Jazz/Rock schematic differences - which is correct?

[markmalin]

Hi guys,

I'm building a pre-amp based on the #183 schematic. I notice there is one node around the jazz/rock switch which is shown connected on some schematics, and not connected on others. This is the top of the Bass potentiometer. I'm attaching a clip of the schematic. Some schematics show the cap C6 connected to the top of the Bass pot, effectively connecting C6 and C4 and tying it to the wiper of the pot. Can someone explain which is correct, or if there are differences on purpose?

Humbly
Mark

[pompeiisneaks]

I'm not sure of other cases, but in this one, those wires aren't connected, they don't have a large black dot to indicate they are tied.

One wire (from C4) connects into the top of the bass pot, the other (From C6) bypasses the wire and connects into the Rock/Jazz switch.

Just a specific way that schematic app works, some show that upsidedown U shape for non connected lines, this one doesn't

~Phil

[markmalin]

Thanks, Phil. Sorry for the confusion - my question is, which is correct to the 183 schematic? I've seen #183 versions out there that have that node connected (i.e. big black dot), and some that don't (like in this version). Not sure which version to trust

[Charlie Wilson]

The .001 goes across the bass pot in a Skyliner. Your schematic is missing the dot. Sometimes comparing the schematic to the layout will help clear up these kind of issues.
CW

[pompeiisneaks]

Gotcha,

From what I understand the best and most 'right' versions are the first one listed here:

https://ampgarage.com/forum/viewtopic.php?f=5&t=13095

BUT looking at #124 as well it does seem that's actually supposed to be connected (Everything I've heard is the only differences between those two's circuit in most cases are the component values but the actual circuit itself is almost 100% identical. It looks like the layout I liked above shows the .001 cap across the 1 and 3 legs of the cap as well, so it may just be an error on that schematic not showing them connected.

maybe talbany or someone else can confirm?

~Phil

[pompeiisneaks]

Charlie beat me to what I found and confirms it... Thanks!

~Phil

[Charlie Wilson]

Or I could put it this way....
CW

[markmalin]

Thanks, Gents! I'll add the dot to my schematic

Man...wooden sides. I hadn't looked closely at that before.

[talbany]

Nobody seems to know why Dumble wired the J/R switch differently on 183 however according to the person who cloned the amp and others who played it said electronically functions the same as how he wired ODS's like 102/124!.That's why the layout is different

Tony

[martin manning]

As far as I can tell the two R/J switch wiring configurations are electrically equivalent, two ways to accomplish the same thing. That’s entirely different from the missing dot... that’s just a schematic error.