dsavitsk

Happy Birthday!

I have a working II+. I pull it out every few years to play Microsoft Olympic Decathlon.

Colin's IV (which is a common base topology) is a good alternative for a current out DAC. It is similar to Jocko's circuit, or Nelson Pass', and it can be made differential without too much trouble. For a voltage out DAC, a simple emitter or source follower works great as a buffer. Even a diamond buffer is a good alternative, and it can be made DC couple-able with the help of a servo (unlike some off the shelf diamond buffers.) Or any of Pass' recent buffers are good options. There is this myth of tubes as being pleasant sounding, and tooby. The reality is that tubes are very linear amplifiers with excellent bandwidth, and the bulk of the added distortion and limited bandwidth attributed to them has to do with the topologies and the surrounding components used. Similarly, the myth of DAC digital glare probably has more to do with the opamps used in the IV than the DAC chips themselves.

I wouldn't. A good switcher is no noisier than a rectifier, and it is generally easier to filter. There are other alternatives to opamps than tubes. The point is that there isn't a proper way to do it as it is the wrong tool for the job. An 8741, for instance, has more drive ability than just about any small signal tube and way less noise and a lower impedance than a power tube. Even the super high gm tubes pale in comparison to a $0.03 transistor, and they are unstable and difficult to use. Edit: The exception to this might be if you need gain. But voltage out DACs typically don't.

The DAC chip they use is $5 at Digikey. What am I missing? This just looks awful:

---------^ That. Tubes are excellent as voltage amplifiers, but they are high impedance devices. For a medium amount of gain, they are about the most linear option available. But a DAC doesn't need the gain, and the impedance is a hindrance.

Tom's house? I stayed at the Intercontinental - room service had good soup.

Pre emphasis correction in dac hardware is trivial. The CS8412 receiver, for instance, has a pin that goes low when it detects pre emphasis, and the PCM1794 DAC requires setting one pin high for pre emphasis conversion. So it is usually just connecting one pin to another, or as above doing so via an inverter or something. That said, I have never seen a pre emphasis track in my life, so I have never even bothered to do that much. But most commercial gear probably still will.

Not sure if this applies to your situation, but when we were considering HE boilers versus older ones, we found that the expected life (and the warranty) of the HE unit was about half as long (10 vs 20 years), and was just long enough such that just as it paid for itself, it was likely going to need replacement. Meaning that over time it would cost 2x as much and, in an effort to move from 90% to 95% efficiency, it would result in an extra boiler being dumped in a landfill.

Silly me, this is what I thought dockercon was ...

I think the issue is two fold - for most phones, the resonance is considerably less pronounced and thus has less of an influence. And for Sennheisers, a little bit of impedance actually helps them sound more balanced. Indeed, my personal favorite way to drive Senns is with pentodes using the impedance as the translated load, thus giving the circuit a tad more gain in the bass and midbass. YMMV.

It sure is. That's what you get for looking at graphs at 3am. The broader point stands. however. I'll defer to your knowledge of the inner workings of orthodynamic drivers. My point was really about the Focals and at least one reason why, unlike some other headphones, they do not perform well when mated with an amplifier with a high output impedance. My experience says that up to about 5 Ohms is OK, but any higher is not ideal.

LCD2's have an impedance of around 30 Ohms at all frequencies. Utopias have a nominal impedance of about 80 Ohms, but it is not constant and peaks to over 300 Ohms at 50Hz. So think of it this way, the output impedance of the amp forms a voltage divider with the load impedance. Assume you have a 20 to 20K sweep signal of 1V. If your amp has an output impedance of 0 Ohms, 100% of the signal goes into the headphones, so both the LCDs and the Focals will have 1V at all frequencies. Now assume your amp has an impedance of 20 Ohms. The LCDs will have a 0.6V signal at all frequencies (with the other 0.4V lost across the output). The Focals, however, will have 0.8V at most frequencies. But at 50Hz they'll have 0.94V. At 100Hz they'll have something like 0.91V. In the case of Focals, this makes them sound bloated.

Happy Birthday!

How dare we let little things like health, safety, and the environment get in the way of Toshiba's profits.

It isn't pop versus non pop. It is goofy versus non goofy. Emphasis is on the weirdos part. I miss the Supernature days.

I miss the days when they were art school weirdos.

doğum günün kutlu olsun

Thanks everyone. I am currently visiting my parents to celebrate their 50th wedding anniversary.

Fwiw, I completely agree with you on Win 8 v 7. I genuinely like 7, liked XP (and 2000, and NT), and find 8 more or less unusable. I had to set up a Windows domain on a Server 2012 (the server version of Win8) and it was a truly terrible experience. I never did get used to it. I just got a new laptop with 10 on it, and I decided to give it a try before reverting it back to 7. My experience so far is that by toning it down and turning off some bells and whistles, it feels a lot like 7. Everything is comfortable thus far. I also set up a Surface Pro with 10 for my dad over Xmas, and I found the tablet stuff to be fine. But, this is coming from someone who has no real apple experience (last time I really used an apple was probably System 6), so I can't compare it.

Not an Apple product, but what about a Yoga that can work as a laptop with a supported screen, or as a tablet to split the difference?

Happy Birthday!

This finally came to Hartford this weekend. It is excellent. The cats are delightful, the people are awesome, the city is lovely.

I believe that's how I won in 2014. Here's what this year's winning bracket looks like.