Phantom Power Over CAT-6? SM7B > the sssnake Cat Snake 3MB > Cloud Lifter > A & H QU16

[podshopstudios]

Hey there, first post on the forum but hoping for some advice on a planned studio build.

We're a podcast studio that has been using a basic setup just to test the market. 4 x SM7B with a Rodecaster Pro 2 mixer and it's done the job. SM7B's are a little noisy, but preamps in the Rodecaster Pro 2 are decent and have been getting a good sound.

We're building a new studio, and looking to update the full setup primarily to increase the inputs from 4 mics.

In terms of mixer, settled on the Allen and Health QU16, and the planned setup was going to be;

Allen & Health QU16 > the sssnake Cat Snake 3FC > CAT 6 > the sssnake Cat Snake 3MB > 4 x Shure SM7B microphones.

I don't have the sssnake products yet, but just tried running the SM7B's straight to the A&H and needed to boost the gain to 60db to get the level closer to 0!! I knew the SM7B's need a lot of power, but the Rodecaster Pro 2 seemed to deal with them okay.

I know a lot of people use these with the Cloudlifters, and I've got one of the CL-1's I thought I'd try and that seems to have worked okay, gain is now set to 28db with a good level. So in theory if I bought 2 of the CL-4's that would be enough for up to 8 mics which is enough.

However, my question is... does CAT-6 allow phantom power to pass through and with the sssnake allow phantom power to boost the SM7B's? Is there a better way around setting all of this up?

Thanks!

[MarkOne]

The sssnake Cat Snake 3FC isn't proper cat 6, it just uses the shielded 4 x twisted pairs in a cat 6 cable to pass the analogue signals between ssnake units and as long as you use grounded foil shielded cat 6 cable it should work OK with phantom power.

Wiring info

[Hugh Robjohns]

Hey there, first post on the forum but hoping for some advice on a planned studio build.

Welcome to the forums.

SM7B's are a little noisy, but preamps in the Rodecaster Pro 2 are decent and have been getting a good sound.

No, the SM7Bs aren't noisy. The only noise you get from dynamic mics like the SM7B is thermal noise from the resistance of the moving coil... and that's incredibly low.

So the noise you're hearing is either electronic noise from the preamp — which is possible as you need a lot of gain with an SM7B — or acoustic room noise because your guests aren't working the mics closely enough.

...tried running the SM7B's straight to the A&H and needed to boost the gain to 60db to get the level closer to 0!! I knew the SM7B's need a lot of power, but the Rodecaster Pro 2 seemed to deal with them okay.

Thats because the Rodecaster offers up to 76dB of gain.

I know a lot of people use these with the Cloudlifters, and I've got one of the CL-1's I thought I'd try and that seems to have worked okay, gain is now set to 28db with a good level.

Yes, the CL1 boosts the mic signal by around 25dB, so you won't need to run the mixer preamps flat out.

However, my question is... does CAT-6 allow phantom power to pass through

I've not tested it myself, and I've read varying reviews, some claiming it won't and others that it will!

Of the naysayers, it looks like they were using unshielded cable... which is silly!

I think it will work fine with phantom power, but only if you use Shielded Cat 6/7 cables, ideally with ethercon connections.

Is there a better way around setting all of this up?

Not really, if you're wedded to using SM7Bs, the Cloudlifters (or equivalents) will probably be required to help out the desk preamps, especially if you're expecting to peak close to 0dBFS.

[podshopstudios]

Thanks all, we are wedded to the SM7B as we have 8 of them so can't really swap them out. But the QU16 can be returned, and I've not purchased a preamp/CL-4 just yet.

To be honest, I'm not overly impressed by the QU16. The majority of the noise seems to be coming from that, 60dB of gain but very noisy which isn't present on the Rodecaster when boosted to 60dB.

This isn't to do with anything in terms if guest distance from the microphones, this is me at the desk with the microphone about an inch away.

If anyone could suggest a setup from these requirements, would be massively appreciated;

- 16 channel mixer that can record multi-track to a SSD with good pre-amps. We use the multitrack as a backup recording
- If we need need a pre-amp, needs to have 8 inputs and output
- This will be connected to a Broadcast Bionics video server (so these is some technical requirements here, which I've been advised that ideally the individual mic sends from the mixer to pc would be post-fader
- Budget of about 3.5/4k for the mixer and pre-amp

[sonics]

I would get the inline preamps. You said that sounded good with the Shure mics when tested. The Qu is really not a noisy desk if you're not cranking the preamps to max. Plus you're a podcast studio, so you don't really need to achieve the same low noise floor as a music studio. Just some subtle NR or expansion in post is all you need if you really think it's required.

[podshopstudios]

I would get the inline preamps. You said that sounded good with the Shure mics when tested. The Qu is really not a noisy desk if you're not cranking the preamps to max. Plus you're a podcast studio, so you don't really need to achieve the same low noise floor as a music studio. Just some subtle NR or expansion in post is all you need if you really think it's required.

Noted, can you advise of a good 8 channel mic preamp with a low noise ratio please? Would rather solve with a preamp rather than in post, the studio is available self service, so we don't who's dealing with the audio in post.

[ef37a]

There are any number of 8 mic input ADAT units around e.g. Audient ASP800.
I am sure the top blokes here will know which have the gain and noise performance you require?
Pity Cranbourne don't make an 8 way jobby! I guess a fully loaded 500 lunchbox would be over budget?

I have sent phantom power over CAT5e shielded. Just make sure you do a solid job of soldering the drain wire.

Dave.

[sonics]

I would get the inline preamps.

Noted, can you advise of a good 8 channel mic preamp with a low noise ratio please? Would rather solve with a preamp rather than in post, the studio is available self service, so we don't who's dealing with the audio in post.

I meant simply getting two CL-4 units. Sorry for not being clearer.
If you're offering the studio as self-service I would think a more complicated preamp would risk confusing clients, so the CL-4s would be the simplest option.

[podshopstudios]

I would get the inline preamps.

Noted, can you advise of a good 8 channel mic preamp with a low noise ratio please? Would rather solve with a preamp rather than in post, the studio is available self service, so we don't who's dealing with the audio in post.

I meant simply getting two CL-4 units. Sorry for not being clearer.
If you're offering the studio as self-service I would think a more complicated preamp would risk confusing clients, so the CL-4s would be the simplest option.

Sorry for the slow reply, yes this is my plan B. But I was wondering if there was a single unit that perhaps gives more clean gain than the CL-4s that would look after all 8 channels.

The unit is going into a locked comms cab anyway so access isn't an issue and will be set and left as is, but space is a concern.

[Saxum esse et non provolvere]

At a pinch I've sometimes used a Behringer ADA8200 (other similar units, some of higher quality, are available !) with its ADAT out looped back to its ADAT in as a standalone 8-channel preamp. Obviously there's some penalty in terms of latency while the A/D and D/A processes occur, but it might be worth considering.

[sonics]

But I was wondering if there was a single unit that perhaps gives more clean gain than the CL-4s that would look after all 8 channels.

For reliability I think two CL-4s is the best way to go. 25dB of clean gain (you don't need more) and nothing to adjust. They sound like a perfect fit to me!

(If you really want more gain the the newer CL-X has 36dB. You'd need eight of those, of course.)

[Hugh Robjohns]

I second the CL-4 pair.