CS 48 mic pres?

[Sheldon Radford]

Hi Brad,

I meant SC 48 mic pre. I edited the original post to make this clearer.

Sheldon

[digimidi]

Just to clarify, the Digidesign PRE is 3 db steps. No digital control.

Gil

[BradLyons]

<-------is going to go stand in da cornuh now cause I feel stoopit!

[digidesigner]

Thanks Sheldon and Gil, in case you are willing to share some additional info, what makes a mic pre different in the situation where three consoles share a mic and might all have +48 turned on?

[Sheldon Radford]

There are really two issues that come into play...

In a live setting it's not uncommon to split a mic 2, 3 or even 4 ways, all done passively (with wiring and sometimes transformers). In this case the mic is wired in parallel to each console, so the mic pre's input impedance needs to be high enough that this passive split doesn't cause significant signal loss, but not so high that it's susceptible to noise. In the studio the mic is usually only connected to one pre.

Re +48V: on a live gig it's possible to have multiple consoles all feeding phantom power through the passive split (unless transformers are used). In this case, there must be sufficient protection to ensure the multiple +48 V sources don't damage the mic pre. This is done with a simple diode protection scheme.

Sheldon

[digidesigner]

Originally Posted by Sheldon Radford

There are really two issues that come into play...

In a live setting it's not uncommon to split a mic 2, 3 or even 4 ways, all done passively (with wiring and sometimes transformers). In this case the mic is wired in parallel to each console, so the mic pre's input impedance needs to be high enough that this passive split doesn't cause significant signal loss, but not so high that it's susceptible to noise. In the studio the mic is usually only connected to one pre.

Re +48V: on a live gig it's possible to have multiple consoles all feeding phantom power through the passive split (unless transformers are used). In this case, there must be sufficient protection to ensure the multiple +48 V sources don't damage the mic pre. This is done with a simple diode protection scheme.

Sheldon

Hi Sheldon and thank you for the answer. But are you saying DigiPre input impedance would not suit into this type of situation? (being one of 4 "consoles" lets say in live recording situation?) Also does DigiPre lack of such diode protection scheme?

[mackerr]

Originally Posted by BradLyons

Are you saying that the 6dB stepped-gain is on THE PRE (outboard unit) or on the console's pres? I'M CONFUSED NOW!

Originally Posted by Sheldon Radford

Re: the gain step size.
The Mix Rack/SC 48 mic pre uses a combination of analog and digital gain over its full range. The analog gain is relay-switched in 6 dB steps. In between these steps digital gain is then used to give 0.1 dB gain increments. From a user's perspective you have full control of a mic pre from +10 dB to +60 dB in 0.1 dB gain increments (the transitions between analog and digital gain are handled automatically as the gain is adjusted). This hybrid approach gives the best combination of fine control and high quality audio performance.

My bold.

Mac