This thread continues a side discussion started in:
So, I was out running errands, drove by Radio Shack and figured I would pick up the parts to make nikongod's micro-transformer impedance step-down box. $12USD and change later:
I went with the DE-luxe phone jacks, otherwise, I could have saved three bucks and gotten the cheap versions they stock and this could have been attempted for under $10USD. This is one of the simplest builds ever. No additional parts are required as the transformer wires are plenty long enough. Even the ends are tinned out of the box. Ten minutes later and we are in business:
So how does it sound? Not too bad. The micro-transformers are pretty much bandwidth limited (rated: 300-10,000Hz +/- 3db) and roll off on the top end pretty hard, but, hey, what can you expect from a $3 part this freaking small? The mids are very nice and the noise floor is contained. If you have bright phones, this will certainly tame the top end a bit.
But the comments on the sound miss the point. Through my Image 5's, I was able to pretty much max out an iPod touch in volume and still have PLENTY of output. At full, they were far louder than I would normally listen. All of this goes directly to nikongod's main point, most modern devices have PLENTY of gain inherent in their design. Using this technique you are able to have ZERO digital attenuation and ZERO analog attenuation and have an acceptable listening level (at least for most folks and most IEM's). The entire signal is allowed to come though unabated, nothing is thrown away prior to hitting the transformers. The source sees what it likes to see and the phones see what they like to see. The trade off made in voltage gain is distributed nicely to current gain and everything maintains a very nice level of control. Very cool. No wonder active unity gain buffers are so popular for all but the most demanding of headphones. You get the signature of the design without loosing any precious signal. Certainly a path I am going to explore a bit more. I might even pick up a couple of better transformers and see how far we can take this implementation.
Anyway, thanks to nikongod for the concept, execution and low-cost/high-return nature of the project. It was fun and quite informative. I have to wait until I finish my Altoids and then I will box this puppy up.