Now that we’ve covered “how we got here”, let’s take a look at “why” and “how”.
Why? We had a number of goals in mind:
- Reduce or eliminate coupling between components and/or leads
- Reduce or eliminate flying leads/wires
- Make the signal path as short as possible
- Where wires must cross, do so at right angles and on a different Z-plane
- Keep grid components as far as possible from sources of interference
- Make proper grounding technique easy to achieve
How? With some creative orientation of sockets and components, as well as extensive utilization of the Z-axis, we were able to meet all these goals. A sketch of these basic principles looks like this (for a B9A basing):
B+ wires are in red, heater wires are in green. Note that all the HV lines are on the opposite side of the tube socket from the coupling caps (which are generally leading to controls). Grid stoppers are right on the socket where they belong. Stage ground points are easy to aggregate at the filter cap, and utilizing them is natural – grounds from stage input controls or voltage dividers land right at that stage’s cathode circuit ground, requiring only one short flying lead to aggregate at the filter cap ground. Heater wires run at a right angle to everything else, and on a different Z-plane. By placing the tube socket close to the control panel, flying leads to controls can be very short or eliminated altogether (by bridging the cap with the components themselves).
Here’s a working example – the first push-pull amp I built using this method, which has been in HEAVY (ab)use since 2007:
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