Hi everyone, new here and this will be my first pedal build... The circuit I want to build is on a Radioshack IC PC Board (276-159) and I want to transfer it to vero to see if I can shrink the physical size circuit down. Trouble is I have no idea how to do this! I have soldering experience but only with guitar circuits - not pedals (yet!).
It currently looks like this... This view is from the top, components facing up, traces facing down. I cant figure out how to embed it right now but will try again later.
http://postimg.org/image/dzde6k1q3/
If any of you guys out there would be able to help me convert this from IC to Vero I would be very grateful!
Cheers!
From IC PC Board to Vero?
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jallenshaw
- Breadboard Brother
Here's a site that might be of help to you....
http://tagboardeffects.blogspot.com/201 ... guide.html
http://tagboardeffects.blogspot.com/201 ... guide.html
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induction
- Resistor Ronker
The general idea is to convert the layout to a schematic, then use the schematic to create a vero. There's no other recipe for going from a Radio Shack board to vero.
Alternately you could find a schematic and use it to create a vero.
Or you could just find a vero layout.
What is the circuit? Some kind of oscillator? That's the only op-amp circuit I'm familiar with that has feedback to both the inverting and non-inverting inputs (not that I'm an expert). But this seems to have a signal input at point B.
Also, I won't say it's wrong, because I don't know what it's for, but I notice that R2 goes from the cathode of the series polarity protection diode to nowhere. How sure are you that this is an accurate layout?
Alternately you could find a schematic and use it to create a vero.
Or you could just find a vero layout.
What is the circuit? Some kind of oscillator? That's the only op-amp circuit I'm familiar with that has feedback to both the inverting and non-inverting inputs (not that I'm an expert). But this seems to have a signal input at point B.
Also, I won't say it's wrong, because I don't know what it's for, but I notice that R2 goes from the cathode of the series polarity protection diode to nowhere. How sure are you that this is an accurate layout?
Ah, I haven't got much experience doing that so maybe I'll just stick to the PCB. I can shave a few mm off each side to shrink it, I'll look into reversing a PCB to schematic though, I'm sure it'll come in handy in the future!induction wrote:The general idea is to convert the layout to a schematic, then use the schematic to create a vero. There's no other recipe for going from a Radio Shack board to vero.
Alternately you could find a schematic and use it to create a vero.
Or you could just find a vero layout.
What is the circuit? Some kind of oscillator? That's the only op-amp circuit I'm familiar with that has feedback to both the inverting and non-inverting inputs (not that I'm an expert). But this seems to have a signal input at point B.
Also, I won't say it's wrong, because I don't know what it's for, but I notice that R2 goes from the cathode of the series polarity protection diode to nowhere. How sure are you that this is an accurate layout?
I missed some jumpers on the PCB so have added them in and I removed wires I'm not going to incorporate the switch they went to. If anyone could check the circuit out that'd be great, make sure there are no loose ends etc. http://postimg.org/image/n7j1k2ib5/
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induction
- Resistor Ronker
That looks better. That's a basic non-inverting boost with noiseless biasing. I take it you have an actual working unit that you copied this from? Mind sharing where it came from or what it's called?
The input isn't shown, but it should go to the non-inverting input of the op amp, which is where the leftmost lead of R6 connects. It's also missing an input cap. The way it's drawn it will pop when engaged, and will leak dc into your pickups or whatever is in front of it in the chain. Along with the input cap you should add a pulldown resistor, also to prevent pops. The tone knob should probably connect to Vref (the junction of R2 and R3) to keep DC off the pot, but connecting it to ground will probably work also (though it might crackle a little bit when you adjust it). It wouldn't hurt to add an electrolytic cap (10uF to 100uF) from V+ to ground to limit power supply noise.
Here's a schematic. The missing parts are in red. It would be a good idea to look it over and see how the schematic corresponds to the layout.
Here's a couple of articles to get you started on how it works.
Here's a link to diylc, which is a free program for drawing layouts and schematics (I used it to draw the above schematic), in case you want to try to draw up a vero. If you do, post it here and I'll look it over for you.
Welcome to the madhouse.
The input isn't shown, but it should go to the non-inverting input of the op amp, which is where the leftmost lead of R6 connects. It's also missing an input cap. The way it's drawn it will pop when engaged, and will leak dc into your pickups or whatever is in front of it in the chain. Along with the input cap you should add a pulldown resistor, also to prevent pops. The tone knob should probably connect to Vref (the junction of R2 and R3) to keep DC off the pot, but connecting it to ground will probably work also (though it might crackle a little bit when you adjust it). It wouldn't hurt to add an electrolytic cap (10uF to 100uF) from V+ to ground to limit power supply noise.
Here's a schematic. The missing parts are in red. It would be a good idea to look it over and see how the schematic corresponds to the layout.
Here's a couple of articles to get you started on how it works.
Here's a link to diylc, which is a free program for drawing layouts and schematics (I used it to draw the above schematic), in case you want to try to draw up a vero. If you do, post it here and I'll look it over for you.
Welcome to the madhouse.
induction wrote:That looks better. That's a basic non-inverting boost with noiseless biasing. I take it you have an actual working unit that you copied this from? Mind sharing where it came from or what it's called?
The input isn't shown, but it should go to the non-inverting input of the op amp, which is where the leftmost lead of R6 connects. It's also missing an input cap. The way it's drawn it will pop when engaged, and will leak dc into your pickups or whatever is in front of it in the chain. Along with the input cap you should add a pulldown resistor, also to prevent pops. The tone knob should probably connect to Vref (the junction of R2 and R3) to keep DC off the pot, but connecting it to ground will probably work also (though it might crackle a little bit when you adjust it). It wouldn't hurt to add an electrolytic cap (10uF to 100uF) from V+ to ground to limit power supply noise.
Here's a schematic. The missing parts are in red. It would be a good idea to look it over and see how the schematic corresponds to the layout. Here's a couple of articles to get you started on how it works.
Here's a link to diylc, which is a free program for drawing layouts and schematics (I used it to draw the above schematic), in case you want to try to draw up a vero. If you do, post it here and I'll look it over for you.
Welcome to the madhouse.
I did indeed copy it from a current circuit but I wouldn't be happy sharing the details of the pedal, its a one man business and I don't want to interfere with his job and pedal making life.
The input on the pedal goes to the volume, then tone and then to the board via the wire that says tone. so effectively the tone wire is the input... hopefully that makes sense and works - I mean I know it works... but if it can be done more conventionally as per building a pedal I'd love to know how that'd be done. Oh and also how this effects the schematic you drew up?
Thanks for the schematic and the links by the way I'll look over those!
This really is a madhouse... bring it on!
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induction
- Resistor Ronker
Ah, I see. So it's actually an inverting boost (see the Wiki page I linked to before). You can ignore most of what I said in the last post (especially the connecting the tone pot to Vref, I'm pretty sure I was wrong about that anyway). Basically, the schematic is the same as before with most of the red parts removed. C3 is the input cap. I'd keep C5 if you plan to use it with an adapter, you can skip it if you only use batteries or regulated adapters.
I didn't include the volume and tone pots, since they could be wired a few different ways. If they are wired like a 50's les paul, it would look something like this.
But check the working unit to see how they are really wired. There are a lot of other ways it could be.
I have scrawled out how the circuit is wired (inputs, power, pots, switch and pcb) so will neaten it up and upload it when I finish. Then I'll be able to explain how they are wired up using the picture... I think its quite similar to the schematic you've posted but we'll see.
How do I decide the value of C5 in red? Whats the difference if I use a 10uF cap vs a 100uF cap?
Also why do C3 and C5 have polarity markings whilst C1 and C2 & C6 don't?
Thanks for your help so far, I really appreciate it.
How do I decide the value of C5 in red? Whats the difference if I use a 10uF cap vs a 100uF cap?
Also why do C3 and C5 have polarity markings whilst C1 and C2 & C6 don't?
Thanks for your help so far, I really appreciate it.
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induction
- Resistor Ronker
First off, I had a wrong connection in my second schematic. Here it is corrected:
C5 is just for getting rid of ripple on the power supply. Anything from 10uF to 1000uF would work, but caps start getting pretty big above 100uF. There shouldn't be an audible difference between them. Use what you have available. Op-amps have pretty good supply noise rejection anyway. C2 is more important because that filters ripple from the input of the op-amp, where it would be amplified if present. Both of these are marked as polarized because it's hard to find nonpolar caps above 2.2uF. They can be electrolytic or tantalum, as long as the voltage rating is high enough. Smaller caps like C1 and C2 can be film or ceramic, which are generally nonpolar.
Ah okay. Can I just use these no polarised Electrolytics and not have to worry about polarity? http://www.bitsbox.co.uk/capacitors/nonpolar.html
Here's the wiring layout the two blocks connected to the pots are capacitors, I didnt number them because I noticed you missed out a C4 on your schematic.
Here's the wiring layout the two blocks connected to the pots are capacitors, I didnt number them because I noticed you missed out a C4 on your schematic.
- Attachments
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induction
- Resistor Ronker
Yes, you can use those.
Background info: You don't want to reverse the polarity on a polarized cap because it will die. Nonpolar electrolytics are useful when the voltage across the cap will swing both positive and negative. They are usually more expensive the polarized electros. In this case, the voltage is constant so polarized are ok, but those NP's look cheap enough that it doesn't matter. You can always sub nonpolars for polars, but not the other way around.
I had a C4 on my first schematic, but it was removed in the later ones. I didn't want to reuse it in case it caused confusion.
Background info: You don't want to reverse the polarity on a polarized cap because it will die. Nonpolar electrolytics are useful when the voltage across the cap will swing both positive and negative. They are usually more expensive the polarized electros. In this case, the voltage is constant so polarized are ok, but those NP's look cheap enough that it doesn't matter. You can always sub nonpolars for polars, but not the other way around.
I had a C4 on my first schematic, but it was removed in the later ones. I didn't want to reuse it in case it caused confusion.
Perfect. Time to try and turn this thing into a vero... Well tomorrow anyways!induction wrote:Yes, you can use those.
Background info: You don't want to reverse the polarity on a polarized cap because it will die. Nonpolar electrolytics are useful when the voltage across the cap will swing both positive and negative. They are usually more expensive the polarized electros. In this case, the voltage is constant so polarized are ok, but those NP's look cheap enough that it doesn't matter. You can always sub nonpolars for polars, but not the other way around.
I had a C4 on my first schematic, but it was removed in the later ones. I didn't want to reuse it in case it caused confusion.
Gotcha, makes sense! Thanks again!
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induction
- Resistor Ronker
Looks fine. Good work.
You'll need a current limiting resistor for the led (something in the vicinity of 1k). Lots of people attach that directly to the led lead (either side is fine), others (like myself) prefer to put it on the board. If you don't mind it standing up, you can fit it on there with one additional track cut.
You'll need a current limiting resistor for the led (something in the vicinity of 1k). Lots of people attach that directly to the led lead (either side is fine), others (like myself) prefer to put it on the board. If you don't mind it standing up, you can fit it on there with one additional track cut.
My actual plan for this circuit is to use it with a JHS mini bomb boost vero I found. I plan to leave the pre amp on and want a clean boost for solos.
I want the boost after the pre for a clean boost to make my signal louder not before driving the pre harder.
If I wire the whole unit like this will I be able to do the following things?
Pre on via toggle, boost available via footswitch **OR** Pre off via toggle, boost still available via footswitch. As if the pedals were separate pedals... just in one enclosure.
Oh yeah, I used a 2.2K Limiting resistor on the LED, only wanted one for the footswitch, and I can easily add another if I need it. Wired the toggle using a 3PDT toggle... no idea whether I need and ON-ON or and ON-OFF?
I want the boost after the pre for a clean boost to make my signal louder not before driving the pre harder.
If I wire the whole unit like this will I be able to do the following things?
Pre on via toggle, boost available via footswitch **OR** Pre off via toggle, boost still available via footswitch. As if the pedals were separate pedals... just in one enclosure.
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induction
- Resistor Ronker
Yup, you've got it figured perfectly.
As for the toggle, all two position double - throw toggles are on/on. That's what you want. (The second 'on' connects the dry signal in bypass.) There are three position double - throws with off in the center (among other types), but you don't need that here.
Here's an article that explains a little more.
As for the toggle, all two position double - throw toggles are on/on. That's what you want. (The second 'on' connects the dry signal in bypass.) There are three position double - throws with off in the center (among other types), but you don't need that here.
Here's an article that explains a little more.
Awesome. Looking forward to building this thing!
So an SPDT like this one would do the trick? http://shop.pedalparts.co.uk/SPDT_Toggl ... 73381.aspx
The outer pins are the two signals and the middle a ground correct?
So an SPDT like this one would do the trick? http://shop.pedalparts.co.uk/SPDT_Toggl ... 73381.aspx
The outer pins are the two signals and the middle a ground correct?
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induction
- Resistor Ronker
You'll need a 3PDT toggle just like in your diagram if you want an led, or a DPDT if you don't. With a 3PDT you can add an led later if you want one. Just leave the third pole empty, no need to attach it to ground like in the diagram. Alternatively, with a DPDT you can add one later with a millennium bypass daughter board (search this forum for that).
As an exercise, visualize what happens when you flip the switch in your diagram. The first pole switches the input, the second pole switches the output. The top throw switches in the circuit, the bottom throw is bypass.
As an exercise, visualize what happens when you flip the switch in your diagram. The first pole switches the input, the second pole switches the output. The top throw switches in the circuit, the bottom throw is bypass.