SMD vs conventional electronics

Rossi

Rossi

New member
Since I noticed there are some guys on this board who know a lot about electronics, perhaps there's someone who can answer this question: Is SMD electronics inferior to conventinal electronics? The reason why I'm asking is that I had a dispute with the German distributor of Nevaton microphones. In their newer models they introduced SMD electronics. I wasn't convinced they could keep up the quality of their microphones that way. Most microphone electronics use a lot of capacitors, and, given the space limitations of SMD technology, I don't think you can use first rate film capacitors but must resort to smaller tantalum types. For all I know (which isn't much, to be honest) you shouldn't use tantalum capacitors in audio equipment. Still, the distributor insisted that there was no difference in quality between SMD and conventional technology. So who's right? Does anybody know?
 
Your concerns about SMD are valid. It is indeed difficult to make very small devices in some of the lower noise technologies. That does apply to capacitors especially. However, the rules of good design are the same whether it is SMD or not. If you buy a quality microphone, it should have the same noise characteristics whether it uses through-hole, SMD or even fully integrated solutions.

In many cases, I have done very low-noise designs using SMD, but I had to do more work. When working this way, the old "rule-of-thumb" method that many of us use don't work. For example, I may traditionally use a 10uF capacitor, just because I always have. With SMD technology, a 10uF may be too big so I have to go calculate whether I actually need 10uF to get the bandwidth I need or will a 1uF, say, give me the needed bandwidth with the desired headroom, etc.

If it were my money, I wouldn't worry about SMD over through-hole, but I'd want a liberal return policy from whomever I bought it from so that I could return it if it turned out to be inferior. Then I'd test the heck out of it as soon as I got it to find out.

Hope this helps.
 
Thanks a lot, haburton! What about tantalum vs film capacitors (for all I know there are no SMD film capacitors) -- is there a difference in audio quality?

There is no problem with Nevaton's return policy, btw. It was more like a theoretical argument between two people who didn't really know what they're talking about ;-) So I wanted to make sure I had made a valid point. I really wanna learn more about stuff like that.

Thanks again for your help!
 
Well, you have a very valid concern about tantalum capacitors. They are not of the same audio quality as others. I know you can get aluminum electrolytics for sure, but they are not much better. The best would be polypropolene, polystyrene or polyester film capacitors. I'll have to check and see if they are available SMD. I believe they are, but I'll have to check. You might cruise the Digi-key or Mouser Electronics catalogs.

Some other places to look would be on the Sprague, Cornell-Dublier, or Kemet capacitor website. I'll check around and leave some more posts about it.

You are definately on the right track. I just did a preamp and really paid a lot of attention to the use of metal film resistors, polypropolene capacitors, gold plated connectors and well regulated and quiet power supplies. It really works well. I am still testing it, but from first brush, I'm impressed. More on that later.
 
I just did a quick cruise of Digi-key and Mouser and both have a pretty good selection of specialty caps. There are polyester, ceramic, specialty electrolytics, dipped silver mica. These are all pretty good types. Not only that, but they have metal film resistors in 0.2% tolerance. I want to build a preamp with these some time. Oh well, another project.

Keep up the good work, but as I'm sure everyone else here will verify, test, test, test.
 
I just did a quick cruise of Digi-key and Mouser and both have a pretty good selection of specialty caps. There are polyester, ceramic, specialty electrolytics, dipped silver mica. These are all pretty good types. Not only that, but they have metal film resistors in 0.2% tolerance. I want to build a preamp with these some time. Oh well, another project.

Keep up the good work, but as I'm sure everyone else here will verify, test, test, test.
 
Thanks again, haburton. I'll check out those websites; they seem to carry a lot more parts that the German stores I found so far. The SMD resistors I found on www.conrad.de were just 5% tolerance types. But they're more oriented towards home projects.

So it seems SMD technology is not as compromised as I thought. But I think I'll go and check out further what's available in SMD and what's not.

Thanks alot for your research!
 
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