In xovers mylar tends to dull overtime , i have experienced this. JC , what made blackgates so special , what was different about them..?
Competitor ...!
Sutherland Engineering 20/20 phono preamplifier | Stereophile.com
Competitor ...!
Sutherland Engineering 20/20 phono preamplifier | Stereophile.com
So show us the only one repeatable measurement with properly valued coupling capacitor (fc bellow 3Hz) with visible distortion (spectra) in audio band , caused by capacitor...The only argument till now was " I hear it" (-140dB bellow signal)...Embarrassing.
Why bother with that? Why don't you get some "bog standard" film caps and put them up against some expensive audiophile boutique caps?
se
Back in the mid 1980's, Hi Fi News or HFN did a serious audio cap comparison. I will try to look it up and perhaps be able to try whatever vibration test they used. As I recall, a MYLAR cap performed the worst. I bet it was a construction issue. Believe it or not, not all caps are made to the same standard of quality.
FYI --- FACTOID: Time is money -- caps which are to be made at lowest cost or highest profit have to be made quickly. The higher the thru-put or caps per unit time making them, the lower the cost, greater productivity etc. OK. When caps are wound very fast, they trap air between the layers. The cap value is within some tolerance BUT the air trapped between layers reduces the breakdown voltage and reduces reliablity as well... via damaging corona affects etc.
For the audiophile, it also allows for vibration to modulate the C value. [I have measured C change from external physical pressure] The best caps are made by slow, air tight winding, then annealed to remove air pockets and make a solid piece AND you will notice some caps are flattened?.... that is part of the process to make them a solid, air-tight cap... when the cap is heated to the 'plastic' state, then pressed to remove the air pockets and voids et al... you get a non-microphonic cap and longer/more reliable one.
If you were to saw a cap in half, most will shred like cabbage and some others are like bar stock metal cutting thru them.
THx-RNMarsh
For the audiophile, it also allows for vibration to modulate the C value. [I have measured C change from external physical pressure] The best caps are made by slow, air tight winding, then annealed to remove air pockets and make a solid piece AND you will notice some caps are flattened?.... that is part of the process to make them a solid, air-tight cap... when the cap is heated to the 'plastic' state, then pressed to remove the air pockets and voids et al... you get a non-microphonic cap and longer/more reliable one.
If you were to saw a cap in half, most will shred like cabbage and some others are like bar stock metal cutting thru them.
THx-RNMarsh
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I see some 8-legs on page 2, they're not in the signal path are they? Quelle dommage.
I suspect it is not the speed of the winding, but how well tension is controlled. If you run the roll speed over 2 or 3 Krpm and up range, you have no process control.
When you flatten a jellyroll where one component of the roll is a compliant plastic, the sides not being compressed will fluff out, introducing air. The best way to avoid this is to place the dielectric under tension.
Partially melting the mix to achieve a monolithic structure will certainly help against compressive forces such as physical pressure.
However, there are an awful lot of decimal point shifts between squeezing the cap with a vice or pliers, and acoustic pressures within a closed enclosure placed in a room where humans can survive the spl.
jn
I went one better on that- I used V-Caps ($500 or thereabouts) versus bipolar aluminum electrolytics as coupling caps. The details are in my Linear Audio article on listening test design (available on their website as a pdf).
You also have to consider the amount of tension. That's where PTFE falls down, its tensile strength approaches that of cooked ramen noodles. Biaxial polyprop is nearly as good as it gets.
They certainly have no reason to exist here except as phono input. INA103 designer is an old friend, we never thought the compromises of running bipolars at that current had a big conventional instrumentation market, the SSM2219 and THAT1512 are geared toward audio and don't burden themselves with precision DC specs.
As I said to Ed, it is pretty easy to get something out of a cap with blunt force trauma.
Scott , monobloc version ....
Sutherland Engineering Phono Block monoblock phono preamplifier Page 2 | Stereophile.com
Sutherland Engineering Phono Block monoblock phono preamplifier Page 2 | Stereophile.com
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