[4nradio]

I'm a relative newbie to portable audio, but have lurked on the fringes for years. My main passion is tuning long distance AM radio (DXing) from East Asia and the South Pacific, and I run an active blog for owners of a specialized SDR (software-defined radio) receiver called Perseus (made by Microtelecom in Italy).

Anyway, I thought I'd try my hand at building the simple "natural crossfeed" circuit described by Jan Meier, but condense the component layout so it would fit inside of a 1/8-inch stereo plug on a homebrew interconnect.

Three sample images are shown above. A slide show with other photos and description of this project is found in my posting on my SDR radio blog.

The crossfeed sounds great, although not quite as pronounced as the settings I used in a Rockboxed iPod Photo. For a first DIY portable audio project, I'm happy with how this turned out.

This short interconnect is used with a Biosciencegeek CMOY amp, iPod Touch, and HD-595 headphones.

 

[guzzler]

Very nice job...

 

[aloksatoor]

v nice idea

 

[FallenAngel]

Cute, but are you sure you want the signal passing through tantalum caps?

 

[4nradio]

FallenAngel,

I wanted a polypropylene cap of the right value, but the only cap in stock at Digi-Key was too large for this project. Small size was the most important criteria here. I didn't want to add another box between the source and the amp.

 

[LingLing1337]

Very cool stuff! Can you give more details, or maybe even a tutorial?

 

[ShinyFalcon]

Will polarity of the tantalum caps be an issue here?

 

[4nradio]

I used non-polarized caps for this project, so no problems with polarity.

For construction tips, I suggest making all leads as short as possible and allow the parts to support one another. You basically duplicate the schematic shown in the Jan Meier article, but rearrange the caps and resistors physically to keep the maximum dimensions to what will fit inside of the 1/8" plug's shell. Isolate any leads that might touch or short to ground by using heat shrink tubing or chunks of small diameter Teflon tube.

The caps seem large in comparision to the 1/8 watt, 1% metal film resistors. They caused most of the difficulty in construction due to their relatively large size. However, for anyone that has a steady hand and some prior soldering experience, it won't be too difficult to duplicate this, due to the low parts count.