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Posts by wakibaki

OK, thanks. I had no idea that I2S has that wasted bit, and I thought it was 24-bit. Actually I thought it was capable of running with only 16 bits when that was all that was being used. w 1000 posts!
Could you explain the operation of the circuit please Avro_Arrow? What is the format of the data? I'm kind of expecting 16 bits*2, which, yes would give 4 shift registers, but they would be paired into 16-bit outputs, each with it's own resistor network. Stereo DAC. Fred
The earpads. I couldn't find them in my purchase history. I think these are identical:-http://www.ebay.co.uk/myb/SavedSellers?ssPageName=STRK:ME:LNLK:MEFSX&_trksid=p3984.m2034.l3390 They look like what I remember, lots of detail in the advert, which is why I went with them. Pleather might give a better seal, but that's just a detail. I do have some stainless steel wire gauze, but I've got the PCB stators cut already, I don't want to get sidetracked into experimenting...
I'm sorry, ab initio, the dB does indeed inspire considerable confusion, but your explanation has not improved matters, and it's completely wrong in places. dBA has nothing to do with amplitude, the A means 'A-weighted', and is based on the 40-phon Fletcher–Munson equal-loudness contour. The measurement is integrated across the audio band, with different frequencies contributing greater or lesser amounts to the total depending on the sensitivity of the human ear at those...
  Still trying to put a pair of phones together. I just have to spray the stators with insulation, stretch and glue the diaphragms, dismantle and rebuild everything with moisture membranes and the cable in place.   I went with this very simple adjustable headpiece, it's a bit heavy, needs some bits slimmed down, but it's at least functional for a first experiment. The headband is velcro, the earpads velour from ebay.   Of course I still need to build some kind of...
The B22 is very highly thought of, but can be a very expensive build. You will probably not find anything that performs significantly better at any price, however the O2 is widely regarded as transparent, and is probably indistinguishable from the B22 with the very large majority of 'phones, and costs a lot less. w
In a single-ended battery driven circuit ground is best located at the battery negative terminal. A simple strategy that is often effective is to wire each grounded point in the circuit back to the battery negative with individual wires. w
OK, I misunderstood about Vcc-. The opamp will not work with either of it's power pins unconnected. If you are using a single rail (one 9V battery), both Vcc- and the battery negative must be connected to ground. If connecting them causes the output to disappear, then there is a serious problem elsewhere in your circuit. bootdsc's comments are well taken, it's not really accurate to claim that the circuit is working. w
Here's a good source of information on electrets and powering them:-http://sound.westhost.com/project93.htm It's very difficult to diagnose your circuit in the absence of a diagram. The opamp Vcc would normally be connected to the positive supply, but if you don't know this, you don't know much, so be prepared to destroy a few components. Don't connect anything of value, such as expensive headphones, to the output, and look for a DC offset at the output with a meter...
Excellent, thank you, no, that will do.   I was pretty convinced anyway, but that provides quite a lot of substantiation.   You are a mine of information, it's just that getting at it can be like pulling teeth.   w
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