Cad M179 p. Pwr requirment

flatfinger

flatfinger

Use every dam bit!
Hey guys,
I'm wondering if I have to rule out the CAD m179 because of the 8ma Phantom pwr requirement......I'd be using it through a emu 1820m(break out box) and although I upgraded my dell's power supp to a 450w antec, I've got to admit, the fact that most mics out there are only drawing 1 or 2 ma makes me think I should look elsewhere. To bad , looks like a sweet deal! :confused: :confused:

What do you think??
 
get a phantom power supply. the m179 is a mic worth having around and i would'nt let wimpy phantom power get in your way, if that's the case with the 1820m. art makes some affordable phantom power boxes.
 
Most Standard phantom power supplies should supply a Max of 14mA so 8mA should not be a Problem.....

If it is you can easilly build a Phantom power supply with some minor electronics skills.....

Cheers
 
I've gotten some great stuff out of mine. They were exactly the kind of sound I was hoping to find when looking for them.
 
Thanks for the replies fellas,

I found some good info in the randym49 post in this thread http://www.homerecording.com/bbs/showthread.php?t=212015


I'm going to go in a different direction as I want to be able to use 2 at a time(16 ma!) not going to even risk it. :(

Most 48v power supplies only have around 2 ma of current. So you need to look at the specs for your supplies and find out if your supply can handle that much current.
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theres nothing on the emu site about the max PP current available , and it is after all, a break out box that takes 12vdc from the computer and uses it to give two xlr's phantom power output. Seems like too much of a possibility of wasted tail chasing , could cause distortion or worse. :mad:
There's to many mic's out there to choose from that only need 1 or 2 ma, so I'm going to err on the side of caution here! :)

Thanks for the responses


Cheers
 
Just for anybody who might search info on this mic or the e-mu 1820m;
I sent the following to e-mu tech support;

I would just like to know what the maximum recommended current draw ( in milli amps) is for the phantom power supplied from the 1820m break out box . I am considering using a mic that says it needs 8ma to function(CAD m197) and since most mics only draw 2 or 3 , I don't want to exceed the capacity of the unit. Thank you!
Click to expand...



This was their response;

8ma should be fine assuming it draws from + and - . If it only draws from one side it could be a problem. Any commerically available mic should work fine.
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I've even powered my M179 mics from Behr MX and UB mixers (and Yamaha MG, Mackie VLZ) without any problem, with 6 other condensers drawing phantom power at the same time. No problems. I never had a problem with a stand-alone preamp (or mixer with separate phantom control for each channel). Maybe we should start a list of low-current offenders?

I never regretted buying my M179 mics.

Paj
8^?
 
Thanks guys,
I guess i'm a bit of the cautious sort! This mics definatley on my short list! :D

Thanks for the replies. :)
 
8ma should be fine assuming it draws from + and - . If it only draws from one side it could be a problem. Any commerically available mic should work fine.
Click to expand...


It doesn"t sound like these Tech guys know what they are talking about....

Phantom power is a Positive + DC Voltage on Pin 2 and 3 of the XLR, there is No negitive Voltage just the Ground on Pin 1 so there is no way a Mic could draw Both Positive and Negitive voltages because they just aren"t available from Phantom power.....

Phantom power is +48V DC run through a 6.8k resistor on each of pins 2 and 3 and when shorted to ground can deliver a Max of 14mA of current....If the resistor was Higher then it would deliver less current and if it was Lower it would deliver more current but as a general Rule all phantom power is generally run through the 6.8k resistors which limits the current to 14mA....


I have built several Phantom power supplies and can tell you for a fact that there is only a Positive voltage.....

Cheers
 
the m179 uses op amps in the headamp

that use a bipolar power supply

(see quote and schematic below -

the schematic is the e100

but the power supply is

the same as or similar to the 179 iirc)

with voltage and current

drawn off the phantom voltage

(which btw can be as low as 24v

according to their specs)


maybe the emu people thought

this (bipolar supply) would have some bearing

on the current draw from phantom



additionally, the power supply

is connected to internal batteries

which i presume can charge

in times of low current draw

and supply extra current when needed



m179 user manual said:
Typical FET (field effect transistor)
condenser microphones use
discrete designs. This means they
use individual transistors that
must be carefully matched for
proper characteristics. Even with
careful matching, discrete designs
are inherently nonlinear. M
Series microphones use a different
approach. We do not use any
discrete FETs. Instead, we use
advanced high speed OpAmps
(Operational Amplifiers).
These OpAmps are individually
laser trimmed for optimum performance
and have very high
gain. This allows a large amount
of negative feedback to be used to
significantly reduce any non-linearity.
We have also integrated a new
discrete high efficiency power supply
circuit allowing greater dynamic
range and lower self noise.

The CAD M179 combines an advanced
headamp design, with
extremely efficient power circuitry,
and a vintage capsule design, resulting
in superior transient response,
low distortion, low noise, and high
output level. The bottom line is we believe
you will find the M179 to have a
remarkably open and clean sound
that will enhance any project.
Click to expand...
 

Attachments

  • e100schem.webp
    e100schem.webp
    33.2 KB · Views: 92
Looking at the pdf owners manuals from the website, it doesn't look like the 179 has the rechargable battery's does it???
 
you're right

i am wrong

i guess i thought since they both used op amp circuits

they would use the same power supply



i can't find a schematic for the 179

it would be interesting to see what their

"new discrete high efficiency power supply
circuit allowing greater dynamic
range and lower self noise"

looks like



don't know what to tell you

regarding using 2 mics (16ma) from the same supply

it would probably work fine

as others have attested
 
Well most Opamps can run of off a single supply rail ,and the TL082 opamp used in the above schematic can run off of a single supply and has very low power useage.....
I don"t know why they are useing the OPA2107 at the input as it isn"t even really a audio opamp but it is fast and has a very high input impedance so that is probably why it is used ....
It"s not the best Fet input opamp but it only costs about .25c each so that is why they probably use it as opposed to a High end fet opamp which costs 10 times as much.....


Cheers
 
Minion said:
It"s not the best Fet input opamp but it only costs about .25c each so that is why they probably use it as opposed to a High end fet opamp which costs 10 times as much.....


Cheers
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.......Very interesting................. you guys got the details!!!! I actually prefer the battery idea as I could charge it up else where and then use it on the break out box, oh well I went El Cheapo and got an MXL!!!

The Trion 8000 is my new object of lust any how so bye bye m179!!!!!!!!!! :p So many mic's so little time :D
 
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