I just grabbed an Ibanez SRX550 model bass on eBay.
Here's the model: http://www.zzounds.com/item--IBASRX550
It's missing the knob furthest from the bridge closest to the neck... Guessing that's volume?
Could someone please help me identify what the actual part is and where it can be ordered? http://ibanez.com/parts/2004_PARTS/e...dex_parts.html