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iPod Accessory Device

This is a small "Accessory Box." Its supposed to be used with my Apple iPod to convert the iPod output to differential as well as power the input stage of my GainClone, which can be switched to accept external power.

Here are the features of this little device:

Features

This is up and working, it really make a difference to connect this to the GC or BOSOZ (preamp or amp) rather than just using the standard adaptors.

For anyone wondering what parts were used, lets see if I can identify the key ones and some construction issues. The case is a Penn Fabrication "heat sink box" obtained online at partsexpress, note you have to buy the front and back panels separately. Its just big enough to fit the board, with the batteries installed I had to be careful about what to put on the top and bottom of the board to have it fit. The case has to be drilled and tapped to fit screws in order to fasten the front and rear panels to the case. Kind of a pain, also the end panels are steel, not aluminum. I used frontpanelexpress to label the rear panel and they could not etch the steel so had to recreate the panel in aluminum, which is why the rear panel looks a little different from the front panel. The rear RCA connectors are WBT, the XLR are Switchcraft. The illuminated on/off switch is a NKK TL series, which I bought online at Digikey (Mouser has these as well), this is a very expensive part but I liked the look. The miniplug 3-conductor recepacles are Digikey part No. CP-43502PM-ND, but should be available almost anywhere.

Click on Graphic For Zoom Click on Graphic For Zoom Description
Setup Angle 1
Setup Angle 2

Here is shown the iPod with the iPod Accessory Box. Also XLR cables leading out of the box and a miniplug to RCA cable for connecting the iPod to the box. Not shown are other cables for connecting the DC output of the box to the input stage of the Gainclone amp. The Kimber PBJ cable shown was modified. One end connects to a miniplug to fit the iPod.

Connected Angle 1
Connected Angle 2

This shows an iPod connected to the appropriate connections.

Rear View 1

Rear View Zoom
This is the rear view. Nice small little case. If you click on the "zoom" picture you will see that I made a capitalization error on the rear labeling. Sorry. The miniplug on the rear is to output +DC, -DC and ground to an external device. I hope I don't hook up headphones or an iPod to this someday, it would be very bad. The 9 pin connector provides signals for all inputs and outputs. Everything is in parallel so you should only connect to one input and output at a time

Front View With GainClone

Front View - Power On

This is the front view. As you see the on/off switch is an illuminated switch. Its a "TL" series from NKK switches. Also, you see a front miniplug connector. This is a stereo miniplug input. So This unit has two inputs, an RCA on the rear panel and a miniplug on the front panel. Also, the DIN-9 connector on the rear panel has pins for all inputs and outputs, as well as for all generated DC voltages and ground. So there are actually three inputs, though they are in parallel there can only be one connected input device at a time.

Partially Open

Fully Open

This is the rear view with the box open, you see the circ. board and the DRV134 chips. Also shown is a 2200 uF capacitor for the negative DC power supply rail. Another capacitor is on the underneath of the board for the positive rail.

Bottom of Board

Schematic

This is the bottom of the board and the schematic.

The DIN-9 connector is for removing the items on the front panel when taking the case apart. The front panel and its connectors can be independently removed from the circuit board. Also shown is a 2200 uF capacitor for the positive DC power supply rail.

The schematic is kind of rushed but mostly accurate, I think I used larger capacitors than depicted, maybe 50uF. I also had extra capacitors, the two large 2,200 uF capactitors you see in the pictures. These provide good energy storage, the unit can operate for a second or so after power is removed. Make sure you look at this full size or it will look kind strange and be hard to read. Note that for U1 and U2 (The DRV134 chips), the symbol on the schematic is not right, they only have one input not a + and - input. Its shown that way because the library in the drawing program that I used didn't have the matching schematic symbol.