Phantom power killed my guitar tone for the past year or so

[ahjteam]

I just noticed a reason why my guitar tone has sucked balls for the last year and half. As some of you may have heard some of my guitar tones, they sucked cock. I blamed the cabinet for a long time... but today I accidentally noticed that SM57 doesn't like phantom power. I don't know if it's modded or something, I bought it second hand, but it sounds totally different with phantom power on and phantom power off.

Phantom power on: http://dl.dropbox.com/u/1338211/mf2.mp3
Phantom power off: http://dl.dropbox.com/u/1338211/mf3.mp3

I used exactly the same settings except phantom power off and different level on the preamp because it started clipping when I turned the phantom power off. I have no idea what is causing that big of a difference in the tone, any ideas. The tone is still not 100% best in the world, but it's way better than the sound with the phantom power engaged.

I'll make a quick youtube video out of this soon just to spread the word.

edit: here it is:

 

[Habsburgs]

holy shit.. nice tone night and day!

stupid phantom power

 

[bryan_kilco]

Isn't phantom power used for condenser mics? You'd not normally have it ON with a 57 hooked up.....

 

[ahjteam]

Isn't phantom power used for condenser mics? You'd not normally have it ON with a 57 hooked up.....

I use Rode M3 for podcasting and Shure 57 for guitar tone, that's why I had it on all the time on the M-Audio interface, but now when I was trying out the SPL Track One, I noticed that turning off the phantom power improved the tone a lot.

 

[BLUElightCory]

That's definitely bizarre and it's not normal.

Does the phantom power affect the 57 with both the SPL and MAudio pres? If the 57 is wonky with phantom engaged on another pre, you know there's something wrong with the mic. You can also try switching out the 57 with another dynamic mic, to see if all dynamics are affected or just that particular 57. This should help you figure out if it's the mic or the pre causing this issue.

 

[JeffTD]

Check with another pre, I've never had this happen.

 

[Lasse Lammert]

Phantom power shouldn't affect the dynamic mic at all, I'd suspect your preamp

 

[ahjteam]

Okay, update on the situation...

- I checked the SM57, it seems to be real according to these specs, but not sure if it's modded or something
- I tried the phantom power on and off with the M-audio preamp, didn't affect the sound at all, so I figured out the problem must be between the two cables or on the SPL.
- Then I tried and changed the cables going to the SPL, tried the phantom power on and off and now it worked just fine.
- I reconnected the old cable and it gave me the problem again, so I came to a conclusion that it was a faulty cable, but the problem was still real

I tried opening the connectors on the faulty cable to see if there is a short or something because it sounds like the pins 1 and 3 are flipped or shorting as there is no low end on the clip, but I couldn't get the Neutrik connector open without breaking it even tho I used a lot of force. I'm going away from home for the summer so I have to fix it when I get back.

edit: I used more force, got the connector open and they it seemed okay, but there was one point in the cable where it looked like it was squeezed, so it might be broken from that point. But like I said, I'll have to check the situation later when I get back.

 

[C-Martin]

How come you didn't check this before? To me it just seems like that's something i would have checked and corrected 2 min's after i recorded and heard the results. I mean it's clear that something was wrong, you can hear it quite clearly with the clips you posted. There is some serious lack of bottom end on the first clip with the phantom power on, that should've given you a huge sign that something wasn't working properly. Not trying to be an ass btw, i just don't understand why it took a year and a half to figure this one out.

Good that you figured it out though.

 

[if6was9]

So were you using the same cable for the guitar all the time?

 

[drew_drummer]

Sounds like some sort of capacitance issue with the cable.

 

[AudioGeekZine]

Has the transformer been removed from the 57?

The transformer is supposed to block phantom power from getting to the capsule. Seems like the capsule is being forced outward (like when you attach an 9v to a speaker) and isn't able to move freely.

 

[Fox Mulder]

Phantom power shouldn't affect the dynamic mic at all, I'd suspect your preamp

Exactly. +1

Has the transformer been removed from the 57?

The transformer is supposed to block phantom power from getting to the capsule. Seems like the capsule is being forced outward (like when you attach an 9v to a speaker) and isn't able to move freely.

My intuition tells me this is the case.

 

[ahjteam]

Like I said: the problem was in the multicore cable going to the SPL. When I changed the cable, the problem was fixed. But the reason for the 57 reacting to the phantom power? I didn't get a chance to prove my theory 100% before I left, but my intuition tells me that the problem was that the ground and minus pins were shorting.

The cable ground has two purposes: to protect from RF noise and to transmit phantom power.

Since the plus and minus pins get reversed when it gets to preamp, the effect happens only when the phantom power is engaged because phantom power is essentially just 48V amplified DC voltage. When you amplify the bleeding RF noise (that the ground shield was originally protecting the signal from) in the minus pin, it removes the low end, "good mids" and amplifies the "bad treble" that was not in the original signal.

I opened the connector and noticed that the connectors and soldering were fine, but there was a squish in the cable under the connector, so the problem most likely is there.

 

[Soundlurker]

I was 95% sure you're trolling us with these clips

Must have been an epic facepalm for you.

 

[ahjteam]

Must have been an epic facepalm for you.

Yup

 

[Mago]

Ouchm but good for you that you figured it out finally
Now go and cook up some kick ass guitar tones

 

[Wolfeman]

This is exactly why I own a cable tester. $20 and saves you a lot of heartache

 

[Jind]

This is exactly why I own a cable tester. $20 and saves you a lot of heartache

This - my cable tester has helped me resolve several issues over the years. I think every musician and/or engineer should have one in their gig bag right next to the can of contact cleaner (one of the most overlooked troubleshooting steps when determining reasons for bad sound).

 

[egan.]

This is exactly why I own a cable tester. $20 and saves you a lot of heartache

...or a multimeter.