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Post by Deleted on Apr 22, 2017 12:09:19 GMT
BIG YES!
Jim reminds that we are working on an Audio Plan for HBR: "Any suggestions on the audio cables I will need to feed the xmtr from 150 ft. away?"
TODAY I will post my recommendation for a professional balanced line audio transmission line that will NOT be expensive, and WILL be inexpensive and easy to accomplish.
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Post by Deleted on Apr 22, 2017 14:42:45 GMT
Getting Started With Audio Transmission - Part 1OBJECTIVE: Design a 150' Balanced Audio Transmission Line to Interconnect Computer Audio with AMT5000 Transmitter. TEXT VERSION - In this document we will describe textually the steps involved in achieving our objective. In a later version we will provide schematic illustration. Step 1: In a small mini-box build a stereo-to-monaural mixer (circuit will be identical to that employed within the AMT5000, except that we want it to exist at the computer end of the line, not at the transmitter end). a. using a stereo female 3.5MM phone plug (all metal construction preferred). b. cut a length of 3-conductor shielded audio cable to about 1'; C. connect one end of 1' audio cable to the stereo female plug: tip = left signal; ring = right signal; ground tab = shield; D. Push other end of 1' audio cable through a drilled hole into a small project box; E. To the left conductor of the 1' audio cable attach 1-end of a 10K 1/4 watt resistor; to the right conductor of the 1' audio cable attach a 10K 1/4 watt resistor; connect the other ends of both 10K resistors together, (stereo to mono mix is thus achieved); F. Cut a 1' piece of 2-conductor audio cable. Attach the center conductor to the junction of the 2 10K resistors; attach the shield of this audio 1' audio cable to the shield from the 1' 3-conductor audio cable from Step A; pass the 1' 1-conductor audio cable through a hole in the small project box and attach it to the RDL Line Amplifier linked in the next step; G. Link to RDL Line AmplifierTo Be Continued
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Post by Deleted on Apr 22, 2017 21:23:45 GMT
Continuing With Audio Transmission - Part 2
This custom plan for sending professional monaural audio over a 150' balanced line for Jim Henry's AMT5000 installation continues.
In Part 1 we described a consumer-level connection from computer audio output jack into a home-made mini-box containing an audio mixer to convert the stereo line to a mono mix, conventionally known as L+R.
The output from the mini-box carries the mono signal, in un-balanced configuration, to the RDL STA-1M Line Amp.
The 2nd page of the Application Sheet for the Amp shows how to attach the wiring to the Input in un-balanced configuration. That instruction is self-explanatory and need not be described here.
Now we approach wiring the output of the STA-1M Amp in balanced 3-wire configuration to 150' of balanced line-level cable, also shown on Page 2 of the Line Amp Sheet.
Next stop will be the far end of the balanced 3-wire audio line at the connection to the AMT5000.
Part 3 will be sent in the very near future.
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Post by Deleted on Apr 23, 2017 14:50:05 GMT
Audio Transmission Line Reaches Termination At the Transmitter - Part 3
In Parts 1 & 2 we've described how to convert a consumer stereo audio output to a mixed L+R audio signal, made connection to a RLD STA-1M Line Amp which converts the signal to a balanced 3-wire audio line at a professional line level of +4 dB for transmission over a 150' shielded balanced cable.
In Part 3 we will terminate the audio line at the AMT5000 Transmitter.
Consulting the Manual, ours is Instruction Manual Revision: R1, PCB 5000-03 Dated Sept 2011:
Page 9 - We see an illustration of the Circuit Board showing Component Locations. Down at the bottom edge of the circuit card, starting from the left, we see J5 - a Terminal Block which provides for the professional user a screw-termination point for both power line and balanced audio line. At this time we are connecting the audio line to three screw terminals marked GND, -AUD and AUD+ ;
Page 15 - Right side top of page Screw Terminal Blocks... you will see J5 listed here, but because of an oversight in manual preparation, there is no check-box for installing terminal block J5, so make sure your transmitter has the part installed;
Page 26 - Right column near bottom: Preamplifier and Compressor/Limiter -
- paragraph 2 - "The AMT5000 allows connecting either a consumer audio (the unbalanced RCA plugs) or Professional Audio Source.
- paragraph 4 - "A Professional Balanced Audio mono source can be connected via standard shielded twisted pair cable to 3 adjacent screw terminals labeled GND, - AUD and AUD +... etc.";
Page 42 - Circuit Diagram - On lower left side of diagram, just above the RCA phono inputs we spot J5 the terminal block for connecting power and audio.
In Part 4 we will begin to collect any details so far not covered, including a proposed Power Transmission Line to send low voltage power over the 150' distance between studio and transmitter.
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Post by Deleted on Apr 23, 2017 15:33:53 GMT
Audio & Power Transmission Lines - Part 4In Parts 1-3 we have described a detailed 150' audio connection between studio & transmitter. In Part 4 we will collect afterthoughts, corrections and further instructions. IMPORTANT - Changes will be made to this same post as new information is added. There will be no additional Parts in this series. Please check this Part 4 posting for changes and additions as time goes on.eBay happens to have the RDL STA-1 M Line Amp for $100. I do not know what a dealer would charge, I'll let you do your own shopping. New Info: The needed power supply for the Line Amp is PS-24AS. I do not see one listed in the eBay add. 4-HOURS LATER - AMT5000 Power Supply Transmission LineThis topic deserves some discussion inasmuch as I have an opinion only and we might do better by asking around. LINK TO POWER LINE DISCUSSION AT PART15_USArgument For Line Amp: -- The RDL Line Amp is essential for this project because... The audio outputs from the computer are two unbalanced (stereo) consumer lines at -10 dB. When unbalanced audio lines are extended beyond about 10-feet they are apt to lose high frequency content through capacitance roll-off, and pick up RF interference and AC hum from the surrounding environment. To compound this likelihood, -10 dB is a comparatively low audio level. The fact of two (stereo) lines doubles the amount of line loss which will occur; Conversion to a single balanced line at +4 dB will raise the signal level above any noise-floor, and the differential nature of balancing will reject external interference from entering the signal. ALSO, AND OF KEY IMPORTANCE - The AMT5000 Manual specifies that the Balanced Input (J5 Terminal Block) is designed to be driven at +4 dB.Line Level as Defined at WikipediaUsing sine-wave test tones generated from your computer at 100% set the Output of the Line Amplifier according to the "Line Levels and their approximate nominal voltage levels Chart" at the above link. Stand by for more info.
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Post by jimhenry2000 on Apr 24, 2017 3:15:04 GMT
Yes so far my transmitter has always been tuned indoors. Answers Straight AheadMost recent post from JH: " Unfortunately I don't think I have a signal strength meter." At this time you won't need one, Jim, I think DHR might have been asking me about that, and I already have the answer thanks to my spectrum analyzer, which will be posted along with a full report. Yes, during my window of opportunity between 4 and 4:30 PM CDT I was able to run a complete re-tuning of the AMT5000 and the results will be posted soon along with a batch of information about jumper settings and other tips. JIM - Was your transmitter indoors when you last tuned it?
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Post by jimhenry2000 on Apr 24, 2017 3:40:40 GMT
Carl, Again thanks so much for your help! I have ordered the RDL STA-1 M Line Amp via Amazon and think I got a bargain, $60 plus $5 shipping. Of the 4 that came up the next least expensive was $107. I think this may have been a mistake as within an hour after my order they raised the price to $108, but my order details still show that I am getting this for $65. Today I ran my 120 vac line on my strand out to the transmitter site so that is all ready. Now I need to know if I can use STP for the audio feed or something else, and if the amp is really necessary Jim Audio & Power Transmission Lines - Part 4In Parts 1-3 we have described a detailed 150' audio connection between studio & transmitter. In Part 4 we will collect afterthoughts, corrections and further instructions. IMPORTANT - Changes will be made to this same post as new information is added. There will be no additional Parts in this series. Please check this Part 4 posting for changes and additions as time goes on.eBay happens to have the RDL STA-1 M Line Amp for $100. I do not know what a dealer would charge, I'll let you do your own shopping. New Info: The needed power supply for the Line Amp is PS-24AS. I do not see one listed in the eBay add. 4-HOURS LATER - AMT5000 Power Supply Transmission LineThis topic deserves some discussion inasmuch as I have an opinion only and we might do better by asking around. LINK TO POWER LINE DISCUSSION AT PART15_USStand by for more info.
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Post by Deleted on Apr 24, 2017 12:18:35 GMT
Getting Somewhere For SureGreat News about the RDL Line Amp from Amazon. As mentioned above in Part 4 the RDL Line Amp needs a power supply: The needed power supply for the Line Amp is PS-24ASOne company that distributes RDL equipment is Markertek
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Post by Deleted on Apr 24, 2017 13:00:46 GMT
Special: Adding New Information to Part 4
Reminding that Part 4 of this series is an active page to which new information is still being added.
At this moment I am adding:
"Argument For Line Amp".
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Post by jimhenry2000 on Apr 24, 2017 21:00:17 GMT
Yes, my transmitter has never been outdoors. Carl, Again thanks so much for your help! I have ordered the RDL STA-1 M Line Amp via Amazon and think I got a bargain, $60 plus $5 shipping. Of the 4 that came up the next least expensive was $107. I think this may have been a mistake as within an hour after my order they raised the price to $108, but my order details still show that I am getting this for $65. Today I ran my 120 vac line on my strand out to the transmitter site so that is all ready. Now I need to know if I can use STP for the audio feed or something else, and if the amp is really necessary Jim Audio & Power Transmission Lines - Part 4In Parts 1-3 we have described a detailed 150' audio connection between studio & transmitter. In Part 4 we will collect afterthoughts, corrections and further instructions. IMPORTANT - Changes will be made to this same post as new information is added. There will be no additional Parts in this series. Please check this Part 4 posting for changes and additions as time goes on.eBay happens to have the RDL STA-1 M Line Amp for $100. I do not know what a dealer would charge, I'll let you do your own shopping. New Info: The needed power supply for the Line Amp is PS-24AS. I do not see one listed in the eBay add. 4-HOURS LATER - AMT5000 Power Supply Transmission LineThis topic deserves some discussion inasmuch as I have an opinion only and we might do better by asking around. LINK TO POWER LINE DISCUSSION AT PART15_USStand by for more info.
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Post by jimhenry2000 on Apr 27, 2017 5:39:25 GMT
Carl, I am still trying to get my head around this. I have rolled out the cable and confirmed I still have plenty of STP CAT 5E to run from studio to transmitter. From what I read in the manual I'm thinking I might not even need the amp. It's on the way though if I do need it. Can't I just run the PC output to the two RCA phone jacks to the audio inputs on J5 ? Continuing With Audio Transmission - Part 2This custom plan for sending professional monaural audio over a 150' balanced line for Jim Henry's AMT5000 installation continues. In Part 1 we described a consumer-level connection from computer audio output jack into a home-made mini-box containing an audio mixer to convert the stereo line to a mono mix, conventionally known as L+R. The output from the mini-box carries the mono signal, in un-balanced configuration, to the RDL STA-1M Line Amp. The 2nd page of the Application Sheet for the Amp shows how to attach the wiring to the Input in un-balanced configuration. That instruction is self-explanatory and need not be described here. Now we approach wiring the output of the STA-1M Amp in balanced 3-wire configuration to 150' of balanced line-level cable, also shown on Page 2 of the Line Amp Sheet. Next stop will be the far end of the balanced 3-wire audio line at the connection to the AMT5000. Part 3 will be sent in the very near future.
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Post by Deleted on Apr 27, 2017 12:34:32 GMT
Audio Choices
Jim Henry's question: "Can't I just run the PC output to the two RCA phone jacks to the audio inputs on J5 ?"
Your description contains a contradiction. You can't run audio to BOTH the RCA jacks and terminal block J5 because they are different inputs. It is an either or choice.
Revised question: Can you run audio from the computer outputs to terminal block J5?
Answer: No.
Why not?: Several reasons. The output from the computer is stereo and J5 is intended to accept a mono signal; the output from the computer has a line level of -10 dB (consumer level) but J5 is designed to accept a line level of +4 dB (professional level); the audio lines from the computer are each unbalanced (2-wire per channel) and J5 is a balanced (3-wire channel).
What you can do is run the lines from the computer to the RCA jacks on the AMT5000.
You might be lucky and may be satisfied with the result.
No harm will be caused by this arrangement... the only problems COULD BE loss of high frequency audio content, introduction of AC induced hum picked up from the environment by the unbalanced audio cables, pick up of RF energy from the environment by the unbalanced audio cables consisting of buzz.
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Post by jimhenry2000 on Apr 28, 2017 1:55:18 GMT
Carl, Again, thanks so much for your help. I have tried to take your instructions and put them in a text file that I could follow and I also included a parts list of what I think I need to buy. My questions and comments are in red font. The main jist of my effort is can I run to the professional audio inputs WITHOUT the line amp, and only add that if necessary. Please read the attached and if you will, provide any advice that you can. Thanks as always. Jim P.S. I have tried to upload this text file and the system gives me the Error message FORBIDDEN! So I will send it to you via email. Thanks. JimAudio ChoicesJim Henry's question: " Can't I just run the PC output to the two RCA phone jacks to the audio inputs on J5 ?" Your description contains a contradiction. You can't run audio to BOTH the RCA jacks and terminal block J5 because they are different inputs. It is an either or choice. Revised question: Can you run audio from the computer outputs to terminal block J5? Answer: No. Why not?: Several reasons. The output from the computer is stereo and J5 is intended to accept a mono signal; the output from the computer has a line level of -10 dB (consumer level) but J5 is designed to accept a line level of +4 dB (professional level); the audio lines from the computer are each unbalanced (2-wire per channel) and J5 is a balanced (3-wire channel). What you can do is run the lines from the computer to the RCA jacks on the AMT5000. You might be lucky and may be satisfied with the result. No harm will be caused by this arrangement... the only problems COULD BE loss of high frequency audio content, introduction of AC induced hum picked up from the environment by the unbalanced audio cables, pick up of RF energy from the environment by the unbalanced audio cables consisting of buzz.
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Post by Deleted on Apr 28, 2017 13:46:50 GMT
Email Received - Answers To Follow
Jim Henry ongoing audio project: "I have tried to take your instructions and put them in a text file that I could follow and I also included a parts list of what I think I need to buy. My questions and comments are in red font. The main jist of my effort is can I run to the professional audio inputs WITHOUT the line amp, and only add that if necessary. Please read the attached and if you will, provide any advice that you can. P.S. I have tried to upload this text file and the system gives me the Error message FORBIDDEN! So I will send it to you via email. Thanks. Jim."
Your Email has been received and replied to, I'll also post any additional information here for the benefit of those following the progress. This is a weekend project.
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Post by Deleted on Apr 28, 2017 15:02:50 GMT
IMPORTANT CLARIFICATIONS
Reading your red comments in the E-mail, Jim, I immediately want to clear up several things:
1. The terminal block J5 in the AMT5000 does NOT contain 6 audio screw-terminals!!
The first 3 screw-terminals (from the left) are for POWER connection to the AMT5000!!
The second 3 screw-terminals are for MONAURAL BALANCED AUDIO AT +4 dB LINE LEVEL!!
2. An UN-balanced audio line in all instances is a 2-conductor cable with a center conductor for the (+) polarity of the audio, and the SHIELD for audio (-) and GROUND.
IMPORTANT - A stereo UN-balanced audio cable consists of 2 inner conductors and shield, but it is in fact TWO Un-balanced audio lines sharing a shield, it is a LEFT and RIGHT set of signals SHARING a single shield. It is NOT a "balanced" line.
3. IF you go ahead connecting the consumer level computer audio to the AMT5000 in the UN-balanced (2-wire per channel) form that you think will work, you WILL NOT need the stereo mixer/project box, whose only purpose would be to prepare a proper input for the RDL Line Amp (if used).
For UN-balanced go directly from the output of the computer to the RCA inputs on the AMT5000.
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