Project files: Little helpers – Alps PCBs II

What is it?
Not exactly the most complex designs ever made 😉 A couple of PCBs for mounting Alps (or pin-compatible) potentiometers. Unlike the previous boards these ones have screw clamps for input and output, making them better suited to testing use and people with fat fingers (like yours truly) 😀 There are two versions, a 2-channel (for stereo) and a 4-channel (for balanced) amps.

How big are the boards?
The SE board measures 1.15″ x 1.975″ (app. 29 x 50 mm) and the balanced board measures 1.975″ x 1.975″ (app. 50 x 50 mm.)

What is the status of the boards?
I’ve called these version 1.5 since they are based on the previous boards of the same type, just modified with screw clamps for the input/output connections.

Does it use any special/expensive/hard-to-find parts?
Mostly there’s only one real part on the board and that is the pot itself which can be a bit expensive, so yes, I guess so 😀

Anything else I need to know?

• These are “preamp” style boards have a ground plane and a ground pad that can be used if you grounding scheme requires the shaft of the pot to be grounded. Use a piece of wire connected from the ground pad to either one of the screws on the back of the pot or soldered to a ring terminal wedged between the pot and the chassis.
• The stereo board has a four-hole footprint to fit various pots that use that configuration, but the last set of pads isn’t connected to anything so will not work directly with a loudness tap.
• The boards can also be used to make separate, passive preamps. In this case, a 10k potentiometer should be used.
• The screw clamps are standard 5mm pin spacing types, but of course it is possible to solder bare wires to the boards as well.

Downloads:
Download design files here

Related information:
Note: Always read the “intro post” for additional important information about my designs.

As usual, please remember to consult the manufacturer’s datasheet as well if you use a different pot than the recommended type.

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