[sdiy] Possible 4 channels scope.. Siglent SDS1104X (-U or -E)

Neil Johnson neil.johnson71 at gmail.com
Tue Apr 6 22:24:34 CEST 2021


Hi,

Aaron B. wrote:
> I actually missed out on a good condition HP 3580A spectrum analyzer by
> $5 on eBay recently.
>
> Are there good new model spectrum analyzers out there, specifically in
> the audio range?

What you're looking for is called a Dynamic Signal Analyser, such as
the vintage 35660A or 35665A, which come from a long line of machines
from HP.
The 3580A is really vintage, and very analogue - it shifts the audio
up into the MHz region for the IF filter and level detection.
The 3582A was about the first audio-band FFT-based dynamic signal
analyser (dual channel), but limited bandwidth (0.02Hz to 25.6kHz)
Then the 3561A (single channel) and 3562A really took the market by
storm, covering the range 125uHz (64uHz for the 3562A) to 100kHz.
These were superseded by the aforementioned 35660A and 35665A Dynamic
Signal Analysers, which were aimed at the acoustics, vibration, and
control systems folks.
Replaced by the 35670A, which is discontinued but still in support.

For low-cost there is the PC route: you need a good analogue front
end, and a decent PC running analysis software.  For example:
https://quantasylum.com/collections/frontpage/products/qa401-audio-analyzer
But note the availability issue due to the AKM fire.

Other options exist, for example: https://trueaudio.com/rta_abt1.htm
And see their supported interface page.

If you want to analyse audio for things like THD, then nothing comes
close to an AP.  But that's another story....

Neil


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