Low Noise Transformer Input Pre-Amp Design - A Solution that Eliminates CMID

Kovinic M, Drincic D, Jankovic S. Low Noise Transformer Input Pre-Amp Design - A Solution that Eliminates CMID. In: AES Convention 126. Audio Engineering Society; 2009. Paper 7760. Available from: https://aes.org/publications/elibrary-page/?id=14956

@inproceedings{Kovinic2009_14956,
  author = {Kovinic, Milan and Drincic, Dragan and Jankovic, Sasha},
  title = {{Low Noise Transformer Input Pre-Amp Design - A Solution that Eliminates CMID}},
  booktitle = {AES Convention 126},
  note = {Paper 7760},
  year = {2009},
  month = may,
  publisher = {Audio Engineering Society},
  url = {https://aes.org/publications/elibrary-page/?id=14956}
}

TY  - CPAPER
TI  - Low Noise Transformer Input Pre-Amp Design - A Solution that Eliminates CMID
AU  - Kovinic, Milan
AU  - Drincic, Dragan
AU  - Jankovic, Sasha
T2  - AES Convention 126
M1  - Paper 7760
PY  - 2009
DA  - 2009/05/06
UR  - https://aes.org/publications/elibrary-page/?id=14956
PB  - Audio Engineering Society
LA  - en
AB  - This paper examines more closely the advantages of input transformer-op amp configurations, especially those implemented in low-noise designs. Usual transformer input stage topology works in non-inverting architecture, since it allows the transformer to work with optimum loading, to maximize the signal-to-noise ratio. However, this configuration is subject to Common-Mode voltage Induced Distortion - CMID. The susceptibility is further increased if the amplifier source impedances is not perfectly matched. This is illustrated by tests on popular audio op amps. Advanced transformer input stage topology proposed in this work completely prevents this kind of distortion. Noise performance remains unaffected, yet listening tests in practical application confirm the sound to be more pleasant.
ER  -