Author Topic: I'm really really sorry but... that noisy guitar setup again (Read 1514 times)

Roobubba · « **on:** October 18, 2007, 02:04:01 PM »

I've just been jamming with the amp turned up a little bit, as I'm at home during the day today.

I couldn't be bothered to set the ISP decimator up, so I just plugged straight into the amp for a change.

I found that when I do a pretty hard picked strum and mute with my *left* hand (I'm right handed), there is a sound which rings after the main noise - it sounds, for want of a better description, like a spring.

Now, when I went back in behind the pickups a couple of weeks ago, I actually found a spring stuck to the back of my miracle man, it must have attached itself without me knowing when I originally installed the pickups. I got rid of that spring, and packed some foam into the cavity behind the pickup, in case that space was a problem. Could it be that the springs on the screws are vibrating, and this is giving me this funny "spring-like" electrical sound after any stopped note?

It seems like *something* isn't right, and I was wondering if anyone here had any new ideas in the light of this new strange evidence. This might be the source of many of my feedback and squeal woes, but I'm not sure what to try!

Cheers in advance,

Roo

FELINEGUITARS · « **Reply #1 on:** October 18, 2007, 02:07:32 PM »

No - sounds more like a microphonic valve - maybe a power tube.

gingataff · « **Reply #2 on:** October 18, 2007, 02:22:55 PM »

Probably a valve as Jonathan says, but there is another possibility.
Your guitar has a Floyd type bridge doesn't it? The springs in the back often ring a bit like a spring reverb. Some foam under them helps a lot.

Roobubba · « **Reply #3 on:** October 18, 2007, 03:46:08 PM »

Right, a couple of things as a result of this

a) THANK you for your responses!

It turns out that if I tap the guitar (unplugged) I can hear the same "springy" sound.

So, working on the principle that if it sounds like a spring, it probably is a spring, I ripped out the neck and middle pickups. I never use these anyway and had them set really low to avoid string pull.
That seemed to do it, until I re-screwed in the bridge pickup and re-tightened the strings, and "boooing", it's back!
Hmm.

So, I've packed foam under the floyd rose bridge springs - and also damping them by hand doesn't stop this springy sound. I loosened the bridge pickup mounting plate and damped the springs on the pickup by hand - again doesn't stop the pringing sound.

There aren't any springs left in my guitar to rule out! I'm now at a bit of a loss trying to work out where it is.
It's definitely the guitar, not the amp (relief as gig on Sunday and I don't want to put my old (backup) tubes back in!

Any ideas?

The second thing is this:
having removed the pickups, I don't really want the pickup selector either. Do I solder the red bkp wire from my MM straight to the lug of the volume pot where the remaining live from the pickup selector current is? Or could it go direct to the tone pot, which comes back to the same lug?

Many thanks again for your repsonses! So near and yet so far!

Roo

gingataff · « **Reply #4 on:** October 18, 2007, 04:13:27 PM »

Loose bolts on the locking nut or tuners? make sure everything is tight but don't strip the threads. Maybe the pickup springs are too loose and the pickup is vibrating? That could explain the feedback problems you've been having.
I'd don't know what a rattly truss rod sounds like but I suppose that could be another alternative.

FELINEGUITARS · « **Reply #5 on:** October 18, 2007, 04:23:15 PM »

Have you access to another guitar that you can try through the amp
A hardtail like a Gibson or whatever would be good
If the problem goes with a different guitar then we know it is only the guitar we are looking at because although the guitar makes the sound unplugged - there is no gaurantee that the amp hasnt got an issue of some kind
What guitar is it - superstrat? Ibanez?

Does this happen when the guitar is in a "normal " tuning?
Or just when it is downtuned?

Certain things can change a lot when the tensions on a guitar are dropped/lowered - hence my question.

Bob Johnson · « **Reply #6 on:** October 18, 2007, 06:33:56 PM »

It could be that the truss rod has no tension in it, the truss rod, if loose, will resonate in sympathy with certain frequencies whether you are plugged in or not. If you hear it when you tap the guitar it could well be the truss rod.

Roobubba · « **Reply #7 on:** October 18, 2007, 09:42:56 PM »

OK, so it appears that what I was hearing was actually the strings between the machine heads and the bit of nicely polished metal at the neck end - unbelievably, this was ringing out every time I hit the strings and that was feeding back through the pickups.
That's not the whole issue sorted, the guitar is still very noisy at band practice, but like I said somewhere else, the ISP is dealing with most of it.
I stuck a bit of rubber from a bike light fixing under the metal bridgey bit at the machine head end of the guitar, and this stopped that "springy" sound completely. I've also removed both of the other pickups, and removed the pickup selector, too.
I have another guitar, but it's also got a floating bridge, and is also downtuned to silly. I will try at high volumes with that, too to see if it makes a rude sound as well.

I found that there is quite a bit more noise in the effects loop with the ISP decimator there and not in use than with the effects loop off altogether. I spoke to the guy at ISP and he suggested cutting the ground on one of the cables to the second ISP decimator channel (to cut the ground loop there), and I did that, but it doesn't seem to have helped.

I will try the truss rod as well, thanks for those suggestions.

I know I need to try a few more things, and so will do those before I report back here, so I've a bit more useful info to help diagnose the problem. Maybe it's just because I'm playing with silly gain levels!

Roo

PS gig on Sunday night, woo!