[Neogeo333]

Any update with April Music BrainFood?

 

[BrainFood]

Nada, so far...

 

[Neogeo333]

This also happened to me when i ask Simon on the spec of the amp section.  I just hope i made a right decision when i pulled the trigger on the DP-1.  But then again I always said this is a DAC with a bonus amp. 

 

[sanne]

I had this unit briefly.
 
The DAC section is nothing short of phenomenal.  
 
Completely underwhelmed by the headphone amp though, although my unit had occasional distortion problems with the volume dial set anywhere close to the halfway mark.  I ended up returning it instead of going through the hassle of getting it replaced.  I did not feel that it was powering my AKG K702's their fullest potential.

 

[BrainFood]

Quote:

 
Completely underwhelmed by the headphone amp though, 

 

[K_19]

Quote:

I had this unit briefly.
 
The DAC section is nothing short of phenomenal.  
 
Completely underwhelmed by the headphone amp though, although my unit had occasional distortion problems with the volume dial set anywhere close to the halfway mark.  I ended up returning it instead of going through the hassle of getting it replaced.  I did not feel that it was powering my AKG K702's their fullest potential.

I currently have the HP100 that was formerly yours. How do you find the DP1 headphone amp section compares to the HP100, roughly from memory?

 

[AppleheadMay]

Quote:

I had this unit briefly.
 
The DAC section is nothing short of phenomenal.  
 
Completely underwhelmed by the headphone amp though, although my unit had occasional distortion problems with the volume dial set anywhere close to the halfway mark.  I ended up returning it instead of going through the hassle of getting it replaced.  I did not feel that it was powering my AKG K702's their fullest potential.

 
I can't say I share the same opinion.
Before I sold the K701 I used it to test everything new that came in because of the K701's neutrality. Now I do that with the HD800.
I extensively used the K701 with the Eximus.
Now the K701 needs power to sound right and the Eximus HP section has that in spades.
I surely never had any distortion on the K701 (nor do I have it on the HD800), not even at halfway open.
I can't try it much louder because halfway open is pretty damn loud I must say.
 
So because of the distortion and the lack of power you experienced, I guess something was wrong with your unit.

 

[internethandle]

Hm, I'm looking for a vibration/resonance control solution on the cheap and these moongels sound pretty interesting. The only issue I can see though is that they're adhesive/sticky, which makes me slightly uncomfortable re: placing them under or on expensive-ish hifi gear. Are there any non-adhesive versions available to your knowledge, or do you have any experience with how sticky they actually are (do they leave residue when unattached, e.g.)?
 
Quote:

The Eximus beats the Lyr in the headphone amp on LCD2's, you will find that out when you get yours. I have tried them both.
 
One quick update on the gel pads if anyone is curious. I sent a set to a friend of mine and he brought out the moongel drum damper pads to compare. He hears that the moongels are slightly  better. Good news, you can buy these on Ebay for $6.99 shipped for a set of four. Those will work under the Eximus DP1. If you are using headphones only, I am not sure if you need them, probably not.
 
I have now found a new killer amp for speakers for $500, it beats any tube amp under $3K. PM me if interested.

 


 

 

 

[Neogeo333]

6.99 is a cheap way to tweak/play around.  Maybe you can wrap it with some sort of plastic film like those used to cover leftovers.  I ordered some on ebay and I still dont have my DP-1.

 

[sanne]

I am assuming that the headphone amp portion of my unit was simply defective.  I did not feel it compared well at all to my previous HP100, but this could very well be because the unit itself was damaged.  I can vouch for the DAC section of this unit, particularly the USB input.  It is truly top notch in every way.
 
Quote:

 
I can't say I share the same opinion.
Before I sold the K701 I used it to test everything new that came in because of the K701's neutrality. Now I do that with the HD800.
I extensively used the K701 with the Eximus.
Now the K701 needs power to sound right and the Eximus HP section has that in spades.
I surely never had any distortion on the K701 (nor do I have it on the HD800), not even at halfway open.
I can't try it much louder because halfway open is pretty damn loud I must say.
 
So because of the distortion and the lack of power you experienced, I guess something was wrong with your unit.

 

 

[BrainFood]

Quote:

 
but no one's concerned that the Eximus' "discrete component headphone amp" claim is either a outright lie or a "misunderstanding" by a copy writer?
 

 
 
Just been digging a bit further and I cannot see anywhere where it says  'discrete component headphone amp' in the six moons review.  Where does it actually say this, Jcx?
 
It says 'discrete component headphone drive module' in pic below, but that in itself is not incorrect, is it?
 


 
The manual says 'the PCB has discrete circuitry for digital and analogue' but that is not incorrect as such.
 
 
http://www.6moons.com/audioreviews/aprilmusic8/1.html

 

[BrainFood]

Heard back from April Music.   The 'discrete' reference in the review was meant for the 'A3 module'.  They apologise for any confusion if this was not clear.
 
Dac output buffers are two separate OPA627s, fully discrete A3 module (unity-gain buffer, custom designed by April Music) buffer.  They used OPA627's rather than discrete circuits after much listening and measuring.   In all, there are three stages of output buffer
 
For the headamp out, they use TPA6120 and two additional buffer stages.
 
There are additional facets to the design but this cannot be disclosed for reasons of confidentiality.   The DP-1 took almost seven years to realise.

 

[AppleheadMay]

Quote:

Heard back from April Music.   The 'discrete' reference in the review was meant for the 'A3 module'.  They apologise for any confusion (also to Mr Ebaen) if this was not clear.
 
Dac output buffers are two separate OPA627s, fully discrete A3 module (unity-gain buffer, custom designed by April Music) buffer.  They used OPA627's rather than discrete circuits after much listening and measuring.   In all, there are three stages of output buffer
 
For the headamp out, they use TPA6120 and two additional buffer stages.
 
There are additional facets to the design but this cannot be disclosed for reasons of confidentiality.   The DP-1 took almost seven years to realise.

So what does all of this mean for the rest of us who don't know anything about those chip numbers, opamps or buffers?
Good stuff? Quality parts?
 
 

 

[BrainFood]

 
Quote:

So what does all of this mean for the rest of us who don't know anything about those chip numbers, opamps or buffers?
Good stuff? Quality parts?
 

 
 
I'm not qualified to say, so maybe someone else can chime in.  It was jcx who started this all off 

.
 
Perhaps he was making a meal of things because nowhere in the 6 moons review did it say 'Discrete component headphone amp.  The only inaccuracy, afaict, is the remark on page 2 by Simon Lee "the output stage is of course fully discrete" but I guess that could have been a typing screw up.
 
 
Quote:

but no one's concerned that the Eximus' "discrete component headphone amp" claim is either a outright lie .....?

 

 

[jcx]

The OPA627 is highly respected as an audio op amp, one of the lowest input noise for a fet input op amp, best input impedance nonlinearity in Samuel Groner's measurements http://www.sg-acoustics.ch/analogue_audio/ic_opamps/index.html
 
while older the 627 DiFet input stage isn't clearly outperformed even by recent op amps - in the press for speed jfet input's noise performance actually got a little worse in the latest chips aimed at the same performance specs
 
so properly applied the OPA627 can still be considered "State of the Art" for its unique strengths
 
 
the TPA6120 is a rebadged THS6012 DSL driver op amp - as an early generation DSL driver they hadn't fully decided on the most competitive specs and were still trying for ultra low distortion at the DSL 100 kHz -1 MHz signal band without regard for low quiescent power
 
DSL output transformers are often designed to look like 25 Ohms Z - so the output drive ability is well matched to lower Z headphone loads
 
this means the the TPA6120 is one of the best matches to the needs of a dynamic headphone driver op amps I know of - again later, more recent op amps of this class pulled back on the distortion spec to save power in the chips - the wrong direction for us
 
TI apparently realized the match of this chip's abilities to headphones and did audio specific measurements for a new datasheet, offer a headphone amp demo board for the "audio" TPA6120 part number of this chip
 
 
I think you can build "audibly perfect" headphone driver amps with these chips using advanced multiloop design topology for any headphone adequately driven by their output V,I
 
 
my "cage rattling"  interest was in seeing a few of the Eximus enthusiasts professing the "discrete is always superior" belief system that may have had their expectations stroked by the Review misstatement  about the "discrete component" headphone out now having to "explain" their glowing reviews since its unlikely they would really consider changing their discrete is superior belief
 
the "discrete is superior" meme was sometimes true 30 yrs ago, for some audio line level amp applications, still true for special cases like microphone preamps or where higher output I,V  than monolithic chips cover is needed - but all the money is in advancing monolithic op amp fabrication processes, internal designs to meet needs far beyond audio's requirements
for the majority of audio line level applications - for the latest generation of analog chips - you can't buy comparable discrete transistors, build discrete circuits that match as well, perform as well on any audio distortion metric
 
 
apparently Eximus did decide the need to pander to the outdated "discrete is superior" crowd was a commercial necessity with the line driver output