HiFiMAN EF2 USB Headphone Amplifier is Available
Jul 5, 2009 at 6:15 PM Thread Starter Post #1 of 19

Nankai

Sponsor: HiFiMAN
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EF2 Order Link


Price 189 USD

Imput Impedence: 47k
Output Impedence: 32-300 Ohm
Output at 32 Ohm: 3 v, 320 mw
Output at 150 Ohm: 6.2 v, 256
Freqency: 20-20khz +-0.2db
S/N: 95db
DAC Chip: Burr-Brown PCM2702
Tube: China 6J1 * 2 pcs
Input Voltage: 16 v to 18 v; 500 mA
Power Supply: 110 v or 220 v

Defaut computer volume for EF2 USB DAC is 50%. Customer will have to maximize computer volume after connect EF2 as USB DAC.

Posts about EF2

http://www.head-fi.org/forums/5750592-post21.html
"EF2 was the best in show for anything below $200"

http://www.head-fi.org/forums/5803500-post853.html
"I would take the EF2 over the $350 NOVO with any headphone (similar to my EF1 findings), but I am not sure about the SRG - but then the SRG is also $700 vs $189"


Ship via EMS Express Mail with tracking. Will arrive in 5 to 7 business days.

30 days refund and 90 days replacement


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HiFiMAN Innovating the art of listening. Stay updated on HiFiMAN at their sponsor profile on Head-Fi.
 
http://hifiman.com
Jul 6, 2009 at 12:41 PM Post #4 of 19
Quote:

Originally Posted by oxophone /img/forum/go_quote.gif
Is it possible to get an EF-2 with a pair of different tube [raytheon, mullard, etc] pre-installed/rolled, instead of China 6J1? What will be the price?


We do not have raytheon tube. You can find these tubes at ebay.
 
HiFiMAN Innovating the art of listening. Stay updated on HiFiMAN at their sponsor profile on Head-Fi.
 
http://hifiman.com
Jul 7, 2009 at 12:40 AM Post #6 of 19
I'm guessing there is no dac-out?
 
Jul 7, 2009 at 6:56 PM Post #8 of 19
Quote:

Originally Posted by vkvedam /img/forum/go_quote.gif
Are the tubes replaceable?


I guess it's pretty obvious they are, otherwise you wouldn't be able to change them in case of a tube going bad...
 
Aug 7, 2009 at 7:17 PM Post #10 of 19
atsmile.gif
I had been waiting to purchase the EF2 since I heard it at CanJam 2009 in LA. I had been poking Fang ever since the show like a kid in the back seat of the car going on vacation (is it here yet? is it here yet?).

Well I finally got the amp in my hands on July 10th. It has been just under 30 days of daily use (today is August 7th). I have the amp hooked up to my workstation at work and I listen to music 8 - 12 hours a day and I can honestly say, I am very satisfied with the value of the EF2. My previous setup was a Creative Labs X-Fi Audio, analog out via Audio Quest Copperhead cables connected to a Project Head Box. Nice but detectable EMI and a serious loss of oomph in overall power of the music (home system is Project RM6 turntable, Semiko MMC Blue Oyster Special, Project Phone Tube Box, Rotel Pre and Amp, Quad 22Ls) and I always felt like my music at work was tinny, thin, and lacked that staging without tweaking the X-Fi crystallizer and CMSS settings which always flavored the music in many directions (at home everything is flat, pass through).

I really wanted to dump the internal sound card and go outboard and tubes. So that was my goal when I went to CanJam to find a hybrid or two piece capable of the DAC and Amp sound I wanted but within the family man's price range (I was hoping for $200 - $400 max). I spent a long time at Woo Audio being "woo'd" by the sound of nice tube amps in the $600 range but that would not solve my DAC concerns. I went to several other vendors enjoying some premium sounds but knowing that was a pleasure not an audition to buy. When I sat down at Fang's table, I listened to the EF-1 and was impressed with sound for value and told him it was nice, but it lacked the USB/DAC thing I was hoping to find. Well he pointed to the EF2 on the table and said "try this". I looked and saw USB input and two tubes poking out of the acrylic just like the EF-1 and I plugged in my Audio technica ATH-A700's I brought with me and I listened for 15 minutes.

I was very impressed with the sound sitting there at the table and I was ready to hear a $300 - $400 price tag and my jaw must have dropped when he told me they were shooting for a sub-$200 dollar price on this when produced. I grabbed his business card, shook his hand and left, confident I had found the solution to my thorn in my side.

Well, skip forward a month and here I sit today, having auditioned them now for nearly thirty days with all kinds of genres of music and several file types (mostly 160Kbs MP3's via Rhapsody, but occasionally I will listen to my FLAC collection and a concert DVD or two (Moby Live, Queen live, U2 in Boston, UMF 6, Depeche Mode, etc.).

I used my Audio technica's for the first 3 weeks and then this week a good friend of mine lent me his Denon AH-D2000's before leaving for vacation (he knows I love their tight, deep bass). I have the Denon's on now and they sound brilliant on the EF2. The bass is very deep, but tight and not booming. They lack the sweet mid-range of the ATH-A700's but when I am working I like the beats fast, tight and deep and I am not listening for the timber of the wood of the piano on Horowitz playing Tachovsky.

Oh yeah, I bought a CyroParts USB cable for $11 in case the USB cable furnished was run of the mill. Well I have the Cyro-Parts cable hooked up, but I could have easily used the cable supplied as it was of the same build quality) minus the extreme cold treatment) as the one I bought, so a note to you when you buy this, try the supplied cable first and then upgrade if you want more (I am ordering the step up Cyro-Parts $70 cable now).

All in all I am very happy with the upgrade in sound as I have already mentioned the bass and overall musicality of the system has improved, but the single most notable difference is the sound stage that I noticed when I first switched over to the EF2 (I keep the X-Fi Project setup next to it to compare time to time). The sound stage opened up, off of my ears and became instantly more pleasant and enjoyable without the hollowness that happens with you try to do this with signal manipulation.
My only peeve at this point is the sound output, although significant and powerful, is somewhat limited without bumping it up from the source a bit. I run most of my music with the knob in 12 o’clock or even 2 o’clock position most times and I worry about pushing near max values of the tube/OpAmp interface. If I drive the phones to 3 o’clock I can hear a bit of overdrive in the preamp and that is too be expected, and at that SPL I don’t listen long, it is usually a song I want to hear played loud and strong and then I dial it back a bit after that.
Perhaps a better power supply could fix that, or maybe I can play with the tubes and try other brands (although there seems to be limited info on alternatives to the China 6J1 tubes that were chosen). Don't get me wrong. This is a sub200 dollar all in one solution that sounds so good, I look forward to getting to work to listen to my music (and thank-you Eddie for the loaning of the Denon's). The Audio Technica's sounds very sweet and easy to listen to for hours while the Denon's wear you down a bit, but kind of in a good way as the assault on your ears is without the wrong kinds of distortions and it engages you to listen and enjoy).

In summary, I am grateful to Fang and Head Direct for filling a void in the hybrid market and doing it so well with parts chosen with purpose (I did not get into the TI OpAmp much but suffice to say, it is very good choice) and value in mind. The fact he put together a unit of this caliber at a price point of a DIY'er thrifty buyer amazes me. For the cost of an external Sound Blaster X-Fi he has something that sounds so much more musically enjoyable and I am going to enjoy my time at work for the foreseeable future. They made my life a little bit better.

And that's the God's honest truth!

DannyBuoy
 
Aug 27, 2009 at 7:39 PM Post #13 of 19
I would love to see a matching DAC for this unit something around the same price provided as an upgrade path.
I'm enjoying some Mccoy Tyner out of mine rigth now with a pair of K400's this setup gives a really nice sound with jazz but many seem to mention that the DAC is the weakest part of the combo, so it would be great to have a possible upgrade that matches in size and sound.
 
Nov 5, 2009 at 7:05 PM Post #14 of 19
Been using the EF2 daily for 4 months now and have recently rolled in JAN-GE 5654W tubes which appear to add a bit more bass and sharper treble and right now I like the change. I have it connected via Cryoparts USB and plugged in with ATH-A700's (Dynamat and baffled).
I waiting for the HE5/EF5 combo to come in now and I am going to invest into the next level of Head-Direct technology as the EF2 has proven itself to me. The EF2 sounds and works great, if you are thinking about getting it, you should do yourself a favor and do so.
 
Dec 27, 2009 at 10:24 PM Post #15 of 19
I can't imagine a switch mode power supply being good on tubes, let alone output AC current. All switch modes I see output DC. (as laptop power supplies are switch mode).

Good ol fasion transformer like the EF2 comes with is good enough, that is, if the problem with the PSU quality control was fixed. I'm still using my home-made 16v wallwart with a good transformer as my original PSU died in 2 days..
 

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