Bottlehead Forum
Bottlehead Kits => Legacy Kit Products => Quickie => Topic started by: tubefrk on October 23, 2012, 09:36:54 AM
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Hello all, did I over hear someone talking about replacing the one thousand mic. electrolytics in the Quicke with some film Caps??????
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Yep, I built an alternate souped up version and replaced the 1000uF caps with Erse Pulse X 51uF 250V caps. They are a LOT bigger caps.
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Thank you mister Dog. Did you do anything to the circuit I need to know about? Thanks, Mike
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You can go a bit lower than 1,000uF, I think PJ said 50uF or bigger is OK. Voltage rating on this cap can be 5+ VDC. FWIW, Parts Connexion has a ton of audio grade electroyltics that will work in this position, many of them are not particularly expensive (we used the 1000uF/35V cap because it was already in our inventory).
-PB
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I went as low as PJ suggested with the idea that if it was lacking then I would go back higher. I mostly wanted to try a film cap versus electrolytic. But I've been really happy with the sound. Bass lines are tight and well defined. Music sounds a bit faster and livelier compared to the stock caps in my original quickie. I'm still curious to try a higher value sometime down the road. Maybe try some bypass caps.
Here's my overbuilt quickie:
http://www.bottlehead.com/smf/index.php/topic,3332.0.html (http://www.bottlehead.com/smf/index.php/topic,3332.0.html)
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The bias voltage is about 2 volts. There are also those polymer electrolytics like OsCons that have a good reputation (low ESR up to high frequencies) and are available with low voltage specs like 4v. Normal practice with electrolytics is to run them at 50% to 80% of rated voltage; however the only documented problem with lower voltage is that they can lose their high voltage capability - you can't take the 35v cap out of a Quickie and count on it to take 30v in a SEX amp.
There are some lower-voltage Mylar caps that are small with high capacitance, and not too expensive. They might be worth listening to.
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. . . the only documented problem with lower voltage is that they can lose their high voltage capability - you can't take the 35v cap out of a Quickie and count on it to take 30v in a SEX amp. . . .
Would this be a case of capacitor forming?
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Hello all, did I over hear someone talking about replacing the one thousand mic. electrolytics in the Quicke with some film Caps??????
I first replaced the electrolytic with a Elna Silmic ll that I had laying around. Then I went with the Mundorf MKP 56uF. I think I remember an improvement in sound with the film. I'm sticking with the MKP. Not sure if it makes sense going crazy on this cap.
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You can go a bit lower than 1,000uF, I think PJ said 50uF or bigger is OK. Voltage rating on this cap can be 5+ VDC. FWIW, Parts Connexion has a ton of audio grade electroyltics that will work in this position, many of them are not particularly expensive (we used the 1000uF/35V cap because it was already in our inventory).
-PB
Do you happen to gotta list of said audio-grade electrolytics? I've used Elna Silmic II's and I think they sound real purty, but that's the only brand I know of.
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Parts Connection has the good stuff! I'm not sure you will do significantly better than the Elna, in an electrolytic. I would go film.
Here is an electrolytic cap test:
http://tech.juaneda.com/en/articles/electrolyticcapacitors.html
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The reason I wanted to try a film cap was because the ESR is typically a fraction of what you'll find from an electrolytic cap. I'm no expert but I've read with regards to power supplies that keeping the ESR low is desirable. I'm pretty sure I hear a difference.