More on capacitors
Posted: November 1st, 2020, 1:19 pm
Those of you that know me personally and -- even some that don’t -- have witnessed my preference to Electronic Concepts polycarbonate capacitors. For me they definitely have a place in passive speaker crossovers and in many cases a place in electronics’ signal path preferably when bypassed with complementary Teflon capacitors especially those made by Custom, CRC, or Tex-Cap hermetic capacitors.
That said – it was time to re-cap (all power supply electrolytics) my pre-amplifier (a Balanced Audio Technology VK-3i – 6DJ8s or 6922s or 7308s with 6V6 current sources). Since time has passed, the BAT pre-amp was already 23-years-old and yet I had no desire to replace it. Since the work involved full disassembly I also took a hard look at the output coupling caps for upgrade plus some resistor upgrades. Since it is a balanced design we’re talking about four matched output caps. The stock offering was Jensen aluminum paper-in-oil caps that I bypassed years ago with Teflon caps. Those of you that have heard my system recognized that the pre-amp acquitted itself very well.
Before committing to a change -- I performed trials using a DC-coupled pre-amp (Spectral DMC-10) and an adapter that I made to evaluate coupling caps and resistors in the signal path against a straight wire. I was leaning toward my preference until I discovered some Russian caps in my inventory that I long since forgot about. To make a long-story-short these caps were represented by the seller as polycarbonates and they were set aside since they did not perform well in trials for my speaker’s crossover.
As it turns out they were NOT polycarbonates but hybrid capacitors. HUH? They were confirmed by the product number K75-24 and as it turns out have a “cult” following with one manufacturer using them in their hi-end phono pre-amps. (the $12,000 Brinkmann Phono stage “Edison").
These caps are a metalized-paper-in-oil together with a mylar (polyester) dielectric. Products of the Cold War that defy reason or experience when it comes to all things audio. Bypassed with Teflon caps the combination provides an open, grain-less, flesh-on-the bone level of reproduction that far exceeded any expectations I had. WOW!! “See-through transparency" – amazing 3D mid-range performance – together with a smooth-musical character that does not smother. Vocals especially are a treat. Strings do not sound like screaming cats. Keeping in mind that the Jensens were the product to beat. Hell -- my polycarbonate favorites didn’t even make it a contest.
Who knew?!
That said – it was time to re-cap (all power supply electrolytics) my pre-amplifier (a Balanced Audio Technology VK-3i – 6DJ8s or 6922s or 7308s with 6V6 current sources). Since time has passed, the BAT pre-amp was already 23-years-old and yet I had no desire to replace it. Since the work involved full disassembly I also took a hard look at the output coupling caps for upgrade plus some resistor upgrades. Since it is a balanced design we’re talking about four matched output caps. The stock offering was Jensen aluminum paper-in-oil caps that I bypassed years ago with Teflon caps. Those of you that have heard my system recognized that the pre-amp acquitted itself very well.
Before committing to a change -- I performed trials using a DC-coupled pre-amp (Spectral DMC-10) and an adapter that I made to evaluate coupling caps and resistors in the signal path against a straight wire. I was leaning toward my preference until I discovered some Russian caps in my inventory that I long since forgot about. To make a long-story-short these caps were represented by the seller as polycarbonates and they were set aside since they did not perform well in trials for my speaker’s crossover.
As it turns out they were NOT polycarbonates but hybrid capacitors. HUH? They were confirmed by the product number K75-24 and as it turns out have a “cult” following with one manufacturer using them in their hi-end phono pre-amps. (the $12,000 Brinkmann Phono stage “Edison").
These caps are a metalized-paper-in-oil together with a mylar (polyester) dielectric. Products of the Cold War that defy reason or experience when it comes to all things audio. Bypassed with Teflon caps the combination provides an open, grain-less, flesh-on-the bone level of reproduction that far exceeded any expectations I had. WOW!! “See-through transparency" – amazing 3D mid-range performance – together with a smooth-musical character that does not smother. Vocals especially are a treat. Strings do not sound like screaming cats. Keeping in mind that the Jensens were the product to beat. Hell -- my polycarbonate favorites didn’t even make it a contest.
Who knew?!