RandyP

I decided to use the Tape Hack to get quality sound from my iPod without waiting for a solution integrated with the Head Unit. When I turned it on, it was GREAT! Then I decided to get some power to the iPod - and the trouble began.

I saw a posting about the Monster Charger:

I happened to buy my tape unit from ectomort, so I read this and bought one. What a disaster!

I don't know what the difference is between ectomort's installation and mine, but I got sound so terrible that it hurt my ears. The audio was broken and distorted, and a high-pitched whine was produced whenever the engine got over 3500 RPM or so. I checked ectomort's post again, and yes, I'd bought the same unit he referred to. (Note - ectomort, why do you feel there is an inverter inside the Monster unit? I googled it but the only references to the unit and "inverter" are in your post.)

How bad is it? I made a 80-second sample of Joni Mitchell's "Both Sides Now", switching between internal iPod battery, the Monster, and the solution that works for me. iPod volume at 50%, earphone output to tape unit, Bose amp at 28. Click the link to hear for yourself: Audio Test
I have no idea why ectomort would have perfect audio with the Monster, but you can hear clearly that mine sucked. I was bummed, to say the least. I started searching for "noise" and came up with the suggestion to use a Radio Shack "Ground Loop Isolator".

I can't say I felt good putting a $15 piece of Radio Shack low-end audio equipment between my iPod and my ears. But I had read it about it a lot, both here and at iPodLounge, so I bought one and hooked it up. What a total disappointment, yet again! The thing absorbs nearly all the high frequencies and attenuates the whole signal. I made a recording of "Wildflowers" by Dolly Parton, Emmylou Harris and Linda Ronstadt, comparing the same passage with and without the GLI. iPod volume at 75%, earphone output to tape unit, Bose amp at 25; second half is with the GLI. I can't believe people would drop a few hundred for the quality of an iPod and then rub it into the mud with a GLI. You can see the loss in amplitude easily:



I felt like I'd have to wait for a digital solution to get good, powered audio from my iPod. Then I recalled a forum member who said an inverter followed by a power supply worked for him. I grabbed a Linksys Power2Go I had laying around the house, plugged in the standard Apple iPod Charger... and got the Holy Grail of Undistorted Audio!

How good is it? Listen to the Joni Mitchell clip to hear a direct comparison of the Monster and the Inverter/Apple solution.


I found a great place to install the inverter and iPod charger: the nearly useless CD compartment behind the cupholders. I've posted some DIY images to show how nicely it all fits.

RandyP

It's necessary to have a short AC cord between the Linksys and the iPod Charger. Here's a very safe way to make a short cord out of a long cord and some heat-shrink tubing.

RandyP

RandyP

RandyP

RandyP

The sliding cover slides forward without a problem. The audio signal wire runs through the center console into the tape unit for a clean, hidden installation. I still think I want the iPod mounted where I can see and control it easily, but I'm so happy to have the audio sounding good I'll probably just enjoy it for a couple weeks.

bobclevenger

Nicely done Randy. My experience has been that using an inverter like that works but creates some noise. Go figure! Just different equipment I guess. GLI's are useful, but not usually for cases like yours, yeah you lose some amplitude, but if it kills the noise I can live with that. The loss of high frequencies in intolerable, and probably due to the impedance mismatch between the 4 to 6 ohm headphone out to the 600 or 1000 ohm GLI input.
Bottom line is that you came up wit a solution that works!

RandyP

It surprised me, I have to say. The Linksys is a modified sine wave, not a pure sine wave. I wanted to give the arrangement a try with the Linksys before buying a pure sine inverter, but I ended up not needing it.

And I get to button up the center console!!!