True Phantom® from PREMA Semiconductor

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mediatechnology
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True Phantom® from PREMA Semiconductor

Post by mediatechnology »

"True Phantom® Power Supply Minimizes Condenser Microphone Distortion"
PREMA IC PR2301

TruePhantom® is a high impedance phantom power supply for condenser microphones with a servo-regulated output voltage of 48V. This decreases the load for your microphone considerably.

Compared with standard phantom supply circuits, TruePhantom® reduces distortion from a condenser microphone output by between 3.6 dB and 14 dB, minimizing especially the third and fifth harmonic. It complies with standard IEC 61938, P48.

The PR2301 integrates the required circuits in one IC, making it easy to replace standard phantom by TruePhantom® and enhancing the quality of your mixing console.
True Phantom: https://www.truephantom.nl/
Product Page: https://www.prema.com/index.php/en/assps-en/audio-ic
Data Sheet: https://www.prema.com/index.php/en/assp ... d34a3316f6

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I learned about this in 2017 and just now remembered it after reading about the "Cloud Lifter."
Though they are completely different things both re-examine the microphone to preamp interface.
emrr
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Re: True Phantom® from PREMA Semiconductor

Post by emrr »

Hmmm…..and then I’ll run it through some transformers to get more 3rd back in….so…transformer output mic contribution swamp this reduction? Hard to get excited on the face of it

OTOH there’s a growing list of high dollar standalone phantom supplies on the market. $400 2 channel devices, etc. Hard not to think of PT Barnum, unfair if there is something to it, but practical reality says my $ is best spent elsewhere. Only hubris says “I’ve covered EVERY other base so now let’s tackle this”.
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mediatechnology
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Re: True Phantom® from PREMA Semiconductor

Post by mediatechnology »

I kinda dismissed it back in 2017.

The utility or lack of utility of the Cloudlifter made me think about the 2017 email regarding True Phantom. I got curious, decided to dig and found they actually made silicon.

It would be OK if True Phantom were a tertiary or secondary feature of the product but the first question I asked when looking at it was "how do I turn phantom off?"

As I mentioned elsewhere there might be a market for a dedicated phantom IC if it had the simple basic functions of turning phantom on and discharging the capacitors controlled by logic-level signals. Every CPU-controlled mic input channel needs this basic functionality and if were smaller and cheaper than roll-your-own solutions it might sell. The monthly volumes for a dedicated switch could potentially be in the tens of thousands.

Gus on GDIY brought up the question about whether True Phantom would reduce mic output transformer distortion (even order) by reducing DC in the winding.

Well it might, but at phantom turn on a differential transient current is caused by input coupling capacitor tolerance mismatch of the pair that would magnetize iron in the transformer. So though True Phantom could reduce steady-state magnetization currents it could do nothing about the already-magnetized core.
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Re: True Phantom® from PREMA Semiconductor

Post by AnalogJoe »

I don't know why it would be a problem to load the capsule if it is with the right impedance. If the microphone is designed to see 1.5 K, for instance, then you make the equivalent resistance between the phantom resistors and the pre input impedance to be 1.5K, how is that bad? Also, 14 dB of THD reduction? I am tempted to call it BS, but I should look more into it before giving a final veredict....
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