RODE S1 Condenser mic with QU-32 desk

[oceanroadParticipant]

Hi,
I’m wanting to know if there have been any reported issues with powering up condenser microphones using the QU-32 (48v) option?

I have had 2 x separate RODE S1 microphones plugged into the desk trying to get them to work properly
each one has either muffled or only very slight sound coming from FOH. They have been swapped out by manufacturer 2 x twice

I have changed channels, changed cables etc etc.

The microphones work perfectly fine on our A & H ZED420 analog desk and other branded desks.

Any clues to why this would happen? other condensers we have work fine (Sennheiser e914, Shure KSM32, Shure SM81)
all work fine.
Is it a case whereby the mic just needs more than normal? anyone else had these issues????
thank you

[AndreasModerator]

Not sure if the S1 has significantly different phantom power requirements than other Rode condensers, at least I never had issues yet with my M2/M3/NT2-A/NT3/NT5…

[GCumbeeParticipant]

I can’t understand any reason for this if in fact another condenser mic works on that channel without anything being changed and the S1 works ok on another mixer. It just makes no sense.

The only thing would be if for some reason the phantom supply is being loaded down. I once saw a case when a church had 6 Neumann KM84’s over choir. They called me saying their mics quit working. I went over. It was a Soundcraft analog desk. They were preparing for an Easter production and had rented 6 wireless mics. The receivers were plugged into channels with phantom on and they were loading the power supply down. I measured the voltage on a connector for the km84’s and it was less than 12vdc. Neumanns require at least about 43vdc minimum to work. I turned off the phantom on the wireless channels and the voltage came back up.

So. Check any channels that might have phantom on that’s not needed. See what that does. Maybe these mics are similar to Neumanns and require a full voltage. Many and most condensers will work anywhere from 9-52vdc. But there are exceptions.

If you have a digital it even analog volt meter set it to read DC voltage and measure between pin 1 and either 2 or 3 on the affected channel and see what the voltage is. That might tell you the problem.

[AndreasModerator]

I did a quick search on the net and the S1 indeed seems to be somewhat picky regarding phantom power, there are also other users with issues getting that particular mic to work.
Stumbled over some strange specs (not from Rode but some dealers) which specify some 4.4mA current and minimum voltage of 44V. If that’s the case, they hardly can work. P48 is specified with an impedance of 6.8kOhm. 2.2mA (half of 4.4mA since we have two lines) at 6.8kOhm causes a voltage drop of about 15V, so we only have 48-15 = 33V at the connector (@oceanroad maybe you could measure that?). If the Mic really needs 44V it only would operate with phantom supply out of spec (> 59V). I don’t take these numbers too serious…
If the mics operate correctly on other desks, maybe the Qu has some protection circuit within the phantom supply.
The Wikipedia Phantom Power article states, that the original spec allows 2mA only but several newer mics require more current (up to 10mA).

Btw: That article repeats the Disable-Phantom-When-Connecting statement along with explanations why this could damage the input circuit and/or the mic, so take it serious.

[oceanroadParticipant]

Thanks guys for your input, very insightful & interesting opionions. BTW, no other channels were activated with phantom power at the time of troublshooting the issue. I think there’s some voltage testing we need to do by the sounds of things. I just find it quite bizzare for such a great microphone & a pity we cant use it on this particualr desk at present. Appreciate your inputs.

Thank you

G

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