Comprehension issue with schematic's output

[minersrevolt]

Hey everyone,
I'm a new user here and working on my first pedal, the multi-fuzz by Jack Orman - http://www.muzique.com/tech/muzz.htm

I am having problems understanding how to connect a 3PDT switch to this pedal. The problem comes with understanding how the output node is actually wired. When I built the pedal on my breadboard, I connected the tip of the output jack to the node labeled OUT1 and the sleeve lead to the wiper lead of the VOLUME pot (shown below). This works great, and the pedal sounds great.



The problem is trying to get a single output node as is needed for a 3PDT switch. I have tried connecting the VOLUME pot wiper to the OUT1 node, and then connecting the tip terminal of the output jack to that node, and the sleeve jack to ground (shown below). This leads to numerous problems in the output, all the knobs work up to about 50% capacity then there is a syncopated thrumming through the amplifier, and the sound is mostly cut off.



I really don't know how to connect this to work with a switch! I realize this is probably a very simple solution, and any help would be greatly appreciated!

edit: formatting.

[LucifersTrip]

check out some of these first

http://tinyurl.com/lnkbzg7

[minersrevolt]

I've looked at many of these and understand how the switch is wired to the board. The problem is that creating the single output on the circuit. The only way it works is if the sleeve terminal of the output jack is connected to the wiper VOLUME node, and not ground as all the 3PDT schematics demand.

I'm sorry if this isn't clear - I am basically just not understanding how he is saying the circuit is built. Does the wiper on Volume connect directly to OUT1? Then the output jack connects to that and ground?

[tubegeek]

Well, first a basic concept: the two contacts on a TS (Tip/Sleeve) jack are "Hot" (audio signal) connected ALWAYS to the Tip, and "Shield" which is ALWAYS connected to the Sleeve. The shield braid of an input or output cable is ALWAYS connected to the Sleeve, and these connections are typically connected to the metal box that the effect is housed in and also to the circuit ground.

The bypass switch typically leaves all the Sleeve connections and the box unchanged when it is switched. Usually the only changes are made to the Tip connections. For some effects (mostly, the high gain ones) it is important to connect unused input connections to circuit ground when the effect is bypassed. The other path necessary in bypass mode is for the input jack "Hot" to connect directly or through a low-resistance path to the output jack "Hot."

When the effect is NOT bypassed (when it is engaged) the connections that must be made are 1) from input jack "Hot" to the beginning (input) of the effect and 2) from the output of the effect to the output jack "Hot." In this mode neither "Hot" connection should be grounded.

However, the circuit you are building looks like it has an input buffer (the circuit section from the point marked "IN" to the part marked "Out1") that is always in the signal path.

For this circuit type, you want to connect the output jack "Hot" EITHER to the "Out1" spot (buffer-only mode, so bypassing the fuzz effect) or to the Volume wiper connection (effect mode, including the entire circuit.) The Volume wiper (effect output) should never connect to the sleeve of the output jack. Notice that the bottom end of the Volume pot is already connected to ground and so connecting the wiper to ground through the output jack sleeve basically shorts out the lower portion of the Volume pot, which is not typically the desired behavior.

[minersrevolt]

However, the circuit you are building looks like it has an input buffer (the circuit section from the point marked "IN" to the part marked "Out1") that is always in the signal path.

For this circuit type, you want to connect the output jack "Hot" EITHER to the "Out1" spot (buffer-only mode, so bypassing the fuzz effect) or to the Volume wiper connection (effect mode, including the entire circuit.) The Volume wiper (effect output) should never connect to the sleeve of the output jack. Notice that the bottom end of the Volume pot is already connected to ground and so connecting the wiper to ground through the output jack sleeve basically shorts out the lower portion of the Volume pot, which is not typically the desired behavior.

Wow, this was exactly the issue. I can't believe I didn't try this simple thing... I have been staring at this for an embarrassing amount of time really. That one node marked OUT1 just dominated all of my thoughts, I felt had to do something with that node damnit!

Thanks so much for the help, I can't wait to finish this project now!

[tubegeek]

Thanks so much for the help, I can't wait to finish this project now!

Glad to be of help - enjoy!

[minersrevolt]

Since I still have this thread open I was hoping someone could take a look at my perf-board layout. I just built it and attached it to the 3PDT setup (which works, confirmed separately), and I only get the clean channel. I have checked the continuity in the connections with a DMM and everything is connected as shown in the diagram, which leads me to believe that the diagram is faulty somewhere, but I can't see where.

I used an NPN version with 2N5088's and flipped the polarity of all the electrolytic caps.
Is there an electrical problem with the diagram, other than the general newbie-ness of it?

ORIGINAL


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