Potato Cakes

Re: D-AOC PCBs - the building and help Thread
« Reply #1500 on: November 04, 2019, 12:26:27 AM »
Hello, everyone,

I found buried in the GDIY posts where someone offered a formula for doing stepped log pots. Since I am building a mastering version D-AOC, I thought I would repost that here with my findings for position values for 100k and 500k log on a 24 position switch.

First here is the formula:

(Position number/Total number of positions)^3.3 * Potentiometer Value

Here is what I found for resistance values per each step 1-24. The values represent the math and not the resistor values that fit within a decade, etc., so you'll have to figure out what is close enough based on what is available or what you have on hand, which is what I did. Also, I started with position 1 being whatever worked out in the formula, so if you want the first step to be shorted to the pole, then you'll have to decide if you want to follow the scale or make your own adjustment(s) to based on how you decide to do your switch layout. Now, on to the numbers....

100k:

1. 3
2. 25
3. 77
4. 166
5. 295
6. 468
7. 685
8. 952
9. 1269
10. 1638
11. 2061
12. 2541
13. 3078
14. 3673
15. 4328
16. 5046
17. 5826
18. 6670
19. 7580
20. 8554
21. 9597
22. 10207
23. 11888
24. 13137

500k:

1. 13.94
2. 123.36
3. 386
4. 828.7
5. 1472
6. 2330
7. 3418
8. 4746
9. 6327
10. 8169
11. 10281
12. 12670
13. 15347
14. 18317
15. 21587
16. 25164
17. 29053
18. 33263
19. 37795
20. 42659
21. 47857
22. 53397
23. 59280
24. 65516


I hope this helps.

Thanks!

Paul


 

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