Waddycall Posted September 30, 2019 Share Posted September 30, 2019 I need to replace the blend pot in my Ibanez sr1820 which I took delivery of at the weekend. I’m having difficulty sourcing a genuine spare so now looking for an alternative. The original pot is AC500K. Can this be replaced with a Bourn MN taper pot? The bass is both active and passive. I’ve been doing some research but the more I find out the more my head spins! I’m handy with a soldering iron so no probs there. Just need to know what part to fit as I can’t find an AC taper pot. cheers Quote Link to comment Share on other sites More sharing options...
itu Posted September 30, 2019 Share Posted September 30, 2019 I would use that MN taper. It was my other option but turned to active mixing, so to Noll Mixpot. 1 Quote Link to comment Share on other sites More sharing options...
Hellzero Posted September 30, 2019 Share Posted September 30, 2019 This is what you need : https://www.banzaimusic.com/Partsland-BLEND-500K-AC.html 1 Quote Link to comment Share on other sites More sharing options...
BassBunny Posted October 1, 2019 Share Posted October 1, 2019 If you want a genuine Ibanez replacement, https://www.meinlshop.de/en/ibanez/spare-parts/e-guitars/potentiometers/ibanez-potentiometer-ac500k-3vr3pc0004 If in the UK just Google "AC500K Blend Pot" and loads of options come up. I'd go for a CTS or Bourns one personally. 2 Quote Link to comment Share on other sites More sharing options...
Waddycall Posted October 2, 2019 Author Share Posted October 2, 2019 Thanks for the suggestions. Ive managed to order a genuine spare through Mansons. I only need to wait until 2020 to receive it 😳. I’ve also ordered the Bourn MN taper pot which arrived today. Stupidly when I was looking for pots I didn’t notice that the one on the bass (which is mounted in a small PCB) has 8 terminals as it’s centre tapped. I can only find 6 terminal ones online and the Pot that’s arrived has 6 terminals. Ive been trying to trace the tracks on the PCB to figure out what’s going on but I’m out of my depth. There is a small capacitor (I think) bleeding some signal to ground from the output but I can’t work out why. The bass has passive tone control but I can’t believe it’s for that as it’s nowhere near the treble/tone pot. The output from the balance pot goes to the volume pot - a hot and a ground. im hoping that I can basically remove the old pot and it’s pcb and connect the pickups and output to the new 6 terminal pot but that would eliminate the capacitor. does anyone know what the capacitor does or if what I’m planning seems feasible? I’m keen to get this bass working. cheers Quote Link to comment Share on other sites More sharing options...
itu Posted October 3, 2019 Share Posted October 3, 2019 Is the 4th terminal simply ground? Quote Link to comment Share on other sites More sharing options...
Hellzero Posted October 3, 2019 Share Posted October 3, 2019 Looks like that, indeed. Quote Link to comment Share on other sites More sharing options...
Waddycall Posted October 3, 2019 Author Share Posted October 3, 2019 (edited) The fourth terminal is a centre tap on the resistive track so I’m assuming gives a 250k resistance. The output seems to come from these joined together. Terminal 1 of the upper track goes to ground and terminal 3 of the lower track goes to ground. Seems to make some sense but what I don’t understand is what the capacitor does. badly drawn diagram - Edited October 3, 2019 by Waddycall Quote Link to comment Share on other sites More sharing options...
Andyjr1515 Posted October 3, 2019 Share Posted October 3, 2019 If the capacitor is where you show it on your diagram, it looks to me like it is just bleeding some treble off at all settings. 1 Quote Link to comment Share on other sites More sharing options...
Waddycall Posted October 4, 2019 Author Share Posted October 4, 2019 20 hours ago, Andyjr1515 said: If the capacitor is where you show it on your diagram, it looks to me like it is just bleeding some treble off at all settings. Yep, that’s makes sense. I’m sure that’s where the cap is. Not sure the pot is connected up quite like my diagram as it seems both pickups could end up being off. i think I’ll just disconnect it and try the bourns pot and see what happens. Don’t think I’ll blow anything in the process. Quote Link to comment Share on other sites More sharing options...
Waddycall Posted October 5, 2019 Author Share Posted October 5, 2019 Well ive fitted the bourns pot as per an Aguilar OBP diagram for MN taper blend pots and it works, sort of! in active mode it’s absolutely fine although there’s is a bit of a jump in tone once moved from centre towards the bridge. It’s not too bad so can live with that. The other difference is lack of treble control in passive mode. The treble control now acts as a second volume pot. still it’s now useable at least and I think I can live with it until the ibanez part arrives in the new year. its a bit of a lash up as I wasn’t sure it would work. As it’s temporary it can stay that way! cheers Quote Link to comment Share on other sites More sharing options...
Waddycall Posted October 5, 2019 Author Share Posted October 5, 2019 Forget the bit about the passive tone control not working. It’s fine. Not sure what I was thinking there. Quote Link to comment Share on other sites More sharing options...
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