Cheapo guitar buzz & hum

[charliejames]

OK. I've played for years, but never got into the guts of a guitar. I bought a cheapo Rondo SX SJM on Ebay. I admit I did it for the looks alone. I am a Mustang player, and the look for the money ensnared me. I knew from reading reviews at Harmony Central that it would need work right off the bat. I resolved to make it a project. I replaced the Jaguar style bridge with a Mustang bridge. String issue solved. The guitar has two P90 soapbar style pick-ups. when you turn this guitar up, it hums very loudly. I took off the pick guard and vibrato plate, and everything looks tight and in place. The ground wire runs from the tone knob through a hole and into the cavity for the vibrato, where it is supposed to be pinned down when the plate is screwed down. Can anybody point this bonehead (me) towards a first step at cleaning up the sound on this thing? All the controls must be crap at the price I paid for it, but the 10 H Central reviews did not mention noise problems, so maybe it is set up wrong. I thought of replacing the whole insides, stem to stern, so any help would be greatly appreciated. I'm a sucker for the look of the machine, and fixed up it would be dynamite. I have soldered a few things, like a wah wah pedal, and I'm a fast learner. (For anybody tempted to buy one of these guitars, be advised that mine came with two vibrato plate screws missing and the proprietor of Rondo, named Kurt, who was very nice at first, ended up refusing to send me the screws and cut off our email communication! Granted, he's passing these things from china to the customer here in the USA, but he could have helped me out and did not.)

[duhvoodooman***]

Hi, CJ! Welcome to TheFret. Stop by The Players forum and introduce yourself!

Keep in mind that the P90 is a single pole pickup design, and therefore very prone to AC hum. If you switch to the dual pickup position, I would espect that to be hum cancelling and most of the noise should go away. It's not likely that the pots have much to do with it--cheap unshielded wiring and lack of good shielding & grounding practices in general are probably to blame. There are many excellent ideas for things you can do HERE.

[charliejames]

Thanks for the insight. Here's a funny thing—in the center position I get more hum. Could they have installed the pickups backwards or turned around or something? I'm going to try flipping them

[duhvoodooman***]

Don't bother. The hum-cancelling orientation is not a spatial one, but electromagnetic. You'd need a reverse wound, reverse polarity P-90, as I understand it. Better focus on improving the guitars shielding & grounding....

[charliejames]

Well, I shielded the inside of the electronics enclosures as per instructed. The guitar is substantially quieter. The problem comes when I fire up the RAT and WAH WAH. The guitar goes nuts and sets up this big underlying hum. Are these pickups made for quieter playing? Or very clean playing? Because I can get loud with it in clean mode. I was wondering if I could mod the guitar with a double coil and a single coil Fender style setup. I think there are double coils oput there that will fit into a P90 size hole. Not sure about the single coil (as in a Mustang style single coil). Any clues?

[duhvoodooman***]

Do other single coil guitars create a lot of hum with your Rat and Wah pedals?

Seymour Duncan makes a hum-cancelling P90 model, and a whole bunch of humbucking Strat-sized pickups. I'm sure other p'up makers have 'em, too.

[M29]

Hello charliejames,

Yes welcome and please introduce yourself in the Players forum. I would check the solder joints real good there may be a bad connection on a ground, that can produce hum although it would hum even at low volume if it were a bad ground. Also check to see if the bridge is grounded good. There should be a wire leading from the bridge to a volume or tone pot housing.

Hope this is of some help.

M29

[duhvoodooman***]

....welcome and please introduce yourself in the Players forum.

Ummm, he already did, M29.

[M29]

Ahh yup...time to go to bed...

M29

[Katastrophe]

GFS makes a reverse wound P90 neck position pickup that should be hum cancelling when both pups are selected... $33.95.

http://store.guitarfetish.com/gfsalviwosoc.html

If everythings grounded and shielded, you may just have bad pups...

[charliejames]

When I shielded the SX SMJ guitar at home, it reduced the hum significantly. I compared it to my mexican strat, and it was actually a little quieter. But that was on a small practice amp with no pedals involved. The strat plays acceptably quiet when at the practice space and on stage with the Rat and Wah. My regular guitar it a Mustang, and it is the quietest of all with the pedals. It is this quality that I am looking for. I may have to just break down and buy a Japanese Mustang, so I can rely on it as similar sounding on stage as a backup guitar. That was my original reason for buying the SX. But it is a humming feedback monster when the Rat turns on. My conclusion is that it has something to do with the P90s and overdriven sound. I hooked up a friend's Epiphone Les Paul (P90s) and it squealed worse than my guitar did. So Maybe I badmouthed the Rondo guitar unfairly. That's why I am now thinking about switching to a hunmbucker and a Mustang-style single coil, or two Mustang style single coils for the SX. I need that distortion without the guitar going haywire. But then the pick guard pickup openings become a problem. They will need to be modified somehow...