I've been hunting around for an analyser for measuring basic things like THD but hoped to get some more current advice than 'buy the QA400'. I have an old oscilloscope but want to be able to carry out distortion analysis.
The QA400, whilst probably being exactly what I need is unobtainium here in Oz, especially for the much quoted '$200' figure. I saw an old used one go on auction for about $200usd recently and the QA401 is listed at $449USD (well over $600 AUD after shipping). Don't think the domestic finance director would be happy with that! ;-)
The HP 339a doesn't seem to be available for much under $500AUD except for some shipping from Israel (shipping costing more than the unit).
So...
Does anyone have a recommended setup that works well for them with either a purpose made unit, or USB interface, capable of fairly decent hobbyist accuracy for under $250 AUD
And is something that is actually available here in Oz? (I went through a big list of USB sound cards recently but they all ended up being cheap in the US but extortionate in AU).
Or does anyone here in Oz have something that perhaps they just don't need anymore?
Thanks!
The QA400, whilst probably being exactly what I need is unobtainium here in Oz, especially for the much quoted '$200' figure. I saw an old used one go on auction for about $200usd recently and the QA401 is listed at $449USD (well over $600 AUD after shipping). Don't think the domestic finance director would be happy with that! ;-)
The HP 339a doesn't seem to be available for much under $500AUD except for some shipping from Israel (shipping costing more than the unit).
So...
Does anyone have a recommended setup that works well for them with either a purpose made unit, or USB interface, capable of fairly decent hobbyist accuracy for under $250 AUD
And is something that is actually available here in Oz? (I went through a big list of USB sound cards recently but they all ended up being cheap in the US but extortionate in AU).
Or does anyone here in Oz have something that perhaps they just don't need anymore?
Thanks!
I am happy with Focusrite Scralett 2i2 2nd gen. I use it with REW and also tried it with ARTA. It works fine with both. My tests of the unit are here.
Regards,
Oleg
Regards,
Oleg
Despite being on our national coat of arms.. the EMU are pretty hard to come by here...
Any other recommendations for a good USB interface?
The RMAA looks good though thanks!
I think your $250 AUD budget is a bit unrealistic... but this one is pretty close, and ships locally: https://au.rs-online.com/web/p/digital-oscilloscopes/7933654/
Thanks jazbo. Can you give me an idea of what a realistic budget would be?
Some of the external sound card and software options are in the ball park of $200US/250AUD, so getting measurements on a lowish budget is achievable.. but is there a massive jump in quality / capability, for instance, between a Focusrite 2i2 with say MRAA/ARTA and a $600+ QA401?
@avtech23 - Sorry, I didn't read your post carefully, I thought you were looking for a scope, not an analyzer... so disregard my comments above. With a decent soundcard, you can get very good results as many have shown here on the forum. It's just a matter of finding a combination of HW and SW that you are comfortable with. Obviously, the lower the THD that you are trying to measure, the more expensive the soundcard is going to be, if you are not planning to get down to tiny THD, then any modern pro-sumer card should work.
Thanks Oleg, an interesting read.
Do you use the balanced - SE converter circuit in that thread?
Haha I could always tell her I thought it was $225.00 but the decimal point was in the wrong place!!
Unfortunately not. Despite having all the parts at hands it is still on my todo list.
Haha I could always tell her I thought it was $225.00 but the decimal point was in the wrong place!!
"That trick never works."
I repair, service & sell used Audio Precision test system and APIB USB Interface adapters to work with XP through Win10. I get many systems in my shop that were from EBay and many were used in a production line and do require many new parts so they can meet the SPECIFICATIONS. The cost is typical investment is $2500 or more and this typical leaves the hobbyist to use other equipment.
The QA401 and other analyzers are good alternative to the hobbyist who typically have limited budgets.
Duke
The QA401 and other analyzers are good alternative to the hobbyist who typically have limited budgets.
Duke
I'm looking primarily for something to do basic measurements such as THD and FFT.
I want to quantify whether a board is at 1% or 0.1% etc (I don't think my ears are tuned well enough yet!) and the harmonic profile so I verify the effect of component selection or potential noise sources.
Honestly I would love to spend $2500 or more (buy once, cry once) but unless I can use it for production, I can't realistically spend that much.
I want to quantify whether a board is at 1% or 0.1% etc (I don't think my ears are tuned well enough yet!) and the harmonic profile so I verify the effect of component selection or potential noise sources.
Honestly I would love to spend $2500 or more (buy once, cry once) but unless I can use it for production, I can't realistically spend that much.
The QA401 has several benefits over a soundcard, being designed for this task. It has a much higher input max (20V RMS), quasi-autoranging (switches in an input attenuator when the input goes higher) and it has differential in and balanced out. The software is pretty good and just works. There is hope for a soundcard interface capability in the driver soon.
However a decent soundcard can work fine with ARTA. However you will need to fabricate interface cables for amps so you don't fry your soundcard.
With a soundcard, interface cables and ARTA or RMAA you can test almost everything. Its just more work and clumsy. If you do it once then great. if you are troubleshooting daily probably not great.
However a decent soundcard can work fine with ARTA. However you will need to fabricate interface cables for amps so you don't fry your soundcard.
With a soundcard, interface cables and ARTA or RMAA you can test almost everything. Its just more work and clumsy. If you do it once then great. if you are troubleshooting daily probably not great.
Just a very low-cost way - The soundcard ESI Juli offers SE and balanced inputs /outputs working simultaneously (e.g. single-ended amp input, balanced output at class-D amp speaker terminals ) , 40Vpp full scale for the balanced input (i.e. between the positive and negative line), allowing to measure 20W/8ohm without any divider. While a regular PCI device, it can be used in a class II device, breaking any ground loop. It is an aged device but for less demanding tasks still quite capable Headless Amplifier Measurement Workstation
At this price point, you'll have to decide between (A) the classical sound card + your software of choice or (B) a dedicated low-cost audio analyzer with it's own software.
(A) is flexible in terms of software choice, and you can always upgrade to a better soundcard as your requirements (and finances) change. The drawback is that soundcards usually blow up if you abuse them with excessive test voltages, and calibrating signal voltages in absolute terms is difficult because many soundcards have variable gain ("volume knobs") that are tricky to set to an accurate level. You could modify the pots with a stepped attenuator to get reproducible settings though. A notable exception is the RTX6001 "soundcard", which was designed for audio analysis from ground up. Its performance approaches AudioPrecision territory, but I guess it's a bit more expensive than what you have in mind.
(B) is the QuantAsylum route. I have no experience with those analysers, but I guess they do what it says on the box. You're stuck with their software, so if the software does not do what you need/want, you're screwed.
That said, I used a Behringer UMC 202 HD for a while. It's cheap, does 192 kHz, and works fine for loudspeaker work and everything else that does not require ppm distortion levels or accurate (absolute) voltage levels. I now have an RTX6001, and I love it. Audio performance is great, and the accurate signal level switches are soooo much easier to work with than the variable "volume pots".
(A) is flexible in terms of software choice, and you can always upgrade to a better soundcard as your requirements (and finances) change. The drawback is that soundcards usually blow up if you abuse them with excessive test voltages, and calibrating signal voltages in absolute terms is difficult because many soundcards have variable gain ("volume knobs") that are tricky to set to an accurate level. You could modify the pots with a stepped attenuator to get reproducible settings though. A notable exception is the RTX6001 "soundcard", which was designed for audio analysis from ground up. Its performance approaches AudioPrecision territory, but I guess it's a bit more expensive than what you have in mind.
(B) is the QuantAsylum route. I have no experience with those analysers, but I guess they do what it says on the box. You're stuck with their software, so if the software does not do what you need/want, you're screwed.
That said, I used a Behringer UMC 202 HD for a while. It's cheap, does 192 kHz, and works fine for loudspeaker work and everything else that does not require ppm distortion levels or accurate (absolute) voltage levels. I now have an RTX6001, and I love it. Audio performance is great, and the accurate signal level switches are soooo much easier to work with than the variable "volume pots".
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