the voltage and temperature considerations (mostly) will be a bit different from the usual 9V supply effect pedal - but its mostly applicable. the long and short of it is that its way more complicated than you think and a simple statement such as 'metal films are better than carbon films' is invalid. in such a small simple circuit like this, i would venture to say that most people would hear no difference in the noise between carbon film and metal film, and for those that would it will be negligible.

sorry if i might come across as rude - not intending to be - had a kak day and my written tone is reflecting that :/

Don't worry man, I understand! I admit I don't have the full knowledge of the subject and my statement was purely based on some assumptions and loose peices of half written information. So my apologies for sticking my neck out like that!
But thanks for the link. I'll do some reading!

mtmattan

Hey man,

1. Make sure you can get a bypass signal. ie the 3pdt switch is wired correctly.
The lugs on the jack don't work the same as when facing "horizontal" vs "vertical".
There are tons of wiring diagrams on Google.

2. Definitely connect the ground wires on the jacks.
You have grounded the jacks to the chassis, but not the chassis to the DC jack.
It's not the same as "grounding" for AC purposes to avoid shocks.

Good luck!

Shibbibilybob

Those 2.2k resistors are going to cause problems. The 2.2M is significantly larger and increases the resistance between your collector and ground.
Presumably the important ratio here would be the 2.2M to the 10K from the collector to 9V. 2.2M or any other value significantly higher than 10K is probably required.
I've not had a proper investigation, but I think you're wasting your time troubleshooting unless you've already fixed any known issues.

One more possible course that I can see is this: It looks as if you may have continuity between some of the tracks on your veroboard. If the flux of the solder connects two rails, they could conduct. Which is to say, you need not have a link containing solder, just the flux conducts. After I finish building a circuit I always run a stanley knife between the tracks, just to break any continuous flux.

Good luck dude

Nicholas-L

Just from what mattocaster said I went and looked at your switch wiring and it seems to be wrong. Wiring should be done with the lugs horizontally. ??? Just double check that.