[Raphael]

Hey Guys,

I am going for a Sonicap Dock for my upcoming 5.5gen iMod. I have a question about it though. I will be carrying a separate bag to house all this in, so size is not of an issue to me. The V-Cap dock uses a 4.7uf cap, and I'm planning to get one with the same size in Sonicap. I'm wondering if there will be any benefit in SQ if I go over 4.7uf. I'm not worried about how big the cap is. Essentially, my question is, what is the optimal size capacitor to go with for this dock? Many thanks in advance!

 

[Raphael]

*bump*

I have DIY'ers waiting on me. So I gotta know what to tell 'em. Any suggestions at all?

 

[joneeboi]

If your rig is going to be portable, I'd recommend getting the smallest caps as you can. The capacitors are there to block DC, and size is irrespective of this characteristic. This means that you can get any size capacitor you want. Typically, the bigger the capacitance in a particular line of capacitors, the better the quality. In that sense, all you really need to figure out is what size works for you. What amp are you going to be using with the iMod? If you know the input impedance of your amp, then you use that value to calculate the size of your capacitor according to the equation,

C = 1/(2*pi*f*Z)

where
C is capacitance,
Z is the input impedance,
f is the -3db corner frequency.

The corner frequency relates to the high-pass filter you're creating between the iPod and the amp. You let through the high frequencies and the bass begins to roll off at a certain point depending on your C and R. That means if we choose f to be lower than the human threshold of hearing (meaning below 20Hz), you're getting all the bass information you can really use. Suppose we choose f = 5Hz and Z is 50KOhms,

C = 1/(2*pi*5Hz*50KOhms)
C = 0.6366uF

If we choose f = 5Hz and Z is 10KOhms,

C = 3.183uF

That means the 4.7uF Sonicaps will serve you well if you're giving them an amp with at least 10KOhm input impedance.

Now, to answer your initial question of whether anything larger than 4.7uF gives you better sound quality, that's only something you can really decide. I will add that when one of the 22uF Black Gates in my diyMod broke one of its legs and I replaced it with a 47uF BG, I started noticing a whole lot of bass. It isn't placebo because when I was listening, I was wondering why all this bass started appearing out of nowhere: I had forgotten I changed the cap. I know that sounds kind of bogus, but that's the story I'm sticking to.

Bottom line: 4.7uF is fine, but experiment if you're interested in finding the best fit.

 

[Raphael]

Thanks for the info. That really helped