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Interconnection-1

Introduction

This note, originally written in 1985, continues to be one 

of our most useful references. It’s popularity stems from 

the continual and perpetual difficulty of hooking up audio 

equipment without suffering through all sorts of bizarre 

noises, hums, buzzes, whistles, etc.— not to mention the 

extreme financial, physical and psychological price. As tech-

nology progresses it is inevitable that electronic equipment 

and its wiring should be subject to constant improvement. 

Many things 

have

 improved in the audio industry since 

1985, but unfortunately wiring isn’t one of them. However, 

finally the Audio Engineering Society (AES) has issued a 

standards document for interconnection of pro audio equip-

ment. It is AES48, titled “

AES48-2005: AES standard on 

interconnections —Grounding and EMC practices — Shields 

of connectors in audio equipment containing active circuitry

.”

Rane’s policy is to accommodate rather than dictate. 

However, this document contains suggestions for external 

wiring changes that should ideally only be implemented by 

trained technical personnel. Safety regulations require that 

all original grounding means provided from the factory be 

left intact for safe operation. No guarantee of responsibility 

for incidental or consequential damages can be provided. 

(In 

other words, don’t modify cables, or try your own version of 

grounding unless you really understand exactly what type of 

output and input you have to connect.)

Rane Technical Staff

RaneNote 110

© 1985, 1995, 2006, 2007, 2011, 2015 Rane Corporation

Sound System 
Interconnection

•   Cause & prevention of ground loops

•   Interfacing balanced & unbalanced

•   Proper pin connections and wiring

•   Chassis ground vs. signal ground

•   Ground lift switches

RaneNote

SOUND SYSTEM INTERCONNECTION

Summary of Contents for SM 26S

Page 1: ...claration of Conformity 22369 10 0 2 4 8 6 10 0 2 4 8 6 10 0 2 4 8 6 10 0 2 4 8 6 10 0 2 4 8 6 10 0 2 4 8 6 10 0 2 4 8 6 10 0 2 4 8 6 10 10 6 2 6 2 10 10 6 2 6 2 10 10 6 2 6 2 10 10 6 2 6 2 10 10 6 2...

Page 2: ...he power cord is the AC mains disconnect device and must remain readily operable To completely disconnect this apparatus from the AC mains disconnect the power supply cord plug from the AC receptacle...

Page 3: ...r le courant alternatif AC et doit absolument rester accessible Pour d connecter totalement l appareil du secteur d branchez le c ble d alimentation de la prise secteur 16 Cet appareil doit tre branch...

Page 4: ......

Page 5: ...roper output level The MASTER INPUT LEVEL control adjusts both Right and Left Input signal levels together WEAR PARTS This product contains no wear parts 10 0 2 4 8 6 10 0 2 4 8 6 10 0 2 4 8 6 10 0 2...

Page 6: ...ight Master Input program to each channel s MONO OUT PAN When used as a MIXER this control pans the Mono channel Input between the LEFT and RIGHT MIX OUTPUTS 4 MASTER OUTPUT LEVEL controls the gain of...

Page 7: ...sions possible with the SM26S NOTE These Expand Outputs are not buffered from the Master Inputs Therefore it is not possible to mix both balanced and unbalanced lines in the same channel between sever...

Page 8: ...t only be done with the power off by qualified service personnel If an SM26S needs to have an additional set of indepen dent outputs as in a 2x4 stereo distribution amplifier see Swiss Army Mixer Figu...

Page 9: ...es at once For instance Inputs 1 through 3 may be mixed to the left and or right output buses while at the same time Outputs 4 and 5 are delivering signal originally applied to the Left and Right Mast...

Page 10: ...rtion SMPTE 0 009 002 60 Hz 7 kHz 4 1 4 dBu unity gain Signal to Noise Ratio re 4 dBu 20 kHz noise bandwidth 120 2 dB Mono Outputs unity gain 98 2 dB Mix Outputs unity gain Crosstalk L R Panning 60 1...

Page 11: ...with panning ability on every input Many musical instrument performers find the SM26S indispensable for combining various effects and expanding the available loops on their signal processors The SM26S...

Page 12: ...requirements pending The unit shall be UL and cUL listed pending The unit shall be entirely constructed from cold rolled steel The unit shall be a Rane Corporation SM26S Architectural Specifications T...

Page 13: ...er amplifier It has 12 dB of gain and better than 80 dB of attenuation The distortion products are less than 008 and the noise floor is a trifle 35 microvolts Inside this RaneNote is found a gruelingl...

Page 14: ...nd Right Mix Outputs The Output from each of the Mix pots feeds the individual Mono Channel Level stages through a Figure 1 SM26S Complete Block Diagram switching contact associated with the MONO IN j...

Page 15: ...act opposite mode as described above When wired per Figure 3 the SM26S becomes a 2 In 6 Out Splitter Distribution Amp The master stereo signal is con nected to the Left and Right input jacks and is s...

Page 16: ...control NOTE One additional channel can be gained by rotating all the PAN pots fully CW and using the LEFT INPUT and LEFT MIX OUTPUT or rotate tully CCW and use the RIGHT IN and OUT combination MONO I...

Page 17: ...he SM26S s while their respective Left and Right Mix Outputs are used to cascade the chain by con necting to the Left and Right Inputs of the next SM26S and so on RIGHT INPUT LEFT INPUT 1 2 3 4 5 6 TO...

Page 18: ...available as 6 buffered Outputs if needed Stereo Headphone Mixer Figure 8 shows how the SM26S can be used as a 6 In 2 Out stereo mixer driving the HC 6 Headphone Console Six Mono Inputs are brought in...

Page 19: ...Stereo mixing is done in the exact opposite man ner Up to 4 stereo pairs are brought into all Inputs by connecting one pair to the Left and Right INPUT jacks and the three remaining lefts to Channels...

Page 20: ...he splitter with their pan controls all the way to the left bus Since the MONO IN jacks know that an individual Input overrides the master Input Channels 4 5 and 6 will act as the mixer with their pan...

Page 21: ...onnections Grounding and EMC practices Shields of connectors in audio equipment containing active circuitry Rane s policy is to accommodate rather than dictate However this document contains suggestio...

Page 22: ...connect is not compat ible with unbalanced The small physical nature and short cable runs of completely unbalanced systems home audio also contain these ground loop noise currents However the currents...

Page 23: ...CTICE RECOMMENDED PRACTICE OPTIONAL CASE 1 2 3 3 1 2 CHASSIS GROUND SIGNAL GROUND CHASSIS GROUND CHASSIS GROUND The Next Best Right Way To Do It The quickest quietest and most foolproof method to con...

Page 24: ...ounded and therefore immune to ground loop hums and buzzes Ground lifts are simply another Band Aid to try in case of grounding problems It is true that an entire system of properly grounded equipment...

Page 25: ...guarantee that a hum free intercon nect can be achieved nor is there a definite scheme that will assure noise free operation in all configurations References 1 Neil A Muncy Noise Susceptibility in An...

Page 26: ...20 24 24 19 18 17 B B B B A A A A A A FEMALE BALANCED XLR NOT A TRANSFORMER NOR A CROSS COUPLED OUTPUT STAGE FEMALE BALANCED XLR EITHER A TRANSFORMER OR A CROSS COUPLED OUTPUT STAGE BALANCED TRS NOT A...

Page 27: ...RED SHIELD RED SHIELD SHIELD RED RED BLACK N C N C N C RED BLACK RED SHIELD N C BLACK RED BLACK RED 3 NC 2 RED 1 SHIELD 2 RED 1 SHIELD 3 BLACK 2 RED 1 NC 3 BLACK 2 RED 1 NC 3 BLACK 2 RED 1 SHIELD SHIE...

Page 28: ...3 BLACK 2 RED 1 SHIELD 3 BLACK 2 RED 1 SHIELD SHIELD BLACK SHIELD RED BLACK SHIELD RED BLACK RED SHIELD SHIELD BLACK RED SHIELD BLACK RED SHIELD BLACK RED SHIELD BLACK RED SHIELD BLACK RED SHIELD RED...

Page 29: ...ECTS IN MATERIAL OR WORKMANSHIP THE SPECIFIC PERIOD OF THIS LIMITED WARRANTY SHALL BE THAT WHICH IS DESCRIBED TO THE ORIGINAL RETAIL PURCHASER BY THE AUTHORIZED RANE DEALER OR DISTRIBUTOR AT THE TIME...

Page 30: ...IN THE USA If the product is being sent to Rane for repair please call the factory for a Return Authorization number We recommend advance notice be given to the repair facility to avoid possible need...

Page 31: ...ompliance with the LV directive and EMC direc tive in the event that the equipment is modified without written consent of the manufacturer This declaration of conformity is issued under the sole respo...

Page 32: ...5 4 3 2 1 MIX OUTPUT EXPAND OUT MASTER IN 100 240 V 50 60 Hz 7 WATTS RANE CORPORATION This device complies with Part 15 of the FCC Rules Operation is subject to the following two conditions 1 this dev...

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