4CM hissing

saxxamafone said:
The hum exists even when the axe-fx is bypassed in the GRX4! but if i disconnect the axe-fx, the hum goes away....
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Please try something for me....

With the Axe connected and bypassed, turn off the Axe. Now disconnect the Axe's AC power lead.
 
KINGSFAN said:
I am still having no luck with the hiss issue.... HELP!!!!!
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Well... I'm trying to.
widrace said:
With the Axe connected and bypassed, turn off the Axe. Now disconnect the Axe's AC power lead.
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I asked saxxamaphone (you out there?) to do the experiment above. It's just a diagnostic check. I know it may seem a bit odd but there is a method to the madness. I ran across a situation with 4CM where the Axe was connected and bypassed similar to the above configuration and it made lots of noise. Switched off the Axe and it was still noisy. Disconnected the Axe's power lead and the noise quit. I ended up building a simple little box that fixed it.

If your a forum member and your rig does what is described above you might want to try it, I'll just send you one. A couple of guys just built their own - I didn't have to send a box to them because they were savvy enough to build one with just a description. Since it messes with the AC, I'm not going to post a schematic. PM me. For the curious, it just optimizes/matches the resistance to AC ground via a knob and has a bypass ground fault path.

Awhile back I offered up a noise reducing 'tutorial' to eliminate the basics first. That can be found here.....viewtopic.php?f=23&t=7271&start=10 on page 2 about 1/3 down the page.

Specifics related to the fix for the AC hum part of the equation can be found here viewtopic.php?f=23&t=7271&start=0 on page 1, almost to the bottom of the page.

jimosity...if your reading this what was the result? - you just vanished.
 
I abandoned using the Axe with my M4 months ago. But since then, I've eliminated several noise sources from my signal so I'm going to try it again this weekend.
 
Any further info from anyone on this? I was planning on using the 4 cable method, as that's really what makes the axe-fx worth it to me.... to be able to use pre-amp type fx and post-amp type fx. otherwise, it's not all that useful to me anymore, and I might be better off with something more simple and affordable like the eventide timefactor/pitchfactor.

Otherwise, I'll be resorting to buying another tubescreamer and a phaser and maybe wah to run in front, and then the axe-fx is starting to feel less and less worth the money to me.
 
JoshuaLogan said:
Any further info from anyone on this? I was planning on using the 4 cable method, as that's really what makes the axe-fx worth it to me.... to be able to use pre-amp type fx and post-amp type fx. otherwise, it's not all that useful to me anymore, and I might be better off with something more simple and affordable like the eventide timefactor/pitchfactor.

Otherwise, I'll be resorting to buying another tubescreamer and a phaser and maybe wah to run in front, and then the axe-fx is starting to feel less and less worth the money to me.
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Have you tried the 4CM and had trouble? If not, just do it. Many guys seem to be OK with 4CM straight off. That said, some of the folks I've tried to help don't get back with results. I suppose they either give up or everything is good now and their just playing their arse off - don't know.

4CM is fertile territory for potential problems but there's usually nothing that can't be resolved with a little effort. Other than noise associated with gain, rigs should be and can be dead quiet – no hiss, no hum.
 
I have tried with a JVM205c, and I get a lot of noise when not using the clean channel. I tried the 4CM with different cables just to check if it would make a difference... Well, it did not.

Any suggestions? Is this like a bug that is never going to be fixed?
 
It's not a bug. It's just the way it is sometimes when you interface unbalanced gear. Since your good with the clean channel, that says the problem is most likely the level returning to the amp is too high. Getting the input/output gain structure right is everything with the 4CM. Try doing an A/B comparison between 4CM vs. straight in to the amp. If straight in isn't as loud (or less gainy) your probably driving the amp harder with 4CM, which will certainly increase noise.

If that doesn't do it try lifing a signal ground from all but one of the cables that interconnect the Axe and the amp. You only need one signal ground to allow the two units to play together nicely. More than one is a loop, which is just asking for noise trouble.

Here is detail on how to do this. Find my 11:30 am post and then check out the realworld 'fix-it' diagrams that follow further along the thread. viewtopic.php?f=23&t=7271&start=10
 
Hi:

I didn't read this whole thread again but I did get a quiet 4cm going with my tube amp. Here's why I understand there is noise and how I solved it.

- My understanding (maybe an expert can confirm) is that the Axe's "send" output is balanced. With 4cm we are taking the balanced signal from Axe's "send" output and feeding it to the instrument input of the amp. This is where noise can get generated. It is not a problem with the Axe but rather the result of feeding a balanced signal to the front of your amp.
- I solved the problem using one of these re-amping boxes between the send output of the Axe and my Amp's instrument input. This solution makes sense since this box converts a balanced signal back into an instrument level signal like what comes out of your guitar.

http://www.radialeng.com/di-xamp.htm

- Using this I got a nice quiet 4cm.

- You could also probably use this cheaper one (I have not seen any others)

http://www.radialeng.com/re-prormp.htm

Hope this helps
 
Thanks for the suggestions. I will try the first one, and then go for the reamp solution if it does not work. I will let you know about the results.
 
The XLR's are balanced, the 1/4 jacks are not. Reamp boxes and the like physically decouple a connection - breaking the ground loop. You can do the same thing by lifing the ground in the cable. Just make sure one ground is left intact per earlier blurbs...

What you cannot do by just lifting the ground is raise or lower the signal level like some boxes do.
 
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