TS808 schematic variants 08/ 09 /10 that part with C3 and R4 (pin 2 of OpAmp, 47nF and 4k7)

[j-pee]

hi,

I'm just building IVIark's layout -- this -- of the TS808...

and without any intention I realized that "that part" of the schematic has been "erroneously" laid out....
(discording with the schematic at electrosmash)
 

this part:




........................................

now, in this schematic what I see is:   @ pin 2:   C3->R4->GND

on that layout (same spot):   4k7->47nF->4v5

then I checked service manuals for TS 9 (2 copies, A, B), and Ts 10,
and I found:  
                        TS 9/A:    47nF->4k7->4v5
                        TS 9/B:    4k7->47nF->GND
                        TS 10:    47nF->4k7->4v5

in the two layouts by IVIark, too, this part is not the same...

in the normal version: 4k7->47nF->4v5
whereas in the "width clipping switch" version it's:  47nF->4k7->4v5


at first I thought I spotted an error... now I know it can go any way...

but can it, really?



///////////////
the service manuals you can see here:
classicodschematic.pdf
and
ibanez_ts-9_tube-screamer_sch.pdf
and
ibanez_ts-10_tube-screamer_sch.pdf

(source: elektrotanya.com)



             

[nocentelli]

j-pee wrote

at first I thought I spotted an error... now I know it can go any way...

but can it, really?

Yes. The order of components in series makes no difference to operation if there is only a single "input" and a single "output" to/from that particular branch. In this case, the input could be considered to be the opamp's inverting input, and ground/vref is the output: The order of the cap and resistor that join these two points is irrelevant.

On a second issue, actual ground (zero volts) and virtual ground (4.5v) also have no functional difference from the point of view of the opamp's inverting input IF A CAPACITOR IS USED, so that cap + resistor can be connected to ground (0 volts) OR to vref (4.5v) with no functional difference in the circuit's operation. You will occasionally see a circuit with the opamp inverting input connected to vref directly through a resistor with no cap present, but never directly to ground without a cap.

[j-pee]

thank you so much for the explanation! :)

everyday logic also tells me, sure, that components in series can go in any order...
but I think I know that circuits are organic arrangements and any part (section) can "form" something, like a filter...

thanks very much,