Getting Started with a QuantAsylum Audio Analyzer

[Rick Sykora]

Per request on another thread from @peng, here is a list of key parts you will need to use a QuantAsylum 401 or 402 to measure the performance of other electronics:

1. BNC loopback cables like these. These might be a bit short if you have larger hands, so may need to adjust length.
2. 50 ohm terminators like these.
3. While you might build a cleaner cable, I use these to adapt BNC to RCA. I then use my RCA to XLR cables to connect the analyzer to the amps balanced input. Ofc, these are convenient to connect the analyzer outputs to unbalanced inputs too.
4. You will need some non-inductive dummy load resistors. If you keep high power testing to short durations (seconds rather than minutes), you can use the ones recommended here.
5. The load resistors need a good way to be connected. I use banana jacks like these. I had some around that handle larger gauge wire. I find them more useful than the ones made for smaller speaker cable.
6. I use sawtooth banana plugs like these to ensure good connections.

 

[pma]

Looking forward your measurements. This thing has excellent value/price ratio.

 

[Rick Sykora]

Btw, no need for a power supply, but you do need a good USB printer cable to power the analyzer.

Most of the parts list in my original post can be found on the QA401 page. For some reason, they did not repeat it for the QA402. I own a QA401, so there might be some aspects that are different for the QA402.

 

[MakeMineVinyl]

I purchased the QA402 a couple months ago and have been using it both at my home shop and at work at the power amplifier sausage factory. I bring out the BNCs to a panel on my bench which has standard banana jacks, the outputs being single ended and the inputs being balanced. So far I'm thrilled with its performance which while not Audio Precision level, is plenty good enough for the measurements I do. There are a couple changes in the software which I've suggested and which have been implemented, so its good that they are both responsive and answer queries in a timely manner.

 

[Rick Sykora]

Also you might want a set of these...

Proster 100 MHz Oscilloscope Clip Probes with BNC to Mini Grabber Test Lead Kit BNC to Mini-Grabber Clips Oscilloscope Probe: AmazonSmile: Industrial & Scientific

If you do not want probes, I find the test clips to be very handy.

 

[DualTriode]

I purchased a QA401 when it was current and used it often. A year or so I purchased a QA 402 when it was just offered, it is still new in the box.

Now I will purchase the newly released QA403, it looks like it has more auto ranging relays to improve performance.

I use leads that I have soldered on Mueller BU30BL miniature alligator clips. I like these clips better than the mini-grabbers.

Thanks DT

https://www.muellerelectric.com/product_files/203/DS-BU-30.pdf

 

[somebodyelse]

Btw, no need for a power supply, but you do need a good USB printer cable to power the analyzer.

When you say 'USB printer cable' do you mean a normal Type A to Type B cable that's not marginal on spec so can handle the slightly-above-standard current?

 

[Rick Sykora]

When you say 'USB printer cable' do you mean a normal Type A to Type B cable that's not marginal on spec so can handle the slightly-above-standard current?

Yes, while I do tend towards the heavier gauge cables, am also using ones with built-in noise suppression.

 

[BDWoody]

Now I will purchase the newly released QA403, it looks like it has more auto ranging relays to improve performance.

I bought Jan Didden's autoranger for my QA401. That's a pretty nice piece of gear. (One of @SIY 's reviews.)

Fresh From the Bench: The Linear Audio Autoranger Mk II Measurement Interface

Stuart Yaniger explores new possibilities in audio measurement systems, expanding on the basics of using sound cards combined with new accessible-to-all software tools, such as REW, and a recently improved measurement interface option. That option is the Linear Audio Autoranger Mk II Interface...

audioxpress.com

 

[DualTriode]

Jan Didden's autoranger goes only half way there. It is only one channel. Half the time that is all that you need.

Thanks DT

 

[radix]

What do people use for BNC + and - phase to XLR? Or do you make your own cable?

 

[BDWoody]

What do people use for BNC + and - phase to XLR? Or do you make your own cable?

I had blue jeans cable make me a few custom sets.

 

[MakeMineVinyl]

Make my own cables using whatever wire I have available.

 

[DualTriode]

Make my own cables using whatever wire I have available.

Do not look now.

You can purchase "The Worlds Best" (name brand) cables for less money than buying the parts and making your own.

Thanks DT

 

[radix]

You can purchase "The Worlds Best" (name brand) cables for less money than buying the parts and making your own.

The issue is one needs either 2x RCA or 2x BNC to each of the XLR + and - pins. Usually XLR to 2x RCA are splitter cables where both RCAs come from the same + phase.

 

[Blumlein 88]

I really like the World's best cable with Canare L 4-E6S and Amphenol connectors. They also make some Gotham cable with Amphenol connectors which I've not tried.

 

[JonathanB]

QA403 user checking in

A-weighted self noise test.

 

[DualTriode]

Hello All,

For all kinds of BNC goodies to make connections to your QA40x analyzer go to Allelectronics.

https://www.allelectronics.com/?page=seek&id[m]=pattern&id[q]=bnc

https://www.allelectronics.com/item/rca-bnc/rca-female-to-bnc-male/1.html

https://www.allelectronics.com/item/bnc-133/bnc-male-to-2-banana-jack-binding-posts/1.html

All Electronics | Electronic and Electro-Mechanical Parts and Supplies at Discount Prices

www.allelectronics.com

Thanks DT