From sam Sent Fri, Jan 25th 2019, 15:45
From sam Sent Fri, Jan 25th 2019, 15:45
The tropical fish caps are made by Mullard - here's one used in the Minimoog: https://syntaur.com/Items.php?Item=1285 Sam Mims Syntaur On 1/25/2019 1:14 AM, Brian Willoughby wrote: > There’s more to a capacitor than its capacitance. There’s also ESR and leakage, as well as microphonics. Just because the same capacitance is reported doesn’t mean it’s the same cap. > > Many modern surface mount caps are exactly like their through-hole ancestors. However, a few kinds of capacitor chemistries simply aren’t available SMD. One example is for Sample and Hold, where super-low-leakage poly caps simply aren’t available in SMD. Of course, there are other SMD caps that are good enough for S&H, but maybe those tropical fish caps were poly? Maybe they were mica? Foil? I’d be curious to know the manufacturer and model of those caps. > > Lots of old caps were really bad, and nobody really wants the problems any more. Again, it’s not that their value changes, it’s that they don’t act exactly like a pure capacitor, but more like a complex combination of capacitor, resistor, and inductor. > > That said, why hasn’t someone just recreated the flaws of the old tropical fish caps by adding parallel or series resistors and inductors? > > Brian > > > On Jan 23, 2019, at 8:10 PM, M V <xx_xxxxxx@xxxxxxx.xxx> wrote: >> Speaking of the new and old SEMs though, it's pretty well known that there is a clear difference between the new and old filter (more than TO would care to admit it seems). The former is brighter and sharper when resonance is at max, and not just because of an increased cutoff range. However, it came to light recently through the work of Oldgearguy over on GS that the likely culprit is the tropical fish caps that the old one uses and the new ones do not. OGG pulled the tropical fish cap on his old SEM and replaced with a modern hi-fi cap and found that the filter pretty much sounded the same as the new SEM. So this is sort of proof through absence of evidence because he didn't/couldn't put the through hole trop. fish cap in the new SEM's SMT PCB, but it does strongly suggest that with some very minor tweaking, one could get the new ones to sound identical to the old. >>