It seems that QA software has come a long way (native or MarkZ third party) .
I think the time is near for me finally get a SA dedicated to audio. The only tools I have (own) are a Siglent 1202X-E , a Focusrite Sacrlett 2i2, and TinySA.
My primary current interest is using the SA to analyze phono stages and cartridges. I assume the QA403 is clean and sensitive enough for analysis of MC carts which can output (0.2) to (0.5) millivolts ?
On the topic of phono …
How well (cleanly) does the QA function as a, say, USB Audio Interface for Recording (similar to Focusrite or RME)?
I’m using a Focusrite Scarlett 2i2 for ripping vinyl. It is decent. But since QA is especially designed for audio measurements, I thought the sonic results might be superior.
(Note: Lynx and RME babyface used to be the preferred devices for better ADC phono rips).
If you have the Siglent signal generator you can do automated Bode Plots - but it is tedious at best.
the QA will not function as a recording interface at all, it is an audio analyzer and is more than up to the task of looking at phono stages.
If you are using your interface to record and looking to upgrade (and do not use plugins) but not go crazy and just need a couple good channels… look at some of the older Mytek dedicated AD and DA converters. They may not test as well as newer units, but they do sound really really good. I see people tracking on Universal Audio and more commonly studios will still be running the Digidesign 192 units with ProTools. Then mixing down to two tracks through Myteks or something similar - even running through 1:1 transformers to smooth out the edges. Lots of options when it comes to recording and mixing - and mastering.
The QA has an ADC chip like RME or Focusrite. One of reasons Tom C/Neurochrome suggested a Focusrite in the same audio analyzer video with QA. So I think the QA can work as an interface, unless the QA developers jump in to this thread and say it can’t.
About my Siglent…its a 1202 oscilloscope that has a Math feature that can do some SA. Not sure what you mean about “Siglent signal generator “?
My Siglent 1202 scope (which is not too low end) has noise issues with raw time domain graphs, like square waves, when I feed it raw cart signals (before phono preamp). May be difficult task in general. How might a QA deal with raw, MC 0.1mv signals? Is there a dedicated earth ground topology in the QA design?
BTW, I’m on Linux, so am I’m okay with native QA and third-party (MarkZ) software???
It’s fine down to millivolts, but at 100uV you will degrade your phono front end measurements due to some noise (attenuators are active but still…) You can measure it and calculate the degradation if you want.
An outboard attenuator for the gen might help, but you’d have to consider the values to a) not distort the DAC and b) present a reasonable source impedance to the MC stage which is expecting a transducer(cart) of 10-20R.
Sure it will, just install ASIO401 and you can use it as an ASIO soundcard for recording.
Usually, I connect the probe leads at the phono preamp inputs (with preamp powered off) , with the connected table/cart being tested “raw”. I assume this terminates the cartridge properly (passive impedance) w/o electrical interference from preamp.
If I can simply, passively terminate the cartridge (maybe even at the 4 pins on cart body, leaving out the table and leads), then this might be worthy. If so: Suggest a jig.
HAve you tried? I mean, have you actually used the 403 as an audio interface?
Yes, I have used it with Audacity (special ASIO version). And also with REW.
QA does manuf that mic preamp QA472, which seems like a decent interface for a follow-up adc module or chip. Not sure that a combo of those is what 403 is.
But enough speculation on my end. QA officials may need chime in for clarification or confirmation.