Unless you see something on the data sheet saying that I wouldn't make such an assumption. It may be to insure the parts will solder well after sitting, or some more innocent explanation.SUBass wrote:Well...I got the caps in..
AVX Niobium Oxide
Nichicon Aluminum Polymer
Panasonic FP in both 6.3V and 16V
Murata Aluminum Polymer
Both the Murata and AVX appear to be environment sensitive as they were shipped in sealed bags with dessicant and a humidity gage to see how much humidity they were exposed to. That makes me a little uneasy about using them in a piece of gear that will be used in non-controlled environments. That's a real pity too because they were my favorites.
If subtle differences are audible they are measurable.Do you have any data to support your observations.Spectral changes can be measured with analyzers, dynamic changes can be parsed out with tone burst testing or similar benchmarks.Each one of the caps changed the spectrum and dynamic response of signal going through it. It's mainly a subtle difference, but in spending time with each cap I could distinctly pick out their subtleties. I have a specific application that I tired these out in, coupling from a buffer to a couple of preamps in my bass rig. At first I populated a cap or two on the buffer board and started playing. Swapping different caps to different pres, and comparing to no cap at all as well as bass straight into the amp. After getting a feel for the caps, I tracked a DI bass track into my DAW and setup a reamp to feed the buffer. That way I could put each cap into the signal path, track, then sit back and listen more critically.
not yet... With that dramatic of an audible difference I would be tempted to do some null tests between cap A and cap B to better quantify and qualify the actual differences.Going through the list...
The AVX rolled off some bottom (perhaps need a bigger value) and compressed the signal a bit. It also had a slightly forward midrange around 2.5k. It's possible that the apparent midrange boost is really due to the attentuation of the lows. Signal through the AVX didn't seem as "relaxed" as signal without a cap. It did make things seem "tighter."
Nichicon Al Polymer. This was a really interesting cap. It tended to preserve transients better but made things "sit back" a bit. Again...There was a seeming shift in really low end of the sound...But it was a "tighter" "smoother" sound.
Panasonic FPs. As should be expected...There was not detectable sonic difference between the 6v and 16v parts. They sounded the same. The transient response and midrange/top end of the FP was pretty good. The bottom end was a little weak though. This again makes me think the value of 47uf is a little low.
Murata Al Polymer. This was perhaps my fave of the group. Many times when I was blind AB'ing I picked it as my preferred sound over the no cap path. It sacrificed the bottom like the other caps but didn't seem to do so as much as the others. It also did the same "smoothing/tightening" thing that the Nichicon did as well as a bit of the mid boost of the AVX. The transients were a slight bit smeared which gave the no-cap path a slight edge.
I'll pull the exact model of all the caps if anyone is interested.
1/(2 x pi x R x C)
How does one go about calculating the appropriate size for a coupling cap?
JR