This should be simple, but it ain't...

[aro]

I am (another) noob trying to build my own pedal(s). I am good with soldering and following instructions to the letter, but if there are some instructions missing than I'm lost. I hope to get some help here so that I get over the initial stupid questions...

I got from another board a schematic and the board diagram and I built the thing. However, surprise, it doesn't work. Well, sound goes through, but it cuts down the volume a lot.

This is the schematic:



And this is the breadboard, which is what I used:



On the breadboard the text and drawings in red are my additions. My question is this: are my additions correct? As I said, the volume is lowered a lot when using this device. My guess is that if I assembled the board correctly the problem might be with the wiring.

I would appreciate any help. Thanks.

[~arph]

Correct me if I'm wrong.

But from looking at it I interpret that this thing has no gain and acts just as a filter and in turn you lose gain. So you would need a gain recovery stage after it.

[aro]

Correct me if I'm wrong.

But from looking at it I interpret that this thing has no gain and acts just as a filter and in turn you lose gain. So you would need a gain recovery stage after it.

You're right, sorry, I should have described its purpose. This box goes between the Out of a digital MFX (Vox, Boss etc.) and the Input of a power amp/PA. Basically it filters out the "fizz" that comes out of a digital effects unit.

[~arph]

  I've seen the thread 

[aron]

Is the author still around? Did you ask him if your circuit is working properly?

[head_spaz]

Vref is missing.

[aro]

Is the author still around? Did you ask him if your circuit is working properly?

Well, the author is on another site (for some reason that site's name is replaced here by periods, like this '...'). Somehow that site seems to be less responsive with simple questions such as mine. I don't know, I could be dead wrong... Anyway, the circuit apparently works; another guy over there built it and posted some samples. I think I'm gonna PM him and hope he'll reply.
I'm also thinking that maybe some components were faulty. I guess I'm gonna rebuild this thing and check each component as I go.

[anchovie]

Is the author still around?

I'm not sure the 'author' of the original design would be too happy about helping someone debug a clone of his commercial product! 

[aro]

I'm not sure the 'author' of the original design would be too happy about helping someone debug a clone of his commercial product! 

I'm not sure what you're saying. The design I posted has been developed as a "open source project" by a member of that other site, independent of any existing commercial product. It's not a clone, a rip-off or anything like that. It's an original design, it is not copying in any way the commercial design (which BTW is unknown). Just the result is similar to that of the commercial product: fizz suppression.

[anchovie]

Ah OK, not to worry then.  I shan't make such assumptions when something has an incredibly similar name in future!

[pjwhite]

Vref is missing.

It's there, at the top of the page, left of center.  Two 10K resistors divide the power supply voltage and bias the first stages through the 1M resistor.  All the stages are DC coupled, so the bias follows through until finally blocked by the output capacitor.

[aro]

Now I have a really basic question. When I look at the breadboard that I first posted I see that some of the strips have a red square with a red dot inside them. What are those squares? Are they meant to cut the signal?
For some reason I always assumed they are irrelevant, but now I don't know anymore... It they are supposed to cut the signal, then this might be the answer to my problem.

[biggy boy]

Yes you are to cut those sections of the copper away, thats not a breadboard it's vero board sort of like perf board, for the finished build.

Glen

[aro]

Yes you are to cut those, thats not a breadboard it's vero board

Glen

Thank you, thank you Ain't I stupid...?

But hey, there's hope for my project after all

[biggy boy]

Yes you are to cut those, thats not a breadboard it's vero board

Glen

Thank you, thank you Ain't I stupid...?

But hey, there's hope for my project after all

No not stupid. When I first came here to this forum, I didn't have a clue what it was.

[biggy boy]

I see the board was created by bajaman, who is a memebr here.
Not sure if it's the same bajaman or not thou?

Glen

[aro]

I see the board was created by bajaman, who is a memebr here.
Not sure if it's the same bajaman or not thou?

Glen

I didn't know he's a member here. Anyway, I guess it would be difficult for someone else to debug what I have here. I cut the traces but it's still not doing the job. I'm gonna redo the whole thing on a breadboard (real breadboard, not veroboard).

[frequencycentral]

.

[biggy boy]

Did you cut under R7, R8 and R 11 plus under the IC ? Oh and C3
plus I just noticed theres small jumpers on some of the IC pins to one and other.
But then it does say to cut under the resistors and cap.


Glen

[aro]

Did you cut under R7, R8 and R 11 plus under the IC ? Oh and C3
plus I just noticed theres small jumpers on some of the IC pins to one and other.
But then it does say to cut under the resistors and cap.


Glen

Yeah, I did all that. Maybe I'll have more luck with the breadboard version.