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Re: low voltage DC phantom (was new firmware for M-Audio Microtrac=

Subject: Re: low voltage DC phantom (was new firmware for M-Audio Microtrac=
From: Rob Danielson <>
Date: Thu, 24 Nov 2005 02:16:40 -0600
k  2496

At 9:50 PM +0100 11/23/05, Klas Strandberg wrote:
>Of course, I share everything with you...
>
>He has a design which is completely stable at 100 kHz

Hmm,.. is the "100kKZ" the switching frequency of the power supply?
The Rolls PB224 apparently "utilizes a proprietary high frequency
power supply to greatly reduce noise,"


>(or whatever choose) any circumstances and can therefore never
>become audible.They can be made portable, running from a 9 volt
>battery. Big as a cig pack.

Running on 9 volts would do it and an external DC input too. Still,
its impressive that the Sound Devices MP2/Mic Pre uses 3 volts for 2+
hours powering of phantom and pre.

>
>I will ask if he can think of producing a number of such power supplies an=
d
>the cost. Let me guess that he wants at least 2-3 times as much as a Rolls=
.

Thanks for asking. Might be some hard core folks willing to do this.

Logically, if the Rolls is contributing noise, it can't be much if
the 722's pre/phantom performance is considered near the best (based
on consistent comparison tests). And, if the Rolls is adding noise,
the HiMD pre becomes even more impressive. Rob D.


>
>Klas.
>
>At 04:16 2005-11-23, you wrote:
>>Does the phantom power supply he's designed produce less noise? Are
>>you free to tell us more? Is it portable? What operating voltage? Rob
>>D.
>>
>>    =3D =3D =3D =3D
>>
>>At 9:15 PM +0100 11/22/05, Klas Strandberg wrote:
>>  >According to my friend it is more or less by chance all the time if a =
power
>>  >device works or not. He sais that all modern IC-circuit for the purpos=
e
>>  >have a tendency to drift away in frequency. In his experience only one=
 of
>>  >them work under all circumstances, stable and pure. In his opinion, th=
e
>>  >Rolls is a very conventional and thereby unreliable device. ... if it
>>  >works, it works... kind of.
>>  >
>>  >Klas.
>>  >
>>  >At 19:43 2005-11-22, you wrote:
>>  >>One would think that a good phantom circuit would be easy to include
>>  >>like a good mic pre, but the demands might be at odds with small size
>>  >>and the low DC voltages involved. The 722 and 744 had phantom issues
>>  >>all the way through beta testing and they're ~11 volts and up. There
>>  >>are quite a few audio interfaces/pres that the run on AC wall warts
>>  >>apparently because of phantom powering demands. Len Moskowitz cited
>>  >>likely problems with the MT24/96's phantom when he first laid eyes on
>>  >>it.  Are there other ~3-4 volt DC voltage devices that have good
>>  >>phantom circuit performance besides the Sound Devices MP2 and MixPre?
>>  >>Rob D
>>  >>
>>  >>At 6:18 PM +0100 11/22/05, Klas Strandberg wrote:
>>  >>  >Yes, I will appreciate that! It makes it a much better recorder.
>>  >>  >Thanks Oryoki!
>>  >>  >I just wish they had a better phantom power supply installed.
>>Might come
>>  >>  >with the next model.
>>  >>  >
>>  >>  >Klas.
>>  >>  >
>>  >>  >At 16:14 2005-11-22, you wrote:
>>  >>  >>M-Audio has released a firmware update for
>>  >>  >>the Microtrack 2496.
>>  >>  >>
>>  >>  >>Klas, you'll appreciate these two fixes:
>>  >>  >>
>>  >>  >>1. The level meters now work in REC/PAUSE mode.
>>  >>  >>
>>  >>  >>2. When recording from mic or line inputs, the
>>  >>  >>headphone monitor now works in REC/PAUSE as well
>>  >>  >>as REC mode.
>>  >>  >>
>>  >>  >>Before rushing out to buy this $350 machine,
>>  >>  >>nature recordists should take note of its low
>>  >>  >>record levels relative to the Sony Hi-MD
>>  >>  >>recorder.  This is demonstrated in message
>>  >>  >>20599 posted by Rob D.  Thanks again, Rob!
>>  >>  >>
>>  >>  >>--oryoki
>>  >>  >>
>>  >>  >>
>>  >>  >>
>>  >>  >>
>>  >>  >>
>>  >>  >>
>>  >>  >>
>>  >>  >>
>>  >>  >>"Microphones are not ears,
>>  >>  >>Loudspeakers are not birds,
>>  >>  >>A listening room is not nature."
>>  >>  >>Klas Strandberg
>>  >>  >>Yahoo! Groups Links
>>  >>  >>
>>  >>  >>
>>  >>  >>
>>  >>  >>
>>  >>  >
>>  >>  >Telinga Microphones, Botarbo,
>>  >>  >S-748 96 Tobo, Sweden.
>>  >>  >Phone & fax int + 295 310 01
>>  >>  >email: 
>  > >>  >         
>>  >>  >
>>  >>  >
>>  >>  >
>>  >>  >
>>  >>  >"Microphones are not ears,
>>  >>  >Loudspeakers are not birds,
>>  >>  >A listening room is not nature."
>>  >>  >Klas Strandberg
>>  >>  >Yahoo! Groups Links
>>  >>  >
>>  >>  >
>>  >>  >
>>  >>  >
>>  >>
>>  >>
>>  >>--
>>  >>Rob Danielson
>>  >>Film Department
>>  >>University of Wisconsin-Milwaukee
>>  >>
>>  >>
>>  >>
>>  >>"Microphones are not ears,
>>  >>Loudspeakers are not birds,
>>  >>A listening room is not nature."
>>  >>Klas Strandberg
>>  >>Yahoo! Groups Links
>>  >>
>>  >>
>>  >>
>>  >>
>>  >
>>  >Telinga Microphones, Botarbo,
>>  >S-748 96 Tobo, Sweden.
>>  >Phone & fax int + 295 310 01
>>  >email: 
>>  >         
>>  >
>>  >
>>  >
>>  >
>>  >"Microphones are not ears,
>>  >Loudspeakers are not birds,
>>  >A listening room is not nature."
>>  >Klas Strandberg
>>  >Yahoo! Groups Links
>>  >
>>  >
>>  >
>>  >
>>
>>
>>--
>>Rob Danielson
>>Film Department
>>University of Wisconsin-Milwaukee
>>
>>
>>
>>"Microphones are not ears,
>>Loudspeakers are not birds,
>>A listening room is not nature."
>>Klas Strandberg
>>Yahoo! Groups Links
>>
>>
>>
>>
>
>Telinga Microphones, Botarbo,
>S-748 96 Tobo, Sweden.
>Phone & fax int + 295 310 01
>email: 
>         
>
>
>
>
>"Microphones are not ears,
>Loudspeakers are not birds,
>A listening room is not nature."
>Klas Strandberg
>Yahoo! Groups Links
>
>
>
>


--
Rob Danielson
Film Department
University of Wisconsin-Milwaukee

[Non-text portions of this message have been removed]



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