Primal

If you got your transistor reversed, you may have fried it. You did buy multiple components, right? You should definately try a new one. As for biasing, you did have the + and - power hooked up to the circuit, right? No, resistors are not polarized. Their directions makes no difference. Update on my sustainer project: Got it finished today! And man its smokin' (in a good way)! I got my distortion problem sorted out, which also sorted out the sqealing. I ended up putting a 1K trim pot between pins 1 and 8 on the opamp and adjusted it to the point just below where it starts squealing and distorting. Now the sustainer works perfectly in both fundamental and harmonic mode. Swing on over to the tutorials section. I just posted my sustainer project pics there.

Dezz, make sure that you have the multimeter set to the right voltage setting. Mine has a setting for various voltages. If it's set too high, it won't register anything. Also, if you have the ground messed up on the other side of the transistor, there will be nowhere for the electrons to flow to and thus no voltage.

You would have to build some sort of converter to convert the input signal to squar waves. Not very practical, in my opinion.

Square waves..? Could you perhaps be talking about clipping, i.e. distortion? Clipping is where the amplitude of the signal gets too large and the top of the wave gets "clipped" off, thus producing a wave the looks like the top has just been leveled off.

Yes, I'm getting sustain, and even though the driver doesn't work perfectly, I can still get some pretty cool sounds happening, so it was worth the mod already. I'm going to try building the amp again and do some more tweaking. The first thing I want to try is disconnecting the single coil pickup that is right beside my driver to see if that helps any. I wish I was able to record the distortion I am getting, but my amp is way too far away from my computer, and there is no room for an amp next to my computer.

One point to take note of though, at least with my Epiphone, the solder used on the factory electronics takes a LOT of heat to melt. I had to use a high wattage soldering gun over my soldering iron, and I still had a LOT of trouble.

The guitar and the circuit share the same ground. Otherwise, you wouldn't be able to get the signal from the pickups to the driver amp. The best way to do it, I believe, is to have a ground on the circuit bored, then run a wire from the circuit ground to guitar ground.

1. The other lead will go to ground. As for the input from the pickup, I've found it easy to keep the wiring intact and just solder a wire going to the circuit from the guitar's common ground (i.e. the back of one of the pots) and the terminal on the pot where the pickup connects to it. 2. The coil contacting the metal core would have absolutely no affect on the coil itself. You should definately follow Pete's instructions for making a driver, though. I used a pickup bobbin for mine, and I'm having a few problems getting mine to work well. I haven't figured out if its my coil or my circuit yet (I've got some distortion problems that I need to work out).

My fault, I was looking at a reference page for a bipolar transistor, not a JFET. But yes, the base is the gate, collector is drain, and emitter is source. For further reference: http://encyclobeamia.solarbotics.net/articles/symbols.html As for the potentiometer, the sweeper for the 100k trim pot is directly connected to one of the other terminals, depending on which way the pot is oriented. In the case of the volume control, the sweeper is connected to pin 2 of the opamp.

1. If you look at the capacitor, it should have a blue stripe down the side with a - symbol. That is the negative side. 2. The middle terminal, i.e. the sweeper, is the on that has the arrow pointing to the resistor symbol in the potentiometer symbol (make sense?). 3. The base is the left side, the collector is the upper-right, and the emitter is the lower-left. With that chip, the base and collector, I believe, can be interchanged (see your packaging to make sure). 4. Adjusting the trim pot adjusts the bias. Take your multimeter and put one terminal (or whatever you call those things on the multimeter, haha) on the B+ and the other after the pot. Adjust it so that when reading voltage, the voltage is 4.5v. 5. Yes, 9v- is generally always ground. Common ground just means that every part of the circuit that goes to ground goes to the SAME ground.

If you print the picture out at 300dpi it should come out the right size. I believe thats still generally the standard, right? If its a PDF, it should print out the right size regardless. Do be careful about "finding people to wire it up" for you. Even the simplest of circuits (i.e. the Ruby amp) can take awhile to troubleshoot and get correct. You will soon wish you had just experimented and tried to build the circuit yourself, as you will feel less guilty for taking up the other person's time.

For a pcb layout, look earlier in this thread. I believe somewhere in the mid-70s pages.

Do yourself a favor and buy a breadboard (shoulda mentioned it earlier). It will let you basically setup the circuit exactly like the schematic so you can test, tweak, etc.

The other caps are just non-polarized caps. I believe the 22n will look like a green chiclet, and the 100n will look like a small disk with two wires sticking out of it. Also note that the caps MIGHT also be marked .1uF and .022uF, respectively, rather than 100nF or 22nF. As I understand, thats a thing the really only do here in the US (don't blame us, we can't change what the manufacturers label them as!), so you might also find them in Canada.

I would beg to differ. My stepfather used to be a professional electrician. First we shorted pins 1 and 8, no resistor. Then we added resistance and got more gain...

Hi pete, thanks for the reply. I'll be sure to try the 10uF cap from pin 1-8. I am not using a power supply for my sustainer, I'm using a standard 8-AA battery clip (which fits quite nicely in my LP control cavity). Interestingly enough, over half of the current draw when idle is coming from the LED, haha. When actually sustaining, the max current draw I've measured was 130ish mA. I don't think I'm putting too much current through the coil. It seems that with this particular chip, the higher the resistance across pins 1 and 8, the higher the gain. It also makes sense that it works that way because, if you look at runoffgrooves page about the amp, you can use either a 1k, 2k, or 5k pot for the gain control, with the higher pots giving more overdrive. My plan is to get a 1k or so pot, set volume control to max, and adjust the gain to get the loudest possible clean volume as per runoffgrooves advice. I did use a test driver and a test circuit before I mounted it all in my guitar, and everything seemed to work alright, even directly over the neck pickup. My problems lead me to believe that it is something with the circuit. My stepfather noted that the circuit seems rather unstable -- one moment it will give me one result, the next time I try it, it gives a different result. I have a feeling that I need to reduce the gain control. I feel that that is where the distortion is coming from. The squeal is almost like the microphonic squeal you get when you turn on a ton of distortion and place the guitar an inch from the amp speakers. If the distortion is off, it wouldn't feedback that close to the speaker. Here is what I will do: 1. Adjust the gain for maximum clean volume to see if that takes care of the problem. 2. Place a 10uF cap from pins 1 to 8. 3. Try repotting the driver. 4. Look at other mods to the circuit. 5. Rewind the driver.

http://projectguitar.ibforums.com/index.php?showtopic=8569 That thread should provide a good primer. Comparing a PCB layout to the schematic will not likely yield good results for a beginner unless the circuit is VERY simple.

Okay, PSW, be prepared for more questions! I just finished my sustainer. I am having some major problems though (might have to do with my driver, however). First off, there is a lot of distortion in the signal when I turn on the sustainer. My stepdad has experimented with various things, but haven't been able to cure the problem. Also, when I turn the volume all of the way up, the sustainer seems to sqeal (microphonically) for the last few degrees of the pot's turn. It seems to be linked to the distance between the driver and the bridge pickup, however I have the driver in the place of the upper coil on the neck pickup (the coil with the adjustable pole pieces). Another problem I can't figure out. I wonder if it has anything to do with running the circuit on 12v rather than 9v, although it seems rather unlikely to me. I will have to run it past my step father. Oh yea, I also can't seem to get it to work in fundamental mode. It suffers from the same squeal problem as the upperend of the pot in harmonic mode, however it takes place over the last 45 or so degrees of the pot's turn. We can't seem to get the volume up to the point where it will actually vibrate the strings before the squeal sets it. The squeal also seems to be very sudden. Its not gradual at all -- one moment no squeal, the next moment eardrum piercing squeal. Any ideas? Thanks EDIT: I think I've figured out the distortion problem. DUH! I've got a 1k resistor going from pin 1 to pin 8 on the 386 chip. I'll do some tinkering tomorrow to figure out the optimum resistance there.

Looks like a good parts list. You will have to build the Fetzer-Ruby amp, however. PSW was talking about putting kits together for people, but thats still in the works. As far as I know, unless you can pay someone on the forum, you will have to build the circuit yourself. EDIT: By the way, I am finalizing my sustainer system today. Just finished up the circuit and after lunch I'm going to put everything in place. I will post pictures soon, however I doubt I'll be able to get any sound clips.

Explain what exactly you are trying to do better so we have an idea of what you are actually asking.

Consider an Epiphone. They make SGs, and if they are anything like their LPs, I've been quite satisfied.

Maybe it just needs some different pickups?

Braided wire does help with the reduction of hum, probably for the very same reason a Faraday cage does.

Any veneer will work, as long as it doesn't have any adhesive on it. Try Rockler.com.

Hey, chill out guys. Its just an opinion, sheesh. And personally, I find the heavier the instrument, the better. Every lightweight instrument I've ever played just feels horrible. I can't even stand the feel of an SG. I'd take a 10 lb Les Paul over a 5-6 lb whatever any day of the week.