Active/passive circuit issue.

Hclafkir

Hclafkir

Apr 4, 2020
14
1
2,551
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#1
View attachment 4803303 View attachment 4803317 Hey everyone. I’ve recently tried this circuit in my bass with the exception of the pan pot. I only have a single DiMarzio SplitP. So, the hot from pickup goes straight to the tone pot.

This works great in active mode. But, when I press the button to switch to passive, there’s a bit of a “pop” sound and then I get no signal. Switch back to active and all’s good again.

Any suggestions?

Active:Passive circuit.png
 
Last edited:
#3
rojo412 said:
Are you sure that the active mode is the one that is producing sound?
Got any pics of the actual wiring you have going on?
Click to expand...
Thanks for replying rojo412.

I'm pretty sure it's the active that's working because I have the button pressed down when I get a response.

Here's an attempt to show you my wiring so far:

A: Volume pot
2 goes to connector 3 in illustration F
3 goes to 1 of tone pot

B: Tone pot (top section is passive - bottom section is active mid)
1 white goes to 3 of volume pot
1 red is hot from DiMarzio Split P
active mid is prewired harness to preamp

C: EQ pot (top section is high - bottom section is low)
both are prewired harness to preamp

D: not sure why I skipped D when labelling?!?

E: DPDT latching push button switch (see F for legend)
1 to preamp input (black shielded cable white inner core)
2 output to jack
3 to lug 2 on volume pot
4 from preamp output
5 to ground connection
6 jumped to 3

F: Switch labelling
Red indicates the labelling on the switch that I couldn't get a clear picture of
C is common
up arrow is up position
down arrow is down position

G: ground connections
shielded component mentioned in E1 above
ground from pickup
ground from E5
ground to bridge
ground to volume pot
ground screwed to shielding

H: showing ground screwed to shielding

I: all of these go to the preamp

I hope this is a clear enough description of what I've done. Please let me know if I've missed anything.

A.jpg
B.jpg
C.jpg
E.jpg
F.jpg
G.jpg
H.jpg
I.jpg
 
#4
Sorry, I misspoke in item I when I said, "I: all of these go to the preamp"

The correct description should be:

I: Jack wiring goes to
White: terminal 2 on DPDT switch
Red: preamp
Black: preamp
 
#7
Output jack should be connected to what you labeled as 4 on your switch. (assuming it is a typical DPDT terminal layout)

This is how you expect a DPDT switch to work. It is two independent switches.

A1 B1
A B
A2 B2

Position 1 connects A to A1 and B to B1.
Position 2 connects A to A2 and B to B2.

Bypassing the preamp has to get the signal from the A side to the B side. You notice the wiring diagram uses the jumper wire to bridge the two sides when in the correct position. The passive position also grounds the input to the preamp, so it would kick out noise.
 
#8
I just looked at picture F again. Are we sure 1&2 are the “common” (unless I misunderstand what you mean by common)? I’d expect the 3&4 to be common so that, in one position 3 connects to 1 and 4 to 2. Then in the other position 3 connects to 5 and 4 connects to 6.

Which is just repeating what @MidlifeBeginner said but he’s right.
 
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