telemaster Posted March 18, 2007 Report Share Posted March 18, 2007 OK, second post here, and I hope I get a response this time... I have now wired up my custom telecaster with 1. a volume, 2. pickup balance blend and 3. a No Load Tone. Its works fine, however... The problem is, that when I sweep the balance pot towards the neck pickup (Seymour Duncan STK-T1n), there seems to be a distinct "low volume" point midway between the balance blend pot halfway mark (equal bridge and neck pickup blend) and the full neck position (no bridge pickup in the blend). Once the balance blend pot is fully towards the neck pickup , the volume is fine. The volume of the blend sweeping towards the bridge pickup does not appear to drop in volume like it does sweeping towards the neck pickup. N>>>>>(drop)<<<<<<N+B===============B Q. Why is it doing this? is it normal, or does it need a fix? Any help would be gratefully appreciated. Quote Link to comment Share on other sites More sharing options...
curtisa Posted March 19, 2007 Report Share Posted March 19, 2007 Neck pickup is out-of-phase with the bridge? Balance pot is too low value? Got a schematic handy? Quote Link to comment Share on other sites More sharing options...
telemaster Posted March 19, 2007 Author Report Share Posted March 19, 2007 Neck pickup is out-of-phase with the bridge? Balance pot is too low value? Got a schematic handy? Please excuse my poor schematic but this is what I have done. http://img256.imageshack.us/img256/4124/te...nceblendvr9.gif Quote Link to comment Share on other sites More sharing options...
curtisa Posted March 19, 2007 Report Share Posted March 19, 2007 I think you have the balance pot wired up funny. With the pot in mid rotation you'll have half the total resistance of the pot in series with each pickup, which will cause the drop in volume you're experiencing. I think the proper way to do it is to shunt each pickup's output to ground, not to add more resistance in series with them, kinda like the volume control, plus you'll need "tapering" resistors around the balance pot to get a good blending characteristic. I'll have a think about it, don't have much time at the moment, hang tight in the meantime Quote Link to comment Share on other sites More sharing options...
telemaster Posted March 19, 2007 Author Report Share Posted March 19, 2007 Ok, I'll hang tight. I'm certainly looking forward to your ideas. Thanks again for your help so far! Quote Link to comment Share on other sites More sharing options...
telemaster Posted March 20, 2007 Author Report Share Posted March 20, 2007 Hopefully the URL is fixed now. Sorry about that! Quote Link to comment Share on other sites More sharing options...
jnewman Posted March 20, 2007 Report Share Posted March 20, 2007 (edited) Stewmac has a wiring diagram for the blend pots. It looks like you're missing one thing. You have the bottom left lug going to "output", and on the stewmac diagram the bottom right lug should be going to ground. Your schematic is missing this connection to ground. Edited March 20, 2007 by jnewman Quote Link to comment Share on other sites More sharing options...
curtisa Posted March 20, 2007 Report Share Posted March 20, 2007 Ahhhh yes, he's right Check out http://www.stewmac.com/freeinfo/i-4137.html for the whole story. Quote Link to comment Share on other sites More sharing options...
telemaster Posted March 20, 2007 Author Report Share Posted March 20, 2007 Ok thanks guys, I'll get on to it tonight and let you know how I go. I really appreciate your input! Quote Link to comment Share on other sites More sharing options...
telemaster Posted March 20, 2007 Author Report Share Posted March 20, 2007 Ok thanks guys, I'll get on to it tonight and let you know how I go. I really appreciate your input! Sorry guys, no luck, I've grounded the balance pot as per the StewMac schematic andI still have the same issue. Onward and upward. It may just be an inherent problem without going active. I believe EMG have some great solutions in their bass accessories... Quote Link to comment Share on other sites More sharing options...
Saber Posted March 20, 2007 Report Share Posted March 20, 2007 You might have the wrong type of pot. Your problem sounds similar to this guy's. http://www.talkbass.com/forum/showthread.php?t=303190 Quote Link to comment Share on other sites More sharing options...
telemaster Posted March 20, 2007 Author Report Share Posted March 20, 2007 That is certainly an interesting angle Saber, I'll have to investigate whther I have the wrong type of blend pot... in fact mine came from StewMac also!! Quote Link to comment Share on other sites More sharing options...
davee5 Posted March 20, 2007 Report Share Posted March 20, 2007 I have a very similar issue with the one I just installed myself. I did some digging and it seems this can also be the result of using the wrong leads for in & out. This seems logical to me now since the audio/log taper of the pots would not be terribly friendly to being used backwards. This also seems logical because I wired ALL my pots backwards. Tonight I hope to rewire them and I'll let you knkow if reversing the blend output/input leads helps. -Dave Quote Link to comment Share on other sites More sharing options...
curtisa Posted March 20, 2007 Report Share Posted March 20, 2007 The pot really needs to be a dual log/antilog type to get the correct feel out of it. You'll have a hard time trying to find one at a reasonable cost. The next best thing will be a dual linear pot with tapering resistors around it. After that you may get acceptable results just using a linear pot with no resistors, but you'll probably still end up with the same volume drop problem you're already experiencing. Just check to make sure you've got the right pot from Stewmac - use an ohmmeter, set the pot to mid rotation, and measure the middle lug to either outside lug of each element . If it's linear taper you'll have half the total resistance between middle and outside for both elements. If it's dual log you'll have about 60% across one side and 30% across the other for both elements. If it's dual log/antilog you'll have 60/30 on one element and 30/60 on the other. Basically the dual log/antilog pot will work exactly as you've drawn that diagram (with the earth of course), the dual linear pot will need the tapering resistors, and the dual log pot will never work in this application. I have a wiring diagram at home for a blend control using a dual linear taper pot and the additional tapering resistors. I'll see if I can dig it out tonight. Quote Link to comment Share on other sites More sharing options...
telemaster Posted March 20, 2007 Author Report Share Posted March 20, 2007 Thank you Curtisa, I'm looking forward to that diagram, and your reasoning re: the taper is good news. Quote Link to comment Share on other sites More sharing options...
curtisa Posted March 22, 2007 Report Share Posted March 22, 2007 Hi Telemaster, Here's the blend pot modification I've found. Basically it's exactly the same as yours except for the addition of the tapering resistors across each input of the blend pot: http://i153.photobucket.com/albums/s222/ac1176/blendpot.gif All the rest of the diagram has been omitted for clarity - it should just substitute straight in as is. The pot has to be a linear taper type. Cheers, Curtis. Quote Link to comment Share on other sites More sharing options...
Jasperfish Posted March 23, 2007 Report Share Posted March 23, 2007 Funny enough I have a custom Tele with vol, tone, and blend pot (only just been finished). Mine works pretty well apart from the trouble I'm having setting up the action. I have linked my wiring schematic, apologies for the bad drawinf but it was by hand on a PC (if that makes sense). http://www.jasperfish.co.uk/guitar_bulid/t...om_wirogram.jpg Quote Link to comment Share on other sites More sharing options...
jnewman Posted March 23, 2007 Report Share Posted March 23, 2007 One comment on your schematic: there's no reason to have two wires going from the blend pot to the volume pot. You only need one. Quote Link to comment Share on other sites More sharing options...
telemaster Posted March 23, 2007 Author Report Share Posted March 23, 2007 Thanks, I'll give it a try! I post back if I have any success. Quote Link to comment Share on other sites More sharing options...
telemaster Posted March 25, 2007 Author Report Share Posted March 25, 2007 jasperfish..do you have a volume drop between the Neck and Bridge+Neck positions? Your diagram looks very similar to what I have already?? Quote Link to comment Share on other sites More sharing options...
venominox Posted March 25, 2007 Report Share Posted March 25, 2007 My question is: Is the potentiometer linear (proportional phenolic wafer) or logarithmic (gradual)? Quote Link to comment Share on other sites More sharing options...
Jasperfish Posted March 26, 2007 Report Share Posted March 26, 2007 (edited) I have little or no drop in the blend pot centre position. I'm afraid I have no idea what kind of blend pot it is. Sorry. Edited March 26, 2007 by Jasperfish Quote Link to comment Share on other sites More sharing options...
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