Variable hi-pass/bandpass filter Continued...

[bufftonz]

I also forgot to ask, so where exactly does the middle lug of the variable pot go to?

Also can the variable pot be 50k, or does it have to exactly be 47k? I could not find any 47k pots at two local electronic shops, the closest values I found were the 50K. Would 50k be alright?


                                        R1                    C1
(input from IC chip)---------/\/\/\-------------|(----------------------------> (to middle lug of Repeat control pot)
                                         20k       |         .1uF                     |
                                                      |                                    |
                                                      |                                    |
                                                      |                                    |
                                                      |         R2         ? C2 ?    |
                                                       -----/\/\/\---------|(------
                                                          47K VAR       0.47uF
                                                                |
                                                                |
                                                                V
                                                                ?


--Chris

[ollie]

For the value of the pot, I would assume there will be a tolerance - say 5%. That gives you approximately 2K5Ohms room which, at the lowest end, is 47K5. I shouldn't think it'd have that much difference at all

For the pot, I'm sure you only need to use 2 lugs if it's going there in you circuit, have the middle connected to the signal going in and the right as the signal out. (May need someone to confirm this bit as it's true for trim pots but I'm not 100% sure in this case)

[alanlan]

Connect one wire to the wiper (middle lug usually) and the other wire to one end of the pot.  You can connect the other end of the pot to the wiper:

|                                                      |
|                                                      |
----------------/\/\/\/-------------|(-------
                |     ^
                |      |
                ------

I didn't specifically suggest 47K in the first place - it's just a guess.  Experiment with different values to get what you want.  If you're up to it, you can calculate the best pot and cap values but i don't think you'll be very far out with the suggested values.

[bufftonz]

Cool! I'll give it a try!

Right now I'm in the process of finding a best-fit shape for the tone-apparatus to be added to the main delay circuit, so far the measurements look good. Now it's just a matter of experimentation/trial-n-error, etc.  Many thanks.

--Chris