I picked up a new piece of gear for the shop recently, the Keithley 2015 THD Multimeter.

It was a fantastic deal – a refurbished and calibrated unit for about 10% of the MSRP. These have been manufactured for about 20 years now and are still being sold for around $4000 and have about all the features you could ask for in a basic lab bench meter: 6.5 digit precision, 2- and 4-wire resistance measurements, direct readout in dB/dBm, temperature display from an external thermocouple, and most interestingly to me: a low-noise audio source 20Hz-20KHz, frequency counter, and distortion analyzer.

This meter will come in very handy in power amplifier repair, but also for performing FM alignments – it’s not always easy to check the alignment with a scope, but with this meter, you can watch the distortion decrease as the circuit comes into alignment. Dave at the EEVBlog has a teardown review of this exact multimeter posted last year. His teardown was instrumental in deciding to get this particular model over several others I was considering.

It’s not going to be used every day, but it’s going to be indispensable when it does come out.