Bias / Bypas question

[A.C.CHILDRESS]

I'm new to audio electronics so some of the things I did before might not be right in audio construction. I just built a small tube amp just to get started and it came out well.

My question is illustrated by the two photos included. The "as drawn" schematic shows the bias resistor grounded and the bypass cap. grounded separately. When I built the amp I was tight on space and it just seemed like a good idea to "piggy back" the cap. on the resistor. Is there any reason that this is a bad idea?



As drawn.


AS built.

[Enzo]

There is absolutely zero difference between the two schematically.

The second drawing style is avoided because it clutters up the drawing. The cap goes to ground either way, so showing it connected to something grounded is redundant. The schematic is not a wiring diagram, it does not show how things are laid out. that is why Fender used to provide schematics and wiring diagrams both.

if the two compnnents were to be grounded top different spots, the schemtic should show different ground symbols. You used the triangle shaped ground symbol here, as opposed to the one that looks like a garden rake. If the resistor and cap were to be grounded differently, then we might find a circle or a square around one of the triangle symbols. it is not unusual to see multiple grounds in complex and high gain amps. SOme peavey schematics show as many as six grounds. Ultimately they all interconnect somewhere.

Your first drawing does not indicate a separate grounding of parts. A schematic would not show any difference betwen two parts side by side or one of them piggybacked on the other - parallel is parallel. If ther was some specific need for a part to be mounted different than all the other parts, a note would be made on the drawing.

A schematic shows the electrical relationship of the parts in the amp. A wiring diagram or layout shows the physical relationships.

[A.C.CHILDRESS]

Thanks, that's what I wanted to hear.