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

[mrarroyo]

Today I received the NOS Sylvania 6AK5/5654 made in October of 1953. Straight out of the box I can say that the individual improvements are minor and many of us would have a hard time describing the differences. However the sum of the parts does make for an audible difference. IMO the overall presentation is clearer and more detailed while retaining the smoothness I liked so much. No, it has not turned into a hyper detailed unit. I will wait and report in 24 hours.

[mrarroyo]

Here are pics of the tubes I received.

[mplee79]

Hello. Read your wonderful review about the EF2 and am itching to purchase one. I had a few questions prior to hitting the order button:

1. Does the unit come with all cables like power adapter, USB line for my laptop

2. Any idea if the internal DAC will sound better than my iphone 3g line out?

3. Is the amp powerful enough to hook up to a set of high efficiency bookshelf speakers?

thanks

[FullTwisting]

Originally Posted by roker

I think that'd annoy me too much. I'd like my knob to be completely free. Things like that can be a deal breaker for me sometimes.

I know exactly where you are coming from. I was initially looking at a Travagans White, and it has a detent at each level (1-10). I've never used that amp, but my thought was that it likely would have drove me nuts.

However, there are a whole bunch of detents on the EF2 volume. That is what I meant to say when I said they were "very fine". The difference in volume between detents is just barely perceptible. You can put the knob between detents, it won't "suck" the knob to the next one. However, I have not yet had the need or urge to do so.

[FullTwisting]

Originally Posted by mrarroyo

Here are pics of the tubes I received.
<images snipped>

Hey, neat! I just received those exact same tubes. I'm still breaking in the stock setup, but I couldn't resist the urge to pick up some vintage tubes.

I also picked up some black plate GE JAN 5654W tubes from 1985.

It will be interesting to see if my novice ears can tell the difference between these 3 tube types.

[FullTwisting]

Originally Posted by mplee79

Hello. Read your wonderful review about the EF2 and am itching to purchase one. I had a few questions prior to hitting the order button:

1. Does the unit come with all cables like power adapter, USB line for my laptop

2. Any idea if the internal DAC will sound better than my iphone 3g line out?

3. Is the amp powerful enough to hook up to a set of high efficiency bookshelf speakers?

thanks

I can only answer one question with authority: The unit does come with a power adapter and USB cord.

The EF2 system sounds much better than my PC headphone out. This may not be saying much though, as the PC in question is rather old and is a low end model to boot. Sorry I can't comment on the EF2 vs. the iPhone out.

[mplee79]

Has anyone compared this unit to the Zero 24 bit/192khz dac/amp combo with USB? I know we're comparing apples and oranges with the zero being a solid state amp but many reviewers have stated that with the proper opamp choices, there is an inherent tube like sound to the unit.

It seems to me that the Zero is more versatile because it has a digital line in as well as rca output and can be used as a preamp if wanting to expand later to a full blown home theater or 2.1 channel listening station.

But like everyone else here, sound quality comes first

[mrarroyo]

Originally Posted by mplee79

Hello. Read your wonderful review about the EF2 and am itching to purchase one. I had a few questions prior to hitting the order button:

1. Does the unit come with all cables like power adapter, USB line for my laptop

2. Any idea if the internal DAC will sound better than my iphone 3g line out?

3. Is the amp powerful enough to hook up to a set of high efficiency bookshelf speakers?

thanks

Yes the unit comes with a wall wart power supply and USB cable. I have not opened up the EF2 to find out the type of dac chip so I can not answer your second question, howerver I can tell you that the iPhone can not be connected via USB to any dac. I would not use a headphone amp to drive speakers unless it was specifically designed for it. Something the EF2 does not seem to be designed for.

Originally Posted by FullTwisting

I know exactly where you are coming from. I was initially looking at a Travagans White, and it has a detent at each level (1-10). I've never used that amp, but my thought was that it likely would have drove me nuts.

However, there are a whole bunch of detents on the EF2 volume. That is what I meant to say when I said they were "very fine". The difference in volume between detents is just barely perceptible. You can put the knob between detents, it won't "suck" the knob to the next one. However, I have not yet had the need or urge to do so.

I agree there are plenty of indents and the volume difference between them is quite small so as not to be intrusive (IMO).

Originally Posted by FullTwisting

Hey, neat! I just received those exact same tubes. I'm still breaking in the stock setup, but I couldn't resist the urge to pick up some vintage tubes.

I also picked up some black plate GE JAN 5654W tubes from 1985.

It will be interesting to see if my novice ears can tell the difference between these 3 tube types.

Enjoy the experience and please post your results.

[HeadphoneAddict]

Originally Posted by mrarroyo

I have not opened up the EF2 to find out the type of dac chip so I can not answer your second question...

I mentioned in my review that it uses a Burr Brown Japan PCM2702E DAC, like the 3MOVE and XM5. I have not directly compared the USB DAC feeding the amp vs the iPhone 3G line out feeding the amp, but I suspect it will be close.

[koven]

Is it a good idea to hook these up to active/powered speakers? I have a 2.0 setup which I was thinking of using w/ the USB DAC. Will it be any improvement to the SQ if the speakers are self-powered/bi-amped?


Also, do you think Sennheiser or Denon would have better synergy w/ the EF2? I'm in the process of deciding between the HD580 and D2000..

thanks!

[HeadphoneAddict]

Originally Posted by koven

Is it a good idea to hook these up to active/powered speakers? I have a 2.0 setup which I was thinking of using w/ the USB DAC. Will it be any improvement to the SQ if the speakers are self-powered/bi-amped?


Also, do you think Sennheiser or Denon would have better synergy w/ the EF2? I'm in the process of deciding between the HD580 and D2000..

thanks!

You could feed the headphone out to the active speakers, to be able to use the DAC instead of the computer's line out. I don't think it would sound bad.

I reported that the EF2 works well with most headphones, and would not be able to predict which you would like more.

[roker]

Originally Posted by FullTwisting

I know exactly where you are coming from. I was initially looking at a Travagans White, and it has a detent at each level (1-10). I've never used that amp, but my thought was that it likely would have drove me nuts.

However, there are a whole bunch of detents on the EF2 volume. That is what I meant to say when I said they were "very fine". The difference in volume between detents is just barely perceptible. You can put the knob between detents, it won't "suck" the knob to the next one. However, I have not yet had the need or urge to do so.

I suppose that doesn't sound so bad, I don't want to get stuck nitpicking.

I keep reading how well the EF1 performs with low impedance cans. So I guess my question now is:

How does the EF2 compare to the EF1?

Should I just save up for an EF1 instead of buying an EF2? I don't really need the DAC either, so that's far from my deciding factor.

[Skylab]

Originally Posted by roker

How does the EF2 compare to the EF1?

Should I just save up for an EF1 instead of buying an EF2? I don't really need the DAC either, so that's far from my deciding factor.

I have not heard the EF2, but in general, if you don't need the DAC, I can't see how buying a $200 amp/DAC combo would make sense in that case, versus a $300 dedicated headphone amp. There simply have to be SOME compromises there.

And again, haven't heard the EF2, but in general I think there are better sounding 12AU7 tubes than 6AK5's. Food for thought.

[HeadphoneAddict]

Originally Posted by roker

I suppose that doesn't sound so bad, I don't want to get stuck nitpicking.

I keep reading how well the EF1 performs with low impedance cans. So I guess my question now is:

How does the EF2 compare to the EF1?

Should I just save up for an EF1 instead of buying an EF2? I don't really need the DAC either, so that's far from my deciding factor.

The two amps sound very similar.

The big advantage of the EF2 is the DAC and the very precise low volume channel balance for using it with IEM.

The big advantage of the EF1 is the higher power output and current available for hard-to-drive cans - the EF1 was able to drive a 4-8 ohm orthodynamic headphone like the RE5 at CanJam nicely and the EF2 can't, nor can the EF2 drive a K1000 to a moderate volume level.

[koven]

Originally Posted by HeadphoneAddict

You could feed the headphone out to the active speakers, to be able to use the DAC instead of the computer's line out. I don't think it would sound bad.

I reported that the EF2 works well with most headphones, and would not be able to predict which you would like more.

Thanks, I purchased a stock HD580 off a fellow head-fi'er... I will report how they sound with the EF2.