Hi ! i would like to know if anyone knows of a usb ad converter solution with very low noise to be used both for some noise measurements It could be also a kit but not smd of course ... i am a beginner. Possibly not that expensive. The option of external power supply and not rely only on USB voltage from the PC would be nice as well. Thank you so much.
P.S. if another thread treating this issue already exists please direct me there.
P.S. if another thread treating this issue already exists please direct me there.
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I have been looking at similar offering too. For boards/kits the selection is rather small. The boards offered for reasonable money do not have stellar parameters.
IMO your best option is a decent USB soundcard, pre-owned at best. For low-noise measurements you will need balanced inputs, I have not seen a USB ADC board with them (apart of some expensive evaluation boards).
As of SMD - it is a standard now, through-the-hole components are long gone in the low-signal world. Especially if low noise is required. I am afraid you will have to learn SMD techniques eventually if you want to go beyond pre-assembled boards.
IMO your best option is a decent USB soundcard, pre-owned at best. For low-noise measurements you will need balanced inputs, I have not seen a USB ADC board with them (apart of some expensive evaluation boards).
As of SMD - it is a standard now, through-the-hole components are long gone in the low-signal world. Especially if low noise is required. I am afraid you will have to learn SMD techniques eventually if you want to go beyond pre-assembled boards.
Hi ! i was thinking below 200USD ... and sorry not having checked first. Yes you are right ... new chips come almost all in smd format.
So diy is out of my reach ...
Hi ! thanks a lot for the very kind and valuable advice. Yes i would go that way
Sorry ... could you explain me why balanced inputs are needed ? i see that scope probes are usually unbalanced if i am not wrong
I need some instructions on noise measurement procedure but i do not really know where to look for ...
i understand that the smd soldering stations are very expensive ... intended for pros i guess ... anyway good to know. It is a completely new field for me.
Thanks a lot again
Kind regards, gino
Noise measurements for an A/D converter don't require measuring analog noise, you take the FFT of the output and do spectral noise density plot. You just need to short the input to get the intrisic noise of the converter.
When I design my mixed pcb's I add a row of vias next to each SMD IC so I can check for shorts between pins. Even though a SMD IC looks good you can sometimes get shorts out of sight.
I put a blob of flux paste on the pcb where the SMD IC goes and place the IC on top. This holds it in place while you solder first pin. I solder first pin by letting solder run up pad to IC. If you touch IC it can move.
I then put plenty of solder on all the pins and wick off excess with copper braid. Then I buzz the via's for shorts.
Any awkward shorts can sometimes be got rid of with quick dab of soldering with plenty of flux on pins.
Anyway, loads of SMD soldering tutorials on you-tube.
"Yes", if you need professional station like JBC, Metcal, etc. And "No", if you will go to EBay/AliExpress and by Bakon/Quick/Atten, etc. For ~50 euro you can buy the soldering station (with soldering iron), for ~100 - together with the hot air gun.
I am quite satisfied with KSGER V2.1S T12 Digital Temperature Controller Soldering Station Soldering Iron | eBay and 10pcs t12 soldering iron tips set for hakko fx951 fx952 Sale - Banggood.com . Very inexpensive and good to work with, in my limited experience.
To de-solder SMD stuff (and multiple-legs non-SMD) I occasionally use a low-cost alternative to ChipQuik Wood's metal (Bismuth, Lead, Tin, Cadmium alloy) 75 g. Wood Woods alloy | eBay , a very nasty stuff but works OK. I melted the pellets in syringe in boiling water and injected the metal into plastic straw to get a rod. I guess better would be non-cadmium Rose's metal 75g - Alloy Rose / Rose's metal / Roses metal (Lead, Bismuth, Tin alloy) | eBay but I have not tried one yet.
To de-solder SMD stuff (and multiple-legs non-SMD) I occasionally use a low-cost alternative to ChipQuik Wood's metal (Bismuth, Lead, Tin, Cadmium alloy) 75 g. Wood Woods alloy | eBay , a very nasty stuff but works OK. I melted the pellets in syringe in boiling water and injected the metal into plastic straw to get a rod. I guess better would be non-cadmium Rose's metal 75g - Alloy Rose / Rose's metal / Roses metal (Lead, Bismuth, Tin alloy) | eBay but I have not tried one yet.
Hi ! thanks for the helpful advice. I think that i will look at usb sound card with very low own noise.
There is another point mentioned that i do not really understand. i intend to measure preamps noise and are usually unbalanced. Why would i need a sound card with balanced inputs if my source of noise is unbalanced ?
Hi ! i really did not know 😱 Thank you very much indeed for the very interesting advice. This will be, parkinson allowing (i am not sick now but it is a family issue), my retirement hobby for sure. I am mad at high fidelity ... i just love everything related to audio. I guess a firm hand is needed ... and i love smd parts ... and i am more intrigued by small signals units than power amps ... i will study about it seriously. Unfortunately i am too busy at the moment. I am still in the learning phase ...
Hi ! thanks for the very valuable advice. As i said above i am scared by smd parts ... even if i understand their advantages ... I am still learning to evaluate and decide what to do
That low-cost Atten is on my bench too. But we are not close friends, I use it mostly for shrinking tubing. I found the low-melting-point "solder" safer for the board and components, maybe I just do not know how to use it properly...
It appears that usb to i2s modules for ADC are not so common as for DAC - Amanero, WaveIO etc. I was looking at this one Hifime ADC i2S Analog to Digital converter and wondering why they chose HDMI instead of usb.
As for smd rework, I've recently acquired a BAKU 702B YouTube local pickup for 70 euro. I think it's rebranded Hakko. Decent at least.
As for smd rework, I've recently acquired a BAKU 702B YouTube local pickup for 70 euro. I think it's rebranded Hakko. Decent at least.
IMO it is just the connector and LVDS that is taken from the HDMI standard. It actually carries I2S signals. Clever solution, quality technology for consumer prices.
http://hifimediy.com/download/Pinout_of_I2S_DSD.pdf
Yes, it's not HDMI and has nothing to do with HDMI other than sharing a connector. It would probably be better if people didn't repurpose connectors with well-defined use cases.
That re-purposing allows driving costs low. HDMI connectors and cables are well proven and inexpensive for the performance they provide. People often have spare HDMI cables at home, no need for another one. Ethernet cables were used the same way for the same purpose.
So it would need something like that in front? http://www.xmos.com/download/XS1-U8A-64-FB96-Datasheet(1.8).pdf
Real HDMI carries audio well enough in its actual implementation.
Best to use BNC cables or some other agnostic controlled impedance interconnect for this purpose.
This is the same thing USB IF failed at with the USB Type C connector. It can be USB 2.0, 3.1 Gen 1/2, USB PD, or Thunderbolt 3 with barely any identification.
i was noticing the same.