one thousand mic electrolytic

[tubefrk]

Hello all, did I over hear someone talking about replacing the one thousand mic.  electrolytics in the Quicke with some film Caps???

[corndog71]

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.

[tubefrk]

Thank you mister Dog.   Did you do anything to the circuit I need to know about?   Thanks,  Mike

[Paul Birkeland]

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

[corndog71]

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

[Paul Joppa]

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.

[Grainger49]

   .  .  .    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?

[earwaxxer]

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.

[E.T.]

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.

[earwaxxer]

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

[corndog71]

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.