I've noticed on Fender eyelet boards they tend to place the PS caps on one end, then the PI components, then the preamp components, with the lowest signals on the far end. Is this intentional, to minimize AC pickup? I want to play with different PIs, and wanted to make a board with just PS caps and preamp, and a separate board for the PI (to then swap with a different PI board). Should I make separate boards for PS, preamp and PI, and keep them a few inches apart? Or add more shielded conductors? Thanks!
This is just the way things turn out when you do good layout and use good earthing techniques.
To do what you want I would make separate board for PS, PI and Pre unless you decide to use Printer2's switchable PI, in that case just bung it all on one board PS to PI to Pre.
When you lay "stuff" out you will find that you sometimes have to mount components a little remote from the tube sockets. Always choose LOW Impedance circuits to put on the longer wires - these will typically be the tube cathode circuits (bias resistors and bypass caps).
HIGH Impedance circuits (Grid connections in particular and to a lesser extent anode circuits) are susceptible to noise pickup and also to getting stray signals coupled in by stray capacitance. This can cause hum and buzz BUT also it can cause instability[parasitic oscillation]). Keep these connections "short and sweet".
Cheers,
Ian
To do what you want I would make separate board for PS, PI and Pre unless you decide to use Printer2's switchable PI, in that case just bung it all on one board PS to PI to Pre.
When you lay "stuff" out you will find that you sometimes have to mount components a little remote from the tube sockets. Always choose LOW Impedance circuits to put on the longer wires - these will typically be the tube cathode circuits (bias resistors and bypass caps).
HIGH Impedance circuits (Grid connections in particular and to a lesser extent anode circuits) are susceptible to noise pickup and also to getting stray signals coupled in by stray capacitance. This can cause hum and buzz BUT also it can cause instability[parasitic oscillation]). Keep these connections "short and sweet".
Cheers,
Ian
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