Based on relative distortion data, it's not an Obsession and electrochemical capacitors are the worst possible capacitor to use for almost any application.
Probably, but they are nothing like as bad as people suggest. Very often they are far better in tweeter sections than some brands of film capacitors. You mention "rolling" capacitors... I will happily roll in Alcaps over cheap film. There's often much more detail, and more body to the sound - which is the perfect combination. In another thread (either here or on the Naim forum) someone replied to me on the subject mentioning that he'd had his Kan Mk1s redone with Solen caps (which I would have expected to work) and it killed the music for him.
Somewhere I have a jpg of some impedance measurements from a decade or so ago of an Alcap vs MKP10 vs a Rubicon ZA and, IIRC, the Alcap is the one that looks most like a theoretical capacitor.
I find that using bipolar types for signal positions and enclosing the capacitors in the AC feedback loop and/or refactoring the circuit to only use film or high quality ceramic types gives measurable and audible benefits.
I agree. I would go so far as to say they are better in some power positions too. If you have an RC on your rail, I would use a bipolar there too. I think Meridian are hip to this too. I saw a part photo of one of their internal amplifiers and it had axial caps in the familiar Alcap blue, right next to the output transistors. There wasn't enough of the circuit board shown to be completely sure of what they were doing but I suspect they were between the rails and ground
Simply untrue. And if your casework has AC magnetic fields IN THE CASEWORK (as opposed to screening them) you have problems on a level we not need to talk capacitors.
Not untrue. I seem to remember this is in Ott and meant to find it for you but was behind in replying here already. I certainly remember my reaction at the time was "Oh, for God's sake! Really?". But of course there are currents in the casework. It's a very good reason to keep the transformers outside the amplifier part.
FWIW, I had a design where polystyrene RIAA EQ capacitors were notably microphonic but silver mica were not.
This is interesting. Maybe those orange drop caps really are the reason only Nakamichi managed to make decent cassette decks. Such an overlooked medium! I've tried to find others that perform as well, including a beautiful B&O 8000 and an award winning Yamaha (where they had obviously tried very hard) but they didn't come close to even a mid range Nak. I've never had a stock of silver mica caps so haven't ever given them a try.
A lot of capacitor problems are real. Ranting that audiophiles are stupid for dealing with them is not constructive.
I think you've misconstrued my position on things audiophile. I would defend almost everything that's usually dismissed as "audiophoolery". In fact I am militantly against anyone who believes that SINAD encapsulates the performance of any piece of equipment (while also not being pro injecting euphony).
Polypropylene is not particularly well damped. Hence my preferrence for stacked film typed in plastic cases, e.g. WIMA FKPxx & MKPxx.
I'd say PP is pretty well damped by comparison to PE, which is why it was used after bextrene in loudspeakers. Sure, it is usually loaded with carbon black in loudspeakers, which helps too, but that was mainly for UV blocking (which it has done amazingly well if you look at a B110 SP1228, 30 odd years on). It's also used in composites for toughness and damping. It is 1/3 as stiff as PET and you can test its properties yourself on any milk container. Or see here:
Plastic Rigidity & Material Stiffness, Units, Formula & Table
FKPs and MKPs are my go-to capacitors. I usually stick to MKP4s as MKP10s can get a little expensive. I thought MKPs were wound. Not sure about FKP but I love them.
"Rolling" tubes, Op-Amps and capacitors or swapping cables (and yes they make differences) are accessible to relative laymen in ways that serious circuit optimisation or restructuring grounding are not.
I have no problem with cables sounding different - and indeed they very obviously do. I don't think there would have been the huge industry in interconnects if we had discarded the horrible RCA phono plug and had followed studio practice in using balanced connections 50 years sooner than we did (which is only about now). It is probably better that it has been brought to light, though. At the other end of the amplifier, speaker cables change the response of the speaker, affect the phase margin of the amplifier, act as aerials, reflect what they pick up due to impedance mismatches at frequencies the amplifier can't deal with, probably affect the junctions of the output transistors, have triboelectric effects, are probably microphonic and are essentially one resistor away from the amplifier's input stage. I don't know how anyone can argue they shouldn't have an effect.
Audiophiles gear tends to use direct coupling and servo's as a result, not that this really helps the way it's usually done, IMNSHO. Amplifier input circuits have sufficient loop area and sensitivity, that is a (say) 27mm long capacitor instead of a 10mm one causes problems, you have to fix the bad layout etc first.
I'm not actually pro DC coupling these days but I would be very interested in how you think a servo ought to be done. I was very taken with how Bruno Putzeys did the input of a preamp by subtracting a low pass from the signal. I think he did it so it became an inverse Chebychev so the ripple ended in the stop band, but that may be one step further than he actually went.
I was thinking more a 70mm long capacitor with a 50mm diameter, rated at 600V, which is the kind of thing that sometimes appears at the input of "exotic" MC phono preamps.
Christian
