Beachtek DXA-8. Any one using it?

[Glenn Davidson]

The December issue of DV magazine has a ad for the BeachTek DXA-8. I am thinking it would be a good match for my FX-1. Oddly, I could find no info on the BeachTek site. But B&H has it. Is anyone using this model? What do you think of it?

http://www.bhphotovideo.com/bnh/cont...ughType=search

[Meryem Ersoz]

works great but is a battery sucker. take plenty of 9V batteries along. when the batteries start to run dry, your audio will get staticky....

[Dan Keaton]

Yes, I have used the DXA-8 and I have been very pleased.

It is a very good device, very worthwhile if you have a camera that has noisy microphone preamps.

For example, If you have a Canon Xl1s, you can connect a phantom powered microphone into your DXA-8, and then plug the DXA-8 into your camera's 1/8" stereo microphone input.

The good part is you can then turn down your camera's preamps, and use the amplifier gain on the DXA to set your levels. When this is done properly, you will obtain nice, quiet, almost hiss free sound.

So, in my opinion the DXA is very worhwhile. If you have the money and don't need something that mounts under your camera, a Sound Devices 302 or 442 will be better.

I always insert a fresh 9 volt battery at the start of every shoot. This will last for hours, but you should turn off the DXA-8 during slack times. Also, you should always monitor your audio. If you hear any static, change the battery.

I wish the device used NIMH AA's, but it does not.

[Ross Jones]

I use a VX2100 and started off with the DXA-8; it certainly improved the overall audio quality. However, the VX2100 is somewhat renowned for poor audio, so I had Greg Winter do his audio mod - but that then needed a higher level audio signal, so I opted for the SD302. The sound quality now is amazing... well worth the cost. The Sd302 really is a gem of a mixer; extremely versatile...
Rgds, Ross.
~~~~~~~~~~~~~~~~~~~~~~~

[David Ennis]

Originally Posted by Meryem Ersoz

works great but is a battery sucker. take plenty of 9V batteries along. when the batteries start to run dry, your audio will get staticky....

If you can't provide phantom power to two XLR mics for a solid 2 or three hours you have a defective unit. My first one was like that. But it's replacement can use the same 9V battery for three hours with phantom on. For more details see my post here:
http://www.dvinfo.net/conf/showthrea...hlight=secrets

[Oleg Kaizerman]

Originally Posted by Dan Keaton

Yes, I have used the DXA-8 and I have been very pleased.

It is a very good device, very worthwhile if you have a camera that has noisy microphone preamps.

For example, If you have a Canon Xl1s, you can connect a phantom powered microphone into your DXA-8, and then plug the DXA-8 into your camera's 1/8" stereo microphone input.

The good part is you can then turn down your camera's preamps, and use the amplifier gain on the DXA to set your levels. When this is done properly, you will obtain nice, quiet, almost hiss free sound.

So, in my opinion the DXA is very worhwhile. If you have the money and don't need something that mounts under your camera, a Sound Devices 302 or 442 will be better.

I always insert a fresh 9 volt battery at the start of every shoot. This will last for hours, but you should turn off the DXA-8 during slack times. Also, you should always monitor your audio. If you hear any static, change the battery.

I wish the device used NIMH AA's, but it does not.

you can use rechargeable , li-ion 9v batteries -500ma
will last at least as the regular , much more in cold weather
about 85 us for charger and 4 batteries
must be good for 300 charges at least .
Thomas distribution , trew audio or any other lectrosonics dealer carry these .

[George Ellis]

I have avoided rechargeable 9Vs. I found that when the voltage drops below 8 volts on standard batteries, dynamic audio starts introducing static. Since most 9V rechargables start around 8.6v IIRC, you are already half-way to the static. I carry a VOM (voltage ohm meter) and always check my battery before recording. Anything below 8.3v is not used if I know I will record more than 1/2 hour. But, 9v batteries are expensive comparitively, so keeping a little herd of rechargables could be an option. I just hate carrying them around loose as they are easy to short.

Also, some mics can provide too much power to the front-end. I have an A-T 835ST and need to use attenuators when field recording things like marching bands. A-T makes switchable pads with -10/20/30dB that passes phantom voltage (I think they are 8202's, but I could be wrong).

[Oleg Kaizerman]

Originally Posted by George Ellis

I have avoided rechargeable 9Vs. I found that when the voltage drops below 8 volts on standard batteries, dynamic audio starts introducing static. Since most 9V rechargables start around 8.6v IIRC, you are already half-way to the static. I carry a VOM (voltage ohm meter) and always check my battery before recording. Anything below 8.3v is not used if I know I will record more than 1/2 hour. But, 9v batteries are expensive comparitively, so keeping a little herd of rechargables could be an option. I just hate carrying them around loose as they are easy to short.

Also, some mics can provide too much power to the front-end. I have an A-T 835ST and need to use attenuators when field recording things like marching bands. A-T makes switchable pads with -10/20/30dB that passes phantom voltage (I think they are 8202's, but I could be wrong).

you are wrong -
the alkaline batteries work true the 6 v under load , every unit like that has dc to dc converter which pop up the voltage to its working level
and what is really matter is the actual capacity of the battery ,
the nimh and li-ion batteries dont fell in voltage under load so it actually preforms well until the battery empty .
second - under heavy load the voltage in alkalies go down fast what might bring the voltage under the minimal requirement you need to power the unit even the battery still carry enouth wattage to drive the unit , with rechargebles it wouldn't happen , you can use 100% of it capacity without voltage drop.
the li-ion rechargeable would out preform any alkaline battery under heavy load like this unit even they are the same capacity .

[George Ellis]

Oleg, you are saying that the voltage will remain above 8V until the battery is depleted?

[Oleg Kaizerman]

Originally Posted by George Ellis

Oleg, you are saying that the voltage will remain above 8V until the battery is depleted?

above 7.4 for lithium ion( 8.4 from the charger)
above 7.2 or 8.4 for for n-mh ( depends on the number of cells).
the capacity is the voltage multiply the amperage of the battery .

the other thing that i can recomend is to use camera batteries with external dc plug ( there is a number of companies who are already make these for sony camcorders) so you can hook the unit with external power true 9v battery dummy head ( not use dc converter dumy head since it drops at least 1.5 v and you will be under 6 v , just 9v dummy head directly from the camera battery.)

[David Ennis]

Originally Posted by Oleg Kaizerman

...the capacity is the voltage multiply the amperage of the battery...

That would be power. The capacity is amperage multiplied by time. Those numbers are intriguing. Did they come from tests you did, or are they published somewhere? I'd like to try them in the test setup I used in the link I mentioned above.

[George Ellis]

I know that when I get voltages below 8 on standard alkalines, any music I am recording gets crackle and tinny portions.

[Oleg Kaizerman]

Originally Posted by Fred Retread

That would be power. The capacity is amperage multiplied by time. setup I used in the link I mentioned above.

sorry VxAxT
The ma you have on the battery
for alkaline - is really depends on your current and how do you use the battery
intermediate or continues - the 9v rated for about 400-550 ma
also the actual temperature would be a big factor for the user .
lets say i live in heven and the Canadians in hell in the winter :-)

[Oleg Kaizerman]

Originally Posted by George Ellis

I know that when I get voltages below 8 on standard alkalies, any music I am recording gets crackle and tinny portions.

under load you will see that the actual voltage is low then 6 v ,
the battery voltage comes alive ( going up )when nothing connected

[David Ennis]

Originally Posted by Oleg Kaizerman

...sorry VxAxT
...

Just to clarify, the amount of charge stored is what I meant by capacity, and that is current x time. The energy stored is current x time x voltage.

The DXA-8 is a constant power device, as opposed to a constant resistance device (like a flashlight) or constant current device. So as the battery's voltage falls the DXA-8 draws more current from it.