Double Bass Need a potentiometer

[Upright4]

I got this bass about twenty years ago from the original owner, who told me he bought it in the 70's in Los Angeles. There was mention of it in an old issue of Bass Player Magazine as the "Barcus Berry Arco Bass." The piezo pickup is a small strip embedded in the E string side of the bridge. The bass came with a small Barcus Berry outboard preamp, which didn't work. I've always plugged straight into my GK MB150S.

The volume control (potentiometer) has been damaged, and I need a replacement. On the pot is printed AB (in an octangular outline), TYPE W, WA4G032P205RA, 2.0 MEG. The body of the pot is about 1/2" across and the connectors the wires are soldered to point straight down from the bottom of the pot. It must be this size and style so it will fit through the opening in the body of the bass.

Between the piezo and the volume pot are a resistor, bands red, red, yellow, gold, and a ceramic capacitor, printed 25U, 120M, 1KV.

I have searched the internet and emailed a few sellers of electronic components, but have come up with nothing. Could anyone here have a potentiometer like this, or an equivalent?

Any info much appreciated.

 

[fdeck]

I don't frequent the EUB forum, but saw your thread title. Any 2-megohm audio taper pot will work. The only caveat is that the 1/2 inch diameter might rule out some larger pots. It might be worth measuring the hole in the control cavity.

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Do you need the volume control? You could wire the pickup directly to the output jack, in which case you'd at least have a playable bass while you look for a pot. You might get better sound, because a 2-meg pot isn't doing you any favors. It will make your sound dependent on the capacitance of your signal cable.

 

[fdeck]

Just a tiny bit more info, AB is Allen Bradley. Very high valued audio taper pots are somewhat of an oddity.

 

[Upright4]

Thank you for your reply.

I've spent hours searching the internet and haven't found a pot like this. The opening in the front of the bass is just over 1/2", so I need this kind of pot, which I have learned is "RV6."

Most sites/forums I've read state that audio pots are used for volume controls and that linear are not suitable. But I found two people, one quite knowledgeable in this field and the other through extensive A/Bing, who prefer linear pots for volume control.

I did find a linear 2 meg, RV6 pot. I'm going to give it a try. Having a volume control on the front of the bass is so convenient that I'd hate to give it up. But if this linear one doesn't work out, I'll be following your suggestion to go without a volume pot.

Thanks again.

 

[fdeck]

The linear one will definitely function, but its "curve" just might not be optimal. You might find that it's rather touchy in the last few degrees of rotation. But it will certainly get you back in business.

 

[drurb]

The linear one will definitely function, but its "curve" just might not be optimal. You might find that it's rather touchy in the last few degrees of rotation. But it will certainly get you back in business.

+1. The linear taper will work but you probably won't like it much.

 

[fdeck]

The OP could also use a 500k audio taper pot and put a 0.01 uF capacitor in parallel with the pickup. This might reduce the overall volume, which could be corrected by turning up the amp, but it would broaden the availability of pots.

 

[Upright4]

I put in the linear pot and, turns out, its not much different than the original one. The new pot begins raising the the volume quicker, but increases it evenly all the way up - works fine.

Thanks for the input.