REVIEW: Head-direct.com HiFiMan EF2 tube Hybrid Amp with USB DAC - Page 67

What do you notice different about the EF2 vs an ipod with your HD600s?

I'm now using my EF2 with my own home made headphones, it works rather well with my homemade drivers!!

34ohms..

a very late great job H.A.-- i am very surprised about this one. do u still have this little guy in your line up? even more interesting is how its dac is comparable to the predator, thou i dont know how impressive that is, im curious do you know what dac is in the predator, maybe its a pcm 2702? i would really like to know what chip it uses, i may have to take it apart lol.

another good read, cheers

After spending 7 months with the EF2, I finally gave up on it.

This is what I heard and my opinion, and I hope this can be respected. I found that the EF2 sound was indistinguishable from my ipod and my computer with Sennheiser HD580 and Ultrasone HFI580. Additionally, my ipod and computer onboard sound provide more than adequate listening volumes. Even changing several different tube types (including mullard CV4010) I noticed no difference. I even added a different DAC for it (DAC Extasy with Wolfsen 8501) with no real change. Maybe this is not the case with other types of headphones, I don't know. But, after this long of listening and testing, It was clear to me that I no longer needed this unit.

Problems with my ef2

Alright. So I hardly post anything on any forum (this one including). It seems I have a problem with my new ef2a though. I received my unit on Monday last week and I initially liked the sound. I couldn't wait to burn it in. After burning it in for who knows how long I really started liking the sound coming out of my ef2. Very warm rich sound which was very pleasing to my ears(I'm very noobish). Here's the problem. I left out of town for two days, now I'm back and I can't stand the sound coming out of the ef2. It's making a lot more staticy background pops and it sounds almost as if its is only making my music only louder now.....no more clean warm sound = ( . I initially thought maybe It's because It needs to warm up. I listened to music for about hour and a half, still no improvement.

I'm using the build-in usb dac of the ef2 through foobar listening to various mp3's, wavs, and flacs. My headphone is an unmodded denon ah-2000. I want to get down to the bottom of this. Here's a recap of my problems with the ef2:

- Not as warm and detailed in sound.
- More noise in the background with more noticeable static hiccups.

I have thought maybe...

- It's the tubes since I was touching them a lot and I don't know much about tubes ( I'm using the stock tubes, getting some new ones soon though).

-a bad power supply?
- maybe I just need to burn it in more?

I have the volume turned all the way up on my computer, and the problem definitely is not a loudness problem. Any help will be very greatly appreciated. Hopefully my ears are just not working correctly and I wake up tomorrow with the same musical bliss that I had before .....

Mellorelishman while you are doing what Larry (HeadphoenAddict) suggested remove the tubes and re-seat them and make sure all the cables are fully inserted. Good luck.

Thanks for the responses! You people are truly dedicated to your hobbies here.... Any who, I had already tried what mrarroyo and HPA suggested before my post to no avail.... However, I let the amp burn in over night and now it sounds fine. The pops are pretty much non existent and the sound is much better. It's really amazing how this amp responds to burning in. I don't understand how some people do not believe in burn in.

I dunno what inspired my inpatients as I usually try a lot of things before posting. If i would have been patient this post would not have happened. My ef2 sounds wonderful again though . I really appreciate the suggestions though. As you can see I have been a part of this forum for a while, however, I really tend to read a lot of posts on forums without posting much myself. I do visit this forum often though.

Mine is making a nasty 60Hz hum that comes and goes.. Im shipping the power supply back tomorrow as it's original is dead and I believe my home made PSU is starting to fail.

my ef2a just arrived, its working well with my d5000. Everything seems clearer and punchier. Rock sounds a lot better

 

 

I had this issue a few years back with a computer and the problem was solved by going into the BIOS and upping the RAM voltage to the next highest step. It was something like bumping it from 2.6 to 2.8 volts.... never had the problem again. I haven't messed with an Apple computer lately though so I can't remember if you can get in and adjust those types of things. If you have more than one stick of RAM you could try taking one at a time out and seeing if problem clears up. If so, then replace that stick. Even just re-seating the ram and the cards might help.

Just got mine the other day. Nasty hum coming out of it, no matter where I plug it in, plug orientation. Varies in intensity with the volume knob when powered on. Does not need to be near other equipment, and doesn't even need the USB cable plugged in. Removed and re-inserted the tubes. Plugged it into a Monster power conditioner. Used different headphones. All to no avail. Sent message on eBay about possible return. No answer from them yet.

 

Are they good at replacing it? Or is there anything else I should do?

How many hours on it?  Maybe you need to just leave it on at zero volume for a little while, like 4 hour stints for a couple days.