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Gear / Technical Help => Ask The Tapers => Topic started by: jbou on March 30, 2011, 06:39:42 PM

Title: AT 8505 - Phantom adaptor?
Post by: jbou on March 30, 2011, 06:39:42 PM
Wasn't sure where to post this.

I have a couple of AT 8505s that I have picked up in a purchase recently. Are these phantom adaptors that can step 48V down to 9V? I know thats what most of the AT mini xlr to xlr adaptors do, but I've had a hard time finding info on these.
Title: Re: AT 8505 - Phantom adaptor?
Post by: jbou on March 31, 2011, 12:18:40 PM
Anyone? Do these work like a Naiant PFA or the AT8533? Or do they only provide power from the battery you can put in them?
Title: Re: AT 8505 - Phantom adaptor?
Post by: SmokinJoe on March 31, 2011, 12:49:03 PM
If they are the ones I'm thinking of... barrel about 6" long, and can take a small battery (N size I believe)... then yes, they are capable of using that battery or phantom powered.

I had one hard wired onto on an AT853.  I ran it off phantom power one night just to see if it worked, and it did.  I think you can treat it similarly to AT8533, 8532 and whatever the rest are.   48v in, 9v out.   The only thing is that when you put a battery in there, it might only supply 1.5v to the cap instead of 9V.   That's just a guess, and I would just test that with a voltmeter.
Title: Re: AT 8505 - Phantom adaptor?
Post by: Gutbucket on March 31, 2011, 06:18:54 PM
Not sure about this model, but I think some barrel shaped AT phatom adaptors invert the polarity of the audio signal if that matters at all to you. Of course it not matter and these may not do it anyway.
Title: Re: AT 8505 - Phantom adaptor?
Post by: jbou on April 01, 2011, 01:09:41 AM
^ what does that mean? Inverting the polarity of the audio signal?
Title: Re: AT 8505 - Phantom adaptor?
Post by: Gutbucket on April 01, 2011, 09:23:37 AM
The start of an impulse produces a negative voltage instead of a positive voltage.  If polarity is maintained along the whole signal path, the speaker cone starts by moving inward at the start of sounds instead of starting by moving outwards. Usually doesn't matter as long as both channels (if recording stereo) have the same polarity.  Cancellation problems happen when the polarity of one channel differs from another.  Polarity may be inverted at other points in the chain as well, so as long as the same thing happens to all channels there is usually nothing to worry about.
Title: Re: AT 8505 - Phantom adaptor?
Post by: jbou on April 01, 2011, 11:24:07 AM
Thanks