I've added In the water by Annie and the Beekeepers from mastersfromtheirday.com which is available as a free download so should be legit. http://www.mediafire.com/file/817pjd19w7hhja5/In-the-water.zip

I've done this before but unfortunately I can't remember what colour was what except gold is ground I think Have a look at this though http://www.anythingbutipod.com/forum/showthread.php?t=55510   Also I would cut open the old connector to have a look

Haha these are awesome, I love the ingenuity, keep it up.

Here it is     function hd(filename) l = 35; %length used in seconds [or,fs,N] = wavread(filename,[1 44.1e3*l]); %import first l seconds from wav hd2nd5p = or + 0.05*(2*or.^2 - 1); %adds 5% 2nd harmonic distortion hd3rd5p = or + 0.05*(4*or.^3 - 3*or); %adds 5% 3nd harmonic distortion...

Ok I'll do that but I'll post up my code soon once I've annotated it, it's not very complicated.

Yes I thought about that but as far as I can tell you can't have something that produces harmonic but not IM. I've thought about this experiment from the amp point of view. If and amp is linear you get no harmonic or IM distortion if its non-linear you get harmonic and IM distortion.

I'm pretty sure you want non-inverting for the higher input impedance but I could be wrong. In a unity gain buffer nothing "touches" the ground you wouldn't be able to have variable gain though, you could do some variable attenuation pre buffer.

Well I've got about 10 results now and they're fairly consistent so I'll tell you what I did. I have added 5% harmonic distortion in the different harmonics from 2nd to 5th plus there is the original. The general consensus so far in best to worst sounding is   original -> 3rd -> 2nd -> 5th...

You are absolutely correct about the separate input buffers. It is crucial to stop the cross talk related to a non zero source impedance don't know why I didn't think of it. In theory you actually only need the buffer on the ground channel inputs but it can't hurt on the others.

Lenni, I did it to the whole file. One of the files it the original by the way. Thanks I'll do that.

I've added another song, the first 35s of Evil Ways by Santana. Got 7 results so far and they're fairly consistent so I might reveal what I've done when we get to 10.

Thanks we're up to 5 now. Thankfully we're all fine at my place except the loss of a chimney and having to use a hole on our lawn as a toilet! Yeah they're great I was actually introduced to them from reading a beta22 review.

We've got three results so far. Keep 'em coming.

Here are the files   http://www.mediafire.com/?t8b6pocc40yxb   I've done something to the files that will shed light on to something that is mentioned a lot but I have never seen any evidence on. I'm not going to tell you what the differences are but it's not compression related or any...

AFAIK that wouldn't work, you could match the frequency response (and phase shift I think) but it wouldn't remove the distortion of the wallmart phones.

Ok yes that circuit is the one I was trying to describe in my last post. I'm not sure on what adding the resistor on + does but I wonder if putting one there corrects DC offset?   In theory it would be possible to hack a M^3 to do ABG, probably won't be too hard either. I'm pretty sure that...

OG should change with gain. OG = G*(IR + IL)/4, gain G.   I think what your are describing is an inverting opamp with a IL ground reference so   OL = IL -G*(IR-IL) where G= Rf/Rin. So you want G = 1/2 giving   OL = 3/2*IL - 1/2*IR so you would need   OG = -1/2*(IL+IR)   which...

Well that is interesting. Could you post a schematic of your current set up?

I think it would be worth bypassing the amp and plugging straight into the laptop to see if any of the crosstalk is caused by the the other components or have you already checked this?

Sounds interesting. That's quite a big output impedance does it colour the sound at all? What cans are you using? The resistors are between the opamp outputs and the headphone correct?

Yip those were the ones I was meaning. Ok that makes sense then. Looks like a good project I hope it goes well.

Yes in your current configuration the 7818 is redundant I believe. The lm317 will charge and power the circuit simultaneously.   The rest of the circuit looks fine although I don't know what all those caps on the feedback loop do.

Hi, I can't see the point in the first regulator other than spreading some of the heat dissipation for the 317. Also I'm not really sure how powering a circuit off a battery being charged by a constant current would perform. I think you need another diode to come from D1 to Vin to the rhs of D2...

No, I don't think so other than using a lower output impeadance opamp.   You're correct though that a non-zero output impedance on your ground channel adds crosstalk. Any amp with an active ground (ABG or ordinary active ground/3channel) has a non-zero output impeadance on ground but I don't...

Well you can just look at as the difference between IL and IG referenced to OG as ground. That's how I looked at it using the same wiki page but what I realized is that it is just a non-inverting summing circuit G*IL + OG.   Yeah it does get quite busy but a nice star ground for OG2 should...