Quickie mods

[earwaxxer]

You will pay more for a higher voltage rating. I tend to think its worth it. There appears to be some consensus that the higher voltage caps sound somewhat better. We all have to decide where to draw the line though. 

[Grainger49]

Your power supply is 36V.  The caps need not be any higher than that.  But to get good sounding caps you have to buy higher voltage ratings than you need.

[mortron]

Going back to the Clarity Cap MR that everyone uses... 2.2uf? And does the voltage matter? I can get the 400V much cheaper than the 630V ones. And the cap in the power supply can be any value, just anything over 36V? How many uf? Thanks

[earwaxxer]

Hey Mortin - I agree to spend some $ on the coupling cap (2.2uf), dont need the super high voltage ones. That one makes the most difference, its also a reasonably small value to keep it 'affordable'.

The electrolytic (1000uf) is a bypass cap for the cathode resistor (Rk) that sets the bias. It eliminates negative feedback (cathode degeneration). Without that cap there would be negative feedback that would decrease gain. According to Paul you can go as low as about 47uf and not have any bass roll-off. I have a 56uf film cap in there. Most people like to get rid of the electrolytics if at all possible for a more restful sleep. Dont go crazy on that one IMO. Dont worry about the voltage rating as long as its 50V or over.

Enjoy -
here is a cathode bypass calculator to give you an idea of how that capacitor works.
http://ampbooks.com/home/amplifier-calculators/cathode-capacitor/

[corndog71]

I think when you add lots of damping and some high quality coupling caps, having the film bypass caps bumps up the resolution just a little bit further.  It's not as noticeable as the couple caps but I think if you want it to sound its best and don't mind the extra expense then it's not a bad investment.  To be fair I lived with my original Quickie w/ PJCCS and stock electrolytics for a couple of years and loved it.  I just wanted to see how far the circuit could go with some refinements.  For the money it's still a ridiculous bargain.

[earwaxxer]

Here's your chance Quickie modders! The coveted Duelund CAST-PIO-Cu now on sale at Parts Connection. Not cheap grant you. These suckers are heirlooms though. I would love to hear the 10uf in my maggies, or the 2.2uf as a Quickie coupling cap. Just sayin. Sure its crazy money, but we have to spend it on something (Granger, hint, hint).

http://www.partsconnexion.com/capacitor_film_duelund_pio_elec_new.html

[adamct]

Ha ha! I love the pictures of the Duelund caps next to the Coke cans...too funny. I actually wish they would do that more often, to give me a better visual feel for how big my caps are before I buy them.

Now, just to make sure I didn't misunderstand something, I could replace the electrolytic 1,000 uf cap in the Quickie with, say, a 100uf film cap? With no performance detriment, and a possible (depending on how much Cool-Aid you've had) sonic benefit?

Best regards,
Adam

[rif]

1) Mr. Grammar says: Dampening is misting with water. Damping is absorbing vibrational energy"  :^)

I think that's vocabulary, not grammar. But what do I know, I'm a former physicist. There's gotta be at least one joke in there: a physicist, an engineer, and a mathematician look at a schematic...

[corndog71]

Ha ha! I love the pictures of the Duelund caps next to the Coke cans...too funny. I actually wish they would do that more often, to give me a better visual feel for how big my caps are before I buy them.

Now, just to make sure I didn't misunderstand something, I could replace the electrolytic 1,000 uf cap in the Quickie with, say, a 100uf film cap? With no performance detriment, and a possible (depending on how much Cool-Aid you've had) sonic benefit?

Best regards,
Adam

It's not supposed to have an audible effect.  I got the idea from another project of mine that surprised me.  I swapped the fancy Panasonic electrolytic power supply caps in my ST35 amp for Clarity TC caps which are giant 700V film caps because they had a much lower ESR. 

I heard an immediate improvement in resolution.  This is particularly noticeable in the bass region.  Music seems faster and there was a distinct lack of haze to the sound compared to the Panasonics. 

I thought if it could work in my little 17.5 watt amp then maybe it could work in my ultimate quickie project.  Granted I made numerous changes in my ultimate quickie just in layout.  So it's hard for me to say what changes made the most significant effect.  Nevertheless my ultimate quickie is better sounding than my original version.

With that in mind you can try them or not.  It's your call.  If you're happy with what you got then don't bother.

[adamct]

Thanks, Rob. I can get a great deal on a ClarityCap SA 100uf. Is there any significant reason to prefer the TC series over the SA? I know the TC series is rated for higher voltage, but for a variety of reasons (including cost, covenience, shipping cost and speed), the SA version would be better for me if it is also suitable to the task...

Best regards,
Adam

[earwaxxer]

100uf would be fine to replace the electrolytics. I used a 56uf film there. There should be no bass roll-off down to about 42uf or so. I thought it improved the sound. Not as much as the coupling caps. I replaced all the resistors at the same time, so it was hard to say.

[corndog71]

Stick with the SA series.  You don't need the TC caps for this.

[earwaxxer]

Definitely, dont go overboard on those. Any films will do the trick.

[adamct]

Great, thanks!

[royewest]

I just received a v 1.1 Quickie kit. The bypass cap is 150uF. I thought I'd upgrade it to a higher quality electrolytic (already spent too much on a boutique pot and the coupling caps). But not many electrolytics come in that value. Any suggestions? Team up a pair of 100s with 48s? Would another value be fine?

Thanks,

__Roy