Replacement pot for PQ-4 Parametric EQ?

[sirlemonhead]

Hi everyone!

I managed to get a PQ-4 for cheap but one of the dual pots is bend slightly. It's the leftmost Presence/Low one - it still works fine but it's a little awkward to use as a result - turning the outer ring will make the inner ring move too at certain points.

Is this pot something that exists in another pedal I could maybe source much cheaper, for a replacement, such as an MT-2? I can solder and desolder things no problem so if I could fix this relatively cheaply, it'd be great!

I don't want to try bend the shaft back straight for fear of properly breaking it, unless there's a way I can do this safely? perhaps by taking the pot apart first? Any advice appreciated

[chromandre]

theres a PQ-4 schematic floating around that says its dual gang 100kW unfortunately the MT-2 dual pot is dualgang 50kC. I'm not sure where to find these pots exactly but I also gotta mention I've never had success bending a pot back to normal I would just wait until you find the pot

[Pepe]

I once had a PQ-4 with a broken potentiometer and it wasn't easy to find a replacement part. I believe it was exactly this potentiometer as well. I think it has an additional solder pin for some reason. I ended up using a potentiometer without that and it worked fine. I also did 1:1 comparisons with my other exemplar (that I still have) and if I remember correctly there was no real difference between the two.

If I were you I would try to bend it back carefully. Maybe with a screwdriver that takes bits - remove the bit, so you have a nut. Use that to bend it back in several tiny steps. That might be the easiest solution.

There is NO way to take the potentiometer apart. It is one of the small and closed ones and it is riveted. I believe you will break it if you try to open it.

[laurie]

I don't want to try bend the shaft back straight for fear of properly breaking it, unless there's a way I can do this safely? perhaps by taking the pot apart first? Any advice appreciated

I've straightened these shafts in the past by careful bending. Not good odds though... Its about 50/50 whether the straightening works, or if the shaft breaks.

The only source for these is Roland direct, and that's what I would do if faced with this. Here in Canada they are pretty good if you call and talk to their service department. Not sure about other countries.

[Pepe]

I just did a small research on my external HD. I had the broken PQ-4 in 2017 and I bought exactly this potentiometer as a replacement:


https://www.banzaimusic.com/Alpha-9-PC- ... k-lin.html

As said, it has one (or two?) pins missing that are on the original potentiometer, but I didn't notice a difference.

[sirlemonhead]

Thank you for the suggestions! I'll go with the banzaimusic pot as that seems the easiest solution as I'm based in the EU too.

[Pepe]

Do you have a photo of the original part? I'd really like to be sure that I recommended the right replacement part.

[sirlemonhead]

hope these are useful!

https://www.dropbox.com/s/e3w2gm4nnyk8r0t/pq4_pot_1.jpg
https://www.dropbox.com/s/r7nnxap9trncrja/pq4_pot_2.jpg
https://www.dropbox.com/s/whybv535qnd2etv/pq4_pot_3.jpg

[Pepe]

Yes, that was the potentiometer that I replaced with the one from BanzaiMusic. As said, I didn't notice a difference in sound, although a few solder pins are missing that cause an interaction of the volume or brightness or whatever.