Capacitor Question ???

[METAL Rulez 4ever]

Hello all,

Happy New Year. I hope everyone and families had a safe and wonderful Christmas.

Just wondering, with Bass capacitors, if i want to modify my bass tone / sound, do i add a capacitor to a pot to turn the pot into a tone pot instead of a volume pot ? So any pot that has a capacitor is a tone control and without a capacitor is a volume control ?

Also too, which number capacitor should i use ? What do the numbers and color of a capacitor represent please ?

Regards,
Naim.

[Simon Barden]

A volume pot has all three of its connection tags used as it's being used as a potential divider. A tone pot has just two of its tags used as it's being used as a variable resistor and is used in series with a capacitor.

Capacitors normally have the value marked on them, so you just need to be able to understand what part of the writing is the value and what is the manufacturers' code. Occasionally capacitors do have values written in coloured bands like resistors do and here's a web site explaining those. http://www.electronics-tutorials.ws/...tor/cap_5.html

If you are referring to 'orange drop' capacitors, then these are just a range of good quality, reasonably high tolerance capacitors made by Sprague, that just happen to be bright orange and generally about the size of a small sweet. They have the capacitance values printed on them.

The value of capacitor you use partly depends on the pickups you are using and partly on how bright the pickups are. The higher the capacitance value, the more treble is taken from the signal at full tone reduction. Brighter pickups like jazz bass single coils might have a tone capacitor of between 0.047uF and 0.1uF (micro-Farads). A slightly duller pickup like a P-bass probably would stick with a 0.047uF capacitor. A passive MM type humbucker might be between 0.033uF and 0.047uF.

It's easy enough to Google what the standard capacitor value is for a particular type of bass, or look up wiring diagrams for them on say the Seymour Duncan site.

If you switch to active pickups/circuits, then the tone controls are generally active and it's all built-in. If not active tone controls, then again, look at the pickup manufacturer's wiring diagrams and they will give you their recommended values.

[METAL Rulez 4ever]

A volume pot has all three of its connection tags used as it's being used as a potential divider. A tone pot has just two of its tags used as it's being used as a variable resistor and is used in series with a capacitor.

Capacitors normally have the value marked on them, so you just need to be able to understand what part of the writing is the value and what is the manufacturers' code. Occasionally capacitors do have values written in coloured bands like resistors do and here's a web site explaining those. http://www.electronics-tutorials.ws/...tor/cap_5.html

If you are referring to 'orange drop' capacitors, then these are just a range of good quality, reasonably high tolerance capacitors made by Sprague, that just happen to be bright orange and generally about the size of a small sweet. They have the capacitance values printed on them.

The value of capacitor you use partly depends on the pickups you are using and partly on how bright the pickups are. The higher the capacitance value, the more treble is taken from the signal at full tone reduction. Brighter pickups like jazz bass single coils might have a tone capacitor of between 0.047uF and 0.1uF (micro-Farads). A slightly duller pickup like a P-bass probably would stick with a 0.047uF capacitor. A passive MM type humbucker might be between 0.033uF and 0.047uF.

It's easy enough to Google what the standard capacitor value is for a particular type of bass, or look up wiring diagrams for them on say the Seymour Duncan site.

If you switch to active pickups/circuits, then the tone controls are generally active and it's all built-in. If not active tone controls, then again, look at the pickup manufacturer's wiring diagrams and they will give you their recommended values.

Thank you Simon for all your info. Very helpful indeed. I will get onto this research and do my homework.

I just purchased this bass with a P style passives on Ebay and it sounds terrible. Gotta crank the amp to hear it, no bass, all treble and heaps of amp noise. Not even the tuner is picking up the strings to tune it. So its either the pick ups or the tone pot with the cap. This bass is supposed to have 1 volume and 1 tone, but the tone pot cuts out the volume instead ! So i reckon thats my problem. I wanna replace the pot and cap and replace it with my own combination of A500K pot and .33 cap.

[WeirdBits]

Post some photos of the current wiring and we may be able to spot the issue(s). It sounds more like mis-wiring than just a tone pot problem, but it could be a couple of things.

[Simon Barden]

Yes, sounds very much like a wiring problem or a faulty pickup. If there's hardly any output from the pickup, then the tone control will knock off most of the mid and treble from it, and it will certainly reduce the volume to almost nothing.

[METAL Rulez 4ever]

Post some photos of the current wiring and we may be able to spot the issue(s). It sounds more like mis-wiring than just a tone pot problem, but it could be a couple of things.

Here are the pics WeirdBits and Simon. Thank you for your help so far, much appreciated.

[METAL Rulez 4ever]

Yes, sounds very much like a wiring problem or a faulty pickup. If there's hardly any output from the pickup, then the tone control will knock off most of the mid and treble from it, and it will certainly reduce the volume to almost nothing.

Here are the pics WeirdBits and Simon. Thank you for your help so far, much appreciated

[Simon Barden]

Is it possible to take another picture (maybe more from the side) with the wiring moved so that it's easier to follow what's connected to what? With several black cables sitting on top of one another, it's not easy to follow the wiring with 100% confidence.

Also, if you can take a photo of the wiring on to the jack socket, that would be helpful.

Cheers.

[METAL Rulez 4ever]

I finally fixed the problem Simon. It was the pick ups that were faulty. I first replaced the cap, but that did not fix the problem, so i changed the pot, still not fixed, so i replaced the pick ups with a spare i had and now the bass plays beautifully. I replaced the original pot and cap, and still works fine. I wanted to know the exact problem, wasnt sure if it was the pot or / and cap or / and pick up. so it was just a faulty pick up. So i learnt a lot from this experience, helped me to finally study on different pots and caps. But i am confused...How can the pick ups still work thru the volume pot but not the tone pot ? Pick ups still gave sound, even though they were faulty ???

[Simon Barden]

With the volume control, the full-range of the signal is being attenuated as you would expect.

If you look at the wiring, the connection to the tone pot is made from the connection on the volume pot that also connects to the pickup output. So if you use the tone pot, some of that signal is going down to earth via the tone capacitor. Because it's the resistance of the pickup that forms the actual R part of the RC tone circuit, and there's obviously something wrong with the pickup, the low-pass circuit cut-off frequency is affected and probably all (not just the high frequency part) of the signal is passing to ground through the tone circuit. Because the tone pot is normally selected as a linear pot, then unlike the log/audio taper volume pot, it doesn't take much turning to significantly lower the pot resistance.