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#76 |
New Boot
Join Date: Jul 2003
Location: Cambridge/MA
Posts: 8
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Dear Mike,
Once again, thank you very much. |
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#77 |
Regular Crew
Join Date: Jul 2003
Posts: 42
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I use this same setup and I haven't detected any kind of hum or other interference. Just use the shortest cable you can to eliminate any impedance matching problems.
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#78 |
Wrangler
Join Date: May 2002
Location: Vallejo, California
Posts: 4,049
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Strictly speaking, the cable length has nothing to do with impedence matching until you get soooo long that cable capacitance starts to make a contribution.
Impedance matching was much more important when the input impedance of the system was way down compared to the output impedance of the microphone. Today, with the high imput impedance of the camcorder inputs, the issue is not too important. I'll still match impedances if I can but in real-world industrial/wedding video, it doesn't matter much.
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#79 |
Major Player
Join Date: Aug 2002
Location: Eugene, Oregon
Posts: 366
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Which XLR Adaptor is Best with VX2100?
I hope that some audio experts read this and comment on my questions near the end of this posting.
So far, the Beachtek and the Sign Video XLR to mini-jack mike adaptors are the only ones I've checked. Which is best and are there any others to use with a VX2100? How do these things manage to work without added power? I'd think that the weak mike signals wouldn't be enough to run passive adaptor boxes like these. I already have my XLR mikes connected with XLR female plugs at the mike ends and 3-wire cords, with special connections into 1/8th-inch mini-plugs. I have combined the return (negative) and balance wires inside the shielded 1/8th-inch mini-plug housings. So, there is no exposure of a two-wire mike connector outside my camcorders. I did this wiring exactly as I was instructed over the phone by the chief design engineer of the company that made my mikes. He said this was the best configuration to get the most out of XLR mikes, when used with mini-plug camcorders. They had once produced an alternate version of this model of mike, equipped with a mini-plug. It was connected with a 3-wire cord, the same way I assembled my connectors. Since the XLR adaptor units use an unbalanced and exposed two-wire cord, 10 or 13 inches long, to connect their mini mike plugs to camcorders, what is the advantage of my using such an adaptor? I'm not considering the benefits of the dual volume knobs and other control features in asking this. Is all the extra shielding value of the 3rd wire in my cords lost by not having an XLR-equipped camcorder into which to connect them, even though this wire is dead-ended properly to the return wire inside the mini-plug? Would I in fact, get a better mike signal into a VX2100 with an adaptor unit, than by just using the connectors I already have for my XLR mikes? Steve McDonald |
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#80 |
Wrangler
Join Date: May 2002
Location: Vallejo, California
Posts: 4,049
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Re: Which XLR Adaptor is Best with VX2100?
<<<-- Originally posted by Steve McDonald : I hope that some audio experts read this and comment on my questions near the end of this posting.
So far, the Beachtek and the Sign Video XLR to mini-jack mike adaptors are the only ones I've checked. Which is best and are there any others to use with a VX2100? -------------------- I have experience with the Sign Video adapters. They work very well. --------------------- How do these things manage to work without added power? I'd think that the weak mike signals wouldn't be enough to run passive adaptor boxes like these. -------------------------- Not really. As long as you don't have any attenuation cut in, they only lose signal across the transformer and that isn't very much ---------------------- I already have my XLR mikes connected with XLR female plugs at the mike ends and 3-wire cords, with special connections into 1/8th-inch mini-plugs. I have combined the return (negative) and balance wires inside the shielded 1/8th-inch mini-plug housings. So, there is no exposure of a two-wire mike connector outside my camcorders. I did this wiring exactly as I was instructed over the phone by the chief design engineer of the company that made my mikes. He said this was the best configuration to get the most out of XLR mikes, when used with mini-plug camcorders. They had once produced an alternate version of this model of mike, equipped with a mini-plug. It was connected with a 3-wire cord, the same way I assembled my connectors. ------------------------ The problem is that your entire system is then unbalanced and very susceptable to RFI. --------------------------- Since the XLR adaptor units use an unbalanced and exposed two-wire cord, 10 or 13 inches long, to connect their mini mike plugs to camcorders, what is the advantage of my using such an adaptor? I'm not considering the benefits of the dual volume knobs and other control features in asking this. Is all the extra shielding value of the 3rd wire in my cords lost by not having an XLR-equipped camcorder into which to connect them, even though this wire is dead-ended properly to the return wire inside the mini-plug? Would I in fact, get a better mike signal into a VX2100 with an adaptor unit, than by just using the connectors I already have for my XLR mikes? ------------------------ The XLR adapter allows a balanced run all the way into the adapter. Only the short lead from the adapter to the camera is unbalanced. Length of the unbalanced lead(s) are the issue here. The longer the lead, the more of an antenna it becomes. You would have to be in a very strong RFI field before the 1 foot lead would give you much of a problem. ------------------------- Steve McDonald -->>>
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#81 |
Trustee
Join Date: May 2002
Location: Barrie, Ontario, Canada
Posts: 1,922
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For my money, I'd buy the Beach Tek DXA-8. run a search, there's been a fair bit posted,
The DXA will give you 1. The balanced inputs you need 2. 15 db of gain, That will bring the audio unput to a level where the camera preamps won't have much to do. The camera preamp is the weak point in the equation. 3. 48 volt Phantom power. This will allow you to use almost any mic. You won't have to rely on battery powered models. 4. Limiters. rather than distort, the input will be compressed. You won't lose valuable audio if the audio levels dramatically increase. This unit will attach to the bottom of the camera the same way the other adapters do.
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#82 |
Wrangler
Join Date: May 2002
Location: Vallejo, California
Posts: 4,049
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Hey Bryan,
Why wouldn't you use a battery-powered microphone preamp instead of an XLR box? I have never used a portable mic pre but imaging that they can handle balanced in and drive a line-level output while providing Phantom Power as well. ?
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#83 |
Major Player
Join Date: Aug 2002
Location: Eugene, Oregon
Posts: 366
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Thanks for the replies and advice. I'll add that I set up my XLR mikes originally to work with a Canon L-1. They have produced very clean audio on every mini-plug camcorder with which I've used them. Since I've connected them with only 16 inches of 3-cord wire, which was just enough to reach from their positions on the mounting crossbar, this may have limited the interference potential.
I've determined that I would need only 6 inches of 2-wire cord to reach from an XLR adaptor to the mini-jack on a VX2100. I would attach the adaptor to the underside of the shoulder-mount rig I use, just below the lens. If I shorten the 10 or 13 inch cords that come on these adaptors and reattach them in a shielded, right-angle mini-plug, would I avoid any detectable amount of interference? I've found some ads for "double-balanced" XLR cords and connectors, that use 4 wires. Has anyone had experience with this type or an evaluation of it? Steve McDonald |
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#84 |
Wrangler
Join Date: May 2002
Location: Vallejo, California
Posts: 4,049
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I think this is Quad-Star cable that has the most resistance to common mode interference. I don't think most of us require that level of protection but if you are going after every little dB of S/N, then it could be important.
That said, you wouldn't use a stock Sony to record the audio in the first place. Short bits of unbalanced wiring aren't going to noticably hurt you unless you get near a strong radio (like a police car) or something similar. Maybe right next to a motor or flourescent light might get you a little noise.
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Mike Rehmus Hey, I can see the carrot at the end of the tunnel! |
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#85 |
Trustee
Join Date: May 2002
Location: Barrie, Ontario, Canada
Posts: 1,922
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Mike
The DXA8 outputs to mic level. With most mics it will alow the on camera gain to be less than 25%. It is a battery operated unit and it does provide all of the features i listed. The beauty of the DXA8 is it's compact, well laid out and attaches to the tripod mount. I agree that line level would be marginally better but none of those type of units are in as small a package as the Beach. The 6" cord that connects to the mic in shouldn't cause any interference "How do these things manage to work without added power? I'd think that the weak mike signals wouldn't be enough to run passive adaptor boxes like these." The passive adapters don't work well, they rely on high output mics and the camera preamp "Would I in fact, get a better mike signal into a VX2100 with an adaptor unit, than by just using the connectors I already have for my XLR mikes?" Do you mean running direct on an XLR to mini stereo adapter cable? The answer is the homebrew cable works and is ok for a short run. Without a preamp you will still depend on the cameras preamp and they will give a less than perfect audio if they are set up over 50-60% For longer runs the transformers in the adapter will isolate the cable from the Beach or Sign Video unit to the mic. I think you need to read some back posts here and at dv.com
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#86 | |
Outer Circle
Join Date: May 2002
Location: Hope, BC
Posts: 7,524
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Quote:
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#87 |
Trustee
Join Date: May 2002
Location: Barrie, Ontario, Canada
Posts: 1,922
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Yes it would, but do you need it?
The DXA-8 fit on my TRV20
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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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#88 |
Regular Crew
Join Date: Sep 2002
Location: St. Paul, MN USA
Posts: 151
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Glensound XLR
Been a while since I logged onto this site, but at least for the VX 2000 BBC is a strong proponent of the Glensound XLR adapter even without the BBC modifications. I never could get an answer from Glensound website however, so my impression is they have bigger fish to fry than dealing with prosumer clientele.
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#89 |
Regular Crew
Join Date: Jan 2004
Location: San Jose, CA
Posts: 180
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XLR adapter from PDX-10 on VX2000?
Does anyone know if the hot shoe XLR adapter from a PD-100 or PDX10 will work on a VX2000?
Is there a difference between the PD-100 and PDX10 adapter? |
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#90 |
Wrangler
Join Date: Dec 2002
Location: Mays Landing, NJ
Posts: 11,791
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I think not, just had a look. The PDX-10 adaptor wedged about halfway so I did't push any further. But looking more closely, here's my ASCII art impression of the VX-2000 hot shoe, which is actually 8 continuous contact bars:
|||||||| |||||||| But on the PDX-10 it's split into 14 separate contact bars with empty space in the middle like this: |||||||| | |||||| | Probably has to do with phantom power on the separate channels or something. The other problem would be that the PDX-10 has both a "dumb shoe" that's used to attach the XLR box and a "smart shoe" that's used for the cable from the box. So even if you could make it work on the VX-2000 you'd need some sort of external bracket to mount it. I never used a PD-100, but I thought I read it used a mini-jack to connect the XLR box instead of a hot shoe? Personally, I have a Beachtek box for my VX-2000... |
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