Paul Marossy

Sounds like a case of a cold solder joint. Interesting that it can have that effect. I will store that one in long term memory. Yeah, that makes life much easier. Live and learn, eh?

Oh boy, I know the type. Good luck with it. I hope you have something nice to show us when you get done with it.

Shielding it will probably do the trick, but there are instances of guitar effects which are shielded picking up radio stations, so I guess also adding that cap would be a good back up measure against it. Let us know what your results are!

Yeah, if you have the pole pieces of the pickup too close to the strings, you can get "stratitis". Read this page and see if it applies at all - http://www.riograndepickups.com/faq.htm

Yeah, looks like a frankenjazz bass to me. It looks like it could be turned into a decent instrument with some work. The body could be refinished and it might actually look good when it's done.

You can usually get rid of RFI by adding a 47pF-100pF cap to ground on the input of the offending circuit.

I thought of that, too. That would definitely make it act like a second volume control while doing nothing as a tone control.

Sounds like a mangled Jazz Bass if it has a Telecaster Bass pickgaurd and wiring that looks like that.

Yep, that's exactly my thoughts on it, too.

It looks to me like it's a guitar that has only a volume control and a 3-way pickup switch. No tone control. It might have a push-pull volume pot for coil tapping. About all you could do to that to make it any more versatile is to add a tone control.

You can break the ground connection on the cable connecting your guitar to the amp and the amp will still pick up the signal from the guitar, but you may have some noise problems because the signal ground is now "floating". The ground in this case is really more of a way of shielding from extraneous noise and safety thing. It does help the amp with a reference to ground as far as the signal is concerned - it's not absolutely necessary, but optimal.

Electric guitar pickups are really nothing more than specialized microphones that use a type of transducer that senses the movement and frequency of the guitar strings and converts that to an electrical impulse rather than the type of transducer that you would find in a hand held microphone, which picks up actual sound. Neither of them have the amplifier sending current thru them. They both send very weak signals to an amplification system which has to amplify them quite a bit to be useful. Open systems vs closed systems is really more applicable to pumps and that sort of thing. Every circuit is a "closed system", if you will. If you leave out a piece of the circuit out, then it won't work. It's basically a loop. If you connect one terminal of a light bulb to the postive on a battery but don't connect the other terminal to the negative on the battery, nothing will happen. In the case of the electric guitar, it is sort of an "open system" in the sense that the hot signal gets sent to the amplifier, but the amplifier doesn't need to close the loop, it just takes what is feed to the input and amplifies it. If the loop is open in the amp, then it will try to close it and complete the circuit by using your guitar to send current thru, which means that YOU become the path to ground, which is potentially fatal. The ground on the guitar serves a few purposes - it is there for safety and it also gives the amplifier a reference to ground, which it needs because it is being fed with an alternating current from the guitar pickup(s) and it helps control unwanted noise by shunting it to ground (EMI & RFI). Using hydraulic terminology, it's sort of like a side arm chemical feed to a closed loop pumping system. Or here is another roughly similar analogy: think of the power section of an amp as a closed loop piping system connected to one side of a heat exchanger. The heat exchanger is the interface between the guitar and the amp, we'll call it the preamp. The other side of the heat exchanger is connected to the open loop pumping system, the guitar. If the heat exchanger were to fail because it ruptured internally, then the two flows would mix and both systems would then be experiencing a massive failure. Does that make sense?

Active EMG pickups are low impedance types. You don't have to worry about cable lengths and stuff like that much with them. And because they are low impedance with a preamp, they are much less susceptible to noise. http://www.emginc.com/pages/whyemg Regular passive pickups are high impedance and pickup noise quite easily in comparison.

That's 100% correct. The pickups sense the movement of the strings, and a small electrical current is generated as a result. The pickup outputs a weak signal which the amplifier then amplifies quite a lot to make it useful. If an amp is feeding the guitar current, then something is very wrong with the amplifier and it is a potentially deadly situation. The jack on a guitar is always an output jack, signal and currentwise.

If you had the pots switched around, it wouldn't cause that problem. It's either a grounding problem or maybe due to reversed wires on your output jack. Or possibly a defective pot. That's rare, but it can happen.

Do you have active pickups? It sounds like you might have DC (direct current) on the pot somehow and/or a bad connection to ground. Look for a "cold solder joint" on your volume control connection to ground.

Just for the record, it's an output jack not an input jack. The signal goes from your guitar out of the jack and to your amp. It's not receiving a signal from something else and into the guitar.

I see. I have no experience with a DIY sustainer, so I'll leave that to your expertise since you are the master.

I don't think it should be a problem. When you have a string of guitar pedals connected to your guitar, they are all sharing a common ground whether they are powered with batteries or a DC power supply. Having on onboard distortion is not really any different that having it connected to your guitar externally. It's just in the guitar instead of a pedal on the floor. And the grounds of all these devices are connected together thru cables and patch cords. Both the sustainer and the distortion circuit have seperate power supplies in terms of the +9V connections.

This is how I would wire that: 1. Provide each circuit with its own 9V battery. The sustainer will use batteries far quicker than the distortion circuit will. 2. Use a stereo jack to switch the power for both circuits. 3. Wire the distortion circuit between the hot wire from your pickup switch and the jack. If you want to true bypass the distortion circuit, you'll need a DPDT switch. This really is not any different than having your sustainer guitar going thru a distortion pedal and then on to something else. The distortion pedal is just in your guitar now.

Yes, very true. The really cheap pickups might sound alright (maybe) but they often hum badly (the single coils) and they very often are also not even potted, which means you'll have lots of feedback problems with any high gain pedals and/or amps. Unless, of course, that is what you want.

That's what I was trying to figure out. Yeah, if it's an arrangement where it excites the strings, this would be good. Not so good if it just sounds like an amp feeding back. Hard to control and not necessarily musical sounding. Having had a Fernandes Sustainer in one of my guitars for a couple of weeks now, I can say that they have the harmonic mode figured out pretty well. You can actually do something musical with that. And the sustain mode works very nicely, it will hold a note until the battery dies. I looked up the patent for this one just for fun - it's 50 pages long!

So if you play a chord and let it ring, it sounds like you have a Ebow on all six strings? Or does it sound like an amp that is feeding back? I'll assume that it's working on the principle of electro-magnetic feedback since there is no speaker involved.

Yeah, true. I have found that you just need a powerful enough soldering iron so you don't have to heat it for two minutes to get it hot enough for the solder to flow.

Ah, I hadn't thought of that. That could be what's happening with the pot that I have.