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R2XL1 

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PROFESSIONAL AUDIO WIRING 

You would think it would be easy to connect professional audio equipment 

together, but unfortunately it’s not. There can be all sorts of issues that come 
up; usually it is AC line hum in your equipment you have to deal with. This is 
normally caused by ground loops in the equipment. This effect can be caused 
by only a very little current and can wind up having a tremendous impact on 
your sound and sanity. We will try to clear some issues up for you by showing 
you how to properly wire XLR connectors and what to do in case of hum. 

 

Audio Outputs: 

XLR connectors provide a balanced connection that rejects common mode 

noise for a cleaner audio signal. Make sure your XLR connectors are WIRED 
CORRECTLY!  Some manufacturers make them incorrectly so you may want 
to check the connectors and re-make them to standards if necessary. Current 
standards dictate that XLR connectors should be wired as follows: 

Ground = pin 1, White = Pin 2, Black = Pin 3. Sometimes you will find red 

instead of white.  Both ends of the cable are wired in the same order, per the 
following diagram. 

Across pins 2 & 3 of the XLR inputs look for +4 dBu (1.228VRMS) as 

equivalent to 0 dBuV. The audio output can deliver up to a maximum of 21.2V 
pk/pk, but then you have to scale the level back down with your audio gain to 
get acceptable sound in your destination equipment. 

 
Solving ground loop hum: 

We don’t expect you to come across this, but if you do, here is what you may 

do. 

1. Try running a wire to connect the chassis of your destination equipment 

to the source equipment AND the R2XL1. If all are grounded well to-
gether, it may prevent the ground loop from traveling down the audio ca-
bles. 

2. Try lifting the shield wire on your XLR cable on the FEMALE end (the 

one that plugs into your R2XL1). This will eliminate the path of the 
ground loop. 

WHITE
BLACK

SHIELD(GND)

2

3

1

WHITE

BLACK

SHIELD(GND)

2

3

1

2 Conductor Shielded Cable

FEMALE

MALE

Содержание RCA to XLR Converter R2XL1

Страница 1: ...n types from RCA to XLR it also gives you the added advantage of independent channel gain control for the proper levels Powered by a 12VAC wall power transformer for ground isolation Stereo Mono switc...

Страница 2: ...Thermometer LC1 Inductance Capacitance Meter RAMSEY AMATEUR RADIO KITS DDF1 Doppler Direction Finder HR Series HF All Mode Receivers QRP Series HF CW Transmitters CW7 CW Keyer CPO3 Code Practice Oscil...

Страница 3: ...t 7 Schematic Diagram 8 Parts Layout Diagram 9 Learn as You Build 10 Assembly 12 Using the R2XL1 15 Professional Audio Wiring 16 Custom Case Assembly 17 Troubleshooting 18 Warranty 19 KIT ASSEMBLY AND...

Страница 4: ...tereo Mono switch It takes the au dio presented on the right input and sends it to both left and right XLR amplifi ers when pressed in This allows you to drive a professional stereo audio de vice from...

Страница 5: ...ng resistors of R1 and R2 to set its gain Use the formula from before to figure out for yourself what the gain has been set for We ll con firm in a moment if you are correct The other opamp U1 A is co...

Страница 6: ...omplish this we use a bridge rectifier consisting of D1 4 to take the AC input voltage and convert it to positive DC pulses This directly is too noisy for our application so C12 was added to smooth th...

Страница 7: ...2 4 7 8 10 2 10K ohm resistors brown black orange R13 14 2 100 ohm resistors brown black brown R3 9 2 560 ohm resistors green blue brown R6 12 Capacitors 2 0 01 uF Ceramic capacitors marked 103 C9 10...

Страница 8: ...R2XL1 8...

Страница 9: ...R2XL1 9 R2XL1 PARTS LAYOUT DIAGRAM...

Страница 10: ...leads and the pads simultaneously Apply the solder to the the pad when the junction is hot enough to melt the solder The finished joint should look like a drop of water on paper somewhat soaked in Mou...

Страница 11: ...ure the part is mounted flush to the PC board unless otherwise noted 3 Orient it correctly follow the PC board drawing and the written directions for all parts especially when there s a right way and...

Страница 12: ...ientation again 5 Install D6 another 1N4002 diode Orientation must be correct or we will get no negative supply Note how this is placed between two large capaci tors Imagine trying to install this aft...

Страница 13: ...o change it now Just make sure that the side NOT marked negative is in the same side marked positive on the board 20 Install C8 another 10 uF electrolytic capacitor Again check polarity 21 Install R14...

Страница 14: ...nical soundness 34 Install J6 our 2 5 mm AC power jack 35 Install C11 a 470 uF electrolytic capacitor Check orientation just in case you forgot 36 Install C12 another 470 uF electrolytic capacitor 37...

Страница 15: ...as your primary audio gain control Since we built in a lot of gain it is too difficult to adjust on the fly Even worse there are two controls to tweak making it even harder to keep these at the same...

Страница 16: ...ent standards dictate that XLR connectors should be wired as follows Ground pin 1 White Pin 2 Black Pin 3 Sometimes you will find red instead of white Both ends of the cable are wired in the same orde...

Страница 17: ...ceive years worth of enjoyment using talking about and remembering the fun you had building your kit In short TAKE YOUR TIME when assembling the enclosure This is the part that you and your friends wi...

Страница 18: ...terference SOLUTION Here is where R6 and R12 come into play The two 560 ohm green blue brown resistors that were left out of the normal construction steps may need to be installed With long cable runs...

Страница 19: ...h be assured that the 1K ohm resistors are actually the missing 10 K parts Hum m m I guess the red band really does look orange Ramsey Electronics project kits are packed with pride in the USA If you...

Страница 20: ...SEY ELECTRONICS INC 590 Fishers Station Drive Victor New York 14564 Phone 585 924 4560 Fax 585 924 4555 www ramseykits com REQUIRED TOOLS Soldering Iron Ramsey WLC100 Thin Rosin Core Solder Ramsey RTS...

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