Differential/balanced input and output circuits ( 40 ) :

• Input

• A New Balanced Audio Input Circuit for Maximum Common-Mode Rejection in Real World Environments - 109KB PDF file   
• Audio Transformers - notes on using audio transformers for balanced signal interfacing   
• Additional RFI Protection for Line Input Circuits - 8KB PDF   
• External Isolation Transformer Box for Mackie (and other) Mixers Eliminates RFI Problems   
• High CMRR Balanced Interface for Crystal 18 or 20 Bit A/D Converters - pdf file   
• Internal Modification to Mic Inputs of the Mackie 1604 Mixer Eliminates RFI Problems   
• JT-6110K-B at Input Stage for Crystal A to D Converters - high performance transformer balanced input stage for Crystal A/D converters, pdf file   
• JT-11P-1 Balanced Tube Line Input Stage   
• JT-11SSP-6M as Input Transformer for Crystal CS5367 A/D Converter - transformer balanced passive input circuit for CS5367 A/D converter, pdf file   
• JT-16-A Improves Performance of SSM2015 Mic Preamp IC   
• JT-16-A Improves Performance of SSM2017 Mic Preamp IC   
• JT-MB-C in Low Noise, High Isolation Line Receiver for Low-Z Sources   
• JP-11P-1 Input transformer improvement for electronically balanced input   
• Jensen Transformers Application Schematics - many circuit examples with transformers   
• JT-MB-C Isolates both Mic and Line Inputs of Inexpensive Mixer   
• JT-MB-C Mic Input Isolation for Mackie Mixers   
• JT-MB-C "Real" Mic Inputs & Phantom Power for Sony DAT   
• Making Differential Probes - for sensing audio signal voltages across devices which are not ground referenced   
• Subtleties count in wide-dynamic-range analog interfaces - article on balanced input designing with some example circuit topologies,   

• Output

• 12 dB Amplifier and High Current Line Driver with DC Servo    Rate this link
• 20 dB Amplifier and High Current Balanced Line Driver    Rate this link
• Driving a balanced line, and getting 3 signals down 2 lines! - Often we get asked "How do you drive a signal down a 600 ohm balanced line", or "How do I terminate a 600 ohm circuit". This is actually VERY easy to do, and all you need is an isolating transformer at each end, and some cheap op-amps to drive / receive the signal, along with a few resistors etc.   
• High Output Line Driver for Single Ended Power Supply - pdf file   
• JT-11-BM High Level Differential IC Output Stage with DC Servo   
• JT-11-BM High Level High Current Differential Output Stage with DC Servo   
• JT-123-S Line Driver with Feedback Around the Transformer    Rate this link
• JT-123-BL High Level Low Impedance Differential Output Stage with DC Servo   
• Low Noise version of High Level Output Stage in 1031 - pdf file   
• Mixed feedback drive circuits for audio output transformers - using feedback eliminates transformer distortion and primary resistance   
• Simple 0 to 24 dB Gain Amplifier and Balanced Line Driver - 18KB PDF   

• Input and output in same circuit

• Balancing Acts - balanced and unblanced interface circuits using tubes   
• Balanced Line Driver & Receiver   
• Balanced Line Inputs/Outputs for Silicon Graphics Workstations - balancing using transformers   
• Balanced Line Technology - Information article and example circuits for both input and output   
• Bridging Line Amplifier - transformer balanced input and output with amplifier in between
• Transfomers for audio interfacing - discussion on using audiop transformers in equipment interconnections, read also   

• Other circuits

• Grounding and shielding in balanced inputs and outputs which are transformer coupled   
• JT-11-YZPC in Unbalanced Long Line Driver/Isolator   
• Long Lines Driver - high current output configuration is ideal for use as a transformerless long lines driver   
• The Allen & Heath GL2 - in anger - The desk was great but the metering -YUCK, so what to do about it. Obviously the metering system needed expanding but how? Ten meters were required in all and a suitable power supply would have to be constructed. This describes how to built those LED VU meters (-21..+6dB range using 10 LEDs).   

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