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Report Review for product Capacitor - SoZo, 500V, NexGen Blue Molded Vintage

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Sozo has learned a few lessons by having a spec OEM winder up the prices on him, without ever sharing the winding specs, so Sozo was left to pick up the pieces, find a new winder and redesign a capacitor in both the blue and yellow flavors. I don't know what a super expensive capacitor tester is, because I use a $7000 LCR, with $1500 leads, $9000 in power supplies, a load, O Scopes, Lisajous audio scopes, audio analyzers, function gens, a millivolt meter and a micro-volt, and even a nano-volt meter. We also jig these caps up and run a clean sine wave through them, to check for noise, microphonics & shielding from EMI & RFI. The LCR runs at around 45 test different points between 10Hz and 20,000 Hz, measuring dissipation, ESR, Q, B, Z, and of course the capacitance, at each preset frequency. The dissipation and Q Z/ESR generally tells us whether or not the caps leak, but for fun, we run them up to their working voltage with a +/- DC millivolt meter and check the time it takes for the meter to settle on ZERO! A bad leaky will NEVER zero out. IT LEAKS DC, SO IT NEEDS TO GO AWAY! A cap that is going bad will have a long lag time when the DC voltage changes, up or down. This makes your tone muddy! The micro-volt meter is also run in concert with a nanovolt Oscilloscope to check AC ripple. These are ALL DC voltages. These just tell me, is the cap going to fail. Sozos won't fail so long as the working voltages are not exceeded. Now we come to the truth test. This is the LCR running at 1 volt, at frequencies from 10 Hz to 30 KHz. The Q, D, ESR, Z, C will ALL change with the frequency being fed through the capacitor. Sozos tend to hold a better Q at lower frequencies than their Mullard and Ajax vintage counterparts. From about 150-300 Hz, on up, they Sozo caps follow the same curves as the vintage caps, very nicely. THE ONLY DEFICIENCY WITH SOZO IS IN SHIELDING FROM EMI, RFI and AC HUM, WHICH IS A FORM OF EMI! Mullard Philips Bianchi mustard caps shield a little better. It's the way they were made back then. Sozos will have a tighter in slightly more your face bottom end than the vintage caps. I cannot honestly say that Mullard caps did not test better 30 years ago, when they were brand new, but Sozo did a super great job making their caps follow the Q curves of their vintage counterparts, and the Sozos are encased better than the Ajax caps ever were. This means the Sozos should drift less when they age. The Mullards, might be a tad better, but I cannot justify the high prices for OLD capacitors. There is no way in blue blazes I will put NOS yellow Philips Mullard film caps in a custom build without a disclaimer, for reliability. Sozo has the edge over NOS every time. The LCR is an ESI Teague 2600 series, video display meter, with an old magnetic tape memory, and tests at frequencies between 10 Hz and 100KHz, with an external bias voltage capability of 50 volts which will be modulated as a sine wave from 10Hz to 100KHz! The machine can record batch results in the 1000s. The DC PSUs are made by Lambda, Fluke, Gates, Yokoshima, and Sorensen, and they are all regulated vacuum tube high voltage supplies. The micro/nano volt meter, is made by the famous Keithly. The O Scope is a Tektronix nano volt vertical range scope, which can tell me ripple bypass, and even microphonic noise, whether it is piezo, or tribo electrically produced. The swing meter is an old Welch Allyn meter, which mostly tells me, how tired my filter caps are! It will also tell me if any Sozo, Ajax, or other cap is leaking as little as 1/2 millivolt. SO AFTER HOOKING SOZOS UP TO over $20,000 in test gear, I still need to use my most valuable testers.........the two horizontal brain vents, on either side of my head, affectionately known as "MY EARS"! My ears really love Sozo caps! BLUE or YELLOW! Even the dog's ears love Sozo caps, and you should see her ears! They are huge, and pointy! She can hear a lizard fart from 6 miles away, and pinpoint its location. So my fart smeller dog even agrees, the guy at Sozo is a pretty smart feller too. He did a good job making these caps track on test equipment very much like the vintage caps, and they kinda sound a little better too, especially in the bass & low mids. These caps are truly epic, but not ridiculously expensive. FMIC is selling some PIO caps for $18-$30 each, and they can keep them. Oddly enough, the Japanese copied the 1960 Gibson Sprague black beauty film caps to near perfection, back in the 1970s. I have a small stash of the .022s. Ibanez was famous for using them. 50 volt caps don't work in tube amps, so stick with the Sozos. - November 17th, 2017