RuudNL

Any thoughts about "True Phantom"?
« on: October 06, 2018, 09:11:59 AM »
Any thoughts about this?  ;)
http://truephantom.nl/

(Personally I am not really impressed by : "0.06 dB louder"...)
There is a solution for every problem!

http://www.vansteenisaudio.nl


Gus

Re: Any thoughts about "True Phantom"?
« Reply #1 on: October 06, 2018, 10:03:34 AM »
Not enough information at the link.

EDIT after finding and reading the patent what I posted below is not correct.

A simple read sounds like two CC devices one goes to pin 2 the other to pin 3. CC devices can be as simple as JFETS wired as CC devices however you might want a little more than 48VDC as the DC source.
Could be two different supply voltages one set at 48VDC (maybe higher) and the other set at a higher voltage for use with a more complex high side active constant current circuit.

Search for constant current supplies and high side constant current supplies for circuits.

Now P48 microphones have different current specs so I am wondering at what current the constant current supply is set.
What I mean if the phantom supply circuit is set to 5mA for each leg(10mA total) and the circuit needs 1mA(.5mA each leg) or 6mA(3mA) each leg.

Not knowing what circuit is used I do not know how the supply will interact with different microphone circuits.

EDIT found this link https://www.soundonsound.com/reviews/triton-true-phantom


Looking for the patent. Until I find the patent to read it I am wondering. How do you patent a textbook circuit like a constant current circuit?

EDIT two
Often the when phantom is switched off just the voltage to the resistors is switched off so the resistors are still in circuit in parallel.
« Last Edit: October 08, 2018, 04:42:09 AM by Gus »

analogguru

Re: Any thoughts about "True Phantom"?
« Reply #2 on: October 06, 2018, 10:37:07 AM »
Any thoughts about this?  ;)
http://truephantom.nl/
.....
My thoughts ?  Another money-vampire who wants to suck your hard earned money with snows of yesteryear.

Technically nothing new under the sun.  AKG sold such stuff since 1969 under the model name A52:
« Last Edit: October 06, 2018, 10:53:15 AM by analogguru »

Gus

Re: Any thoughts about "True Phantom"?
« Reply #3 on: October 06, 2018, 11:02:12 AM »

RuudNL

Re: Any thoughts about "True Phantom"?
« Reply #4 on: October 06, 2018, 12:11:54 PM »
From Sound on Sound:

"the engineering sophistication and elegance involved here is unnecessary in 99.5 percent of real-world recording situations."

The price: £478.80 including VAT  :D
There is a solution for every problem!

http://www.vansteenisaudio.nl

Re: Any thoughts about "True Phantom"?
« Reply #5 on: October 07, 2018, 10:07:46 AM »
every designs created to reduce THD (without disadvantages) are welcome to me...
« Last Edit: October 07, 2018, 10:13:16 AM by granger.frederic »

RuudNL

Re: Any thoughts about "True Phantom"?
« Reply #6 on: October 07, 2018, 10:17:40 AM »
But isn't a price of  £478.80 a bit high for a distortion reduction of  0.0001%?

(You can measure it, but would you be able to hear it?)
There is a solution for every problem!

http://www.vansteenisaudio.nl

Gus

Re: Any thoughts about "True Phantom"?
« Reply #7 on: October 07, 2018, 02:14:47 PM »
Think I found the patent stuff

This took some time to find
Need to read this and try to understand the wording
http://www.sumobrain.com/patents/wipo/Phantom-power-supply-microphone/WO2016171551A1.pdf

http://www.sumobrain.com/patents/wipo/Phantom-power-supply-microphone/WO2016171551A1.html

http://www.aes.org/events/140/presenters/?ID=4865


I wonder what purist's will say when they see the circuity
« Last Edit: October 07, 2018, 02:32:09 PM by Gus »

e.oelberg

Re: Any thoughts about "True Phantom"?
« Reply #8 on: October 07, 2018, 02:58:57 PM »
Funk sells matched resistors for three euros, might have a similar effect  http://www.funk-tonstudiotechnik.de/NETZTEILE.htm

scroll to the bottom

RuudNL

Re: Any thoughts about "True Phantom"?
« Reply #9 on: October 07, 2018, 03:13:06 PM »
To my surprise I received an invitation to attend the paper session at AES convention on October 19 at 9.30 in New York.
Unfortunately no free ticket was added...  ;D
There is a solution for every problem!

http://www.vansteenisaudio.nl


analogguru

Re: Any thoughts about "True Phantom"?
« Reply #10 on: October 07, 2018, 04:11:32 PM »
This guy must have too much money.  I bet that he will never get back all the money he had to in-waste (for lawyer, fees, etc.) to obtain this "patent" (which he would have to - successfully - defend with additional money).
BTW, I highly doubt that he ever will be in a situation where he would have to defend this "patent".  There have been - and will be - made so many good records without this invention....

.....
Found this, page 3
http://lcweb2.loc.gov/master/mbrs/recording_preservation/manuals/AKG%20B-1E,%20N-62E,%20N-62ET,%20N-66E.pdf
The values from the two resistors at the right are 680 Ohm, the other two are 470 Ohm, capacitor is 470pF styroflex.  But this configuration doesn't deliver full 10mA (only about 3mA)...

« Last Edit: October 07, 2018, 05:57:16 PM by analogguru »

moamps

Re: Any thoughts about "True Phantom"?
« Reply #11 on: October 08, 2018, 04:31:44 AM »
Now P48 microphones have different current specs so I am wondering at what current the constant current supply is set.
What I mean if the phantom supply circuit is set to 5mA for each leg(10mA total) and the circuit needs 1mA(.5mA each leg) or 6mA(3mA) each leg.

It looks from the patent that they are using a "voltage  controlled CS". What rises the question is it CS anymore.

Gus

Re: Any thoughts about "True Phantom"?
« Reply #12 on: October 08, 2018, 05:50:39 AM »
Did a first read of most of the following patent application.

http://www.sumobrain.com/patents/wipo/Phantom-power-supply-microphone/WO2016171551A1.pdf

If I am understanding the patent application the following is what I think is happening.

Does anyone know if this patent application is what is used in the supply in the first post?

If anyone else reads the patent application please comment. Let me know if you see any errors in my post.

Looking at fig 3b

The 3b circuit looks like a voltage regulator circuit that sums the voltage at the top of both of the phantom resistors that go to pins 3 and 2 to compare against a 48VDC voltage reference and then controls two semiconductor pass circuits one for each of the resistors that go to pins 2 and 3 with the collectors of PNP transistors as the connection to the supply resistors. The top of the supply resistors are where the sense connections are made

The collectors to the "top" of the supply resistors are set to 48VDC

So it looks like a a voltage regulator circuit with the outputs being collector out (not emitter out) with pin 2 and 3 outputs having separate pass devices. The phantom resistor values are not shown, however reading  the claim section claim 4 and claim 12 are they 6.8Ks?

So is this a 48VDC series voltage regulated power supply with two summed sense connections with two collector out pass circuits for each phantom resistor circuit like in figure 3b?

The top of the phantom resistors are not connected together they go to separate collector out connections.

The sense resistors don't load the phantom supply resistors because they go to the noninverting input.









moamps

Re: Any thoughts about "True Phantom"?
« Reply #13 on: October 08, 2018, 06:25:56 AM »
So is this a 48VDC series voltage regulated power supply with two summed sense connections with two collector out pass circuits for each phantom resistor circuit like in figure 3b?

Most likely. And it doesn't work as it should, IMO. 

abbey road d enfer

Re: Any thoughts about "True Phantom"?
« Reply #14 on: October 08, 2018, 11:26:35 AM »
Most likely. And it doesn't work as it should, IMO.
In the presence of absolutely balanced symmetrical currents, it should. The common-mode impedance is 3.4K, but the differential mode impedance may be quite high. The claimed benefits are not really obvious in the posted examples; however, it may be interesting to compare with dynamic and ribbon mics, that are usually more sensitive to loading than condenser mics.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

moamps

Re: Any thoughts about "True Phantom"?
« Reply #15 on: October 08, 2018, 12:04:02 PM »
In the presence of absolutely balanced symmetrical currents, it should.
There should be two logical servos, one for absolute value and second for the difference.
This design is really sub-optimal, and do not works what the autor claims in the patent.
Quote
....but the differential mode impedance may be quite high...
The output of the voltage regulator presents very small impedance for AC signals so I doubt it.  And this impedance isn't linear in the whole audio spectrum.

abbey road d enfer

Re: Any thoughts about "True Phantom"?
« Reply #16 on: October 08, 2018, 01:13:04 PM »
There should be two logical servos, one for absolute value and second for the difference.
Why? A single servo is needed to make sure the nominal voltage ios 48V. Difference is managed by teh equality of absolute value of AC currents in the two branches. That is the case when the output is transformer balanced; for electronically balanced output, it depends on the actual balance of each side. In particular, some cheap designs that output signal on one leg only (using the other for DC only) may defeat the operation of said power supply.

Quote
The output of the voltage regulator presents very small impedance for AC signals so I doubt it. 
The common -mode impedance is indeed low (6.8k for each branch), but the differential impedance can be very high. When the sum of AC currents is null, the common-mode impedance is irrelevant.

Quote
And this impedance isn't linear in the whole audio spectrum.
Certainly, but does it need to be optimum in the whole audio spectrum? It depends on the interference signal's spectrum.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

moamps

Re: Any thoughts about "True Phantom"?
« Reply #17 on: October 08, 2018, 01:46:53 PM »
Why? A single servo is needed to make sure the nominal voltage ios 48V. ..
The second servo is needed to assure that the DC voltage between outputs is 0V. If it is not, that isn't phantom power. Period.
This is a lousy design, and I don't understand why are you defend it.

 

abbey road d enfer

Re: Any thoughts about "True Phantom"?
« Reply #18 on: October 08, 2018, 04:00:42 PM »
The second servo is needed to assure that the DC voltage between outputs is 0V. If it is not, that isn't phantom power. Period.
Why would it be so? Equal DC voltage is not a requisite for good CMRR. Only equality of impedance is required.

Quote
This is a lousy design,
It's your opinion and I don't share it. The principle is good; achieving claimed performance  indeed depends on actual implementation.

Quote
and I don't understand why are you defend it.
Then you should think about it a little more... IMO it's a brilliant design principle with very little practical value.
Who's right or wrong is irrelevant. What matters is what's right or wrong.
Star ground is for electricians.

moamps

Re: Any thoughts about "True Phantom"?
« Reply #19 on: October 08, 2018, 05:40:17 PM »
Why would it be so? Equal DC voltage is not a requisite for good CMRR...
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.
 


 

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