iPod Dock Pinout
Jan 28, 2006 at 5:08 PM Post #16 of 73
Quote:

Originally Posted by xluben
As for one cable for power and line out, what would be the purpose of this? It would have to split eventually? Why not just use two different cables? I plan on wiring up lineout, power(firewire), usb(syncing) and rca(video out) jacks into my dock.


xluben,

What I am envisioning is an amp with dock on top, with no additional wiring. The audio out pins of the connector would be internally wired into the amp. The amp itself would probably be AC powered, with a Tread inside the case. The iPod connector could be powered by the Tread (with appropriate voltage reduction of course- maybe a 3.3V or 5V regulator- whatever the iPod needs). Now you can put the amp on a table next to you and pop the iPod in, just like it works on some commercial powered speaker amps. The amp, of course, could also be battery powered (or dual ac-battery) rather than wall powered, eliminating that last wire.

My life is full of tangled messes of ac cords, line ins, line outs, etc., etc. This would be a sort of minimalist setup that is easy to use and completely self contained. Something I can pick up with one hand and take out to the patio without an armful of wires, warts, amps, iPods.....

I ordered a few each of the connectors Ridax is selling. I see where you are going by just using the universal dock plate adapter. I guess the connector will have to be glued firmly into place in the plate adapter. When I get the parts I think it will be clearer.

Regards,
Neil
 
Jan 28, 2006 at 5:18 PM Post #17 of 73
Sorry for not being clear. I'll try to paint a better picture here and I hope I'm not highjacking your thread.

I'm working on a Dynalo and I'm using a super regulator power supply in the Dynalo. I'd like to stick a +12V regulator in front of the +15V part of the power supply and run that to the iPod to give it a very clean +12V. I'd also like to take the line out from the iPod and feed it to the Dynalo. I don't want to dock the iPod right into the amp because that would make it awkward to change tracks- I want to be able to hold it in my hand.


Code:

Code: 
[left] ----- Wall Power --->| amp |------------------>iPod | | | |----------------->Phones -----[/left]

Running power in parallel with signal is usually a bad idea because any noise on the power line will make it into the signal via inductance (crosstalk). The pairs in cat-5 network cable have different rates of twist to prevent crosstalk, but they aren't designed with audio frequencies in mind and a cat-5 cable is a little thicker than what I'd want. I have loads of dead computer gear and I was hoping to find a cable that would isolate the power from the signal.
 
Jan 28, 2006 at 10:14 PM Post #18 of 73
Quote:

Originally Posted by NeilR
xluben,

What I am envisioning is an amp with dock on top, with no additional wiring. The audio out pins of the connector would be internally wired into the amp. The amp itself would probably be AC powered, with a Tread inside the case. The iPod connector could be powered by the Tread (with appropriate voltage reduction of course- maybe a 3.3V or 5V regulator- whatever the iPod needs). Now you can put the amp on a table next to you and pop the iPod in, just like it works on some commercial powered speaker amps. The amp, of course, could also be battery powered (or dual ac-battery) rather than wall powered, eliminating that last wire.

My life is full of tangled messes of ac cords, line ins, line outs, etc., etc. This would be a sort of minimalist setup that is easy to use and completely self contained. Something I can pick up with one hand and take out to the patio without an armful of wires, warts, amps, iPods.....

I ordered a few each of the connectors Ridax is selling. I see where you are going by just using the universal dock plate adapter. I guess the connector will have to be glued firmly into place in the plate adapter. When I get the parts I think it will be clearer.

Regards,
Neil


My comments were towards AtomBoy's setup. I think what you are evnisioning would be rather easy to do and would be a great setup for at home amped headphone listening. I don't think I'd want to amp my dock, because I'll be using the dock more for hooking up to my reciever to power my speakers.


Quote:

Originally Posted by AtomBoy
Sorry for not being clear. I'll try to paint a better picture here and I hope I'm not highjacking your thread.

I'm working on a Dynalo and I'm using a super regulator power supply in the Dynalo. I'd like to stick a +12V regulator in front of the +15V part of the power supply and run that to the iPod to give it a very clean +12V. I'd also like to take the line out from the iPod and feed it to the Dynalo. I don't want to dock the iPod right into the amp because that would make it awkward to change tracks- I want to be able to hold it in my hand.


Code:

Code: 
[left] ----- Wall Power --->| amp |------------------>iPod | | | |----------------->Phones -----[/left]

Running power in parallel with signal is usually a bad idea because any noise on the power line will make it into the signal via inductance (crosstalk). The pairs in cat-5 network cable have different rates of twist to prevent crosstalk, but they aren't designed with audio frequencies in mind and a cat-5 cable is a little thicker than what I'd want. I have loads of dead computer gear and I was hoping to find a cable that would isolate the power from the signal.


OK, I understand better now. The drawing helped a lot. I would have suggested Cat-5, but it seems like that won't work well enough. You'll just have to look for something with better shielding, or make something yourself.
 
Jan 29, 2006 at 3:11 PM Post #19 of 73
Quote:

Originally Posted by clarke68
Buy one of these instead.


Well, there is a better one.
A) it is slimmer
B) it has gold plated contacts
C) it is shielded

For those reasons I use it on the cables I build.

2006-01-2216-51-58_0022.jpg

2006-01-2216-28-12_0021.jpg


It can be bought via a guy here in Sweden but I know there was a guy selling the same in the US.

Just an idea.

Rgds Hans
 
Jan 31, 2006 at 7:16 AM Post #23 of 73
Quote:

Originally Posted by AtomBoy
Sorry for not being clear. I'll try to paint a better picture here and I hope I'm not highjacking your thread.

I'm working on a Dynalo and I'm using a super regulator power supply in the Dynalo. I'd like to stick a +12V regulator in front of the +15V part of the power supply and run that to the iPod to give it a very clean +12V. I'd also like to take the line out from the iPod and feed it to the Dynalo. I don't want to dock the iPod right into the amp because that would make it awkward to change tracks- I want to be able to hold it in my hand.


Code:

Code: 
[left] ----- Wall Power --->| amp |------------------>iPod | | | |----------------->Phones -----[/left]

Running power in parallel with signal is usually a bad idea because any noise on the power line will make it into the signal via inductance (crosstalk). The pairs in cat-5 network cable have different rates of twist to prevent crosstalk, but they aren't designed with audio frequencies in mind and a cat-5 cable is a little thicker than what I'd want. I have loads of dead computer gear and I was hoping to find a cable that would isolate the power from the signal.


I have two comments:

1. Remember that the iPod will internally regulate the +12V provided by the dock connector, so you don't need to over engineer the external +12V supply. Also, note that the iPod Nano (should you want to use one) won't work with the +12V Firewire supply, Apple removed Firewire support. My nano won't charge off Firewire, only USB. So you might want to aim for supplying 5V like the Apple iPod AC-DC converter.

2. I'd suggest using the Cat5 for audio and a separate shielded cable for power. I like Cat5 for audio. Whatever you choose, make sure the power cable is rated for at least 500mA. The internal regulators are designed to current limit the draw on the 5V USB to 100mA or 500mA while connected to a USB host, but they have the ability to ignore the current limits all together when no USB host is present (AC-DC wall charging/charging in powered dock).

Example, from the Video iPod:
(5 Volt input)
LTC4066 Linear USB Power Manager / Li-Ion Battery Charger
-Custom version of the LTC4055, added the disable current limit feature
-Current limits: 100mA, 500mA, None (draws as much as needed to charge the battery and run the iPod)
-Charges the battery and regulates battery/5V input for PMU

(12 Volt input)
LM34910 High Voltage step-down converter, I'm pretty sure this is for the FW power input
-Internal current limit: 1.25A, adjustable (down)
-Steps down to 5V internal bus

PMU (Power Management Unit)
Recently (Nano/Video) provided by Phillips
-5V internal bus input, multiple regulators for all other internal power domains
 
Jan 31, 2006 at 4:34 PM Post #24 of 73
BleckLord,

Thanks much for the tips. I wasn't aware that the Nano wouldn't use 12V. As for over engineering- I was just going to stick an LM317 in front of the already over engineered PS in my amp to drop the +15 to +12. From what you said, it looks like its worthwhile to make it +5V from a separate supply. It sounds like the iPod could just decide to pull enough juice to throw my +/- amp supply out of whack (which on a Dynalo means DC to the phones!)

As for the cable- It looks like one could buy S-Video cable where the lines are shielded from each other, but I knew if I tore up enough scrap computer gear I would find something.

Old Sun monitor cables have three shielded single cables and 5 twisted pairs (26awg?). I'm going to try using two lengths of the shielded for left and right line out and one or two lengths of the twisted pair for +V and power gnd. I've got enough of it to try a few different combos. I like it because its much more flexible than any of the cat-5 I have kicking around and I'm not convinced that twisted pair is better than braided shield for blocking solar flares, hard drives, and hair dryers.

(Oh, and BleckLord- welcome to Head-Fi- sorry for your wallet!
biggrin.gif
)
 
Feb 1, 2006 at 8:16 AM Post #25 of 73
you guys who have used the various dock connectors, do they lock on? if so is it easily disabled? id like to build my own desktop dock and wouldnt like to put the ipod in it and have it locked. im assuming ill be able to pull it apart to use only the connector portion and at the same time disable the locking mechanism.
 
Feb 6, 2006 at 12:32 AM Post #28 of 73
Well, Ridax* is the real thing- I got my connectors.

I knew the contacts would be small, but they are small. I mean realy realy small. They do pull out and push back into the body of the connector, so that's how I soldered most of them, but man those pins are small!

ipodcable.1.jpg


I used two shielded cables for left and right line out (the red and the blue) and the twisted pair going to a little +5v regulated suply on a bread board. Its about 5 feet long and I guess I need some Techflex.

Plugging it in the first time was a little nerve wracking. I was picturing my new toy going BANG, but it works fine. There's no hum and the little lightning bolt flashes to say its charging.

* See here http://ipodlinux.org/Dock_Connector for info on ordering.
 
Feb 6, 2006 at 3:55 AM Post #30 of 73
The stamps on the envelope from Ridax were in Kronor, so I can see how the shipping might take a while. I was surprised to get mine as soon as I did.

I might not be as clever as I thought. The sound comes through my cable fine, but it stops charging at random moments. I don't think its a loose connection, because it always tests fine and I don't think its a current thing because nothing gets hot. It will charge for a long time if I leave it alone. Its only when I've been using it that it stops charging- it seems like a software thing? I can wiggle the cable and its fine.

If I unplug and plug back in, it will start charging again after a minute or so.

Footnote (4) here http://ipodlinux.org/Dock_Connector mentions putting different resistors between pin 21 and GND to tell the iPod what its plugged into. I didn't do anything with this pin- I wonder if I shoulda?

I've got an iPod Video with the latest firmware.
 
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