Narcissism Posted October 5, 2008 Report Share Posted October 5, 2008 For about 3 years now, i've had a bass that i wanted to wire with 2 pickups, 2 volumes and 1 tone. I wired it up according to the EMG wiring diagram from their website, and there's a spot on the tone pot on the diagram that made no sense to me. So i just wired past it and delt with having only 2 volume knobs and a tone knob that didn't really do anything. Yesterday i decided "Hey, i want a tone knob damnit." So i got out a diagram and started wiring it up! Now, I've got it wired pretty gosh darn close to the wiring diagram... exactly on if i'm not mistaken. Here's my problem: The tone on the bass is on full trebel side now for both pickups. The volume knobs work properly as far as i can tell, but the tone knob is being... weird. It acts sort of like a volume knob only it'll... Okay, when its turned all the way in one direction, or all the way in the other, the volume is completely off. If you turn the tone knob to the middle, the volume is all the way up. Here's my wiring: The input jack is backwords from a normal input jack, so i believe i have it wired correctly. Any help is greatly appreciated! Quote Link to comment Share on other sites More sharing options...
psw Posted October 5, 2008 Report Share Posted October 5, 2008 Hmmm Firstly...this post should be in the electronics section if you want people who know to find it... Secondly...It is impossible to tell from your picture to tell if it is right without the original wiring diagram... Thirdly...your text is criptic and I don't think I understand at all what the symptoms are... ... The input jack is backwords from a normal input jack, so i believe i have it wired correctly. Okay, when its turned all the way in one direction, or all the way in the other, the volume is completely off. If you turn the tone knob to the middle, the volume is all the way up. Sounds like you wired the tine pot as a pan pot or something...I don't see any tone capacitor...but then none of the wires are labeled so they are all black and white to me... pete perhaps a passing mod could move this to the electronic section and you could link or post the wiring diagram... Hmmm...what I said over at the tools thread... Quote Link to comment Share on other sites More sharing options...
Narcissism Posted October 6, 2008 Author Report Share Posted October 6, 2008 Sorry about that... Here's the original wiring diagram Compared to my wiring: http://i172.photobucket.com/albums/w13/dar...ko/IMG_1016.jpg The only way i can describe how the tone pot works right now is to upload an audio file, and unfortunately i don't have a mic on the computer. Sorry about the cryptic writing, but I'm a little dyslexic, so its kind of hard for me to put into words what's going through my mind. Building a guitar is kinda like therapy for me. Lets see... Lets say ---------------+ would be the tone knob turned all the way up Lets say +-------------- would be the tone knob turned all the way down Lets say -------+-------- would be the tone knob turned half way up/down ---------+ puts out no sound through the amp +--------- puts out no sound through the amp -----+----- puts out sound as if the volume were turned all the way up. The two volume knobs work like normal volume pots would if you have the tone knob at ---------+--------- That ^ would be the output of the current configuration that i have wired up. The input jack i have is the original factory Ibanez jack, and the pins on it are backwords compared to a standard output jack... So that means: Pin 1 = Pin 3 Pin 2 = Pin 2 Pin 3 = Pin 1 I don't know if they're called pins, but i'm using the word pin, because that's what they're called in computers. They're the things that you solder things to that aren't the case of the pot... :D I'm pretty sure that everything else wired up the same as on the EMG diagram. It looks like the EMG diagram doesn't call for a cap, but there's something on the tone knob on the diagram that looks like it could be a cap, or it could be a blob of solder with 1 wire going to pin 1 and another wire going to pin 3, then the body of the pot... If none of this makes sense, i'm just going to shoot a youtube video and post a link to it, lol. Quote Link to comment Share on other sites More sharing options...
psw Posted October 6, 2008 Report Share Posted October 6, 2008 That "blob" is the capacitor...the only difference between a tone pot and a volume control. Because you have both sides of the pot joined to ground, you have the volume turned to zero (shorted to ground) at the extremes...half way, you are probably getting half output... Add a cap to the tone control and only the high frequencies will be shorted to ground...problem solved! pete Quote Link to comment Share on other sites More sharing options...
Narcissism Posted October 6, 2008 Author Report Share Posted October 6, 2008 should the cap not be connected to both pins (1, 3, ground) or should it just be connected to pin 1 and ground? Quote Link to comment Share on other sites More sharing options...
Narcissism Posted October 6, 2008 Author Report Share Posted October 6, 2008 Nevermind, i figured out what you meant! I have a tone knob now! Thank you very much psw! I really appreciate it. That cap/blob had me confused for the longest time. I think that's actually what got me in the spot i was earlier today when i had just two volume knobs. Thanks again! Quote Link to comment Share on other sites More sharing options...
psw Posted October 6, 2008 Report Share Posted October 6, 2008 should the cap not be connected to both pins (1, 3, ground) or should it just be connected to pin 1 and ground? No...see the tone pot bottom "tag" is not used...the cap goes from the other end to the back of the pot and so to ground through the black wire also connected to ground... The tone pot works by using the pot like this kind of ...it is a resistor that varies the amount of signal that goes to ground...the cap is like a filter that only passes the high frequencies and shorts them to ground. By wiring directly without the cap...you have made a volume control that sends all signals (not just the high frequencies) to ground...by connecting both ends you have made it short out at either end of the pots travel (like a kind of mixer thing) and halving the value in the process possibly affecting tone or output. The value of the pot will determine the frequencies that will go to ground...I am not sure what active EMG's might want, but it is probably pretty similar to passive bass values If you wire it as per the diagram it will work...if you don't...it will do something else...as you have discovered! pete Quote Link to comment Share on other sites More sharing options...
psw Posted October 6, 2008 Report Share Posted October 6, 2008 Ok...glad to hear it... Interestingly...the thing you accidently made is actually a cool control for mixing two pickups on a bass. My weird musicman like bass has a huge HB like pickup with 1/2" poles...there is a volume and tone and another control that mixes between on or other of the coils or full HB in the middle...kind of like your dual volume knobs. Similarly with two pickups you could arrange a mix between the two pickups and the other as a master volume...like a fender jazz bass. Sometimes it is good to have a master volume and such a mix control as a kind of variable pickup selector... Anyway...maybe a future mod...otherwise...glad I was of service! pete Quote Link to comment Share on other sites More sharing options...
Narcissism Posted October 6, 2008 Author Report Share Posted October 6, 2008 Gotcha, See, i didn't know that i'd have to alter the pot a little bit. I ended up having to take that top "tag" and unsolder it from the case, because that completed the ground. it came in the EMG pickup box like that. I learned a lot in this post! Well... I learend enough to play around and make some crazy sounds. Hey, is this like... an opening into making stomp boxes and fx processors? Quote Link to comment Share on other sites More sharing options...
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