AM8171 Sequential Switch

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OVERVIEW When Roland developed the System 100M they created a quad signal gate module, the 171, which also had a ton of multiples. The AM8171 module contains the same four signal gates built with modern components, and an onboard LFO clock, making it a very useful sequential switch, for both audio and CV signals.

DESCRIPTION The AM8171 has four separate channels of signal gates based on a modern analog switch. Each gate can be switched on and off by the CV gate inputs or by putting the mode switch into its upper position (preview). Green low current LED's indicate when the gate is on.

In the lower position the mode switch enables each gate to be selected by the sequential clock. The clock is started and stopped by the RUN switch and operates from 0.03Hz to 3Hz. Faster or slower rates can be used by patching in an external LFO. The gates can be manually stepped through using the STEP button.

The length of the sequence can be set using a slide switch; 2, 3, or all 4. There is a clock output, and a clock input which operates in parallel to the internal clock. Each gate has its own signal input and output, and there is a mixed signal output with its own level control.

Each gate can be used with either audio or CV signals (10V p-t-p). An audible click may be heard when using the gates with audio, as zero level crossing detection has not been implemented. The clock RATE potentiometer has a Roland TR808 style control knob.

There are jack sockets for the signal input and output and the gate and gate inverted control inputs for each channel. The bottom of the panel has the clock in, clock out and mix output.

A modern analog switch chip has been used along with a high quality summing Op Amp. The module has a grey powder coated panel, with white silk screen, which has been custom manufactured.

CONNECTIONS There are four jack sockets for each channel:

• Signal Input
• Signal Output
• Gate + Input
• Gate - Input

The sequential clock has three jack sockets:

• Clock Input
• Clock Output
• Mix Out

The module comes with a set of M3 mounting screws and washers, and a standard Doepfer power cable.

MODULE STATUS: PRODUCTION