[Lil' Knight]

If I use 4.7µF / 200VDC GenI, the smaller caps must be the same 200VDC, in parallel ? Correct me if I'm wrong

 

[FallenAngel]

Quote:

Originally Posted by Lil' Knight /img/forum/go_quote.gif If I use 4.7µF / 200VDC GenI, the smaller caps must be the same 200VDC, in parallel ? Correct me if I'm wrong

Nope, the voltage doesn't matter since the output is only 1.5V so you can use any cap over 1.5V

 

[joneeboi]

Update on the Zune 2G's WM8350:

I emailed the nice folks at Wolfson again about the WM8350, and their reply was that there is a non-disclosure agreement required before they send it out. That then means that I could get the datasheet and not tell anyone how to do it, or I could just get a Zune, open it up and poke around inside. I prefer the latter method because it doesn't compromise my integrity, so if anyone is interested in diyModding the Zune 2G, either poke around inside yourself or send it to me so I can figure it out.

Holler.

 

[DrizzitT]

What gauge wires are people using for the hookup in the Ipods (specifically the Mini). I don't have much access to wire and don't really want to use generic EE project hook-up wire, so I was considering buying some.

The first page recommends the e-bay shop or Digikey/Mouser, but one is 24 AWG and the other is 30 AWG. Thanks!

 

[joneeboi]

Most people have been using either 28AWG or 30 AWG wires, so it's really up to you and your wire stripper what you want to do. John's Wire Shop carries anything from 20AWG to 36AWG, so you can pick whatever works best if the stuff at Digikey/Mouser doesn't suit your fancy. I am using 26AWG in my 4G because it doesn't have such a tight fit.

 

[FallenAngel]

On the Mini, the wire runs SUCH a short distance that it really doesn't matter, use the smallest you can. I used 26AWG, and that's fairly thick for the mod, take the 30AWG.

 

[DrizzitT]

30 AWG it is. I figured 24 AWG was a bit much so just wanted to make sure. Thanks!

 

[FS2]

Has anyone thought about swapping the existing caps on the headphone out of the minis? Since I've heard the mini sound quality isn't that great, I wonder if that would help. Biggest problem I see would be finding a cap in the right (physical) size, and trying to figure out what the existing cap value is.

 

[joneeboi]

*raises hand*

I've thought about it, because at first, I couldn't figure out which were the line out caps (but ruZZ.il helped us out with that). I figured we could just send the headphone jack signal to the dock and turn up the click wheel volume. Once that didn't pan out, ruZZ.il came and found us out line out signal caps. First, it's an issue of capacitance, which then returns to the physical size problem. You have to find the proper capacitance for your headphones so that the bass doesn't roll off so bad. [Please refer to our favourite C = (2*pi*R*f)^-1 equation.] Then when you find the right size capacitance to match your headphone's impedance, you have to somehow fit that huge thing into the mini. By no means is it impossible, because ishtob pulled it off in the nano.

Somehow, one could pull it off in the mini, it just may not be as pretty.

And sadly, I sold my mini 2G to ruZZ.il, so brainstorming will be harder on this end. You could very well drill a couple holes in the back of the mini, but for some reason, people don't like that method as much.

 

[FS2]

Well, I'd want to keep everything internal.

And knowing the existing cap value would help as I wouldn't want to replace them with a smaller value than what they already are. Beyond that, there's the question of the circuit that's rigged up in the mini. If it's taken from the datasheet, then I wonder what R should be in this case. I doubt they're using the recommended 220 uF though, as the 1st Gen mini I cracked open had a cap marked "100 4X". (Or at least I think those were the right caps.)

Oh yes, about your first post, the 1st Gen mini I cracked open was using a WM8731L. I think it's only the 2nd Gen that uses the WM8711 (though the pinouts are almost the same... the 8711 seems functionally simpler). I should probably take another look to confirm mine was indeed a 1st Gen...

 

[dumbears]

Perhaps, I've missed this in the past. I wonder if the decoupling caps is recommended to be 220uF. The original ones are 100uF.

Moreover, I wonder if the bass becomes more solid if swapping in 220uF. I know some actually swapped in a pair of BG NX 100uF caps.

 

[joneeboi]

The 220uF recommendation comes into play when headphones are connected directly to the DAC. I wonder what the amplification stage looks like between the DAC and the headphones, as Wolfson's papers all talk about hooking headphones straight into the DAC. Again, we refer to that corner frequency equation, and 22uF seems to work for my 4G with my Millett MAX. IIRC, the input impedance is something around 50K, so the corner frequency is pretty much obliterated at 0.144Hz. The surprising thing was how the 47uF BGs gave me so much more bass. If you want to work straight into the headphone jack, 220uF goes great with 32ohms, and the BG version sizes up at 8mm x 11mm. What were you thinking of doing?

 

[no_eye_dear]

I'm having a play with that sort of configuration at the moment. I wanted to use a remote for the volume into my amp so I'm taking the signal from the headphone out instead of the line-out and using one of those clip-on remote units for my 4G.
The EQ will also give me some scope on DSP for my room/speakers... not much but it will be interesting to compare the line-out quality with the heaphone-out quality after all that internal DSP.
Obviously the output caps can be as usual (no low impedance HPhones) but I may not have any at all with this solution

.......dependant on matching the DC bias input of my DC coupled amp that is..

Should be interesting

 

[ruZZ.il]

I believe there is some space in the mini up around the headphone jack area to stuff 2x47uf 6.3v BG NX caps.. a little round about for the signal cable, but I doubt it'll effect anything.
I should be getting some cf cards soon so I'll be able to play again.. when I get some time too.. hmpf.
been a bit busy, but it should even out soon

 

[dumbears]

Quote:

Originally Posted by joneeboi /img/forum/go_quote.gif The 220uF recommendation comes into play when headphones are connected directly to the DAC. I wonder what the amplification stage looks like between the DAC and the headphones, as Wolfson's papers all talk about hooking headphones straight into the DAC. Again, we refer to that corner frequency equation, and 22uF seems to work for my 4G with my Millett MAX. IIRC, the input impedance is something around 50K, so the corner frequency is pretty much obliterated at 0.144Hz. The surprising thing was how the 47uF BGs gave me so much more bass. If you want to work straight into the headphone jack, 220uF goes great with 32ohms, and the BG version sizes up at 8mm x 11mm. What were you thinking of doing?

I was thinking of swapping out the 100uF decoupling caps in my iPod Photo 60G with 220uF. When I opened out the case, I think it may be possible to go for BG NX 220uF, though I heard sb commented it's already much improvement in using BG NX 100uF.