Bottlehead Forum
Bottlehead Kits => Crack => Topic started by: barbz on December 05, 2020, 09:52:03 AM
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Hi all,
When I purchased my crack I also purchased some parts to eventually modify/upgrade with.
I'm ready to check out the panasonic EZP-E50107MTA capacitors however I can't find anything online or in the datasheet about which terminals on the capacitor to use (of the 4) and the polarity of them.
Could anyone else who has used these or is familiar with them point me in the right direction.
Thank you
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Since they're film caps, they don't have a polarity. As for the pins, I was similarly confused by a 4 pin WIMA cap recently. But when I tested resistance between the pins, I found that the two pins on each short side are wired together -- i.e., they are electrically the same pin. I suggest measuring the DC resistances yourself to verify. If you get the same results, then you just treat the cap as a regular two terminal film cap and connect +ve to one short side and negative to the other short side. (and, again, which side you chose for +ve or -ve is entirely arbitrary). I chose to externally wire together each pair of short-side pins on the off-chance that each pin connected to a difference spot on the same internal "plate" (doubtful, but it only required me to use an extra 1.5" of wire).
Hope that makes sense.
cheers, Derek
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That's the so-called "Kelvin" connection, I think. Each end of the cap has two wires going to it. It's useful for power-supply filtering - one wire for input, the other for output. This way, any resistance or inductance in the wiring is not shared between in and out. Useful at extremely high frequencies, overkill in audio. None of our products uses this technology; in a point-to-point build it would require four terminals instead of two for each such cap. Derek's solution is a good one.
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Thank you
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That's the so-called "Kelvin" connection, I think.
I never have seen it called out in a commercial datasheet. I'm suspicious that there may be 4 pins to help hold the girth of the capacitor itself, but until someone cuts one open we may never know!
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Hello - what gauge/type of wire should we use to solder these replacement/upgraded capacitors to the terminals?
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Solid core, something around 20-22 AWG.
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I think I may have used the leftover wire from the kit on mine. Anyway, here is a pic of how I mounted my caps. I later added Speedball which was no problem.
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Thanks for the help! I was able to get the new Panasonic film caps in there...and they sound...rough. Hoping they just need some burn-in time? On that -- is it okay to remove the tubes and leave the BHC turned on with music going through it?
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On that -- is it okay to remove the tubes and leave the BHC turned on with music going through it?
No, don't do that. With nothing drawing any current at all through the power transformer, you may end up with a little more than 250V across the power supply caps. Additionally, with no tubes in the amp, there will be no DC across the 100uF caps and no signal current going through them, so you won't burn them in.