| AKG C408 phantom powering... [message #233922] |
Sun, 05 August 2007 08:37  |
 Davide Bonetti
Messages: 98
Registered: August 2004
Location: ITALY, North-East |
Nothing Better To Do |
|
|
hello, I have four of these mics that occasionally I could use, but I happen to hate them because they operate on 9V battery via their proprietary AKG adapter...
original AKG adapter to run them with phantom is expensive and I don't wanna buy four of them!
FYI the mic has a tiny 3.5mm mono plug which plugs into the battery adapter...
while googling around I have found this schematic which is stated for powering the mics on phantom. altough I can build this small thing myself I do not have enough theory to know if this thing would work...
... so I am asking you guys before frying my AKG C408s!!!
bye,
davide
|
|
|
| Re: AKG C408 phantom powering... [message #233948 is a reply to message #233922 ] |
Sun, 05 August 2007 10:53  |
 |
Andy Peters
Messages: 5911
Registered: April 2004
Location: Tucson, AZ |
Has No Life
Contrarian |
|
|
| Davide Bonetti wrote on Sun, 05 August 2007 06:37 |
hello, I have four of these mics that occasionally I could use, but I happen to hate them because they operate on 9V battery via their proprietary AKG adapter...
original AKG adapter to run them with phantom is expensive and I don't wanna buy four of them!
FYI the mic has a tiny 3.5mm mono plug which plugs into the battery adapter...
while googling around I have found this schematic which is stated for powering the mics on phantom. altough I can build this small thing myself I do not have enough theory to know if this thing would work...
... so I am asking you guys before frying my AKG C408s!!!
|
You can pay the man and ensure that you don't lunch your microphones.
Or you can spend basically about the same amount of money (remember those cool little barrel adapters are not cheap) trying to build something that might or might not work, and if you don't have much electronics experience you won't be able to troubleshoot it, and if the homebrew thing lunches your microphones, good luck getting AKG to repair them under warranty.
-a
"Any sufficiently advanced incompetence is indistinguishable from malice."
"Your band isn't good enough for my PA."
"On the Internet, nobody can hear you mix a band."
|
|
|
|
| Re: AKG C408 phantom powering... [message #234117 is a reply to message #234108 ] |
Sun, 05 August 2007 20:12 |
Fred Merkle
Messages: 202
Registered: April 2004
Location: Chicago, IL |
Has No Life |
|
|
| Tim Padrick wrote on Sun, 05 August 2007 20:45 |
It seem to me that the top cap should go from pin 3 to ground, not the output. The channel that's supplying the phantom would not be usable for the mic signal, as the 10uf caps will shunt it all to ground. However if you put the caps after the 10K resistors, it should work for the mic signal.
|
That cap on top is the ac coupling that allows the audio "through" (for lack of a better term.) Interestingly, that design is pin-3 hot. (Probably means that the circuit is wired such that the impedance converter is a common-source amplifier.)
That circuit might work just fine. However, without knowing how AKG did the wiring of the impedance converter and what current it requires, you might fry your mics. Andy is right, buy the AKG one unless you're comfortable with electronics.
Good luck.
-Fred
[edited because I didn't fully read something...]
[Updated on: Sun, 05 August 2007 20:13]
|
|
|
|
| Re: AKG C408 phantom powering... [message #234279 is a reply to message #234210 ] |
Mon, 06 August 2007 11:44 |
Davide Bonetti
Messages: 98
Registered: August 2004
Location: ITALY, North-East |
Nothing Better To Do |
|
|
altough not everybody is suggesting it will work, I have decided to build this thing and try... I am not afraid to cook one of those mics...
ah, I now notice that the design is pin 3 hot... I guess I only have to swap the wires going to pin 2 & 3...
bye,
davide
|
|
|
| Re: AKG C408 phantom powering... [message #234316 is a reply to message #234279 ] |
Mon, 06 August 2007 13:21 |
Fred Merkle
Messages: 202
Registered: April 2004
Location: Chicago, IL |
Has No Life |
|
|
| Davide Bonetti wrote on Mon, 06 August 2007 12:44 |
ah, I now notice that the design is pin 3 hot... I guess I only have to swap the wires going to pin 2 & 3...
|
Double check before doing that. It is possible that AKG has the capsule wired up out of polarity already and the pin 3 hot design corrects for that.
Have fun.
-Fred
|
|
|
Welcome to the ProSoundWeb sound reinforcement forums, home of more than 50,000 audio professionals. 
Forum Home
Login
Forum Search
Register
FAQ
