Shaun Merrigan's Information Pages

Category: Audio

Tektronix SG5010 Audio Signal Generator Repair

Posted by Shaun Merrigan in Audio, Electronics, Test Equipment. Comments Off on Tektronix SG5010 Audio Signal Generator Repair

14th December


The Tektronix SG5010 is an audio signal generator plug-in for the TM5000 modular test equipment system. It can generate five waveforms: sine wave, square wave, SMPTE/DIN intermodulation test signal, CCIF intermodulation test signal, and sine wave burst. All these signals may be swept in frequency and amplitude. It can generate very low distortion (THD+N < 0.0008%; my own measurements) sine waves from 20Hz-20kHz. It is CPU controlled with selections made via GPIB or front panel keyboard. These characteristics made it very desirable as part of an audio amplifier test lab. These units command a high price: Several working units have recently (Dec 2023) been sold for $USD 1500.

I recently acquired a non-working SG5010 for a good price. This post documents my efforts (ultimately successful) in getting it working.

Tektronix SG5010 Overview

Tektronix SG5010 Front Panel

First … Read More »

600 Ohm Terminator Build

Posted by Shaun Merrigan in Audio, Electronics, Test Equipment. Comments Off on 600 Ohm Terminator Build

27th December

When doing work on older audio gear it is sometimes necessary to maintain a 600 ohm impedance from, for example, a signal generator to a DUT or a piece of test gear. An easy way to do this is with a 600 ohm terminator. The article will document how I built such a terminator.

First I want to acknowledge the work of ElPaso TubeAmps (David Beard) who covered this very subject several years ago:

50 ohm and 75 ohm BNC terminators are relatively easy to obtain, but 600 ohm terminators harder to come by. The solution is to build one as follows:

Obtain a suitable 50 or 75 ohm BNC terminator . You need the type which can be opened. One clue is that it may have flats on the end of the barrel which were used during assembly.The … Read More »