Baby EROS - observations, questions & opinions.

[Henry2011]

My opinion:  The EROS is one of the great phono preamps.

I finished the build on my stock EROS Friday night.  I found the amp kit to be layed out very well with clear assembly and test instructions that worked.  I enjoyed just building the EROS and having everything check out OK. 

At first play I was a little concerned with low level hum (equal on both channels) and tube hiss (equal on both channels).  By the end of the first record both hum & hiss had diminished a detectable amount.  I am now at about 8 records (about 6 hrs of play time and 2 hrs of non-play time).  The hum has continued to diminish to the point that I have to listen for it between tracks at normal listening volume (normal for me - relatively high volume for most others) and I don't always detect it before the next track.  I assume the diminishing hum is a characteristic that is expected of the new components burning in (tubes, capacitors, transformer) and that it will eventually be effectively undetectable.  **Is that a reasonable assumption?  The tube hiss has diminished but not as much (it is currently at about the level of record surface noise between tracks - about 1/4 the original amount of hiss).  **Should I expect the tube hiss to continue to diminish?  As it is, I plan to accumulate about 100 hrs of play time before making changes to the EROS (if any).  For now, my listening experience improves with each record.

Already, I have experienced some of the strengths of this fine phono preamp.  Individual voices & instruments are more clearly defined spacially (located and foused in their specific place - instead of coming from their general area).  Cymbals, bells, and other such percussion instruments sound right from the strike through the decay.  Generally, I close my eyes and sense the musicians are playing from their specific individual locations in front of me.  Soundstage is accurate & excellent (proper width and depth - not artificially extended).  Sounds at the far edges of the soundstage have better focus and more correct harmonic balance than I have previously experienced.  Bass is very good and improving with time.  The individual performers remain in focus during complex musical passages (again better than I have previously experienced).  I also feel I am experiencing better dynamic range than I did from the V-LPS (or any other phono preamp section I have owned).

The EROS has a lot of gain (not a problem - just an observation).  With my previous phono preamp (Musical Fidelity V-LPS) I used about 65% of the volume potentiometer's range (SEX amp with ClarityCap ESAs and C4S).  With the EROS I use about 40% for the same volume output.

[Grainger49]

Ok, let's see.  First congratulations on a good build.  I'm not surprised that it worked right off the bat.  The vast majority of builds do.  I, too, am impressed with the logical layout  and the exceptional photographs in the Eros Manual.

Several of the official Bottleheads have stated that the cathode of the EF86 tubes needs to form, 40 hours is suggested.  And I would think that this is what you are hearing.  Hum can of course be from interconnects and ground loops as well but you have convinced me that the burn in is making the difference here.

Tube rush, the white noise you describe, is often a product of the tube.  If it persists to bother you after the first 40 hours I would expect you would want to do a little tube rolling.  The EF86 has the greatest impact on the sound but a noisy 6DJ8 could cause noise in both channels since it is the second stage for both channels.  What I tried to say was that having rush from both EF86s is less likely than having rush from one 6DJ8.  But you will want to try some other EF86s because of the impact on the sound that they have.

Here is a link to tube equivalents for the Eros:

http://www.bottlehead.com/smf/index.php/topic,1028.msg7556.html#msg7556

Enjoy!

[Henry2011]

Grainger,

Once again, thanks for the information and the link to the compatible tubes.  I like the strengths of the EROS.  For now, I intend to let it age as is (it seems to improve with every play).  I expect to have about 100 hrs of play time by the end of October.  Most components should be near their seasoned state by then.

Thanks,
Henry Moore

[Henry2011]

Update:  Replaced Electro-Harmonix EF86 tubes with Tung-Sol EF806 SG.  Replaced the Electro-Harmonix 6922 tube with a JAN-Sylvania 7308.  Tube hiss is gone at normal listening levels (and well above).  There is better spacial definition & focus.  Tone is richer (darker) in the midrange.  Bass had continued to improve since the last post but I noticed a significant step improvement following the tube change-out (I was wowed it).  The EROS keeps getting better every day.  I still have a little hum at normal listening levels that I can sometimes hear between tracks.  I'll go looking for it on my next long break.

Henry Moore