My preference on all test equipment is BNC
it is always possible to use a RCA adapter.
Old eyes.
I have invested in some extensive SMT rework capabilities (microscopes, hot air station, Metcal needle size tips etc.) but its a lot of investment for most hobbiests. And its learning new skills. However its worth the effort and we really have little choice.
The .1% SMT resistors seem to be about 10% or less than the cost of the through hole equivalent. That's significant. What I don't know is if they are as stable over time and temperature as the bigger parts.
I have invested in some extensive SMT rework capabilities (microscopes, hot air station, Metcal needle size tips etc.) but its a lot of investment for most hobbiests. And its learning new skills. However its worth the effort and we really have little choice.
The .1% SMT resistors seem to be about 10% or less than the cost of the through hole equivalent. That's significant. What I don't know is if they are as stable over time and temperature as the bigger parts.
Bruce Hofer, founder of AP, told me they now go exclusively with thin film SMD at 0.1% and 25ppm or better, not smaller than 0805. That's good enough for me!
Jan
Hi Jan
You are correct about what Bruce said. When I was developing the ATS2 the first all SMD product @ AP all of the resistors were 0.1% 25ppm 0805. The D2A current amplifier feedback resistor was running about 60mw and the THD% was great @ 1kHz, however @20Hz the THD% was 20x greater. The resistor was heating & cooling cycle by cycle (low thermal mass). When I placed my finger and or an eracer on the resistor the THD% was good again. Reducing the power and adding another resistors resolved the problem. I did talk about in another thread about distortion in power resistors a few months ago (Distortion in low ohm resistors).
Duke
You are correct about what Bruce said. When I was developing the ATS2 the first all SMD product @ AP all of the resistors were 0.1% 25ppm 0805. The D2A current amplifier feedback resistor was running about 60mw and the THD% was great @ 1kHz, however @20Hz the THD% was 20x greater. The resistor was heating & cooling cycle by cycle (low thermal mass). When I placed my finger and or an eracer on the resistor the THD% was good again. Reducing the power and adding another resistors resolved the problem. I did talk about in another thread about distortion in power resistors a few months ago (Distortion in low ohm resistors).
Duke
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All you need to get started in diy smd soldering is a 5mp usb camera, one of those cucumber shaped ones off Ebay, a test tube holder and stand off Ebay for holding the camera steady, a good tcp soldering iron with a small curved chisel tip, some real lead/tin solder, a flux pen, a roll of Chem-wik to assist on the learning curve mis-steps, tweezers and a thin screwdriver with a ball of blue tac for op-amp pick and place for corner tacking.
Plenty of good videos on Youtube showing the actual soldering techniques.
Oh I already do SMT much the way you describe but it is slow and tedious. I see that Sparkfun teaches SMT for medium scale production but I am no where near them. Stencil. solder paste and a 30 dollar electric skillet is supposed to work. Heat the whole board up.
I built up two of those low distortion oscillators (10 KHz and a 1 KHz). The smt soldering was done by magnifying lens and a big iron. Still, I could do it and it wasn't that bad. I have a smaller soldering station added to my bench, so having two makes things a lot easier. No more changing tips all the time.
I'm okay with either, but I find that the surface mount work tends to go a little faster. 805 sizes are easier than the 603 types I used before. Don't be afraid to use 1206 sized resistors Jan!
-Chris
I'm okay with either, but I find that the surface mount work tends to go a little faster. 805 sizes are easier than the 603 types I used before. Don't be afraid to use 1206 sized resistors Jan!
-Chris
Maybe refitting a toaster oven like this: https://www.sparkfun.com/tutorials/60 If someone made a controller that connected to a thermocouple and you just locked the oven in selfclean mode it could be pretty simple.
I would not want it for food later, but one from a thrift store would be around $20 or less.
I would not want it for food later, but one from a thrift store would be around $20 or less.