REVIEW: Head-direct.com HiFiMan EF2 tube Hybrid Amp with USB DAC - Page 60

In terms of audio quality, how does a dac make music sound better compared to how does an amp makes it sound better?

I know the answer to this, but not "how" to answer it.. I'm afraid to even try cause it may come out all wrong.

A loaded question, but I'll take a stab at it.

The quality of the DAC determines the quality of the analog signal. The analog signal is recieved by the amp and increased in intensity by the amplifier and delivered to the output, either speaker or headphone. True audiophiles will tell you that if you can accomplish this task without changing any of the original audio signature then you have accomplished audio heaven. But as with many things head-Fi, what is considered enjoyable is as subjective as sweetness is to the tastebuds. The are many opinions about what is more important but every stage of the process is subjective and until you finally find the combination of gear that makes you happy, the search goes on. and as with anything in life, most of us can only explore within our budget.

Sorry if this is a bit off topic, but this IS an EF2, so maybe it belongs here.
So just the other day I noticed this white...stuff on top of one of the caps inside my ef2, but I'm not quite sure if it's coming FROM it or if it's just kind of there. I have yet to open up the amp because frankly, I'm just afraid of messing something up. Any idea what it is? :S

I would suspect that if there is any type of moisture in the air any minerals in that moisture may be accumulating atop the flat surfaces and visible once the water vapor evaporates. This is one of the reasons we used to go through so many TV's when I was a kid living at the beach with a high salt content in the air. It happens and is probably only notice more because of the plexiglass top the EF2 has and would not be seen with other closed top amps. If concerned, I would unplug the amp, remove the top and clean the area with an alchohol dipped Q-Tip.

Lol, that's not white stuff.

that's glue holding the voltage regulator against the case, securing the bolt

Mine has it too: http://img.photobucket.com/albums/v3...ragon/glue.jpg

So please, DON'T try and remove it.

A DAC is responsible for taking your digital input and converting it to analog output. A good DAC produces nicer analog output, and doesn't have as much electronic noise interference as an internal computer soundcard. Same principle as having a better CD player back before we used computers for these things.

It can definitely, definitely make a difference...a good DAC can completely change a pair of headphones (my SR225's are practically unlistenable without a good source).

My EF2 always seems to have a buzzing sound when plugged into the cable boxes audio output.

Hmm, ferrite core doesn't help it..

Thanks for some of these answers on dacs. What I am really wanting to get at is what would I expect to hear different if I hooked up something like a uDAC to the EF2 compared to the stock burr brown DAC?

Well, when I listen to different DACs, I listen to the high notes and see how bad the quantization of the sound is (i think that's the word).. Like, dithering for low color images, but for audio. For example, if I load my software synthesizer, and hit very high notes on a DAC, they sound distorted poorly, like screeching nails on a chalk board. A good DAC doesn't, and just tickles the ear with only a nice high sound.. (when i say high note, i mean, borderline of not audible to humans)..

What i "was" going to say, was a good DAC represents a waveform more accurately than a cheaper DAC.

For you Carl, I'd honestly not know how you'd tell.. Perhaps listen to a song with a sax and flute, and something deep like a cello, and hear how "well" they are presented?

(I mean, technically my MacPro has a better built in DAC than the EF2. My MacPro's DAC can do 24-bit 96KHz, and I've tested it to be fairly accurate, where the EF2 is only 16-bit 48KHz at max. I only use the EF2's DAC to not have ANY analog audio grounding problems, and since ALL of my music library is 16-bit 44KHz..)

I bit farther back in the thread is a link to Headphone Addict's review where he compares just that. The onboard DAC is minimal and many have opted to use external DACs into the EF2's analog input

http://www.head-fi.org/forums/f5/rev...ef-1-a-375903/

Oh, Carl, something you can do for test in addition to hearing how well different instruments are presented, listen for noise and just overall distortion.

I had tried out a DAC earlier that actually had bass presented in the mids, and very "choppy" sounding too.. Was unique.

SNR is up to the DAC.. So how much noise to actual sound. Like, I could make a WAV file that has ZERO sound, complete flatline, and force the DAC to be active and not idle, and see how much hiss it presents.. Good should be nothing, cheap will have some a little noise in the background. (I once had a DAC SO bad years ago, that moving the mouse cursor created a buzzing sound.. Funny)

Not only that, if I'm actually reading the THD and SNR correctly, my MacPro's DAC is vastly better.

Samplerate: 44,1 KHz, 48 KHz or 96 KHz
16bit, 24bit
SNR: More than 130dB
THD+N: Less than -130dB (0.00003%)

Has anyone tried using a USB switch for two computers with the EF2? I'm thinking about getting a second PC and am wondering if this might present any issues.

Ah, my Mullard tubes came into today. Yay.

I want to listen to them for a few weeks before I do any real comparisons. I'm guessing both the tubes and my ears need to do a bit of burning in.