Lightweight, low-cost, high-density electrical connectors are disclosed that provide impedance-controlled, high-speed, low-interference communications, even in the absence of shields between the contacts, and that provide for a variety of other benefits not found in prior art connectors. An example of such an electrical connector may include a first signal contact positioned within a first linear array of electrical contacts and a second signal contact positioned within a second linear array of electrical contacts that is adjacent to the first linear array. Either of the signal contacts may be a single-ended signal conductor, or one of a differential signal pair. The connector may be devoid of shields between the signal contacts, and of ground contacts adjacent to the signal contacts.