Tag:

balanced audio

Audio Theory

Benefits of balanced headphones interconnection

by nihtila August 6, 2018

written by nihtila

In balanced connection both speakers are individually connected to amplifier using two wires for each channel
Crosstalk can be improved by tens of dB by using balanced interconnection
Common-impedance coupling seriously limits crosstalk in conventional unbalanced headphones
Balanced output can be easily and cost-effectively added on designs; inverted signal is not required

August 6, 2018 3 comments

Projects

Addon BalOut v2 – Balanced output board

by nihtila April 9, 2018

written by nihtila

Simple balanced buffer with very high performance
Noise level: -117 dBV A-weighted (v2.0B)
THD+N ratio at 2 Vrms output signal: -119 dB (v2.0B)
Two versions can be populated:
- v2.0A – traditional balanced output with inverted signal on cold lead
- v2.0B – simplified output with ground on cold lead

Original Addon BalOut was designed for H-DAC but as there has been interest in those boards, this new version is easier to use in other applications:

No filter components
Normal opamps instead of fully differential opamp
Separete input signal pinheaders
Mounting holes
Reference designators on silk screen and cheaper 2-layer board

April 9, 2018 0 comment

HP Buf – High-current buffered amplifier board for HP MoBo

by nihtila February 4, 2018

written by nihtila

Amplifier daughterboard for HP MoBo modular headphone amplifier

High-power high-performance balanced headphone amplifier daughterboard for HP MoBo
Balanced input, balanced output
Jumper link for two gain options, default 0/10 dB
Jumper link for two output impedance options
OPA2134 opamps followed by BUF634 or LME49600 buffers
SNR: 113-121 dB A-w depending on the buffer, load, and gain
THD+N ratio at 100 mW (LME49600)
- 300 Ω: 0.0004 % / -108 dB
- 32 Ω: 0.0007 % / -103 dB
- 16 Ω: 0.0012 % / -98 dB
Max power around 1 W (<0.1 % THD+N)
Update: get even higher performance with LM4562 opamps

February 4, 2018 0 comment

Modular HP Amp Obsolete

HP MoBo – Modular headphone amplifier motherboard

by nihtila February 4, 2018

written by nihtila

Motherboard for modular headphone amplifier system

Motherboard with inputs, outputs, power distribution, and signal routing for amplifier daughterboard
Balanced input
Balanced and unbalanced outputs
Output mute circuit
Requires separate amplifier board

HP MoBo is the basis of a modular headphone amplifier design. It provides input and output connections and simple power supply components (external power supply required), and connections for stackable amplifier daughterboard.

February 4, 2018 0 comment