iTrip Amplifier

 

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DISCLAIMER: This tutorial is for educational purposes only and is against FCC rules.  Owning and.or using one of these devices may not be legal in your area, check your local laws before creating.  I am not responsible for anything you create from this tutorial.

 

I purchased an iTrip off eBay for $30 shipped.  I wasnt expecting it to work good due to the many negative reviews I have read about it.  I started off by pulling the antenna out of the case for a better signal.  It did increase the performance, but not enough.  I found this article and decided to make one.  First off, Radio Shack was only good for2 things, battery snaps and a battery.  I purchased everything from www.allelectronics.com.  The article linked above describes using a 12v car adapter, I wanted to make it portable so I am using one 9v battery.  I had a 12v 200mA AC-DC adapter, it fried 3 transistors so I dont recomend that. T Here is the part list for www.AllElectronics.com, but keep in mind that the resistors and transistors have small minimum amounts for purchasing 

 

Description< xml="true" prefix="o" namespace="" ns="urn:schemas-microsoft-com:office:office">

Part Number

Price

2n4401 Transistor

2n4401

$0.15

220 Ohm Resistor ½ watt

220-1/2

$0.05

10k Ohm Resistor ½ watt

10k-1/2

$0.05

0.001 uF Capacitor

RM-102

$0.05

10 uH Choke

CC-10

$0.33

Circuit Board

PC-1

$0.75

Antenna

ANT-31

$1.15

9v < xml="true" prefix="st1" namespace="" ns="urn:schemas-microsoft-com:office:smarttags">Battery Snap

BST-61

$1.00

 It all comes to a total of $6.65 plus $7.00 for shipping coming to a grand total of $13.65, there is a minimum piece number for most of the supplies but it is very reasonable(minimum of 10 resistors that are $0.05 each).  If you search the part number in the search bar it will bring up the parts, but some of them have more then one result so make sure you get the correct size. It say to use a 65-85 cm antenna in the schematic for the ampifier, but the 23 inch(58 1/2 cm) should be fine. 

 

Here is the schematic, taken from Ipodwizard.net:

 

It was a very simple circuit to complete and can be put on a very small board if needed.  I decided to put mine in an Altoids can.  I installed the antenna by drilling a hold and putting a screw through it holding the antenna in.  There is no nut for the antenna so I had to solder it down  and remove some casing with wire cutters and nibblers.  Be sure you insulate your case before putting the circuit in, no need for a short circuit.  Here are some pics:

I have never used a choke and didnt know anything about them, so I raised it off the board so it would disperse heat, but it doesnt even get warm.  I didnt mount the board to the case because I might make some changes to this.  I may end up putting another 9v battery in and wire it in parallel so I have double battery life.  As for range, it was good before and is much better now.  I was about 50 ft away from my stereo with has a 3 foot wire across the back of my entertainment stand as an antenna, and it would cut in and out and had a ton of static.  I hooked the aligator clip on the iTrip and it became crystal clear.  Hackaday has the original article for this mod, but it also has a comment section and has negative comments for this.  Its great for around the house, I find the station receiving the least signal and tune to that.  It cant take over a station, but can interfere with it.  I got some help from www.electronics-lab.com about improvements and added a .001uF capacitor between the positive and negative lines:

 "It keeps the power supply voltage steady so the transistor can work properly. Without the capacitor then the power supply voltage jumps up and down at 100MHz reducing the output of the antenna."

I added the second 9v by wiring them in parallel.  Here is a diagram for those who dont know what parallel or series is:

I added a switch in the case so I dont have to unplug anything when done using it.  And the last change is the board was cut in half .  I still need to mount the board which I will probaly end up hot gluing it in.

 

 

 

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