Topic: Octamic XTC Feature Request: Adjustable Phantom Power

It would be very handy to have an adjustable phantom power setting for each mic input with the Octamic XTC, i.e. fine tuning the standard 48V in the range of +-4V.

Purpose: Some microphones like the Neumann TLM 170R or TLM 127 for instance allow to remote control their directional patterns by slightly adjusting the phantom power in the range of +-3V. Right now we have to use dedicated phantom power supplies for such remote control tasks, along with their limitations (unhandy physical locations, no automation).

If we could do the same task by software with the Octamic XTC, then we could finally get rid of those additional power supplies and may conveniently save and restore the directional pattern setting of each microphone e.g. with TotalMix.

2

Re: Octamic XTC Feature Request: Adjustable Phantom Power

That would require significant changes in the hardware, means a new XTC II. It's not possible by firmware.

Regards
Matthias Carstens
RME

Re: Octamic XTC Feature Request: Adjustable Phantom Power

Does that mean the soft power on feature per mic is done solely by hard wired components?

I have not looked into the box, but my guess was that the existing slow ramping of the phantom power was to a certain way controlled by firmware controlled components (ucontroller or FPGA), e.g. to be able to adjust the ramp time later on through firmware updates if required for some reason.

I mean I understand that the range 48V +xV might not be possible with the current hardware design, but if the soft ramping is some how controlled by firmware, then at least the range 48V -xV might be possible with firmware update.

4

Re: Octamic XTC Feature Request: Adjustable Phantom Power

Indeed the soft-ramping is a fixed hardware function.

Regards
Matthias Carstens
RME

Re: Octamic XTC Feature Request: Adjustable Phantom Power

Too bad. Then I hope it goes at least onto the feature request list for a potential Octamic XTC 2.

Another issue related to the XTC phantom power control: There are numerous condenser microphones which create very loud noises for several seconds when you turn on or off phantom power (for instance the previously mentioned Neumann models do that). That's not a defect, some models simply do that by design. Therefore it would be preferable IMO if the XTC would automatically reduce gain temporarily to zero for several seconds, both when turning on and off phantom power. Right now I always manually reduce gain to zero (and even enable pad) before switching phantom power on for any one of those microphones. And since I have to setup two dozens of microphones, it feels like something that might better be done automatically.

Re: Octamic XTC Feature Request: Adjustable Phantom Power

Dear RME,

is phantom power switching only dangerous for monitoring devices (or our ears...), or is there already a known case of a damaged XTC by phantom power handling (e.g. by just connecting mics to the XTC while phantom power is switched on?)

Re: Octamic XTC Feature Request: Adjustable Phantom Power

Dis/connecting mics with active phantom power is generally not recommended.


Regards
Daniel Fuchs
RME

Re: Octamic XTC Feature Request: Adjustable Phantom Power

But what can really happen? Did anybody really experience a blown up Neumann microphone or mic preamp? So far I have never heard of real life problems.

9

Re: Octamic XTC Feature Request: Adjustable Phantom Power

Then you should look around in the manufacturer's repair departments...blown up mic preamps are not unusual. In most cases only the protection diodes, in some even the active components (transistor or IC).

Regards
Matthias Carstens
RME

Re: Octamic XTC Feature Request: Adjustable Phantom Power

From my personal experience I can also confirm that mic defects do occur. In my cases though the mic internal preamps were blown due to defective XLR cables in the past. I don't want to name specific brands, but there are microphones which are much more sensitive to pantom power issues (e.g. certain FET circuit designs without transformers) and on the other hand there are mics which you can do almost anything with and they would not suffer any damage.

However since I had such damages in the past, I am extremely cautios when connecting/disconnecting any phantom powered microphone. And I am now only using high quality XLR cables and swap them out for a new cable at the slighliest sign of connection issues. Saving money with your XLR cables is IMO not a good idea.