There is a discussion about the QuantAsylum QA403 Audio Analyzer over on the "Bob Cordell's Power Amp Book" thread that some here may be interested in. The QA403 is a great test instrument that does frequency response, THD, etc. measurements with high performance for only $600. It connects to a PC via USB and is even powered by the USB. Two features of particular interest to some here are built-in A-weighting for noise measurements and an inverse RIAA function for phono preamp equalization accuracy measurement.
Cheers,
Bob
Cheers,
Bob
Version 1 of my Tutorial for the QuantAsylum QA403 audio analyzer is now up on my site at cordellaudio.com. I is under the Audio Instrumentation tab.
Cheers,
Bob
Cheers,
Bob
Version 3 of my Tutorial for the QuantAsylum QA403 audio analyzer is now up on my website and is discussed in the QuantAsylum User Forum. The tutorial walks the reader through all of the pertinent tests for an audio power amplifier, in this case my BC-1 design, which is also described in detail on my website.
The QA403 is an outstanding piece of equipment, especially at only $600. It has pretty much all of the functionality and performance most people could need. It is just as valuable for use with small-signal circuits as well as power amplifiers. One nice feature is that it includes selectable inverse RIAA respnse shaping for measuring phono preamps. It also includes selectable A-weighting for noise measurements. Further, it includes optional user-entered weighting responses. It can usually see distortion products below -120 dB or better, and report THD down to -120 dB or better. It can sample at up to 192 kHz, allowing one to see FFT products up to at least 80 kHz. Sampling to 384 kHz may be available soon. It is powered from its USB connection to the PC on which its software resides, and it is galvanically isolated from the PC side. It has balanced I/O.
Cheers,
Bob
The QA403 is an outstanding piece of equipment, especially at only $600. It has pretty much all of the functionality and performance most people could need. It is just as valuable for use with small-signal circuits as well as power amplifiers. One nice feature is that it includes selectable inverse RIAA respnse shaping for measuring phono preamps. It also includes selectable A-weighting for noise measurements. Further, it includes optional user-entered weighting responses. It can usually see distortion products below -120 dB or better, and report THD down to -120 dB or better. It can sample at up to 192 kHz, allowing one to see FFT products up to at least 80 kHz. Sampling to 384 kHz may be available soon. It is powered from its USB connection to the PC on which its software resides, and it is galvanically isolated from the PC side. It has balanced I/O.
Cheers,
Bob