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High Pitched Scream with Volume
by SportzTawk on 2009-07-13 17:21:29

When I turn the volume up on the Spider Jam, usually around 11-12 o'clock, This shrilling high pitched scream comes out of the amp, which sounds a lot like feedback.  I don't believe it is feedback, because it's dead quiet, until I reach that point, and then bam.  I play with a band, and the amp sounds amazing, but when it comes time to play, I either have to turn it completely down until it's my turn, or I have to deal with this screech in the background thats as loud as we are.

I've messed with the Channel and Master Volume to try and  combat this, but no luck.  It's when I turn the Master volume that it screams.  I have passive pick-ups on a ESP-KH202.  COuld it be the guitar? Or is it something with the Amp?  I just bought this thing in March I believe, and I'd hate to see it busted already.  Any help is needed ASAP.  Thanks so much for any replies.



Re: High Pitched Scream with Volume
by amx05462 on 2009-07-13 17:26:59

unless your in a very small room  it shouldnt be the guitar .   your talking  about half way  on the volume  thats not like your cranking it.



Re: High Pitched Scream with Volume
by SportzTawk on 2009-07-13 17:29:30

Yea I don't think it's the guitar either, and I'm sure it's not feedback, because I used a 10 or 15 foot cable to get as far away as possible and it still screams.  Though sometimes if I hold the strings just right, the feedback stops for a half second, but immediately starts screaming again.



Re: High Pitched Scream with Volume
by amx05462 on 2009-07-13 17:44:05

have you tryed a diferent  guitar cable?   could be a bad ground. maybe creating some kind of loop



Re: High Pitched Scream with Volume
by SportzTawk on 2009-07-13 17:46:28

I noticed that the volume knob on my guitar is a little loose, it still turns right and everything, it's just come loose from the inside body of the guitar.  Could that be the problem? The guitar cable I'm using is fairly new.



Re: High Pitched Scream with Volume
by amx05462 on 2009-07-13 18:04:30

if what you mean is that the  shaft on the  volume pot is loose  it really shouldnt  give you that kind of problem as to cause  a feedback  situation.  . then again im no expert. if you think theres a problem  it wouldnt hurt to replace it. just  get one of the same value.  should say on the back of it. probably 500k like most of the newer guitars. should only take about  half  an hour to  change it out.

        as far as the  amp goes  just try  one of the other  band members  guitars  with your  amp.  use there cable as well  if  it still makes that sound  id return the amp. if it doesnt  make the sound  then its  the guitar or the cable. wouldnt surprise me though if it is the amp.  my tech told me to stay away from them.   i use  vox  and fender.



Re: High Pitched Scream with Volume
by SportzTawk on 2009-07-13 18:31:07

Well I do know thats not the problem now that I think about it, as it still squeels when I flip to the other channel, and use that volume knob.



Re: High Pitched Scream with Volume
by amx05462 on 2009-07-13 18:46:36

does it change if you  sweep the  volume control on the guitar?



Re: High Pitched Scream with Volume
by SportzTawk on 2009-07-13 18:58:59

Do you mean if I keep the Amp turned up, and turn the guitar volume knob down?

I tried to attach an audio sample of it squeeling as I turn the knob.  It squeeled every time I reached about 12 o'clock.



Re: High Pitched Scream with Volume
by amx05462 on 2009-07-13 19:07:26

try bringing the  amp volume down and  the  guitar volum up all the way  then gradually  bring up the amp volume  also  try this  with one  pickup or the other.  also i couldnt hear the  amp test as i have nothing to play that kind of file.



Re: High Pitched Scream with Volume
by SportzTawk on 2009-07-13 19:11:14

Yea I've tried that before, with both.  There is no squeeling on the amp until I reach about 12 o'clock as usual. When I turn the Amp volume up and gradually turn the knob on the guitar, it doesn't squeel until I turn the Guitar knob about 75% of the way up.  So thats what makes me feel like it's the pickups or something, but I can't figure it out, which is why I'm letting you guys assist me

Also... if the guitar is in it's stand, perfectly stationary... I can turn the knob past 12 o'clock without it squeeling. As soon as I pick it up, even when I deaden the strings, it till squeels like crazy.



Re: High Pitched Scream with Volume
by amx05462 on 2009-07-13 19:30:37

sounds  like   a bad ground in the guitar  now that you mention it  happening when you touch thew strings.  first thing id do  is replace that volume pot you mentioned . open the   back of the guitar and look in there to get the value off the back of  the pot  and  go to the local guitar store  you should be able to get a replacement  there.



Re: High Pitched Scream with Volume
by SportzTawk on 2009-07-13 19:46:38

What I'll do, is next band practice, I'll plug in another guitar and test it to see if it does the same thing.  That should tell me if it's the amp or the guitar.



Re: High Pitched Scream with Volume
by amx05462 on 2009-07-13 19:53:22

yeah  that  was what i was saying earlier  .  best to test every angle  before  deciding what to do.

          let me know what you come up with



Re: High Pitched Scream with Volume
by joegillespie on 2009-07-14 02:36:48

Sounds to me like your pickups are microphonic. Some pickups are 'potted' in wax to stop this happening. You can test this by tapping around your pickups with a non-metallic object - a pencil or plastic pen. If you can hear the taps coming though the amplifier, that is the most likely problem. A magnetic object will obviously produce a sound, that's why I'm suggesting wood or plastic.

Some pickups are deliberately left microphonic, especially on semi-acoustic guitars, as it adds to the woodyness of the tone but it means that the guitar can't be played at high volume otherwise there will be feedback. I once had an Epiphone Casino that was like this (P90s) and I couldn't use it on stage at all.

The only 'fix' for microphonic pickups is to have them wax-impregnated but as this is an 'expert' operation, it might be cheaper to replace them with another brand.

Note that as the Spider Jam reproduces a wider frequency range than regular guitar amps, it is possible that you might get feedback in the higher frequencies.



Re: High Pitched Scream with Volume
by SportzTawk on 2009-07-14 12:52:12

Well I tried the tapping thing, and I can slightly hear the tapping from a pen.  And if I actually talk loud enough, I can slightly hear myself.  I'm guessing that means you may be correct in assuming they are microphonic.

The pickups on there are the EMG-HZ or whatever... the passive version of the 85/81 I believe.  The cost of those two pickups would be $200, approximately how much would it be to do the wax thing?



Re: High Pitched Scream with Volume
by joegillespie on 2009-07-14 14:03:02

You would have to get a quote from a local guitar tech on that one.



Re: High Pitched Scream with Volume
by amx05462 on 2009-07-15 16:19:52

http://www.guitarnuts.com/technical/electrical/index.php

     check this out it tells  you how to do it yourself. basicly  it comes down to  removing  the pickups  from  the  guitar  and dipping them in hot  wax.

  if you  just type in  potting  pickups  in your browser   you will  find  some  other  web  sites  as well.

               have  fun  




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