computer 70 feet from amplifier

[tictoc]

I will be setting up a computer in my kitchen as a jukebox (using Musicmatch or something). The trouble is that my amp (and junction for the various house speaker wires) is about 70 feet away (the cable will have to run down to the crawlspace and back up). Is there such a thing as a sound card that will power an amp this far away? Is there such a thing as a remote sound card, which can be driven via 70 feet of CAT5 cable? Any ideas? Thanks!

[mrfeedback]

You need to run balanced cables from your PC to your amplifier for this distance.
This requires an unbalanced to balanced convertor at the PC end, and a balanced to unbalanced convertor at the amplifier.
Running a balanced connection will allow good signal quality at the amplifier end, and will eliminate ground loop humm/buzz noise problems.
This is standard practice in FM broadcast systems when a PC is required in the system.

Eric.

[UrSv]

Oops. Sorry for the blank.

[tictoc]

After exploring around a bit, wouldn't it be better for me to use a USB-driven sound card? Then I could placed the USB device at the location of the amplifier, and use a CAT5 extender to talk to the USB device from my remote computer.

[Rob M]

Here's one option:

http://sound.westhost.com/project51.htm

[deandob]

tictoc,

I do exactly what you are asking for - computer with Delta 410 10 channel soundcard driving amplifiers all over the house, some up to 50 metres of cable.

As Mr. Feedback has explained, balanced line is the only way to go. Use shielded twisted pair (STP) to further reduce any noise, and the balanced cable & balanced tx/rx will do the job nicely. I'd recommend the use of DRV134 as the balanced transmitter and INA2137 as the balanced line receiver. Both the driver & receiver are laser trimmed for maximum noise rejection and this combination is well known for use in pro audio gear.

I also use a PIC controller connected to the PC via the serial port to matrix the 5 channels out of the 410 into 16 zones around the house.

Let me know if you need more info.

Regards,
Dean

[lgruber]

Go to to the TI (Texas Instruments) website and look up the DRV134 and INA134. For the power supply use the Linear Technology LT137 and LT337 regulators for the +/- 15V. supply. Use a toroid power transformer (Digikey catalog). Heat up your soldering iron, use quality components. I suggest not messing around with anyting else. Use quality mike cable for the link (2 conductor with shield). You might be able to get free samples for the silicon or purchase from Digikey or Mouser Electronics. This can be a pretty inexpensive project--a heck of a lot cheaper than using UTC or Lindahl transformers, and with higher performance. if you play your cards right. I use this method as my preamplifier is situated about 30 feet away from my power amplifers and electronic crossovers. Good luck and have fun. Hope this is not too much beyond your DIY capability. --Larry

Ps. hope you are a subscriber to AudioXPress

[amo]

Originally posted by lgruber
Go to to the TI (Texas Instruments) website and look up the DRV134 and INA134. For the power supply use the Linear Technology LT137 and LT337 regulators for the +/- 15V. supply. Use a toroid power transformer (Digikey catalog). Heat up your soldering iron, use quality components. I suggest not messing around with anyting else. Use quality mike cable for the link (2 conductor with shield). You might be able to get free samples for the silicon or purchase from Digikey or Mouser Electronics. This can be a pretty inexpensive project--a heck of a lot cheaper than using UTC or Lindahl transformers, and with higher performance. if you play your cards right. I use this method as my preamplifier is situated about 30 feet away from my power amplifers and electronic crossovers. Good luck and have fun. Hope this is not too much beyond your DIY capability. --Larry

Ps. hope you are a subscriber to AudioXPress

Hi Larry- I am trying to understand how to build a good PS for my pc. Where can I find more info? Also, I though a PC requires 12, 5, and 3.3 volts, not 15.... Thanks.

[lgruber]

I would not use the P.C. power supply to power the balanced line drivers I recommended. Use a totally separate isolated power supply. See my previous message.

BTW, two good books on DYI audio are "Audio Electronics" by John Linslely Hood and "Self on Audio" by Douglas Self. You might want to purchase the CD-ROM back issues of ElectronicsXPress. Good website: http://www.linkwitzlab.com/ SMT soldering techniques are also starting to be necessary, but I'm getting by with a 10X eyeloop and micropoint iron. Good Luck and keep the analog audio hobby alive! --Larry

[Eargasm]

I have two 150' runs of Canare L4E6S cable from my living room out to the garage so that the same music can play on the stereo in the living room, and on the stereo for the garage/pool. Seeings how I dont exactly critically listen to the music in the garage, it works great. That is awesome cable, and is shielded quite well. I honestly dont think you will have any problem with sending the music 70 ft with this cable. It is also comparitively cheap, at about $.35/ft.