SIK IMP: Two problems

[altreality]

Hello folks,

I recently bought the SIK IMP for my 40GB iPod and have two problems:

1. The line out overpowers my head unit's line in (Eclipse 8443) terribly. Sounds like using an iTrip with the volume turned way up. Just lots of distortion present. If I go out the headphone jack and turn down the volume on the iPod a bit it sounds fine, but I want to use the line out for smooth docking and I can't turn down the volume there. What gives? I thought a line-out was supposed to be a low, unamplified signal?

2. If the IMP is powering the iPod I can hear a horrible whining that changes with the rpms of the engine. Remove the power, letting the iPod run on it's battery, and this goes away.

Any thoughts? Perhaps an electronics expert here who can tell me "yeah, just put a 10k resistor here, a cap there, and you're set"?

Thank you for your time.

[Oogle]

What gives? I thought a line-out was supposed to be a low, unamplified signal?
Nope. The line-out is a high, unattenuated signal. The iPod's volume control doesn't amplify. It attenuates.

If the IMP is powering the iPod I can hear a horrible whining that changes with the rpms of the engine. Remove the power, letting the iPod run on it's battery, and this goes away.
Try using a ground loop isolator (http://www.radioshack.com/product.asp?catalog_name=CTLG&category_name=CTLG_002_001_019_008&product_id=270-054)

[altreality]

Thank you for your response.

Is there an easy way to attenuate the line-out signal, then? Perhaps an "in-line attenuator" of some sort that I can buy? Optionally, does the Belkin unit with the volume control attenuate the signal? Although I understand this degrades performance considerably, which I don't want to do, but right now the line-out on my iPod is useless with this head unit.

[Blue_Dawg]

you also might want to play around with the eq settings. I have heard that can make a difference.

[converge]

i have an Eclipse 3442 and had the same problem. there was huge distortion when using the sik imp, even when the head-unit was hardly turned up. i then bought the belkin and the distortion is no longer there. it's because the belkin's built-in amp also acts as an attenuator, as you guessed. sounds great now. i know someone else with an Eclipse and also had the same problem.

[MOCKBA]

I have unopened Belkin, so I could trade it for Sik Imp. However, I do not want to deal with sending it, so please be SFBA local.

[Gewinn]

I'm having a whine problem with my iPod and Imp, but's from the Pod itself when plugged into the charger. The whine is directly related to the harddrive's spin rate. When I unplug the charger or the HD stops spinning, no more whine.

Any clues on this?

[altreality]

Folks,

I gave up on the Imp. The whine wasn't the Imp's fault, but the straight line out simply wasn't compatible with my head unit. I bought a Belkin instead. Adjusted the volume properly and it's perfect. I wired up a new outlet on the same lines as the stereo and the whine is gone now, too.

Why does Belkin not publish the fact that their unit pauses the iPod when it loses power? The signal HAS to come from the Belkin, as no other adaptors do this. I had no idea what to expect as the threads here are mixed as to whether it actually pauses or not. Mine pauses perfectly every time power is removed. This alone makes it several times better than the Imp, in my opinion. Anyway, I called Belkin before I bought it and asked them about the pause feature. They said this unit has no such feature. Funny how it works even though it doesn't exist.

Gewinn, that's an odd problem. I've heard HD whine through the headphone jack especially when connected to an amplified source (and with my iTrip during periods of silence when switching tracks), but it I can't see a relationship with the charger. What sort of charger are you using, and how are you listening to the iPod?

[tanakasan]

Gewinn,

Ground loop Interference.

Try grounding the metal FW connector "outer shield" of the Imp to your common system ground point. Where the two FW cables come together. Otherwise you will need a GLI, works but slightly degrades the sound.

[Gewinn]

I'll try it. Thanks.

[Beefstuinit]

Originally posted by Gewinn
I'm having a whine problem with my iPod and Imp, but's from the Pod itself when plugged into the charger. The whine is directly related to the harddrive's spin rate. When I unplug the charger or the HD stops spinning, no more whine.

Any clues on this?

The alternator whine should be fixed by grounding the imp to the same location as the head unit or using a loop isolater. The hard drive whine MAY be fixed in the process, but it's likely an issue internal to the iPod.

[ov3n]

Originally posted by altreality
Folks,

I gave up on the Imp. The whine wasn't the Imp's fault, but the straight line out simply wasn't compatible with my head unit. I bought a Belkin instead. Adjusted the volume properly and it's perfect. I wired up a new outlet on the same lines as the stereo and the whine is gone now, too.


when using the imp, did you try using the ipod's bass redusing EQ to not overpower your headunits line in?

[tanakasan]

Originally posted by Beefstuinit
The alternator whine should be fixed by grounding the imp to the same location as the head unit or using a loop isolater. The hard drive whine MAY be fixed in the process, but it's likely an issue internal to the iPod.

The hard drive noise was also eliminated in *my* install by grounding the Imp. My interference was so bad that I could hear the charging icon on the sleep screen! As the display advanced to show charging, I could hear "tick, tick, tick" on my system.

[bzeb]

I know for sure that monster's charger with line-out has some primitive attenuator - this is the reason why I don't want to use it anymore, though I like design of their low-profile plug. Sik's din and imp don't alter signal anyhow (confirmed by their support). So if you need a pure line out go with Sik, otherwise Monster or even Belkin. I wonder if new PocketDock adapter has attenuation in their line-out.

[bzeb]

Originally posted by bzeb
I wonder if new PocketDock adapter has attenuation in their line-out.
I've got an answer - according to their support it has direct wiring. I'll get one - love the concept.