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.

Authors: Kovinic, Milan; Drincic, Dragan; Jankovic, Sasha
Affiliations: MMK Instruments, Belgrade, Serbia; Advanced School for Electrical & Computer Engineering, Belgrade, Serbia; OXYGEN-Digital, Parkgate Studio, Sussex, UK(See document for exact affiliation information.)
AES Convention: 126 (May 2009) Paper Number: 7760
Publication Date: May 1, 2009
Subject: Signal Processing

Click to purchase paper as a non-member or you can login as an AES member to see more options.

No AES members have commented on this paper yet.

Subscribe to this discussion

To be notified of new comments on this paper you can subscribe to this RSS feed. Forum users should login to see additional options.

Start a discussion!

If you would like to start a discussion about this paper and are an AES member then you can login here:
Username:
Password:

If you are not yet an AES member and have something important to say about this paper then we urge you to join the AES today and make your voice heard. You can join online today by clicking here.