If the question was about beyers, the 600 ohm version is usually the best - although the difference is not that big. So if you don't plan mobile use, get 600 ohms.   Joachim

  Please google odac may update and choose the first result. This leads to the designer's blog which I'm not allowed to link to - not sure if using his nick is ok again... we used to call him Voldemort for quite a time...   Joachim

  But a 3D printed case is still a bad idea since the metal case with the ground wire provides electrical shielding. So unless one can 3D print with a conductive material, it's not such a great idea.   Joachim

  Hi,   I would recommend to plug something into the input jack of O2 while using the RCA outs - this will break contact between O2 and the ODAC line out on the RCAs. Also I would unplug the RCA out (and the input jack) when using ODAC together with O2.   Having ODAC drive an unpowered...

Hi,   according to a german forum on braun hifi (there's more than shavers - at least there was in until the 80s) the KH 500 was built by AKG for braun. And Dieter Rams (the guy apple designers nicked all their good ideas from) didn't design those.   Joachim

  Hi,   DAC chip is not everything - actually most current ones are so good that you won't be able to tell 'em apart anyways. But you can easily ruin the sound of good chip in the analogue stage or by not following manufacturer app notes... and obviously they got that right. Got my Z30...

Hi,   so does the Z30... I got mine yesterday at work and put in a micro sd with some 24/196 flacs and have to say - wow, this sounds quite good on my eties... even from the stock player...   Joachim

Hi,   as long as the phones are high impedance (say 200 ohms or higher), most vintage amps will be fine. The point with low impedance headphones is that most vintage amps use the power amp with a resistor as a headphone out and the resistor gives this headphone out a pretty high output...

  O2 on low gain at 12 o clock is way louder than I can stand with my sextetts. The idea that it doesn't have enough power is kinda weird.   Joachim

  dscope... the audio analyzer brand is called dscope. The measurements published by the designer are mostly just labeled with the load (usually 15 and 150 ohms) and I think this was not actual headphones since some measurements probably would destroy them - THD vs Uout into clipping with your...

  The AC power supply for O2 contains an old fashioned transformer and thus is either for 110V or 220V. It has to be like this due to the way the O2 power supply works (two way rectifier) - DC switching power supplies don't care about input voltage but won't work with O2 or even break stuff.  ...

  This or a massive overvoltage... thunderstorm anybody? Although this probably would have fried a lot of other stuff too.   Joachim

Seing is believing... although one must wonder at what levels this guy listens... or he burning in sth?   Joachim

  Thanks for the explanation... I would do the math for a Class B output stage like this... Total power consumption is power supply voltage times current.   Pps = Vps * Ips   assuming a sine wave we get   Pps = Vps * 0.45 * Vrms / Rl   so with Vps=24V (both rails), Vrms=1.76V and Rl=35...

  I do this all the time since I had not drill until lately and so couldn't populate the ODAC 1/8" Line-Out socket yet. Of course you are double amping here but I have not heard a problem.   Joachim

  Hi,   care to explain this part, specifically why you subtract the 1.76Vrms from 12V to multiply by 50 mA? I would expect 1.76Vrms times 50mA or 0.09VA (this is apparent power usually expressed in VA instead of W). Probably take this times 2 for stereo.   Also the quiescent current can be...

  It's usually sold only by a few companies and even fewer have a showroom. So your best bet is to go to a meet or find some friendly head-fier with one in your area.   Joachim

 just fine.   Joachim

With ODAC/O2 100% should be fine with 0dB - and that's maximum digital out... unless you use hi gain on O2 but the 98% won't help...   Joachim

  The normal O2 ODAC combos won't have batteries since the ODAC goes where the batteries are. I have see some hack jobs of putting the ODAC under the O2 board...   RCA plugs usually don't have a switch unlike the 1/8" plug...   Joachim

  Hi,   if you plan to use ODAC and O2 always in combination and also on the go, 1x and 2.5x are your best bet. 2.5x is the highest gain which works with a high voltage source like ODAC (2V redbook) on batteries. If you are using it powered and with ODAC, 3.5 is the limit. If you use higher...

  Yes, the input jack from the O2 parts list has a switch and will either ground the input of the O2 when no plug is in (for O2 standalone) or connect ODAC to the input w/o plug (ODAC/O2 combo). You can get the instructions for this if you google for odac may update - we aren't allowed to post...

  Actually the original O2 & ODAC instructions wired the input jack exactly as you described - when you put sth in there, it overrides the ODAC as input. Some suppliers did change this though... If you can solder, it shouldn't be too difficult to hook it up according to the original...

  1) replacing electrolytics in old (like 20 years plus) gear is a good idea for several reasons:   - they do age - sometimes they just sound bad, sometimes you get smoke signals or a blown output stage.   - to properly measure them (capacity, ESR and isolation/leak current) you need a lot...

  The bizarre part from a non-US point of view is that you don't pay sales tax by ordering out-of-state (although it seems that in most cases you should declare every item bought out-of-state in your home state and pay a so-called use tax).   In most other countries sales tax or equivalent...