[HiFlight]

Just 2 days ago, I received my 2nd EF1, this one a later production version with opamp sockets. There are no other changes that I am able to detect when comparing the amp to my first one.

Sound quality, imaging, and detail are all superb, surpassing even the highly regarded O1-DAC. The EF1 is dead silent with no input. No hum, no noise, nothing but blackness.

I am currently using the EF1 as my reference amp. I have to say I like it better than my Earmax Pro, which costs twice as much as the EF1.

I haven't yet swapped out the OP275, as it sounds so good with the RCA cleartop tube.

Be advised that if you damage the amp while rolling opamps, there will be a $100 service charge for repair. This is more than fair in exchange for responding to customer requests for sockets.

HiFlight

 

[mrarroyo]

Ron, do you know if the mods of the new EF-1 are backward compatible? If yes then I would be sending the EF-1 I have.

BTW, they were working on resolving the no sound w/ the volume pot is at zero. Was that corrected?

Thanks.

 

[Skylab]

That's good to hear! I like the EF1 a lot.

 

[HiFlight]

I don't think the installation of sockets can be installed as a retrofit due to the fact that the opamp is mounted on a secondary circuit board that is soldered to the main board with lots of connections. The opamp is only accessible from the top, which makes it about impossible to remove and replace with a socket.

One would have to ask Fang to be certain, but I think the socket is only available on the current production series.

I have changed the opamp and tried several of my mainstay high-end opamps, but found that several of them made no major improvement over the OP275, which is a very good device.

I did find that the OPA627 did improve the detail and soundstage, but that is a pricey mod, as it requires 2 OP627s to be mounted onto a 2>1 adapter.

The AD797 did not sound nearly as well as I had expected. The AD8599 sounded good, but I don't think I could reliably identify the 8599 over the 275.

I have not yet tried the LTC6241HV or ADA4841. I would expect both of them to work well, however I will likely keep the 627s in place for awhile.

With my RS1, I can hear a BARELY audible signal with the volume turned all the way down. If I don't listen carefully in a totally quiet environment, I don't notice it at all. The volume tracks both channels perfectly from minimum volume, so I can't see this being a problem at all.

With my very sensitive Kipsch Image IEMs, I can easily hear the input at a very low level with the volume control at minimum. Again, I can't imagine that this would have any practical significance.

I am using the RCA clear top that was supplied by Fang with the OP675. I haven't even tried the Chinese tube, as the RCA is one of the better sounding vintage tubes.

As mentioned before, as good as the O1-DAC sounds, the EF1 is way better. It truly brings out the best qualities of both my RS1s and DX-1000s.





Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif Ron, do you know if the mods of the new EF-1 are backward compatible? If yes then I would be sending the EF-1 I have. BTW, they were working on resolving the no sound w/ the volume pot is at zero. Was that corrected? Thanks.

 

[mrarroyo]

Quote:

... As mentioned before, as good as the O1-DAC sounds, the EF1 is way better. It truly brings out the best qualities of both my RS1s and DX-1000s...

Good that you found an amp you enjoy so much! I do not concur but so what, we hear differently. Not everyone likes chocolate! Some prefer vanilla, strawberry, etc.

 

[misterDX]

any more updates with opamp rolling?

 

[hertz]

Nice comment on opamps.