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-   -   XLR to mini jack adapter Vs. Beachtek (http://www.dvinfo.net/forum/all-things-audio/42458-xlr-mini-jack-adapter-vs-beachtek.html)

Daniel Knight April 5th, 2005 10:30 AM

XLR to mini jack adapter Vs. Beachtek
 
Okay - so I've just got myself and FX1, and now I want to go out and shoot heaps of stuff. But obviously it doesn't have an XLR socket - so my choices in mics are somewhat limited.

So... in fear of sounding stupid...

What's the difference between a regular XLR to mini jack adapter and a Beachtek. I keep hearing people say that you need a Beachtek, but I'm unsure as to the difference that one would hold (I am of course referring to the low end models).

Do I really need a Beachtek? Will a simple adapter not do the trick?

David Ennis April 5th, 2005 05:23 PM

If the mic is battery powered, you can just use an XLR to mini adapter. It must be wired correctly, like this one:
http://www.bhphotovideo.com/bnh/cont...=158476&is=REG

Depending on the camcorder and the particular microphone, you may get an audio signal that's a bit weaker than if you use a BeachTek (or other XLR adaptor) due to impedance mismatching. You can avoid that by spending a little more:
http://www.bhphotovideo.com/bnh/cont...=154878&is=REG

A basic BeachTek adapter would add the ability to add another mic, or a line level signal from a sound board, and give you option to mix them to mono or keep them separated left and right.

The next level of BeachTek would also supply phantom power. Many high quality mics require that they be powered over the same wires that carry the audio signal. That's called phantom power.

Mark Burlingame April 6th, 2005 01:04 PM

transformers usually aren't needed
 
I have a Pana DV-953 and got the Rode NT-3 mic from B+H and also got that shure impedence matching transformer, however, later I found out that it isn't required. Basically the signal from (most? some?) more modern powered microphones includes circuitry that obviates the need for such a matching transformer and can be run directly into the mic input of your camcorder directly. Impedence matching is much more important with microphones that run the basic mic element directly to the camcorder input without electronic buffering in the path. Sort of like the signal that comes directly of a magnetic phono cartridge (if that analogy helps...) Make sure the mic you have really needs a matching transformer, otherwise you are only adding color to your audio signal path, thought the shure is pretty transparent. (also why spend the money). Phantom power is a different issue, and doesn't garauntee that a matching transformer isn't required to get good signal transfer... Mark

Fred,
I want to run the signal from a yamaha MG10 board into my camcorder which only takes mic level signals, so it appears that the beachtek will act as a pad for the line out from the mixer and bring the signal down to mic level? Is that the case. thx.

Jay Massengill April 6th, 2005 02:58 PM

Your statement is true when working with short cables. However for a longer cable run it is worthwhile to use a transformer at the camera end to maintain a balanced connection for the longest distance possible.
A BeachTek will work directly as a pad between a line-level mixer output and a mic-level camera input as long as you DON'T count the DXA-8 or DXA-10. Neither of them have onboard Mic/Line switches and would require external attenuators.

Mark Burlingame April 6th, 2005 04:10 PM

Thanks Jay,
The beachtek is somewhat dissapointing as the line level input is only mono... I just ordered a bunch of metal film reisistors and am going to make my own pad so I can run the mixer out directly into the camcorder mic input. If it works well, I'll probably make a few of them and offer them for sale to those interested. Depending on the connectors and housing, it should be very cheap. Mark

Jay Massengill April 6th, 2005 06:08 PM

<<<-- Originally posted by Mark Burlingame : Thanks Jay,
The beachtek is somewhat dissapointing as the line level input is only mono... -->>>

Not sure what you mean by that. Are you talking about the mini Aux input on the BeachTek only accepting a mono plug? That's normal and is easy to deal with.
At any rate, all the inputs on all the BeachTeks are mono inputs. But they can all be sent to both outputs equally by setting the switch to mono. Or they can be kept separated for stereo or two-channel mono by keeping the switch in the stereo position. This is independent of the mic/line switches, including with the Aux connector.
How long a distance do you plan to send this signal?
Will you use a balanced output or an unbalanced out from the mixer?

Mark Burlingame April 7th, 2005 12:35 PM

Hey Jay,
Yes the aux input is routed to the right or left side (I think the right side), the MG10 mixer only has unbalanced outputs, I suppose I could buy some RCA to XLR adapters and use the beachtek, but I don't really need the portability, and it seems as though the beachtek is a passive device (except the phantom power) anyway. The MG10 has phantom power. The board won't be more than 10ft from the mixer and I will be putting the attenuator as close to the camcorder mic input as possible. The main reason I want to use a mixer is for the high-pass filter (the rode mics are very sensitive to the low frequencies generated by passing cars, and to run the signal through a stereo effects processor for a noise gate/compressor to eliminate unwanted low level sounds. It seems to me that a simple -40 or -50 db pad is the way to go. The hard part was finding 1% tolerance metal film resistors (carbon film are noisy and don't have very tight tolerances). I'll have them on friday. I am planning on making essentially a RCA to Stereo miniplug adapter with the pad in the middle, should only be around 4" long. Mark

Jay Massengill April 7th, 2005 01:27 PM

The Aux input of the BeachTek is CONNECTED to the right input, but it can be ROUTED to either the right output only or to both left and right outputs. A small point that doesn't really help you but I wanted to mention it.

I see now from the block diagram that the main outs of the MG10/2 are unbalanced as you said.
However they are wired to work with a TRS connector. So you could simply use two standard TRS 1/4-inch male to XLR male cables. They would carry the unbalanced signals successfully to the BeachTek.
As long as you use good shielded cables and connectors, your adapter should be good too.

Mark Burlingame April 11th, 2005 12:31 PM

well, I made my prototype RCA to stereo mini adapter/-40db pad and it rocked!! The resistors I got were very small and I was able to mount them inside some gold RCA connectors so they are completely shielded! no noise problems!


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