Head-Direct EF1

[HiFlight]

It has been some time now since I posted my initial impressions of this new hybrid amplifier from Head-Direct.

After considerable listening, and changing opamps to try to best match with the cleartop RCA tube, I have come to the conclusion that this is one of the best-sounding amps that I have owned.

I feel that the EF1 lacks the recognition that it clearly deserves, most likely due to the fact that Head-Direct is a small company that is often overlooked when shopping for a quality amp.

I finally selected my one remaining set of AD743 opamps for use in my EF1, and they sound absolutely stunning in all respects. I have paired the EF1 with all of my phones, and it performs equally well with each, driving them effortlessly regardless of the impedance or sensitivity of the phones.

Head-Direct graciously offers a 30 day refund if not happy, so there is no risk involved in auditioning this fine amp.

I don't wish to come across as a shill for Head-Direct, but I do like to give credit where due in this crowded segment of the audio marketplace, and in this case, the EF1 certainly deserves credit for its fine overall tonal accuracy, soundstage and sense of realism.

[mrarroyo]

Ron, I have to agree that the EF-1 is a very nice sounding amp. I am glad that the new version allows the owner to swap op-amps. That added flexibility will help taylor its sound to match the needs/wants of the user.

I personally do not see you being a shill for Head-Direct. They offer a very nice product, at an excellent price, great customer service, and a 30 day back policy. I do not see how you can go wrong.

We should get together. This past weekend I visited a friend who has been collecting tubes for well over 35 years (has over 10,000 tubes). Anyways he set up a couple of tube testers and out came a bunch of different 12AU7's. I came back w/ over 12 types, most military grade w/ high test results.

Besides I want to listen to your new AT cans and re-cabled RS-1. You may want to listen to the JVC HP-DX1000 w/ over 500 hours of burn in, they have totally changed from the 250 hour mark. Now the upper mids and highs can be heard over the bass. At this rate I may have to keep them.

[JohnnyLightOn]

Hey Ron, I'm looking for a bedside system for listening before I go to sleep. The EF1 is one of the amps I'm considering. As for phones, I think I would enjoy the HD650, but I'm concerned the open back design might disturb the wife and also that a full-size phone would be inconvenient for lying down.

What do you think of the EF1 with Yuin earbuds? If you know the PK line as well as the OK (and even if not), which do you think would be the best Yuin choice for progressive rock and electronic/psytrance when mated to the EF1? Thanks!

[idreaminhd]

I am very new to all this but after extensive research I believe this will be my first full-size amp. One question though....

Ive read that the Chinese tubes are not the way to go. On Head-Directs site for the EF1 they have "12AU7 RCA Cleartop NOS" listed as the tube. Is that from China or not and should I replace it? Thanks for any info.

[bjarnetv]

i have been itching to pull the trigger on this amp for some time, but i was hoping for some more reviews and impressions before buying.
maybe i´ll wait just a bit longer, for HeadphoneAddicts review

[iozz]

I have to agree. I've spent some time now with a review unit that I've finally bought, and it's a great amp for the price. It's mandatory to change the tube but with a RCA tube the EF1 sounds excellent, a little bright for my taste but very punchy and with a large soundstage.

Great amp!

[Skylab]

First of all I TOTALLY agree that the EF1 is a great amp and should get more recognition. Also, while I liked the sound with the RCA Clear-top, it's a little warmer sounding with a Tung-Sol grey-plate 12AU7 or a Mullard CV4003.

But in any case, wonderful amp that more people should try.

[mrarroyo]

Originally Posted by JohnnyLightOn

...What do you think of the EF1 with Yuin earbuds? If you know the PK line as well as the OK (and even if not), which do you think would be the best Yuin choice for progressive rock and electronic/psytrance when mated to the EF1? Thanks!

I have the Yuin PK1 and the OK1. Both sound great out of the EF1. I do not listen to the same style of music as you do so I can not comment. Good luck.

iozz, I know that like you most will say the Chinese tube is not good. Well, I actually love the sound of the Chinese tube in the EF1 and prefer it to some NOS US and German made tubes. Goes to show we all hear differently.

[HeadphoneAddict]

Originally Posted by mrarroyo

Ron, I have to agree that the EF-1 is a very nice sounding amp. I am glad that the new version allows the owner to swap op-amps. That added flexibility will help taylor its sound to match the needs/wants of the user.

I personally do not see you being a shill for Head-Direct. They offer a very nice product, at an excellent price, great customer service, and a 30 day back policy. I do not see how you can go wrong.

We should get together. This past weekend I visited a friend who has been collecting tubes for well over 35 years (has over 10,000 tubes). Anyways he set up a couple of tube testers and out came a bunch of different 12AU7's. I came back w/ over 12 types, most military grade w/ high test results.

Besides I want to listen to your new AT cans and re-cabled RS-1. You may want to listen to the JVC HP-DX1000 w/ over 500 hours of burn in, they have totally changed from the 250 hour mark. Now the upper mids and highs can be heard over the bass. At this rate I may have to keep them.

I would have loved to compare the NOVO to my EF-1 but the Novo has moved on to the next reviewer. However, from memory I'd say the NOVO was refreshing and clear like sparkling water, and the EF-1 is rich and sweet like chocolate syrup. Okay, well maybe I exaggerate a little maybe it's a mocha latte since it's not thick and slow.

[HeadphoneAddict]

Wow - this EF-1 has crazy synergy with my Denon D2000, like they were made for each other. While the Apogee mini-DAC HP out is technically very accurate and capable with these D2000, the EF-1 conveys better emotion. Sure it's not on the same level as my WA6 Maxed w/PDPS & Sophia or Single Power Square Wave XL, and it's soundstage isn't as big, but it sure is very enjoyable. (124 hours on the amp, 24 on the tube)

How many opamps does it use? Singles Right? I have 2 spare AD743 I could use, right?

[HiFlight]

Larry....
In order to use the AD743s, I had to use a 2>1 adapter as they are single-channel and the EF1 uses a dual channel socket. The adapter raises the top of the opamps slightly above the level of the top of the amp case, so I used 4 black faucet washers to raise the plexi top. You will, of course, have to use longer screws to affix the cover to the case. I found screws that matched the OEM threads at Home Depot. I think I got 3/4" long ones.

The AD743s sound better than anything else I tried. Guard them with your life, as the PDIPs are no longer made and the only case now available is the 16 lead one. There are no adapters available for that one.

I found some AD743s on Ebay, but they wanted $30 ea. Supply and demand, I guess. I made a couple of offers, but they went unanswered and timed out.

[HeadphoneAddict]

My first set of AD743 was used in my iBasso D1, then moved to my Travagans Red. I liked them so much that I paid $19.10 each for 2 of them from Farnell back in July, just so I'd have spares.

Part Num.  Qty.  Availability  Line Price  Description                               Mfr Part #  Mfr Name        
=========  ====  ============  ==========  ========================================  ==========  ==============  
9603689    2     In Stock      19.10       OP AMP, BIFET LOW NOISE, DIP8, 743; Ampl  AD743JNZ    ANALOG DEVICES

Maybe they have some left?

edit - nope they're out.

[HiFlight]

The AD743 has always been the opamp that I return to if the circuit and size allow for use of the 2>1 adapter.

I have an Amperex and Mullard tube enroute. I also am now using the JJECC82 which I find sounds a little better balanced throughout the frequency spectrum than the clear-top. It is not quite so bright.

I am really looking forward to the Amperex, as from all reports, it is a very good sounding tube.

[HeadphoneAddict]

I have 4 cryo'd russian clone mullard long plate 12AX7 on the way for my GES - if I really like them I might try one in the EF-1 and buy an extra for it.

EDIT - can the EF-1 use 12AX7 and 12BZ7, or does it have to be a 12AU7?

[HeadphoneAddict]

Review Link:

http://www.head-fi.org/forums/f5/rev...id-amp-375903/