Grounding schematic opinions please

[tubeswell]

I am still twiddling with the revamped model. (Note that it will have separate filter caps including an extra 22uF 450V).

Before I sling it back together again, I had this idea (based on Merlin's grounding article) about grounding the pre-amp (V1a and V1b) and reverb recovery at the same decoupling cap (cap 1), and grounding the PI driver and PI at the same decoupling cap (C2), and grounding the 'spare' coupling cap (C3) together with C1 and C2 at the input jack ground. I an left wondering if there is anything else I should do in bringing the grounds of cap1, cap2 and cap 3 together at the input jack ground?

The reverb driver circuit and the LFO circuit would ground together at the screen filter cap. The screen cap and the reservoir cap and the HT, and the heater voltage divider/bleeder resistors, and bias supply would ground together.

See attached schematic for the pictoral definition. Any opinions welcomed please.

[tubeswell]

Its great to see that people are interested enough to download the schematic. :-)

Initially I wasn't sure about whether to ground the reverb driver ground returns at the screen filter cap node, since this is also where the LFO ground returns would be going, and intuitively I tend to think of the reverb driver part of the circuit as being part of the pre-amp. But after thinking about it some more, I think this makes sense because the B+ for the reverb transformer etc is being taken from the screen filter cap node, and paralleled 12AT7 triodes draw up to about 10mA (I think?) and this is not likely to be upset by the amount of screen current (I hope?)

I think I'll just try it anyway and post the result here. FWIW for the rest of the pre-amp I've decided to run each group of ground returns, via separate wires, to each respective relevant decoupling cap ground return, and thence run a wire from each such return point for caps 1, 2, and 3 to the input jack ground, and then the same for the screen and reservoir cap ground returns (and their associate clusters of returns). 2CW

[dai h.]

thinking about it

I think I'll just try it anyway and post the result here.

I think this is probably the best thing. That is, thinking about it, then coming up with a rationale, then actually trying the physical wiring out. If you really get stuck, you could always try asking someone here (by "someone" I mean an actual expert--not me! ).

[Wilder Amplification]

Grounding isn't all that hard to understand. Essentially you want to ground each stage right at the smoothing cap that it's drawing current from, plain and simple. This forms a "local star" as Merlin calls it at each smoothing cap. Then run your power string in a "daisy chain" fashion to each smoothing cap.

Theoretically this is supposed to remove audio current from the same wires that carry power current, which to me doesn't make any sense since an amplifier is basically just turning the power supply current into audio current via using your guitar signal to modulate it.

[echuta13]

I like to place my supply caps in the location of the section they support. It falls inline with your grounding scheme. I've never had an issue with noise doing it this way.