[normalwrong]

ic..
coz i heard like if imod doesnt hv resistor, it might possible ruin yr earphone..
then i got more quesiotns come out..

wt if a lod wif resistor work on a normal ipod? nth happens? or it will pull down the SQ?
if i wanna make a lod for ipod touch, i also need to put a resistor in rite?
thz guys

 

 

[FallenAngel]

Quote:

ic..
coz i heard like if imod doesnt hv resistor, it might possible ruin yr earphone..
then i got more quesiotns come out..

wt if a lod wif resistor work on a normal ipod? nth happens? or it will pull down the SQ?
if i wanna make a lod for ipod touch, i also need to put a resistor in rite?
thz guys

 

1) It hurts my head to try to read this kind of "writing", please look the following link for an explanation http://xkcd.com/481/
2) Read the 2 recommendations in my signature

 

[qusp]

i think you are confusing 2 different resistors. the one for touch/iphone is not in the signal path, it has zero effect on the sound quality. the other resistor is the other way around, its to buffer the dac from headphone load and cable capacitance, not the other way around and yes, please this is an english speaking forum

 

[joneeboi]

There are two resistors that are associated with the Wolfson DACs, one in series, one to ground after the capacitor. The one in series, let's call it R1, is to reduce the voltage spike from connecting and disconnecting cables since TRS (tip-ring-sleeve) is deeply involved in all the diyMod applications. R1 protects the Wolfson.
 
The second resistor, R2, is the one to ground after the diyMod capacitor. It discharges the capacitor so it doesn't build up charge. If you let it build up charge, it will discharge into your amp and possibly into your headphones. R2 protects your headphones.

 

[normalwrong]

Quote:

1) It hurts my head to try to read this kind of "writing", please look the following link for an explanation http://xkcd.com/481/
2) Read the 2 recommendations in my signature

Sorry about that coz im not native speaker..
im new here and not familiar wif the search function...
when i type in the key words its like pull up some post that is not related and like the 2007 post is listed at the front...

 

[normalwrong]

Quote:

There are two resistors that are associated with the Wolfson DACs, one in series, one to ground after the capacitor. The one in series, let's call it R1, is to reduce the voltage spike from connecting and disconnecting cables since TRS (tip-ring-sleeve) is deeply involved in all the diyMod applications. R1 protects the Wolfson.
 
The second resistor, R2, is the one to ground after the diyMod capacitor. It discharges the capacitor so it doesn't build up charge. If you let it build up charge, it will discharge into your amp and possibly into your headphones. R2 protects your headphones.

 

Ok...I think I am kinda get it..
what if I want to put the resistor inside the LOD?
because I saw some people is just put 1 resistor inside..
Is it supposed to be 2 then?

 

[normalwrong]

Quote:

i think you are confusing 2 different resistors. the one for touch/iphone is not in the signal path, it has zero effect on the sound quality. the other resistor is the other way around, its to buffer the dac from headphone load and cable capacitance, not the other way around and yes, please this is an english speaking forum

Thanks, I think I am really mess up between these..
Can any tell me whats wrong with my english?

 

[Halfie]

I managed to get the iMod done on one of my ipods. 47uF Elna silmic caps internally mounted on the opposite side to the battery cable, using 29AWG stranded silver cable. I covered any bare metal with Green Goo from Games Workshop (it's some kind of putty that dried rock solid) on the caps to make sure they don't short. The strangest thing I have found, though, is that the iPod will only accept the 80GB drive that I got with it, no longer my 240, any of my other 80's, or even the 30GB. Weird, huh? I've installed Rockbox and I haven't had a full chance to road test it, yet, as the screen is shattered from a biking accident. Just thought I'd let y'all know that the silmics are confirmed as usable for an internal mod.
 
A list of things I had to do to get it in there are as follows: Use a small file to create a tiny groove in the metal from the Wolfson to the back of the ipod, where I put the caps. One is hugging the bottom left of the ipod (opposite side of the battery slot), parallel with the bottom of the ipod, and the other is in the large "groove" where the back of the hard drive has some extra space. I cut a small indent out of the white plastic thingie that goes around the hard drive, Create another groove to lead the cables back out to the front again, soldered it (without removing the resistors) and snapped it all back together  
 
 

 

[Reima]

Well I finally did it, I now have the best of both worlds with my DiyImod! I have internal Blackgate for use with a regular Lod and direct output (without caps) for use with a special Lod. To achieve the direct output I used pins 14 and 17 for the left and right channels.26AWG SCACag was used to do all the internal wiring.
The photos of the frame shows the filing I had to do to be able to run the hookup wire.
As you can see from the photos I also have a 64GB compact flash installed.
RC
 
 

 

 

 

 

 

[joneeboi]

Very nice work, fellas.
 
normalwrong:
 
You can have four resistors, two per channel. For each channel, you have one resistor in series, then the coupling capacitor in series, then one resistor to ground.

 

[normalwrong]

How about if i just only put the resistor in LOD? 2 is the max?
what's the differences between 4 and 2??

 

[joneeboi]

It depends on which 2 you choose. Choosing the series resistors, you protect the Wolfson from current surges when you plug your LOD into and unplug it from the diyMod and the amplifier. Choosing the parallel resistors after the capacitor, you keep the capacitors from charging up and discharging a large amount of charge into your headphones when you plug the LOD into the amplifier. It's recommended that you implement all four resistors. It may not be the way I've recommended in the past, but in order to make the diyMod absolutely safe for your equipment, it must be done.

 

[qusp]

 
 
 
 


Quote:

There are two resistors that are associated with the Wolfson DACs, one in series, one to ground after the capacitor. The one in series, let's call it R1, is to reduce the voltage spike from connecting and disconnecting cables since TRS (tip-ring-sleeve) is deeply involved in all the diyMod applications. R1 protects the Wolfson.
 
The second resistor, R2, is the one to ground after the diyMod capacitor. It discharges the capacitor so it doesn't build up charge. If you let it build up charge, it will discharge into your amp and possibly into your headphones. R2 protects your headphones.

hmmm, yeah ok the ~60R (if i remember the value) in series imo is unecessary, why would you increase the output impedance of your diymod on purpose? I have never experienced any pop, but then good practice should be followed with all audio gear, headphones, nor source should be plugged in while already on if you want to fret about it. as for R2, this DC only builds up when you use it without anything connected, otherwise the pot will shunt it to ground, i also think you will find it pretty minimal if you use decent caps; (again the point of the mod) which should have low leakage and all it would take is to touch the minijack with your hand to discharge it if you worry over your amp not having any mechanism to get rid of dc at any point from input to the output to your headphones
 
not for me anyway, but john is right it is what the manufacturer would recommend in the datasheet, i just dont happen to believe they are important here to us.
 
if this mod was about being safe, people wouldnt do it, opening a perfectly useable ipod to modify it often with little or no electronics experience, is not the 'safe' thing to do; no this is about audio quality and i believe both of them are not in the best interest of audio quality, i always omit these resistors in any AC coupled build i do for home gear as well (or just R1 in DC coupled), i prefer not to worsen damping factor if i can avoid it and then just follow best practices, i havent had an issue yet and i'm dealing with higher voltage than here. next people will be asking whether they should spring for zfoils and the cost of the mod will double or triple
 

 

[qusp]

 
also R1 will form an Rc filter with whatever cap you use, so really you would have to change it depending on the cap
 
edit to add link: a first order high pass filter and if you have a cap at your amp'sinput,combined with your pot you will have an RCRC filter that possibly varies with the pot position depending on the type of pot

 

[joneeboi]

That type of advice is fine for experience modders, but there are many beginners walking in this thread, asking questions. Myself, I don't even listen to diyMods anymore. I almost exclusively listen to music in my car or with my iBuds, so I don't even use the diyMod much anymore. Nevertheless, if I were to do it myself, I wouldn't include any resistors. I'd remember to plug in the LOD before turning it on, but not everyone doing this mod even understands the implications behind some of these practices. Therefore, for simplicity, I recommend including the series resistors and shunt resistors for those who don't know any better.
 
In a sense, I'm covering myself for liability if someone should destroy their headphones by letting their diyMod capacitors charge up before plugging them into their DC-coupled amplifier with their headphones plugged in. It's a really remote possibility of that happening, but it's not impossible or unreasonable to expect to have that happen. Chances are I've probably done it myself a couple times at this point, and just because it does happen doesn't mean that the headphones are actually destroyed. Maybe it doesn't even phase it at all. Of course, everyone assumes all the risk when they take on a mod like this, but even still, I want to limit the damage done to people's equipment. There have been quite a few logic board-brickings documented in this thread by myself or others, and that's a costly and nerve-wrecking position to be in. Hence, that's why I don't recommend desoldering components anymore. Even though this is a mod, I'm trying to reduce the amount of risk for myself and for any participants.