Surface mount components poorly regarded

[capslock]

Ok, Vishay-Draloric is kind enough to provide non-linearity and current noise specs for their resistors.

The SMM0204 - MS1 parts are Mini-Melf (i.e. cylindrical SMD) metal film parts with a rating of 0.25 W. Non-linearity A3 for a 10 k part is 110 dB. I do not remember the exact definition, but I believe it is resistance change per volt and hence should read -110 dB. Current noise for 10 k is 0.05 µV/V.

The D...-CRCW series (available down to 0.5% tolerance) are rectangular metal glaze SMD parts. A 10 k 1206 (also rated at 0.25W) has a nonlinearity of 65 dB, a 0402 will only have 50 dB. Current noise is 0.1 µV/V for the 1206 package and 0.5 µV/V for the 0402.

So we can safely conclude that metal glaze, whatever its composition, is sonically inferior and should be avoided as feedback and filter resistors.

Eric

[MRehorst]

Originally posted by capslock
Ok, Vishay-Draloric is kind enough to provide non-linearity and current noise specs for their resistors.

<snip>
So we can safely conclude that metal glaze, whatever its composition, is sonically inferior and should be avoided as feedback and filter resistors.

Eric

How anyone conclude anything from this data? You have not compared the numbers to the same specs of any leaded parts. You also have not provided figures for audibility of any of those numbers, which I suspect would vary significantly depending upon the application.

This is exactly the sort of jumping to conclusions that makes reasonable people laugh at audio maniacs. Decisions/beliefs are presented as if they are based on science/engineering, but with very little scratching at the surface it becomes apparent how shallow the reasoning really is.

MR

[jwb]

MRehorst, I think you need to work on your reading comprehension before you flame. tiroth only concluded that metal glaze SMD resistors have more noise and worse thermal emf than thin film SMD resistors.

So chill the you-know-what out.

[MRehorst]

Right you are! I missed that one. I apologize to anyone who thought that I was flaming anyone. I was merely disagreeing.

I stand by my assertion that those numbers rule out the use of any of those parts for specific audio applications.

MR

[SKK]

Originally posted by tiroth

Sorry, that was a typo. I meant PPS film, a plastic. Corneil-Dubiler makes the PPS SMT caps I am using; I'd provide a link but I can't seem to get to Mouser. Digikey sells the radial Panasonic ECH-S series, PPS, and according to Harry decent sounding.

Hi there!

Panasonic also makes PPS smd caps, and digikey sells them.
And something quite interesting is "acrylic resin" film smd cap (ECPU series) made by the same company. (Digikey has them too.) They say something like "it sounds very good."
Check out the URL:
http://www.maco.panasonic.co.jp/eccd/index.html

[HarryHaller]

Tempo and Voltage Coefficient seem to be two of the most often quoted specs for high precision resistors. Since the power dissapated in a resistor will very with signal swing, a dynamically changing temperatures are varying the value of the resistance with signal ie. a nonlinearity. A simular argument can be made for
chance in resistance with voltage due to Voltage Coefficient. Data for two of the more highly regarded resistors for audio are at:

http://www.caddock.com/Online_catalo...Lit/TypeTF.pdf

http://www.vishay.com/document/63001/63001.pdf

Further complicating this are thermal conductivity and thermal mass of the resistive film, substate, and encapsalating material.
Several zealots are using "naked" Vishays without the encapsulation. Perhaps the thermal characteristics are better without the thermal insulation. There has also been trend in using oversized resistors by some manfactures. Differences in thermal mass perhaps? I believe there are many engineering parameters that could cause resistors to sound different. The datasheets above will give a bench mark for good numbers for Tempco and Voltage Coefficients for the spec readers.

H.H.

Also for more background:
http://www.riedon.com/handbook_default.htm

http://www.riedon.com/app_notes.htm

http://www.metechinc.com/solutions/voltage.html

[HarryHaller]

The panasonic polyproplene sound good. I have no experience with the PPS caps.

[tiroth]

My bad Harry. Could have sworn it was you who recommended ECH-S, but it must have been another forumite.

[HarryHaller]

http://www.paccom.com/paccom/downloa...ors/rt-499.pdf

http://www.vishay.com/document/63022/63022.pdf

H.H.

[koolkid731]

For my prototyping, and I do a lot of it, I stay away from thru-hole parts. SMD have very low inductance, to allow high bandwidth amps etc...Sure, they're small and difficilt to handle for many. Here's a definite solution to their handling:

http://www.t-rexelectronics.com/