Paul Marossy

But when they start to drain doesn't the signal weaken? No. Internal preamps circuits are designed to be run on batteries, there are thousands of well designed active preamps out there running just fine for years on batteries...you are trying to solve a problem that doesn't exist. I agree. My Parker Mojo Nitelfy can go up to four or five months before the battery needs to be replaced. I'm sure EMG pickups are similar. Is it that big a deal to open a little battery box on your guitar and quickly/easily replace the battery? If you put it in a stompbox, you'll have to remove four screws just to get to the battery. And if you don't have a screwdriver readily available, it will waste more time trying to track one down. Could be a real hassle if you are at a gig and everyone is already running behind. Besides, what if you lose or forget your little box that powers your guitar? You are a dead in the water at that point because it ain't in your guitar.

I agree. Not worth the hassle.

Here's a page with a checklist of items to look for with hum in a tube amp: http://www.geofex.com/ampdbug/hum.htm

Well, start with the tubes and go from there. Might just be a bad tube.

Here are some other pages that are a good read: http://www.billlawrence.com/Pages/Pickupol...troduction.htmp http://www.billlawrence.com/Pages/Pickupol...dy_currents.htm http://www.billlawrence.com/Pages/Pickupology/magnets.htm http://www.billlawrence.com/Pages/Pickupology/windings.htm http://www.billlawrence.com/Pages/Pickupol..._evaluation.htm

One place that sells some nice kits is http://www.allenamps.com One of these days, I'm going to get one of those kits. I've wanted to get one for a long time now.

Could also be due to bad lead dress. Maybe there is a wire picking up AC coupling and injecting it into the signal path. Also, the input jacks mightbe picking up hum if they are connected to the chassis. Try isolating those from the chassis, sometimes that helps a lot. Also, consider star grounding it. I did it to one old amp of mine and it made a huge difference.

Yeah, and I take advantage of this a lot. I can totally change how I sound just by changing the angle of the pick and/or where I am strumming on the strings, in terms of the distance from the bridge. It's not quite a one size fits all kind of thing...

If you have to take the pickup out of his guitar and all that, I personally feel like that is more than a $20 project.

I agree. A different pickup might yield different results. Some pickups have all kinds of harmonics, and others don't. And another thing to consider is the neck material and the neck profile. Those things also affect the resonance of a guitar. And the bridge. And a bunch of other things...

Oh yeah, fiber optics sounds like the way to go to me.

I would try to unwind a turn or two of the coil. If it's well-potted though, that may be impossible. Worth a try, since you can't screw it up any more than it already is. Or if the piece you have to work with is long enough, you can scrape off some of the coating on the transformer wire and solder an extension on it.

Sounds like you are close to getting it figured out...

Might be worthwhile if you do a lot of that sort of thing.

Did you check that with the tank completely removed from the amp? And when you say no resistance, is it literally zero or is it like 8 or 10 ohms or something like that?

Yeah, something with an input buffer would work better. The Little Gem Mark II would even work better.

What you were asking about in the OP will get the job done. It would sound a lot better on 18V than it would on 9V, which would require the N4 version of the chip. It's overdriving so much on 9V because it runs out of headroom and really clips the signal. And also, if you lose the 5K pot between pins 1 & 8 and use a 10K volume pot on pin 2 instead, it should clean up a lot more.

I would do the "Gain Of 20" scenario on this data sheet: http://www.national.com/ds/LM/LM386.pdf and use the N4 version of the chip with can handle up to a 22V supply voltage, and operate it on at least 18V. I have never heard an LM386 circuit running on 9V that I have liked, they seem to always sound yucky no matter what when operating at that voltage.

Boss pedals use the enclosure as a ground connection on one of the jacks. IIRC, if you break the connection to ground at the output jack, then their pedals won't pass a signal. Anyway, glad it was something easy!

OK, that eliminates overvoltage as a possibility. Yeah, I guess you're going to need to get a schematic and measure voltages and audio probe it to figure out what the problem is.

From your description of the problem, it sounds like it might have been supplied with too high of a voltage and it got fried when certain components blew up. Were you using some kind of wall wart when this happened? If the switch simply went bad, it would probably just be stuck in bypass mode all the time. I seriously doubt that it's just a bad switch. They rarely go bad anyway.

See here for Seymour Duncan color codes: http://www.seymourduncan.com/support/schem...tic=color_codes

Yeah, that happens sometimes. My two favorite pickups are the DiMarzio FRED and my vintage Seymour Duncan Allan Holdsworth model. I like the SD a little more than the DiMarzio, more of a resonant midrange to it. They both work very well with the guitars that I put them in.

Yeah, all good points. But trying to copy SRVs live tone for example would be hard. He had so many amps going at the same time!

I hate to say it, but just because you have the same exact pickups or whatever as your favorite guitar hero doesn't mean it will make you sound like them. I see this idea constantly at every forum, and it's a rampant fallacy. There's a lot of factors involved, the biggest one being the player themselves. They will always sound like they do no matter what they are playing. Anyway, things they do in a studio can't easily be reproduced by someone wanting to get the same kind of sound. They could have miked the amp from front and from behind. And where you place the microphone matters a lot, too. And then they tweak the EQ to get the sound just how they want it. Or maybe the guitar tracks were doubled to make it sound bigger, etc, etc, etc. You can't just buy some distortion pedal and use a certain pickup in the same kind of guitar that you know they use and expect to sound like them, it's just not that simple. Not even close to simple. I mean even stuff like what kind of pick you use and how you hold it is even a factor in how you sound. Even string gage is a factor. That's not to say that you can't get close to a certain sound, but the usual formula people use (getting all the same stuff as their guitar hero) doesn't normally work just by itself. When they can also mimic whatever player's technique in how they play guitar, they get a LOT closer.