I have looked trough this forum and google but have not found an answer for dummies. 
So I hope that you will try to help a noob. When measuring audio (primarily amplifiers) you look for THD+N, linearity, phase and much more. But what are the "much more" and what gear do you use to test fore all of these values?
So I hope that you will try to help a noob. When measuring audio (primarily amplifiers) you look for THD+N, linearity, phase and much more. But what are the "much more" and what gear do you use to test fore all of these values?The classic tests for power amps are power output to specified level of distortion into differing loads, signal to noise, input sensitivity/gain, input and output impedances, polarity, bandwidth, distortion as THD, THD+N, nature of distortion products (odd/even harmonics), and maybe output offset voltage and power consumption.
For pre amps gain/input sensitivity, output voltage, input/output impedances, signal to noise from the different inputs, distortion at specified output voltages (and its components), headroom, maybe RIAA compliance.
It'll take too long to describe the equipment, maybe you could read some of the RTX6001 analyser thread on this forum for pointers?
For pre amps gain/input sensitivity, output voltage, input/output impedances, signal to noise from the different inputs, distortion at specified output voltages (and its components), headroom, maybe RIAA compliance.
It'll take too long to describe the equipment, maybe you could read some of the RTX6001 analyser thread on this forum for pointers?
Thank you wary much, that was a reply that I clearly understand.
I have looked at the RTX6001 and some of the treads.
On the way I did find the Audio Precision ATS-1, is it capable to do the tests?
https://www.axiomtest.com/documents/models/Audio%20Precision%20ATS-1%20datasheet.pdf
Edit: forgot to say that, yes I have tried to read about the ATS-1 but again, noob-alert!
I have looked at the RTX6001 and some of the treads.
On the way I did find the Audio Precision ATS-1, is it capable to do the tests?
https://www.axiomtest.com/documents/models/Audio%20Precision%20ATS-1%20datasheet.pdf
Edit: forgot to say that, yes I have tried to read about the ATS-1 but again, noob-alert!
Last edited:
Okay and thanks, fellow noob
I have decided to afford it by saving
My hope is just to get the best for a home tinkerer.
I don't think that ATS-1 is best choice today. It is specced for just -92dB THD+N. Most of good amplifiers would exceeds that.
IMHO something like RTX6001 plus software (like Room EQ Wizard, ARTA, Virtins) is much better and future-proof option. I would even prefer some solid audio interface. Not so plug-and-play like ATS-1 or RTX6001 but can archieve same or even better performance while it costs fraction of price. You can check this thread - Howto - Distortion Measurements with REW
IMHO something like RTX6001 plus software (like Room EQ Wizard, ARTA, Virtins) is much better and future-proof option. I would even prefer some solid audio interface. Not so plug-and-play like ATS-1 or RTX6001 but can archieve same or even better performance while it costs fraction of price. You can check this thread - Howto - Distortion Measurements with REW
Nothing wrong with that. Using a decent source (for example the Frex LT AN67) and a notch filter you can extend that down a further 30-40dB.
I use an old HP 3585B, which really makes only 90dB. I regularly use it to examine THD and distortion at -120dBc
For the OP, in no particular order:
- A decent multimeter. You need to be able to measure voltages and resistances to some degree of accuracy. I use an old Fluke 87, and recently acquired a HP 3478A.
- A couple of lab power supplies. I’m fond of old Thurlby supplies, but a pair of anything that’s good for 30+V and able to set constant current will allow you to power things up without losing too much smoke.
- A signal source. Lots of people use sound cards. I have an Edirol FA-66 which is nice, and my mac has surprisingly good sound output. This tends to be the limiting factor for me, so I have a couple of the aforementioned Frex low distortion oscillators too.
- A load. Big high-power 8Ω resistor. Put it on a heatsink.
- Some things to examine the output with. Sound cards are good, but a bit limited both in terms of frequency response (audio only), and input sensitivity and attenuation range. My HP3585B is my go-to instrument here - DC to 40 MHz. I also use a Tektronix TDS320A CRO, which is invaluable as it makes 100MHz, and thus far none of my audio stuff has oscillated above that
- Cables, attenuators, adaptors, notch filters. I find blown up old minicircuits amps make great project boxes - BNC on each end and room for a few passives or whatever inside.
I have to admit that I may be more towards a "hands on" unit then an computer unit.
I think it's like CNC in wood working, you can program the pc, make perfect cuts and even 3D carvings and then assamble it afterward to a perfect result. But I do prefere my table saw, band saw, hand router and hand tools, even I know that it can never be as perfect as the CNC.
I know that a computer with a great sound card and top notch analytic software maybe could deliver better analyses, better tests and yes better all. But I feel that a unit where I turn the dails, flip the switches and connect cables, is more to my liking.
suzyj: I have thought about the Siglent functions generator series 2000, I do own some handheld multimeters, that I mostly trust, and I have a Rigol MSO5000 oscilloscope.
How much differance is there from the old HP8903b and the old but newer audio precision ats-1?
The price is about 5 times higher!
I think it's like CNC in wood working, you can program the pc, make perfect cuts and even 3D carvings and then assamble it afterward to a perfect result. But I do prefere my table saw, band saw, hand router and hand tools, even I know that it can never be as perfect as the CNC.
I know that a computer with a great sound card and top notch analytic software maybe could deliver better analyses, better tests and yes better all. But I feel that a unit where I turn the dails, flip the switches and connect cables, is more to my liking.
suzyj: I have thought about the Siglent functions generator series 2000, I do own some handheld multimeters, that I mostly trust, and I have a Rigol MSO5000 oscilloscope.
How much differance is there from the old HP8903b and the old but newer audio precision ats-1?
The price is about 5 times higher!
My computer setup is too dynamic to be relied on for testing. I seem to replace the computer every 3-4 years, and each time I do interfaces change, and operating systems change. I’ve gone pci to pcie to firewire for audio card, and next time I change computers the firewire one will likely go in the bin in favour of usb 3 or thunderbolt or whatever the interface de jour is.
My test equipment, on the other hand, has been static for many years. It just works. So what if I take photos of screens or write down numbers - at least it’ll still be the same five years from now.
My test equipment, on the other hand, has been static for many years. It just works. So what if I take photos of screens or write down numbers - at least it’ll still be the same five years from now.
LOL just like me (do I think), I do change my laptop and audio-system at the same time. But I do not think I'll change my scope or other lab gear. You do often see people have their first scope on the shelve among other gear, while the computer is a newer model.
That is also why I do not mind using a bit more money on a used audio analyzer, but it have to be a fairly good one.
Modern measurement devices are computers wrapped into boxes and extended with input/output/control interfaces.
Why not using a computer + soundcard dedicated to measurement that will "just work" for many years? An inexpensive refurbished good brand PC (HP, Dell, FS) with two small SSD drives in RAID1 and linux will do the measurement job easily for 10 years min, without any upgrades or reinstalls. Should one SSD die, just replace it with a new one and resync the array from the other drive, no need for any re-installation for the device lifetime. Easy to automate, easy to add control elements (e.g. $1.5 arduino micro Pro in USB HID mode can generate suitable keyboard shortcuts upon pressing dedicated push buttons), easy adding voice synthesis for headless operation, suspending to RAM for fast startup etc.
Yes, I am enthusiastic since dedicated PCs are my field of interest
Headless Amplifier Measurement Workstation
GitHub - pavhofman/measurement-station: Audio measurement workstation
Why not using a computer + soundcard dedicated to measurement that will "just work" for many years? An inexpensive refurbished good brand PC (HP, Dell, FS) with two small SSD drives in RAID1 and linux will do the measurement job easily for 10 years min, without any upgrades or reinstalls. Should one SSD die, just replace it with a new one and resync the array from the other drive, no need for any re-installation for the device lifetime. Easy to automate, easy to add control elements (e.g. $1.5 arduino micro Pro in USB HID mode can generate suitable keyboard shortcuts upon pressing dedicated push buttons), easy adding voice synthesis for headless operation, suspending to RAM for fast startup etc.
Yes, I am enthusiastic since dedicated PCs are my field of interest
Headless Amplifier Measurement Workstation
GitHub - pavhofman/measurement-station: Audio measurement workstation
Great idea, I have nothing against computers, and yes they are in most gear today. What I am "against" is the compuer gui experience, click there, right clik there, pres this shortcut and so on.Modern measurement devices are computers wrapped into boxes and extended with input/output/control interfaces.
Yes, I am enthusiastic since dedicated PCs are my field of interest
Headless Amplifier Measurement Workstation
GitHub - pavhofman/measurement-station: Audio measurement workstation
If that can be hidden into a box with the oscilloscope or turn(botton) interface, I'd be happyMaybe a micro computer and a 10" touch screen and some shortcut bottons, like I hear you saying, could be a great sollution
The older ATS-1 is a more productive and far superior tool than the even older 8903A/B. I've used both at work. The ATS-1 so easy to use and lighter. The ATS-1 has sold for 1x-2x that of the 8903A/B on eBay. Pricing is all over the place, you can't rely on the current eBay listings.
Things you can do with an ATS-1 that are not available on the 8903A/B
- dual input and output channel
- phase measurements
- crosstalk
- AC mains check for distortion, frequency and level
- device input resistance vs frequency
- swept impedance measurement, e.g. loudspeakers
- wow and flutter
- tunable bandpass filter (2-pole)
- IMD (option)
- dual domain (option)
- bode plots out of the box or hook up an HP parallel port printer for hard copies
- etc.
WOW that sounds as there are no competition, that ATS-1 is the best choice among these two.
May I please ask you on your opinion about DIY-PC as discussed above vs. ATS-1?
DIY-PC is a very specific application and is a one-off thing. The residual THD is lower with the loopback but don't forget that the ATS-1 has a true floating and isolated analog output that is very similar to the AP System One and Two.
If you want to fiddle with test equipments, go with the DIY route of the DIY-PC or HP 8903A/B. If you want to spend more time designing DIY audio projects or commercial products, stick with the AP.
Yes a DIY can be a big task, to know that it works perfect and reliable every time for years. You said something about me "not being able rely on the current eBay listings" I do not understand that sentence, would you please elaborate?
Yes a DIY can be a big task, to know that it works perfect and reliable every time for years. You said something about me "not being able rely on the current eBay listings" I do not understand that sentence, would you please elaborate?
If you search for current eBay listings for the ATS-1, the listed prices are $2,000 and above, mostly from China. The listed price is what the sellers wanted their items to sell for. This is not the real market or final selling price. I would completely avoid AP coming from mainland China unless it is very cheap. Trustworthiness is something that is lacking from majority of Chinese sellers and return shipping is VERY expensive.
The eBay sold pricing listings is quite limited in the period it covers and can also be inaccurate since it doesn't reflect the final agreed price if it was concluded with a "Best Offer" pricing. Some of the completed listings shown as sold are misleading since the item is not exactly sold but the auction was ended by the seller. I've seen this play out on a seller that keeps on re-listing the same expensive and rare item after a few months.
The cheapest ATS-1 that was sold off eBay was $500 in the last 2 months, no history of older listings. There was a slew of ATS-1 that were sold really cheap a few years ago from a single seller when I was actively tracking them.
Don't rush things, track eBay listed items regularly on your smartphone, learn how to use eBay's search filtering system, set up notifications of new listings via email or eBay phone app, practice common sense and you will get a good deal eventually. Patience is a virtue.
I practice what I preach and speak from firsthand experience. I got a fully functional and very good condition Audio Precision System One for a really low price almost 2 years ago as a back up unit
It's cheaper than Udok's APIB USB adapter
Attachments
Oh, thanks so much, that saves me a lot of money!!If you search for current eBay listings for the ATS-1, the listed prices are $2,000 and above, mostly from China. The listed price is what the sellers wanted their items to sell for. This is not the real market or final selling price. I would completely avoid AP coming from mainland China unless it is very cheap. Trustworthiness is something that is lacking from majority of Chinese sellers and return shipping is VERY expensive.
The eBay sold pricing listings is quite limited in the period it covers and can also be inaccurate since it doesn't reflect the final agreed price if it was concluded with a "Best Offer" pricing. Some of the completed listings shown as sold are misleading since the item is not exactly sold but the auction was ended by the seller. I've seen this play out on a seller that keeps on re-listing the same expensive and rare item after a few months.
The cheapest ATS-1 that was sold off eBay was $500 in the last 2 months, no history of older listings. There was a slew of ATS-1 that were sold really cheap a few years ago from a single seller when I was actively tracking them.
Don't rush things, track eBay listed items regularly on your smartphone, learn how to use eBay's search filtering system, set up notifications of new listings via email or eBay phone app, practice common sense and you will get a good deal eventually. Patience is a virtue.
I practice what I preach and speak from firsthand experience. I got a fully functional and very good condition Audio Precision System One for a really low price almost 2 years ago as a back up unit
It's cheaper than Udok's APIB USB adapter
It is so kind of you to use so much time to help me!
I am wondering, I am thinking about the ATS-1 but you choose the one on the picture. Since I am fairly noob, I do not know what to choose to get the best "home tinkerer" model. Do you have any advice?
Clearly define your needs and pick one that will work for you and your budget.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.