freestompboxes.org

I recently finished breadboarding/perfboarding/boxing my first pedal and wanted to clarifying something very basic before moving on:

If a signal "passes by" a few components in a schematic, when translating the schematic to a board, does the space/order of those components matter? Or can they be soldered together in a single point, or even reversed?

If the question isn't clear, a couple of examples where I ran into this type of question:

1. A schematic shows that the output signal comes out of an output cap and then passes by 2 diodes (for clipping) and then finally it hits the input leg of a volume pot. In this case, do the diodes and volume pot need to be spaced apart like the schematic shows? Or can they be wired together? Or even reversed e.g. put the volume pot before the diodes (if they can be wired together, I don't see why they can't be reversed, since they are still "all wired together" even when reversed)?

2. A schematic shows that the +9v, before hitting the actual effects circuit, first passes by a diode (circuit protection) and then a cap (noise filter). Again, do they need to be spaced apart like the schematic shows, or can they be wired together, or even reversed?

In general, if the part of the circuit has only one connection "in" and one connection "out", the order does not matter: E.g. If the signal passed through a cap then a resistor and on to a single connection, order is irrelevant (BUT see caveat below).

In specific terms:

1. In this case, the output leg of the cap, the diodes and volume lug 3 all connected to a single point (node) so the order is irrelevant. You could run a wire from the cap output leg to vol3 and solder the diode pair onto that lug, then solder the other ends of the diodes to ground (maybe vol lug1?)

2. This is a situation where the order might matter: The diode is for reverse polarity protection, and the cap for power filtering. If the cap came first, and reverse voltage was applied (e.g. using the wrong adaptor), it could perhaps damage the cap. This assumes that the diode is drawn in series with the +9v: sometimes the diode goes from ground to +9v, in which case the order would not matter since reverse voltage would short the power supply and the cap would not receive the reverse voltage.


If you could post the schems, it would be easier to give definitive answers.

Thanks for the helpful answer.

The Electra Distortion is actually the exact source for my first example!

For my second example, I wasn't referring to any specific schematic, just a common pattern I've seen. I was referring to your circuit B, where the diode is NOT in series. I've also seen a LED (Resistor+LED) thrown in before the diode. So it also can really be anywhere in between the +9v and the FX circuit, or even after the FX circuit (i.e. in your diagram, to the right of the FX circuit)?

Electronically, it doesn't matter where the LED and current-limiting resistor is placed, but to prevent switch pop, it's best to connect the LED directly to the +9v, i.e before the filter cap. When the switch connects the LED and resistor to ground there is a sudden extra demand for current: putting the cap between the LED and the FX circuit prevents this spike coming through the audio.