abbey road d enfer

Re: Any thoughts about "True Phantom"?
« Reply #20 on: October 09, 2018, 02:40:22 AM »
But it is very important for mikes with a output transformer.  I would never connect this phantom power supply to a 414, U87 and similar.
Any DC current delivered would be constrained by the common-mode impedance. According to specs, it's about 200 kiloohms (or 2 Megs??). As long as the system operates within its linear limits, the worst-case (i.e. with one pin shorted to ground) differential DC current would be about 250 uA, not enough to do any harm to the transformer, nor magnetizing it significantly.
« Last Edit: October 09, 2018, 03:49:24 AM by abbey road d enfer »
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.


Gus

Re: Any thoughts about "True Phantom"?
« Reply #21 on: October 13, 2018, 10:31:20 AM »
the circuit(s) design deserves more discussion.

abbey road d enfer

Re: Any thoughts about "True Phantom"?
« Reply #22 on: October 13, 2018, 12:28:30 PM »
the circuit(s) design deserves more discussion.
Does it really? The patent is pretty clear.
I have been very critical in the past towards the FetHead, that seems to be spiced with too much fairy dust, and it may be the case here too, but the principle is sound.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

Gus

Re: Any thoughts about "True Phantom"?
« Reply #23 on: October 13, 2018, 12:52:59 PM »
I was thinking more along the lines of
Two well matched(better than .1%) 1/2 watt 6.8K resistors
vs
A circuit that has more parts.

Are there power up power down failure issues?

Does it make a difference that can be heard?
I don't trust reviews, videos and recordings on the web I use them as a starting point.

Plus will the user have to remove the phantom resistors in preamps that have them for the full effect of the circuit. Phantom power can be switched out at the phantom resistors power supply node so they are always in circuit.

mhelin

Re: Any thoughts about "True Phantom"?
« Reply #24 on: April 27, 2020, 08:29:43 AM »
Found this schematic with component values by accident in Youtube.

RuudNL

Re: Any thoughts about "True Phantom"?
« Reply #25 on: April 27, 2020, 10:06:45 AM »
Do you have a link to the video?
There is a solution for every problem!

http://www.vansteenisaudio.nl

mhelin

Re: Any thoughts about "True Phantom"?
« Reply #26 on: April 27, 2020, 05:48:34 PM »

gyraf

Re: Any thoughts about "True Phantom"?
« Reply #27 on: April 28, 2020, 05:49:25 AM »
If that circuit is real, I see a whole range of error modes that can bring up voltages to a point (63V DC anyone?) that is really not healthy for many P48-based mics.

I see potential of many smoked output electrolytics in e.g. Neumann TLM and Schoeps-type microphones.

Nobody, Nobody expecs to see over 52V there..

/Jakob E.
..note to self: don't let Harman run your company..

Gus

Re: Any thoughts about "True Phantom"?
« Reply #28 on: May 02, 2020, 11:55:10 AM »
I simmed the figure 4b circuit. I did not sim the one from the youtube video yet.

I might build one for fun to see how it interacts with different phantom powered microphones circuits.





MediaWorksOKC

Re: Any thoughts about "True Phantom"?
« Reply #29 on: May 10, 2020, 07:48:38 AM »
Yo!

It's my understanding that Joost Kist and Triton are separate entities and that Triton has licensed the design. His AES paper is attached below. I'll delete if inappropriate to post. I had some correspondence with him years ago about this.

He said a chip is "in development" to be available at low cost at some point in the future, for some time now... tick-tock. Maybe 3 years since I first looked at his design.

I hear a positive difference in the resulting sound from the design that doesn't correlate to the minor improvements of a few percentage points here or there. It's real. Just sounds more natural. To me.

I would never pay 500 dollars but would happily buy quantities of a 5 dollar chip.

Chris
« Last Edit: May 10, 2020, 08:50:35 AM by MediaWorksOKC »
Then: Artists were Ugly; Art was Beautiful
Now: Artists are Beautiful; Art is Ugly


RuudNL

Re: Any thoughts about "True Phantom"?
« Reply #30 on: May 10, 2020, 02:46:26 PM »
Of course, theoretically it might be an improvement.
But personally I am not really worried about second harmonics at -107 dB (people even like tube microphones for the second harmonic content they produce!) and certainly not about -139 dB third harmonics...
And I am not over excited about the 0.06 dB higher output.
I wish the makers all kinds of luck, but I am afraid that this won't change the world.
There is a solution for every problem!

http://www.vansteenisaudio.nl

analogguru

Re: Any thoughts about "True Phantom"?
« Reply #31 on: May 10, 2020, 04:14:20 PM »
I don't know why but I am unable to see anything remarkable new compared to the current-source-design A52 from AKG from the late 60's:

Gus

Re: Any thoughts about "True Phantom"?
« Reply #32 on: May 10, 2020, 05:27:21 PM »
It is a little different to the AKG
I simmed a circuit based on fig 4B in the following link
http://www.sumobrain.com/patents/wipo/Phantom-power-supply-microphone/WO2016171551A1.pdf
I used  resistors values I calculated that should work for a range of microphone currents about .2 to 10mA

repeating what has been posted in this thread in a little different way

The 6.8K resistors ARE NOT connected directly together at the 48VDC supply
The middle opamp  in the patent adjusts the voltage to current sources that are "feeding" the individual 6.8K phantom resistors the opamp senses the voltages by  resistors. The output of the current sources are  collectors and they have high resistance.






« Last Edit: May 10, 2020, 05:34:03 PM by Gus »


 

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