impedance adapter

bahaha

Member
Joined
Jan 18, 2005
Hi everybody, i was hoping someone here could help me out with this problem. I have 5 Shure LX3 wireless receivers that need to be connected to our mixer. The LX3's will be in a rack backstage and there is cable already run to FOH. The LX3's output is high impedance and needs a 1/4" male connector, while the existing cable is XLR female and will go into a low impedance input on the mixer. I have done a decent amount of searching and this is what i've come up with so far:

http://www.radioshack.com/product.a..._name=CTLG_011_003_001_001&product_id=274-016 connected to http://www.radioshack.com/product.a..._name=CTLG_011_003_001_007&product_id=274-015

or

http://www.shure.com/accessories/a95u.asp

As far as i can tell, these do what i need. The problem is cost. $115 from radio shack and almost $200 from shure. Do these accomplish what i need, and is there a cheaper way. I can't solder but i might be able to find someone who can. Also, this post, http://www.controlbooth.com/ftopict-1367.html, talked about resistive summing networks used for a similar purpose, if that's any help. If you have any advice or know of any other options, don't hold back. Thanks in advance.
 

cutlunch

Active Member
Joined
Jan 12, 2005
Location
Auckland, New Zealand
You seem to be on the right track . I don't know what quality the Radio Shack convertors are, hopefuly someone can tell you.

The other option is to use DI's to do the conversion. These come in units from one channel to many. You may already have some or could possibly rent.

As for cost, if the LX3's are owned by the school you will probably have this problem again so tell the teacher it's an expense that will pay for itself over time.
 

bahaha

Member
Joined
Jan 18, 2005
Thanks. I checked out DI's. They seem like a good option but not really feasible for our school due to cost. I'm glad when they buy us new batteries, let alone over $100 worth of adapters. I'll proably go with the radio shack adapters unless anyone knows for a fact that they're poor quality.
 

mbenonis

Wireless Guy
Administrator
Premium Member
Joined
Sep 1, 2003
Location
Chicago, IL
Do not under any circumstance use a simple quarter inch to XLR cable. The issue here isn't the type of connector used, but rather the impedance of the output of the mic receiver. Basically, the high impedance output of the receivers will degrade the signal if the cable or wiring is over a few feet long. It must be transformer isolated from the mains with an impedance converter in order to work properly.

Just use this Radio Shack adaptor: http://www.radioshack.com/product.asp?catalog_name=CTLG&product_id=274-017. Use a patch cable to attach it to the receiver. I own one of these personally, and it works great for a quick fix (I once used it to attach a guitar to the mains and it worked great).
 

PATech

Member
Joined
Jun 10, 2004
Location
CT (school year); NJ (vacations)
For high to low impedance conversions at my school we use Pro-Co Sound DB-1 direct boxes. We have a bunch of them around. They list for $106, but you can find them for around $60.00. Sure, it's not a nice Countryman DI box, but it works well. This is really an investment, and you'll get the best audio quality possible.

All the best.
 

bahaha

Member
Joined
Jan 18, 2005
Thanks a lot everybody; you've all be very helpfull. It looks like i'll be going with the radio shack adapter. Not the best, but a good compromise for our situation. At mbenonis: I'm so glad you posted. I had never though of using the other version of the adapter. Our patch cords will now connect to that adapter instead of the mixer. I also won't have to worry about a heavy double adapter hanging off of the LX3's for the next 10 years.
 

cutlunch

Active Member
Joined
Jan 12, 2005
Location
Auckland, New Zealand
Bahaha. The only thing to watch with the type of DI Box you are looking at, is that it is a passive type. Passive types are just transformers. Being passive there is a signal loss. In the case of the whirlwind, the output signal is about 21db down on the input signal. If the wireless mike recievers have an ouput level control to adjust the signal you should be right.
 

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