Hello! I'm in search of a replacement driver body for my beloved Etymotic ER4s - I really don't want to throw them out. They are an old model now, so I can't get the part from resellers. I've tried a message to Ety's service department directly, but no luck as yet. Does anyone have an old...

They're positive - the "negative" signs on the PCB are just hyphens...

Every now and again ;)   Unfortunately I lost all my files from back then (probably 2004 for the PCM2702) in a computer failure, so I don't have it anymore. Also my USB-S/PDIF board got lost then. No matter, they're very easy to design. The PCM2702 doesn't have audio in, so you'll have to go...

This is excellent :)

PM sent...

It's pretty much nonsense - the reasons the DDDac is popular are that it's easily available, doesn't cost too much, and is easy to build. The only thing that paralleling chips does is allow you to use a smaller I/V resistor as I is much greater now (V=I/R, so higher I allows smaller R for a...

Quote: Originally Posted by fran I've just bought the DDDac. Have a look at dddac.de. The guy there goes into some detail about stacking the TDA1543 chips to improve bit depth. 8 or 12 seems to be where the sensible limit is. I've had single TDA1543 DAC before, so this will be...

Having said there's nothing dangerous, just look at the power socket: totally uninsulated and he compounds it by running the mains line all the way across the bottom of the box to the front panel. I would start from scratch on this; it's amazing it even does anything apart from electrocute...

Quote: Originally Posted by java On the other hand, can the 192, handle having the ring left "floating" i.e. not connected to anything, is my "niggle" It would much rather be floating than shorted to ground as someone suggested above. FallenAngel's fix is the best.

Very nice job...

It's an inherently bad design - you might have to spend a little more, but it'll be worth it.

1) Yes, you would connect the shield to ground. 2) Yes, both of these just show one channel. 3) If you didn't know these two things, read a lot more before attempting to build these; 400V is more than enough to kill you.

Most commercial players use standard DAC chips (Burr-Brown, AD mainly) so a quick look through the datasheet will tell you. Unless it's a software setup chip, in which case you're going to have to get in touch with the technical department...

Actually it wouldn't be hard to do, but it would be quite hacky. You need something that will convert S/PDIF to I2S - that's easy, CS8416 (basically search for any DIY DAC design and it will be in there, or a similar chip). Run the I2S lines to the relevant pins on your Rotel - you'd have...

Quote: Originally Posted by lordearl the headphone amp circuit looks quite similar to this; Mini DACPre It's nothing like that, aside from using the same chip. That is single ended output, not balanced. The whole design is just application of datasheet circuits anyway. Nicely...