Hi,
I'm building an Aquaboy deluxe delay but I can't find the bourns 25k trim pots for the Bias (I live in Holland and the companies that do have them charge €20 shipping fee). Is it possible to use an 50k pot and just use the bottom half range of this pot?
I hope to hear your thoughts on the alternatives. I hope that there are some because 20 euros shipping for 5 pots seems a little extreme ;)
Regards
Sander
Did you try Tayda? I don't think they have a 25k but a 20k should work. (or a 30k)
You can use 50k in a pinch. You could also use 20k, 22k. Maybe 10k, but I haven't tried it.
The down side of a 50k is it narrows the range a lot on dialing in the Bias and may prove more difficult to make minute adjustments (which can have a big effect on distortion levels). If you have trouble with the 50k, an you have an extra 47k resistor, you could tack the resistor on the bottom side of the board between pins 1 and 3 of the trimmer to half its value.
You could also try and source a 50k multi-turn to give yourself more biasing range.
I used a multi turn 22k trimpot for the bias http://www.newtone-online.nl/catalog/product_info.php?cPath=27_96&products_id=841 (http://www.newtone-online.nl/catalog/product_info.php?cPath=27_96&products_id=841). Works really well!