Hi folks: Seeking some guidance for the impending build above, as follows:
I've struggled to find a 240R 1W resistor for the power supply. I have 220R 1W instead, which all measure closer to 220 than 240. Is this sub ok? Other possibility is to wire 2 470Rs 1W in parallel to get closer to 235R approximately but this will obviously take up a lot of room on the board.
The 240pF cap is also proving elusive, unless in large multiples (25 at a time, which seems very wasteful). Closest I could get was a 220pF MLCC measuring 229pF (just within the 5% tolerance called for). Will this work, noting that I have a 250pF mica cap on order as backup? Thought of socketing both of the above in any case. Any advice gladly received. TIA.
Both of your substitutions are fine. Here's my reasoning. The main point for the 240/220 ohm resistor is that it's 1 watt, and you have those. 220R is close enough, it makes a low-pass filter with C42/C43 and protects the regulator. The 229/240 pF cap is within the specified 5% tolerance (most caps are +/- 20%) and is well above the minimum required to maintain oscillation, which is around 100 pF.
<edit> No need to socket the cap. If you have an inventory of random parts, you can parallel two or more caps and their values add, so your 229pF + 10 pF in parallel = 239 pF, if you had a 10 pF... but 229pF is fine for now. And DO NOT socket the resistor, it's carrying significant current which is why it's 1W, so you need a firmly soldered connection to the PCB.
Thanks @mauman. Appreciate the speedy reply.