PRS Archon 100 FX8 Idle Hum

Shpunt

Shpunt

Member
Greetings Folks,

I am getting a irritating hum from the fx8.
  • I have humbusters.
  • I run them in Mono 4cm.
  • I checked my entire rig up and down for ground loops.
  • Brand new lava, mogami cables.
  • When my loop is bypassed, no noise.
  • When my loop is active but i jump it with a patch cable, pretty much no noise.
  • When i turn on true bypass, much less noise.
  • When i run my fx8 in 4cm. (gate at the end of pre and post) i still get noise.
  • Lowering input/output levels doesn't effect it.
Anybody have any idea what this could be? I'm driving myself apesh*t.

Thanks in advance,
-Shpunt
 
Have you tried plugging the FX8 into a different power socket preferably in a different room ?
 
Try running only the post section in the effects loop of your amp, and then run your guitar directly into the amp input. Does this reduce most of the hum?
 
Well that's weird. Usually the hum gets worse in 4cm compared to 2cm

Again, with only the post section in the effects loop, maybe try some different cables, even if they are not humbuster cables.

Also, I have noticed in the past that if the cables running to the effects loop are positioned in the amp transformer's electric field, in a certain position, I would get hum. Try moving around the cables that attach the fx8 to the effects loop. I know it sounds ridiculous, but I almost drove myself bananas with this problem; sometimes I'd get the hum, then with the same setup, I wouldn't. In that case I discovered I had to keep the cables as far from the transformer as possible -and they were expensive and well shielded cables
 
naka2112 said:
Well that's weird. Usually the hum gets worse in 4cm compared to 2cm

Again, with only the post section in the effects loop, maybe try some different cables, even if they are not humbuster cables.

Also, I have noticed in the past that if the cables running to the effects loop are positioned in the amp transformer's electric field, in a certain position, I would get hum. Try moving around the cables that attach the fx8 to the effects loop. I know it sounds ridiculous, but I almost drove myself bananas with this problem; sometimes I'd get the hum, then with the same setup, I wouldn't. In that case I discovered I had to keep the cables as far from the transformer as possible -and they were expensive and well shielded cables
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I've gotten the same answer from PRS Tech Support. I tried to move them in any position I could and no difference. Before i used the FX8 I had an eventide space and timefactor in my loop. Similar issue, but easily gated. Right now i have to gate my pre and post and i still get some hum. I just can't find where to single it out, but it seems to be the FX8.
 
naka2112 said:
I guess you don't have another amp to test it with?
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I have access to a EVH 5150 III 50w head in my band's practice space. I guess i'll have to try it, i know for a fact that it has a quieter loop. But i've ruled out any possibility besides the fx8. I'm assuming that some global setting or something is screwing me. I've ruled out ground loops in any position also. Tested it with a Ebtech hum eliminator as well.

Also Naka, It isn't plugged into a computer.

Thanks for helping me troubleshoot guys. It's good to bounce ideas around.
 
Try jumping the effects loop with a long patch cable, and see if the noise is worse. On my bogner, I noticed a small jumper cable had minimal noise, but a long cable would interfere with the electric field and create more noise.
 
I've tried jumping it with a 10ft cable. I suppose i should try a larger one. Considering that with the fx8 i have 30ft of cable running between my preamp and power section. If that does solve it however, how can I fix my live rig?
 
Whatever you do, get it quiet in the fx loop on your amp first. Then include the pre section in 4cm. If you try to solve this problem in 4cm, there are too many variables, and it takes waaaaaaay longer to figure it out.
 
Shpunt said:
I've tried jumping it with a 10ft cable. I suppose i should try a larger one. Considering that with the fx8 i have 30ft of cable running between my preamp and power section. If that does solve it however, how can I fix my live rig?
Click to expand...

If its is noisy with a longer cable, that would support the idea the cables are interfering with the amp transformer's electric field. It would essentially rule out a ground loop problem with the FX8. Does the hum happen on the clean channel with the volume quite low?
 
naka2112 said:
If its is noisy with a longer cable, that would support the idea the cables are interfering with the amp transformer's electric field. It would essentially rule out a ground loop problem with the FX8. Does the hum happen on the clean channel with the volume quite low?
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The noise is completely unaffected by volume on either channel. It is consistently the same for both channels nomatter how loud or quiet the master is for either.
 
If you have not already tried this, I would eliminate the power filter out of the equation, and setup in 2cm in the effects loop. Plug the amp and Fx8 into the same outlet. Nothing else connected.

I'd also try it with and without the humbuster cables. Did you make the humbuster cables?
 
naka2112 said:
If you have not already tried this, I would eliminate the power filter out of the equation, and setup in 2cm in the effects loop. Plug the amp and Fx8 into the same outlet. Nothing else connected.

I'd also try it with and without the humbuster cables. Did you make the humbuster cables?
Click to expand...

I've tried plugging it into the outlet without a power conditioner in two different buildings (tested the outlets as well) My humbusters are purchased from fractal. I'll try 2cm when i'm back at the practice space. Hopefully I can progress from there.
 
Try the tests you posted in post #1, but with the noise gates disabled. What results do you get then?

And make sure your Humbusters aren't inserted backwards. :)
 
Rex said:
Try the tests you posted in post #1, but with the noise gates disabled. What results do you get then?

And make sure your Humbusters aren't inserted backwards. :)
Click to expand...
I'm going to test this tomorrow hopefully. And the humbusters are in the correct way I believe. TRS in the FX8 , TS to the amp. One to the return, one to the input.
 
Agreed, try the fx8 with the 5150 50w head. That is a documented rock solid combo.
Do you have something else you can try in the Archon loop? Delay pedal/rack?
That would help narrow down the issues.
I think I read somewhere that the Archon was a great amp but had a crappy loop that was then improved in later versions(?).
If true, it would buzz on anything in the loop.

Good luck. I have had my own loop/midi issues and it is a frustrating experience!
 
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