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My DIY iMod V-cap "dock" Big pics.

post #1 of 41
9/22/07 at 6:05am
Thread Starter 
Well I thought it was time to share my "portable" V-cap dock with the world, in case someone is interested in doing it themselves.

I used OIMP V-caps, 250VDC 3.3uF. I wanted to have charging ability, RCA, mini and 1/4" outputs.

I used a hammond case, solid silver and and SPC internally.

It sounds awesome of course but I don't know how much of it is down to the new cans I'm using it with. I do have a modified ALO iMod dock too, but it's terminated wrong for me to compare them.

Here are some pics:



























Here is the charging imod dock I made from parts of one I bought from Vinnie, with the stock blackgates.








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post #2 of 41
9/22/07 at 6:37am
nice work. v nice! - hmm i am having to dble post this it didnt show,

is that hammond quite large or normal size?

i wish i had half of your DIY skills
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post #3 of 41
9/22/07 at 6:52am
Thread Starter 
Quote:
Originally Posted by Quaddy View Post
is that hammond quite large or normal size?
It's huge! 2 ipods would probably fit in there. I don't care though, if I want to travel with it, it will fit in the little case I keep my travel rig in, I can take it to work etc. Definitely not pocket friendly! The cable is long enough for my forthcoming Pico to fit between the case and the imod though, so maybe if I get a big enough bum-bag I can take it to gym...

Here's the enclosure, but black, obviously:

http://www.hammondmfg.com/jpeg/1455K1201B.jpg

http://www.hammondmfg.com/pdf/1455K1201.pdf

I could have fit everything in a smaller one but it would have been even harder and I don't mind the size.


The work on it wasn't perfect but I didn't care about looks as I wasn't even going to post pics. It will last forever and sounds great, that what matters to me. If I was selling them I would make it much neater and tidier. I would also charge about ten times what Ken is charging as there is so much work involved! Thanks for the compliments though.
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post #4 of 41
9/22/07 at 8:01am
Cool idea! I'm working with swt61 on an iMod dock with similar options. He's doing the woodwork and I'll be wiring it up. For his I'll be putting in a huge 1/8" Switchcraft jack and a USB jack for charging purposes. For mine I'll have RCA outs and the USB jack. He doesn't have an iMod but for mine I'm using a pair of Sonicaps. I found a site that sells PCBs soldered to docking connectors so it makes soldering various configurations a breeze.

Good job!! I love this kind of stuff!
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post #5 of 41
9/22/07 at 5:52pm
where are the caps connected to the ground and signal?

it looks as if the caps are actually part of the signal path, and not just in it.
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post #6 of 41
9/23/07 at 12:33am
Thread Starter 
Quote:
Originally Posted by LawnGnome View Post
where are the caps connected to the ground and signal?

it looks as if the caps are actually part of the signal path, and not just in it.
Yep that's right. L and R pass only through the caps. G just goes along some SPC, alongside the caps.
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post #7 of 41
9/23/07 at 1:38am
Quote:
Originally Posted by stevenkelby View Post
Yep that's right. L and R pass only through the caps. G just goes along some SPC, alongside the caps.
You do know that you don't use caps like that. You don't pass a electricity through a cap.

You have a cap connected to the line and then ground. 30$ capacitors and they aren't even used properly?
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post #8 of 41
9/23/07 at 1:58am
Thread Starter 
Quote:
Originally Posted by LawnGnome View Post
You do know that you don't use caps like that. You don't pass a electricity through a cap.

You have a cap connected to the line and then ground. 30$ capacitors and they aren't even used properly?
$55 caps thank you very much!

I thought that was how to use them? Seems to be working, how would I know? Sounds way better than the HP out.

Are they supposed to just cross over the signal and ground lines?

I asked about this a while ago and that's what I got.

I did post a pic of a high quality schematic I drew with the 2 options all those months ago:




Everyone said option 2 was the way to go. Could be wrong.




I'll look into it. If I'm wrong, thanks for educating me.
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post #9 of 41
9/23/07 at 2:42am
Thread Starter 
Well I hacked all the hot melt glue off Ken's dock and it's wired the same as above so are you saying ALO is wrong also?
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post #10 of 41
9/23/07 at 3:48am
Way 1 is the correct way.

Capacitors bridge between the power/signal line and ground.

They are not meant to actually have a signal/power passed through them.

I can't find any links right now, but I'm sure someone can explain it easier than I.
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post #11 of 41
9/23/07 at 5:11am
Thread Starter 
If they were connected in way 1, wouldn't any DC current just continue along the wire to the amp?

The way I understand it, in the imod, the capacitors are used only to block DC. Passing the signal through them, they allow the AC (signal) to pass, but the DC voltage will not be allowed through. I could be wrong though.

As they are in way 2, in an ALO imod dock, I measured about 1.7 V before the caps, and about 0.4 V after the caps. I don't know what that means though.

Any one else have any info on the right way to do it?
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post #12 of 41
9/23/07 at 6:31am
Quote:
Originally Posted by stevenkelby View Post
$55 caps thank you very much!

I thought that was how to use them? Seems to be working, how would I know? Sounds way better than the HP out.

Are they supposed to just cross over the signal and ground lines?

I asked about this a while ago and that's what I got.

I did post a pic of a high quality schematic I drew with the 2 options all those months ago:




Everyone said option 2 was the way to go. Could be wrong.




I'll look into it. If I'm wrong, thanks for educating me.
Way 2 is correct you are trying to block D.C. but not the audio signal. If you connected it way 1 you would be shorting the audio signal to ground & not likely get any sound at all. Pay no mind to Lawngnome. Capacitors are meant to pass audio signal & block D.C. in this scenerio. If used in a power situation they would be used way 1 but this signal passing not power. Way 1 could also be damaging to the output amps or DACs!!!
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post #13 of 41
9/23/07 at 6:47am
Thread Starter 
Quote:
Originally Posted by germanium View Post
Way 2 is correct you are trying to block D.C. but not the audio signal. If you connected it way 1 you would be shorting the audio signal to ground & not likely get any sound at all. Pay no mind to Lawngnome. Capacitors are meant to pass audio signal & block D.C. in this scenerio. If used in a power situation they would be used way 1 but this signal passing not power. Way 1 could also be damaging to the output amps or DACs!!!
Thank you for the input Germanium, some excellent advice there!
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post #14 of 41
9/23/07 at 6:58am

FYI and a question.

My AT amp, AT-HA5000, has DC off-set caps for one of its two sets of inputs and here is a simplified circuit sketch of its layout showing those caps in-line as option 2 above, please note the AC coupled noted just below the AT-HA5000 notation below:



Looking at it closely I am a bit confused by the two parallel items. One is clearly a cap, what is the other? It certainly is not straight wire.
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post #15 of 41
9/23/07 at 7:27am
Quote:
Originally Posted by slwiser View Post


Looking at it closely I am a bit confused by the two parallel items. One is clearly a cap, what is the other? It certainly is not straight wire.
These 2 components are both capacitors: 100uF electrolytics with a 47nF film cap bypassed. Take a closer look (may be twice) at the schematic and you will see that these capacitors are mounted in serie with the input signal .
BTW, from the audio viewpoint... ordinary electrolytic capacitor in the signal path is NOT DONE... .
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