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Solving mysterious noise in MANLEY TNT
Old 23rd November 2015
Here for the gear

Solving mysterious noise in MANLEY TNT

Hi everyone! Yet another noise/num/buzz thread, I know! To be honest I've been searching online for answers to this and tried almost everything I could given my level of knowledge on the subject, so posting this is really a last resort for advice on what to do next.

Here goes:

My setup is an Apogee Ensemble Thunderbolt + Macbook Pro + Shure KSM32 & Shure SM7B. I got a Manley TNT a couple of weeks ago and that's when problems began... I should note that prior to getting the TNT I had done very little audio recording, since most of what I do is MIDI arranging and mixing.

So anyway, I got the preamp, hook it up, test it out and noticed I was getting a super annoying buzz/hum on both channels of the TNT, that became louder when I hit the gain knob, but especially LOUD when I hit the TRIM knob. Regardless of the Gain level, the Trim knob seemed to especially trigger the noise on both channels. This happened with both my Mics (KSM32 & SM7B).

Now, the first thing I suspected was an electrical issue. So next day I call up a local electrician and have a separate breaker and wiring installed for my studio gear. I suspected this because at the time I was using an APC Back-UPS that indicated a wiring fault with a Red "building wiring fault" Led, so I thought this had to be the culprit. I should add that I had never noticed this warning light before since I never had any noise problems... So I have the new wiring setup, hookup all my stuff but the noise is still there (the "building wiring fault" DID go away though).

I decided to try without the TNT and audio was crystal clear, so that rules out Mic, cables (Mogami XLR's) and Audio Interface. Also tried with a small 2 channel USB interface I have as a backup and there was no noise either.

So I contacted Manley, Apogee and Sweetwater Tech Support to make sure all my connections were good (by the way, I have to add that the Manley customer service guy was kinda rude and unhelpful). According to Apogee & Sweetwater, the correct way to hook up the TNT to the Ensemble is: via the XLR out of the TNT, to the XLR in of the Ensemble and set the Channel input to +4dB. Tried this but still had the problem, so that rules out IMPROPER GAIN STAGING. Even tried via the TNT's TRS OUT & Ensemble's TRS IN and no luck either. The Manley Tech Support fabulous response was:

"This unit uses input transformers which are subject to stray electromagnetic fields (like a power transformer on another unit). Pull the unit out of the rack and away from other units as a first step in isolating the problem."

I did that, no luck. Aren't these things supposed to be built for Rack Mounting!? So, now I try at both a friend's house and at another studio location and I had the same noisy results.

I ship it back to Sweetwater. These guys were really good to me by the way. The tech tells me he'll test my unit against a new one and compare results. He just sent me an email telling me that he could not reproduce the Noise in either my TNT or the new one.

So what is going on?? Is the Manley tech right and is there some sort of crazy E.M. field going on in my studio that only the TNT is picking up? If so, will other transformer based-preamps (which are pretty much ALL OF THEM) behave the same way? Is the Sweetwater Tech lying to me and/or just didn't care enough to properly test it?

I know nobody here reads minds (especially not over the internet), so I guess what I'm asking is WHAT SHOULD I DO TO discard any E.M. interference in my house? Is there a method/device that can help me do this?

I'm afraid of getting another preamp and have the same results... I also want to get a Neumann U87 that uses transformers, and Sweetwater doesn't have returns on this Mic, so I'm even more scared!!

Should I just go with Transformerless everything!?
Old 1st October 2019
Here for the gear

Why did no one reply???This is obviously MANLEY's official BUG.I was in the same situation, two TNT.It happens all the time.Removing the top cover solves the 10KHZ hum.
Old 3rd October 2019
electromagnetic interference is an electromagnetic emission that causes a disturbance in another piece of electrical equipment.
so I guess what I'm asking is WHAT SHOULD I DO TO discard any E.M. interference in my house?
Anything that carries rapidly changing electrical currents gives off electromagnetic emissions. So list everything that uses electricity in your house (please do not, it was just to make you see that no one here can really tell you what to do, as it the EMI can be cause d by your microwave, blender or toaster oven for all we know.
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