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Nomad preamps


Christian Spaeth
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I'd like to hear other users' opinions on the Nomad preamps. Shooting a fiction TV crime series, today we had a very quiet scene, confession in a quiet room, actress speaking really low, almost whispering. Had to crank up the preamp quite a bit, so I decided to go cable instead of wireless boom, but the wireless boom was a lot quieter to my surprise. I used a Schoeps CMIT going to a Sound Devices MM-1. Cable out of MM-1 line in to the Nomad, the preamp noise was notable (which means too high for my taste). Using a Lectro LMa/SRa out of the MM-1 with the Smart NR in the SRa set to normal, the noise was already audibly lower, with Smart NR set to full it was much lower and that's what I opted for eventually. Surprised me a bit, since I know my Nomad's preamps are not noisier than others (they have been tested by my dealer's tech and he said they are among the quietest preamps for location recorders.) I always thought going cable is quieter than wireless boom.

For the record, going in directly with the Schoeps into the Nomad, the noise was even higher than with the MM-1 as a preamp.

I am very happy with my Nomad but this was a situation that showed me the limits of using a single machine vs. a dedicated mixer with quieter preamps AND a recorder. Makes me reconsider whether I will buy the Mix-8 or instead buy an analog mixer for use with my Nomad.

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I've used my Nomad with a Cmit, CMC641, Senn MKH416, MKH 60, and Neumann KMR81 and have not had any issues with preamp noise. I've felt that the Nomad pre's have been probably the most quiet and transparent of any Field mixer or recorder I've used to date. I did notice that the CMIT needed more gain than anything else, the CMC641 just a little less, 416 and 81 fairly high as well, and the 60 only at about halfway up the scale.

Make sure there isn't wrong with your cables or something.

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Had to crank up the preamp quite a bit, so I decided to go cable instead of wireless boom, but the wireless boom was a lot quieter to my surprise.

For a troubleshooting starting point, to me your wireless boom is now your baseline, it's quiet to you.

I used a Schoeps CMIT going to a Sound Devices MM-1. Cable out of MM-1 line in to the Nomad, the preamp noise was notable (which means too high for my taste).

So the changes from the baseline show that noise was introduced at some point from the Schoeps, MM-1, or new cable(s) that you introduced to cause the noise?

Using a Lectro LMa/SRa out of the MM-1 with the Smart NR in the SRa set to normal, the noise was already audibly lower, with Smart NR set to full it was much lower and that's what I opted for eventually.

So following the path, the noise had to pass through the SRa to be influenced by it, that rules out the nomad as it was "quiet" for the baseline?

Surprised me a bit, since I know my Nomad's preamps are not noisier than others (they have been tested by my dealer's tech and he said they are among the quietest preamps for location recorders.)

See baseline above :)

I always thought going cable is quieter than wireless boom.

"It depends..."

For the record, going in directly with the Schoeps into the Nomad, the noise was even higher than with the MM-1 as a preamp.

This would lead my troubleshooting to something new between the nomad and the Schoeps to introduce noise since it wasn't there with the original wireless connection. Or RF interference entering the new cables ect.

Unless I've totally missed your setup, it doesn't appear to be a "Nomad preamp" issue as the noise would be something closer (or at) the Schoeps that sounded like "preamp" noise.

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one thing to also check is your relative headphone gain, I know when I crank up the headphone level on my Fusion the noise floor jumps up a lot towards the end and that noise isn't on the track.

Preamp gain / accuracy is not a zaxcom strength in my experience.

C.

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I think the "issue" is not the preamp so much as it is the Lectrosonics smartNR. Its designed to eliminate the "hiss" sound. If you want to compare apples(although it would be fuji vs a gala) compare the nomad pre to the wireless system with smartNR off. Although the hiss might get knocked down with the wireless system, the characteristic of the sound is different than hard line. Be sure to calibrate your levels while testing so your ear doesn't get fooled by different amplitudes

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I also noticed a high noise level when the headphone level was set beyond 2 o'clock. The actual sound recorded on the card seemed just fine. The mikes were Schoeps Cmit, 641 MK41, and Neumann KM 184-185s, and Audio LTD wireless. I think the Nomad preamps are fine but the monitoring signal is not so good when it is cranked up too high.

Ciao, Sully

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Using LectroSM/COS11 & hard wired boom (Sanken CS1) for interviews last couple of days. trim +3 and pots about 3 oclock into Sony F3 cam, monitor return set to +20. No noticeable noise floor from nomad, and producer said he LOVES the way the boom sounds! Far better than the lav.... That just made my day.... :D

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The Nomad monitor section noise content is the same at full level or infinity. The headphone circuit has no audible noise content.

It is possible that unused inputs were being mixed into the headphone and that is where the noise came from.

Glenn

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I've been testing the Nomad a bit before taking it out to the field.

I set the gain on all inputs on +13 dB (which I found would probably be where I'd set my mics around - so far tested the suitable trim level with Rode NTG-3 and Oktava MK-012), set the faders on 0, limiters, phantom etc off. What I got was:

Input 1: -85.8 dB

Input 2: -76.0 dB

Input 3: -65.0 dB

Input 4: -82.3 dB

Input 5: -75.0 dB

Input 6: -82.0 dB

I tested the file with Nuendo, adding fades to the ends as well. Boosting the gain on the files also showed that some of the inputs were not just exhibiting "regular old" noise, but some electronic noise/RF was also present. The character of the electronic interference was also different on two different instances on channel two. Is this sort of variance and electronic noise (and these sorts of noise levels overall) to be expected? I can post the file if needed.

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I've been testing the Nomad a bit before taking it out to the field.

I set the gain on all inputs on +13 dB (which I found would probably be where I'd set my mics around - so far tested the suitable trim level with Rode NTG-3 and Oktava MK-012), set the faders on 0, limiters, phantom etc off. What I got was:

Input 1: -85.8 dB

Input 2: -76.0 dB

Input 3: -65.0 dB

Input 4: -82.3 dB

Input 5: -75.0 dB

Input 6: -82.0 dB

I tested the file with Nuendo, adding fades to the ends as well. Boosting the gain on the files also showed that some of the inputs were not just exhibiting "regular old" noise, but some electronic noise/RF was also present. The character of the electronic interference was also different on two different instances on channel two. Is this sort of variance and electronic noise (and these sorts of noise levels overall) to be expected? I can post the file if needed.

Post the file.

I don't understand the workflow of the test. You plug mics and measure the noise levels??

Are you in a isolated studio room?

So you amplify the noise floor?

Again try to disable IFB Mode

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I am referring to the noise floor, not RF noise. My headphone level is always 1 o clock. I guess the actress just talked very low so naturally I cranked up the trim which resulted in higher noise floor but as I wrote, the wireless gave me the lowest noise floor. It's the opposite of what I thought, until yesterday.

Every preamp has a noise floor and I don't mind it as long as I don't notice it in my everyday work situations. But yesterday I had this situation and it was noticeable.

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Post the file.

I don't understand the workflow of the test. You plug mics and measure the noise levels??

Are you in a isolated studio room?

So you amplify the noise floor?

Again try to disable IFB Mode

No man, mics are disconnected. I merely used the mics to set a trim level to each channel that I would probably be using in the field if I had my boom mic or a stereo pair connected to a channel/input. I'll post the file once I get home later today.

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You've tested the preamps without a load, which is not a valid noise level test. Heres's why: The microphone preamplifier must have the proper source impedance at its input. If it does not, the preamp will amplify the noise of its internal bias resistors, resulting in much higher noise voltage.

An easy way to do a test with a load is to get a 150 ohm resistor and put it across pins 2 and 3. Redo the test and see if anything changes.

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I was thinking that either something might be off with the device or with the test. Thanks for correcting! I suppose I would (and should) really benefit from brushing up my high school physics and further educating myself in basic electronics.

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Thanks Glenn. That is exactly what happened. I had left some pots open too much. When I did a fast test with an open pot or two, the noise level increased. With all the unused pots down the monitor signal was quiet again. After two months the machine is performing beautifully. The only limit to the unit is an old guy with a slow learning curve. Thanks again, Glenn, for always jumping on potential problems and answering them on this site.

Ciao, Sully

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Hey Armin, no, the Super CMIT is a quiet mic. It better be, at the price. In fact the hiss partly might have been the CMIT's self noise plus the preamp's self noise adding up.

What I learned from this situation is that the SRa's noise reduction works very well and in extreme situations will be better than using a cable.

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In fact of the specs MKH 60 / 70 are more quiet than CMIT / SuperCMIT

MKH 60 40mV/Pa and 8dB(A) noise

MKH 70 50mV/Pa and 8dB(A) noise

CMIT 17mV/Pa and 14dB(A) noise

SuperCMIT 14 dB(a) / 16dB(A) noise

Recently I did another comparison MKH 416 vs. MKH 70

MKH 416 25mV/Pa and 13db(A) noise

and MKH 70 was a bit better but not that much as the specs and my previous experience would imagine.

But I could have heard the noise of SD 552 preamps... Would compare at SQN 4 mini next time.

Good to know of that noise cancelling in the SRa - never heard of it before.

BUT: "For the record, going in directly with the Schoeps into the Nomad, the noise was even higher than with the MM-1 as a preamp."

That really suggests me that the MM-1 Preamp was better than the nomads...?

On the other hand: if noise cancelling in SRa makes a difference if switched on and of there must have been noise in the first place?

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Using LectroSM/COS11 & hard wired boom (Sanken CS1) for interviews last couple of days. trim +3 and pots about 3 oclock into Sony F3 cam, monitor return set to +20. No noticeable noise floor from nomad, and producer said he LOVES the way the boom sounds! Far better than the lav.... That just made my day.... :D

I noticed this as well. I have gotten some very clean audio off the boom, much like he very isolated sound you can get with a lav, but with the drastically better frequency response of a boom with my Nomad. Crazy difference over my old SD 442. I really do love the sou d of my Nomad. They just need to get smooth out the rest of the machine and get it to be a little more solid in the field.

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