4S3

The Tektronix Type 4S3 is a 1GHz dual-trace vertical sampling plug-in for the 661 oscilloscope. It uses two P6038 sampling probes. The probes contain sampling gates but not amplifiers. The front-end amplifier is therefore in the 4S3, and is composed of a 7308 tube (premium 6DJ8) with its two triodes connected in a common-cathode cascode topology.

• Tektronix 4S3 Manual (PDF)

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  In 1963 Catalog