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Old January 19th, 2005, 05:48 PM   #1
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Low to high impedance transformer, or XLR adapter like beachtek?

Hi- I dont know all that much about audio, but thats why i'm asking. I'm doing a project with a camera that has no XLR inputs. I've heard of the beachtek family of XLR to 1/8" adapters, and besides having two channels, what benefit does the Beachtek give over a simple, inexpensive line-matching transformer...(quality loss is my main concern)


Thanks for any help-
Alex Milne is offline   Reply With Quote
Old January 19th, 2005, 06:56 PM   #2
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Phantom power and attenuation/gain; you don't want to feed the camcorder to strong/weak a signal.
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Old January 20th, 2005, 07:02 AM   #3
Fred Retread
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XLR adaptors like the BeachTeks add features, and their best one has a preamp for weak signals, but your solution shouldn't give any less quality. In fact, it's probably a better solution for most than the simple XLR to 1/8" mini adaptor cable that's often recommended here. People sometimes get weak inputs with those due to impedance mismatches.
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Old January 20th, 2005, 07:35 AM   #4
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The Shure adapter in that link will also maintain a balanced connection between the mic and the adapter, leaving only a short distance to go into the camera jack unbalanced. It's also wired properly for feeding balanced mono into an unbalanced stereo jack. As long as you protect the camera connection from getting yanked on, you should be fine with this adapter for using only one mono mic.
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Old January 21st, 2005, 06:43 AM   #5
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Yes the Shure adapter will work, but it is clunky.

The various beachtek are OK, but as mentioned, only the top one actually has the ability to add gain. Dynamic mics frequently need this.

Then there are the issues of noise, (good components, transformers) and good limiters, channel selectivity, high pass filters and various inputs and outputs.

If you want to take your audio to a professional level instead of trying to figure out how to get by with as little as possible, try a Sound Devices MixPre with a proper feed cable. The MixPre has all of the features. My favorites are:
* Dynamic range exceeding 110 dB
* 10 Hz to 50 kHz audio bandwidth
* Maximum of 66 dB of gain per input
* Premium Lundahl input transformers
* Seven-segment, sunlight-readable GaN LED meters
* Phantom power, 48 volts or 15 volts
* High-pass filters @ 80 or 160 Hz, 6 dB per octave
* Inputs hard panned to left, center, or right outputs
* High-power headphone monitoring
* Input AND output limiters.
* Dual mono or linked stereo limiter operation
* Two internal AA batteries
* External 5 to 17 VDC powering
* RF filtering on all inputs and outputs. Free from "Pin 1" grounding problems

The ONLY thing I don't like is that the output is line level only. If your camera ONLY accepts mic input levels (some consumer cameras may),you need to put pads in the line to drop the signal level from line to mic. I prefer using iine level because it's hotter and can survive interference much better than mic levels.

Having said that, the MixPre has a second output; a mini stereo unbalanced TRS that allows you to feed a second record device like an audio recorder, camcorder or whatever.

About the feed cable, sometimes referred to as The Audio Hose. That cable shouid have two balanced channels for the outgoing audio and an unbalanced stereo return that plugs into your camera's headphone jack and returns the camera back to the mixer so you can monitor the camera headphone from the mixer itself.

Also, unlike many camcorders, the MixPre won't be obsolete in three years.

If you hire me to take care of your audio while you concentrate on the picture and client, know that I use the Sound Devices 442. That's the MixPre's big brother.


Ty Ford
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Old January 22nd, 2005, 05:28 PM   #6
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I have a mix pre and a 302, I also have a beach from the days when there wasn't that much spare cash and I survived. The top Breach is 1/2 of what the mix Pre is and it attaches to the camera. (That's a biggie)

There are many people with as many varied budgets. now that i've graduated to the MKH60/MK41 realm, there is no going back, but first we have to get there. ( only a fool spends money he doesn't have.)

"Patience grasshopper"
Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting ".......holy smokin rubber lips...what a ride!"
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