A few questions for a first-time project

[gotw]

I would like to build a pedal with two 25kOhm volume pots, each pot connected to one throw of the footswitch. The idea is to set one pot at one volume and the other at a higher volume to be used as a foot-switchable volume boost in my line-level guitar amp effects loop. I have found that using a standard volume pedal has too much variability in too small a movement and really I just want to stomp on a switch to enable/disable the "boost". The reason I want two volume pots instead of just bypassing the pedal altogether to get the "boost" is that taking the pot out of the signal chain altogether will also change the tone, which is already compensated for at the amp EQ. Switching between two identical pots, just set at different levels, should change the volume but leave the tone intact, much like instantaneously adjusting a volume pedal to exactly where you want to go. I have a few questions:

1) Does this sound like a reasonable thing to do or am I missing something?
2) Will a DPDT switch suffice or should I use a different switch type?
3) I need 25kOhm pots, jacks, enclosure, wire, knobs and a switch. I don't need an LED so I assume I don't need power. I have soldered cables and (incorrectly) built a BYOC pedal so I have solder, iron, wire cutters, etc.
    a) Am I missing anything?
    b) Are there any particular part brands I should purchase or avoid?
    c) Any online store recommendations from which to purchase my parts? I would prefer to buy all at one place.
4) How do I drill holes in an enclosure?

Any help would be greatly appreciated. Thank you

[GGBB]

1) If you are doing this passively, you are attenuating, not boosting. I think you probably realize that, however, what you may be missing is that there really isn't any point in having two attenuation levels when your goal is to have a normal volume and a "boost" volume. One pot set wherever you want for your normal level, bypassed for your "boost" setting. You can bypass it completely as in true-bypass or if you're concerned about tone-shift simply move the output connection from the wiper to pin 3.

2) In the above case you would only need SPDT, otherwise DPDT for true-bypass.

3) I think you have everything covered.

4) There are probably many videos of this kicking around u-toob. Aluminum enclosures are fairly easy to drill.  Measure where you need your holes. Double-check your measurements. Mark the locations with a marker. Use a punch to create a small dent where you've marked. Secure the enclosure to something - vise, clamps. Drill carefully at a slowish speed. Many DIYers use a step drill for this, but you can use ordinary drill bits. If you are not using a step bit, drill a small pilot hole first (e.g. 1/16").

[gotw]

... or if you're concerned about tone-shift simply move the output connection from the wiper to pin 3.

Thanks so much. Regarding your above suggestion, does that only work with an SPDT switch? As I understand, using a DPDT would completely remove the pot from the signal path, resulting in a tone shift, whereas an SPDT switch leaves a connection to the input of the pot and only breaks the output connection to the pot.

Also, do you have suggestions of part brands to purchase or avoid and where to buy parts?

Thanks again.

[GibsonGM]

I always just do a pilot hole (yup, 1/16"), but don't try to make a 'detent' with a punch...I worry that bashing the aluminum too hard might fracture it. 

But I may just be paranoid?   I do use a drill press, which makes it a lot easier to clamp down and so on. 

[MaxPower]

Online stores:
Here if you want to support the site.
Small bear. Caters to the diy community
Mouser. Stocks pretty much everything you need (components, project boxes, wire, solder, etc.). This is where I buy most of my stuff as it is near by so even snail mail gets here quickly.

[digi2t]

I always just do a pilot hole (yup, 1/16"), but don't try to make a 'detent' with a punch...I worry that bashing the aluminum too hard might fracture it. 

But I may just be paranoid?   I do use a drill press, which makes it a lot easier to clamp down and so on.

I use an automatic center punch, like this one;



Never had a fracture. Aluminium isn't that brittle. If it was, it would probably crack around the stomp switch when you stepped on it.

Center drills are a plus too. I used to work in a machine shop several years ago, so I carry a complete set of these;



Not really necessary, but really help steady up the bit off the start when drilling thicker materials.

[GGBB]

Thanks so much. Regarding your above suggestion, does that only work with an SPDT switch? As I understand, using a DPDT would completely remove the pot from the signal path, resulting in a tone shift, whereas an SPDT switch leaves a connection to the input of the pot and only breaks the output connection to the pot.

SPDT - essentially all the switch is doing is flipping the output between the wiper and pin3 - effectively the same as turning the volume control to max.

don't try to make a 'detent' with a punch...I worry that bashing the aluminum too hard might fracture it. 

I've never had a fracture either, but I did push in the top a bit on my first pedal. I now support the underside of the pedal with a wood block when punching and I don't punch that hard - just enough to make a small divot for the tip of the bit to sit in.

[GibsonGM]

I can see where my 'fear' of fracturing the enclosure might be a bit too much, but hey - it works for me   It's only cuz I have a press that I don't have to use the punch - I can clamp it down and ease a tiny bit in to make a pilot.  Before I got a drill press, it was pure luck and much skipping around.

If the punch works, that's great, too!! It's standard practice for metal drilling, so it's probably just me being over cautious.  Might need a little light oil when drilling?  I use some.

[gotw]

1) If you are doing this passively, you are attenuating, not boosting. I think you probably realize that, however, what you may be missing is that there really isn't any point in having two attenuation levels when your goal is to have a normal volume and a "boost" volume. One pot set wherever you want for your normal level, bypassed for your "boost" setting. You can bypass it completely as in true-bypass or if you're concerned about tone-shift simply move the output connection from the wiper to pin 3.

2) In the above case you would only need SPDT, otherwise DPDT for true-bypass.

GGBB, can I use a DPDT or 3PDT (instead of an SPDT) switch and still move the output connection from the wiper to pin 3, so that the pot is still in the signal even when bypassed, to not alter tone? I ask because I am having a really hard time finding SPDT latching switches.

Thanks!

[mth5044]

DPDT and 3PDT switches are made up of two and three SPDT switches, respectively. With the lugs horizontal, the individual switches run left, so if you only want to use one SPDT section of the seitch, just use one vertical set of lugs. I'm thinking GGBB recommended SPDT because they are smaller and less expensive, but you can use a double or triple throw.

Use a multimeter or connectivity or resistive modes and learn about the connects of a switch, it can be very enlightening.