Help me to find a new potentiometer for broken audio mixer EQ pot.

[Rodhex]

Hello guys.
I have a mixer with some eq potentiometers broken (their shaft is plastic), i want to replace them for new ones but I don't understand their part number yet, i mean i know it is a 30MM (shaft) with Center Detent potentiometer but what about the rest specs/code? . This is a screenshot of its service manual. Thanks.


PS. I'm not sure if this post is ok in this forum section.

[knockman]

That service manual scan looks like it could be a Phonic mixer? If so, the part numbers may not mean much other than to Phonic themselves?

The only thing I can add to what you've already stated here is that they appear to be 50kΩ linear taper pots based on the specification "50KB".

Have you removed the damaged ones? If it's just the shaft that's broken and the actual pot still functions, perhaps checking them with a multi-meter could confirm the spec - as well as checking the physical dimensions. Are they panel mount or PCB mounted? Either way, you could probably source identically spec'd replacements from various sources.

[Rodhex]

Yes knockman, it's a Phonic. The 2 eq pots (MID and Low) still work, i put some audio in the channel, then i used a tweezer to rotate the 2 eqs and the sound is ok.
I opened the mixer and wow man, it's not gonna be easy to take apart all that pcbs to be able to measure adequately all the parts of those damaged pots. Anyway, I did took some physical dimensions of the pots and it wasn't easy at all. See some pics of the mixer (marked in orange the 2 damaged pots). Thank you for your reply Knockman.

Potentiometers croquis.


Side view.


Wow, 2 pcbs, one over the other.


These 2 pcbs are connected each other with a lot of soldered cables (red area).

PS: i have the broken parts and the caps but i wanna try to replace the pots instead of repair their shafts.

[Rodhex]

The only thing I can add to what you've already stated here is that they appear to be 50kΩ linear taper pots based on the specification "50KB". .....you could probably source identically spec'd replacements from various sources.

I think i'll buy this but its height is 25MM and I'm not sure yet if its taper should be Audio or Linear, the one i found is taper Audio. The 2 broken encoders to be replaced (i hope) are for EQ Gain, ie when they are at 12 o'clock there's no tone variance, when full right (5 o'clock) there's a 15db gain increment and viceversa (-15db when 7 oclock). Thanks knockman.

[mystran]

The "50KB" almost certainly means "50k with B-taper" which would be linear. In general, these usually make the most sense in circuit in any circuit where you actually care for any sort of precision.

The "audio" taper is basically some sort of approximation of a logarithmic curve, such that if you wire the pot as a volume control directly you're supposed to get something sensible. That's roughly as exact as you're going to get with these pots, but that doesn't really matter here, because you really can't use them in place of a linear one (at least if you expect the pot to behave correctly).