From Marshall Craig Sent Fri, Jan 25th 2019, 16:55
From Marshall Craig Sent Fri, Jan 25th 2019, 16:55
Further side question: Is =E2=80=9Cmuffled fluegelhorn=E2=80=9D redundant? Sent from my iPhone > On Jan 25, 2019, at 08:54, A. Horton <xxxxxx.xxxxxx@xxxxx.xxx> wrote: >=20 > Side question with all this talk; has there even been a SEM patch that > sounded like anything other than a muffled flugelhorn? >=20 >> On Fri, Jan 25, 2019 at 11:50 AM Royce Lee <xxxxxxxxxx@xxxxx.xxx> wrote: >>=20 >> SEM filter observations: hopefully these comments will not be off topic. >> Perhaps this may be relevant to the conversation about Oberheim filters a= nd component differences. First the disclaimer that the only SEM filter I ha= ve is the Dopefer and Studio Electronics SEM filters. But I do like both of t= hem. >>=20 >> Recently I've been using the Nord Modular is a digital oscillator for a E= urorack system, feeding the SEM/doepfer bandpass. I noticed that when sendin= g the SEM a polyphonic signal, say a duophonic oscillator with arbitrary pit= ch spacing (fifth, seventh etc.) the result sounds a bit ring modulated. It t= ook me a lot of patching into alternate filters and double checking everythi= ng to conclude that it is the SEM filter is what was doing this. Perhaps thi= s is simply the effect of filter saturation. But this filter does it more th= an other filters I use. >>=20 >> Royce >>=20 >>=20 >>> On Fri, Jan 25, 2019 at 9:47 AM Sam Mims <xxx@xxxxxxx.xxx> wrote: >>>=20 >>> The tropical fish caps are made by Mullard - here's one used in the >>> Minimoog: >>>=20 >>> https://syntaur.com/Items.php?Item=3D1285 >>>=20 >>> Sam Mims >>> Syntaur >>>=20 >>>=20 >>>=20 >>>> On 1/25/2019 1:14 AM, Brian Willoughby wrote: >>>> There=E2=80=99s more to a capacitor than its capacitance. There=E2=80=99= s also ESR and leakage, as well as microphonics. Just because the same capac= itance is reported doesn=E2=80=99t mean it=E2=80=99s the same cap. >>>>=20 >>>> Many modern surface mount caps are exactly like their through-hole ance= stors. However, a few kinds of capacitor chemistries simply aren=E2=80=99t a= vailable SMD. One example is for Sample and Hold, where super-low-leakage po= ly caps simply aren=E2=80=99t available in SMD. Of course, there are other S= MD caps that are good enough for S&H, but maybe those tropical fish caps wer= e poly? Maybe they were mica? Foil? I=E2=80=99d be curious to know the manuf= acturer and model of those caps. >>>>=20 >>>> Lots of old caps were really bad, and nobody really wants the problems a= ny more. Again, it=E2=80=99s not that their value changes, it=E2=80=99s that= they don=E2=80=99t act exactly like a pure capacitor, but more like a compl= ex combination of capacitor, resistor, and inductor. >>>>=20 >>>> That said, why hasn=E2=80=99t someone just recreated the flaws of the o= ld tropical fish caps by adding parallel or series resistors and inductors? >>>>=20 >>>> Brian >>>>=20 >>>>=20 >>>>> 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 t= here is a clear difference between the new and old filter (more than TO woul= d 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 c= ame to light recently through the work of Oldgearguy over on GS that the lik= ely 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 t= he new SEM. So this is sort of proof through absence of evidence because he d= idn'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 g= et the new ones to sound identical to the old. >>>>>=20