PicoScope 4262, smart choice? - Page 1
Forum section: electronics / testgear

author: JSE009
author_rank: Contributor
timestamp: June 29, 2015, 08:16:01 pm
content: I think about buying a the picoscope 4262 especially for measurements on audio amplifer.Reading the datasheet (16–bit resolutie, low distortion, etc.) of the picoscope 4262 it sounds interesting for measure THD, THD+N, SNR, etc.The main question is if €1.000,= is wise to spent on this scope or are other test equipments (with the same possible measurements) more interested?

author: dadler
author_rank: Unknown
timestamp: June 29, 2015, 09:14:23 pm
content: I have the lowest model PicoScope 2204A.Although it is not a "toy", I seldom use it because having to use PC software to control the scope really is inconvenient in practice. At least compared to a desktop scope with rotary encoders etc.The software is professional, though. Also note that they recently added MacOS support, but the Mac version of the software is lacking most of the functionality of the Windows version. When I do use my PicoScope, I boot to Windows.The model in question has much higher specs than mine, but I believe it uses the same software. Someone correct me if I am wrong.

author: Muxr
author_rank: Super Contributor
timestamp: June 29, 2015, 10:34:54 pm
content: Not worth it imo. 5 MHz, 10 MS/s for $1235? That's a really poor performance per dollar.Unless you want your setup to be super portable it makes little sense to get one. Let's say the software is implemented well (which it rarely is for these USB scopes, Picoscope is one of the better ones though), you still get a quirky user experience and you pay a lot for sub par performance.For audio work it might be sufficient because you mostly deal with low frequencies, but keep in mind that if you have to look at a digital signal 2.5Mhz will be the ceiling of what you can observe when it comes to square waves.Don't get distracted by the 16bit ADC. The front end on these scopes is very limited in the attenuation ranges it supports so 16 bit is their way around that limitation. 8-bit ADC with a proper front end is a better solution because of the sampling speed.Bottom line is, the cheapest regular oscilloscope like the Siglent SDS1052DL will outperform it by orders of magnitude for the 5th of the cost ($279) (even the Owon PDS5022T is a better choice). Not to mention you get proper controls and you don't have to worry about frying your computer.Rigol ds1054z is currently the best entry level scope outhere at $399. PicoScope 4262 can't hold a candle to it.For audio I would rather get an old sub $100 analog scope.

author: JSE009
author_rank: Contributor
timestamp: June 30, 2015, 06:08:12 am
content: Quote from: Muxr on June 29, 2015, 10:34:54 pmThanks Muxr.I agree on you with the most points.But the main reason I have my eyes on this scope is the fact that measurements of THD, THD+N, SNR etc. are standard in the software of this scope.I do not know if there are digital scopes on the market with these functions?If there is a scope (that is to say affordable) then I agree that a USB scope is not the best choice.

author: Muxr
author_rank: Super Contributor
timestamp: June 30, 2015, 07:01:49 am
content: So that is definitely something that it may well be better at, due to the 16 bit ADC. Frequency domain measurements are better suited for a Spectrum Analyser, but PicoScope might have an edge there. I'd defer to someone who's used it for that purpose though.Although for low frequency work (audio) I've seen sound card based Dynamic Signal Analysers suggested.

author: nctnico
author_rank: Super Contributor
timestamp: June 30, 2015, 09:04:39 am
content: Quote from: JSE009 on June 29, 2015, 08:16:01 pmIf you work mainly with audio you can also use a PC soundcard to perform measurements on audio signals.

author: Gyro
author_rank: Super Contributor
timestamp: June 30, 2015, 09:44:31 am
content: I understand your concern about dynamic range for THD measurements etc.I use an old Picoscope ADC216 for audio work. This was Pico's original 16 bit parallel port product for audio use.It is only 333ksps but the lower bandwidth allowed them to achieve a very low noise floor. I use it with the Pico USB adapter, a USB isolator and modified mains adapter (to remove some low level 50Hz harmonics). In this configuration it achieves pretty much the full theoretical 96dB dynamic range on the spectrum analyzer with on-screen measurements, and a useable +/-10mV fsd range (0.6uV resolution).At this sample rate it is of course only suitable for audio and low frequency (down to DC) usage, but of course that's exactly what it was designed for.I'm not sure how the 4262 would compare - it's higher bandwidth, which might actually hamper a little in terms of noise floor. It is also USB powered which is probably the biggest potential worry. I would plan on having to use a usb isolator, assuming it can still operate at full-speed USB (rather than USB 2) with the ability to feed the downstream side with a linear supply.The Pico software IU has always been a little quirky compared to other scopes (eg, Volts fsd rather than V/div and windows type menus for a lot of functions) no problem with it's functionality.Your nearest alternative probably is a PC sound card (or a USB one?) but I wouldn't expect anything like as good a noise floor and with potential ground loop issues.ADC216s do occasionally come up on ebay and similar. If you do come across one then they're ideal for the job - but check that there is a Pico USB adaptor with it, it's proprietary (won't work with any other) and you will be stuck with parallel port without it.

author: Anks
author_rank: Frequent Contributor
timestamp: June 30, 2015, 10:38:57 am
content: could you do a tear down of the usb adapter just out of curiosity I'm interested to see whats inside. My guess is a micro with protected firmware.

author: Gyro
author_rank: Super Contributor
timestamp: June 30, 2015, 11:33:37 am
content: QuoteAh, I was wondering how long it would take for someone to askIt is indeed a Micro, the reason that Pico gave for discontinuing it is that they could no longer source the part. Its a Cypress CY7C64613. The other chips are a 74HCT365 and a 24LC00 (too small for the actual firmware). No parts on the back of the pcb. Actually, just realized that the CY7C64613 is an early member of the EZ-USB family so is ROM-less. The 24LC00 will contain PID/VID and the software will download the firmware when it runs.I know these are still in demand as they support all of Pico's old Parallel port products. You might want to talk nicely to Pico and see if they would be willing to release a hex file to you - I can't see how it would be a significant hit to their sales by now.One concession they did make after the adapter was discontinued was to mod their software (Picoscope 5, not 6 for these products) to support PCI and Cardbus parallel ports rather than just the motherboard com1/2 but I don't think anyone ever got another USB to work as it's a bit-bash interface. You might want to trawl through the Pico support forums to see if there is any update.For something like a 216 it would probably even be worth keeping an old parallel port laptop (Thinkpad) to support it. I doubt if it would be worth it for the rest of the ADC200 family.Hope it helps anyway.