Thoughts on the NuPrime HPA-9

[Aubergine]

I decided to make a thread for a headphone amplifier that i recently purchased i might post some updates and information about it over time here and other people can chip in I decided to start by talking a little about power consumption

One thing i almost always do is plug in anything i buy into a power meter it took until evening today though for me to check my new amp first of all if you turn the volume control all the way to the left power shuts off this might be a bit confusing because there is a physical power switch at the back as well

But both work in the same way there is no power drawn either way makes me wonder why there is a physical switch at the back in the first place

What really surprised me though is the power draw its at 15 watts... yes all the time

the aune x7s has an average power draw of 10 watts this dont change when changing the gain on the bottom the sound blasterx g6 using it as a headphone amp on high gain is 5 watts my v90 hpa musical fidelity draws about three watts

Just to compare this to something a bit different my bx8 D2 eight inch studio monitors with ab amplification draws an average wattage off 13 watts Yes that is only for one speaker but still it is a huge speaker with an 8 inch driver using an ab amp and it draws less power than the hpa 9

My adam audio t7v both speakers draw about seven watts max even when playing at moderate to loud volumes

I guess running a class A amp in single ended really does make it a lot less efficient and makes me wonder what would happen if you designed one to power speakers the power consumption must be enormous

 

[Jimbob54]

But how does it sound? Other than "warm"

 

[Aubergine]

But how does it sound? Other than "warm"

Ahaha it sounds like any other amp i will play though here are some impressions trying to avoid as much " audiophile" lingo as possible

The hpa9 sounds more spacious according to me the sound goes outside of the ear cups while on my Aune x7s the sound stays inside them much better feeling when it comes to bass not the amount just there is more kick more bite you feel it more it sounds a bit " clearer" as if someone has increased the treble this also seems to make it sound a bit sterile at times compared to the Aune x7s maybe its that the Aune x7s sounds a bit fuller overall

surprised honestly hpa9 sounds pretty damn neutral to my ears i was expecting it to be really colored but then i did use high impedance headphones i think the hpa9 might have a high output impedance so maybe i would get more color if i used lower impedance headphones which might have been Nuprimes intention? Who knows

the hpa9 aint like a gigantic improvement over the Aune x7s in many areas they seem pretty close if not equal

Volume wise the aune x7s on 0 gain has a lot less gain than low on the hpa9 which makes me think it might be harder to use lower impedance headphones with the hpa9 if you want a comfortable volume

there is still a decent amount more volume on the hpa9 at high compared to the x7s at 12 db gain looking at the specs though shows that the aune x7s has a good mount more power than the hp9a especially when using the xlr

xlr on the aune x7s 1700 mw into 32 ohms rca on the aune x7s 1000 mw on the hpa9 450 is max into 32 ohms
but for 99.99 percent of all headphones the hpa9 will be fine

hpa9 is a much bigger amp i was surprised how big the hpa9 was
about 4 times bigger build quality is similar neither one really stands out but the hpa9 to my eyes is much better looking

Feature wise the hpa9 has a preamp for speakers and a phono preamp also has two 6.35 plugs and one 3.5 only two gain switches

aune x7s has a balanced output and one 6.35 and three gain settings but they are not easy to adjust

Hpa9 features 4 out of 5 build quality 5 out 5 sound harder to say cause i have not had it long but so far id say 5

13.5 out of 15

Aune x7s features 2.5 out of 5 the stupid way they implemented the gain switches lowers the score and the fact that it uses an analog volume control Aune x7s build quality 3.5 out of 4 the volume control goes way past the max indication which looks and feels cheap
Aune x7s sound 4 out of 5

10 out of 15 the finer details seems to be were the Aune loses points the hpa9 holds up even under closer scrutiny in a way the X7s simply cant they both dont just get warm they get hot which makes me feel a little bit uncomfortable

I paid 326 dollars for my Aune x7s translated from local currency i paid 489 dollars translated from local currency for my hpa9
You can get the aune x7s if you live in the US on amazon for 290 dollars

The hpa9 is now discontinued but you can still buy it on amazon for 649 dollars i found it for 800 dollars on ebay i doubt you can get it for less than 649 dollars new if you aint lucky like i was

Though i use the power supply that Aune sells separately with the aune x7s so that brings up the cost to 478 so about 10 dollars shy of the Hpa9

Apparently according to nuprime " The HITACHI 2SA872 and 2SC1775 transistors are no longer in production. However, we managed to acquire sufficient inventory for HPA-9. "

That might explain why it was discontinued

What the x7s looks like inside

Hpa9 inside something i noticed is how they coupled the heat sink straight to the case which explains why it gets really hot? basically they turned the case into a giant heat sink

 

[Aubergine]

After now having listened extensively to the nuprime 9 i thought i would update some of my thoughts
First i want to mention a bug bear of mine with the nuprime which made me think i might had somehow broken if you change the volume from the front holding it.. it will scratch with the metal at the top if you change the volume by putting your finger along the volume control it wont happen but that is pretty bad design hopefully this aint the case with all units

i much prefer the aunex7s volume control also its much bigger and more comfortable to use even though it is analog

i also in my adventures opened it up this is not something Nuprime says you shouldent do rather they in the manual tell you
that you have to do this if you want to change the setting from MM to MC when using a turntable

i think the way the way attached the top case is kinda ingenious there is a kind of metal tab that gets to be inserted into the front but the screws for the case are way to small i have lost two permanently gone forever

i had enough left to firmly reattach the case which is important because the heatsink is designed to sit flat to the case to dissipate heat so make sure to make sure it is firmly in place when you are done

The white material you see in the above photo in my earlier post.. photo i got from the internet is actually a kind of sticky material that glues itself to the case it was partially stuck to the case when i opened it up as long as you make sure the case is back as normal the glued sticky piece should go back hugging the case

Otherwise the internals looked just like the photos i already seen on the internet nothing new to see here very tidy and pretty
I have done extensive listening before and after i opened it and here are some more impressions

There is definitely a character to the way the 9 sounds it became more and more obvious the more i listened and i will attempt to compare this character to the aune x7s

The 9 lacks body this is a consistent thing i noticed which ended up making certain music sound clinical and anemic vocal performances for example

it is strange because the bass of the 9 is very good it has more of a feeling than the x7s and you can more clearly differentiate it compared to the X7s But it lacks body it can sound tinny at times

Another thing is it is quite sharp there is a lot more treble now why that is i cannot say im not an audio engineer but you know how someone sounds when they have a cold? a bit nasally voices with the 9 sound a bit like that it lacks a body and it is quite treble happy

Sense of space is quite similar it is hard for me to say if anyone of these two is better they are both very good though you dont get that in your head sound that i hate and is why i usually avoided headphones

I watched inspector morse and that did give me a good observation about sound stage performance it was raining in this specific scene and i could clearly hear that on the X7S not on the 9 this because on the x7s the rain was not taking up the same place as the actors in the show which is to say inside my head... but inside the right and left earcups

The 9 because of its lack of space the rain had to share the same place as the actors which made it much harder to hear

There are things the 9 does great and things it does badly so i will make a couple examples of this in actual music i have listened too

The Traveling Wilburys - End Of The Line

Wow with my X7S i want to dance its such a catchy track makes me feel happy the 9 seems to have lost something there are highs and there are lows but nothing in the middle at all it as if the mids have been completely sucked out

Bob Dylan most foul

The 9 does a better job with representing the detail around bob dylans voice especially the bass the whole track is clearer but i prefer the fullness of bob dylans voice with the x7s though this is an early example of the 9 showing its strength which will become much more obvious with the next track this track made it obvious what the 9 is good at which is complexity it seamlessly shows you everything in the track no matter how layered it is never glossing over any part of the song the X7s just seems to want to make good music the 9 cares that you hear everything and wants to make sure you do even if this might hurt musicality

Clark Terry Skylark

Welcome to the one track i found were the 9 easily kicks the X7s butt listening to the 9 makes you suddenly notice so much more in the track as if the x7s had a veil over it it simply sounds higher resolution on the 9 and that might sound pretty esoteric but that is the best way i can describe it as if the 9 was playing the bluray while the x7s was playing the dvd

Coming back full circle to this question of body on the 9

Nathaniel Rosen Suite no. 1 in G major

If you to know what i mean when i say lack of body look up this track the 9 has no body at all the Cello strings aint attached to an instrument on the 9 on the x7s it is a whole instrument

Heaven is a place on earth Belinda carlisle
the bass stops faster on the 9 and it has more of a kick a feeling to it on the x7s its more like a constant baseline but on the 9 it is noticeably more distinct on my studio monitors it sounds like a constant droning in the background so its nowhere close to the x7s or the 9 but the 9 wins over the x7s

there is a portion of this song were it becomes really clear that the 9 has the upper hand at 3.07 to 3 22
This entire section is so much cleaner clearer on the 9 every bass hit is much cleaner and has more feel more power and this is clearly were the 9 wins and kicks the x7s butt it just cannot compete with the sheer amounts of clarity the 9 puts out every bass kick clean separate it has oceans worth of space and separation on the x7s it becomes less distinct and continuous and not at all the same amount of power

Does this part of this song sound distinct to you? does every bass kick live in its own space or is it more like a constant droning baseline? and i do mean everything.. in the part i posted there are very quick bass at 3.17 and it just speeds up .. every hit has to be crystal clear be distinct live in its own space everyone of them has to have separation air and a feeling of power even when it speeds up! that is the grade you have to pass if you want to aspire to do what the 9 does when it comes to out right clarity and the 9 dont do this only to bass but it treats all music as lego pieces belonging to a bigger picture rather than just treating it as a continuous " noise "

my studio monitors end up in sixth place my X7s at second place and my 9 a first place the 9 is the only one that can make what happens at 3.17 sound like every kick is it owns thing the sound belongs to the collection of multiple bass beats it becomes just one solid sound on my x7s and on my studio monitors a continued quick bass line without distinct components

when that quickfire bass line has reached max speed the baseline has become just a blur a single continuous noise on anything but my Nuprime 9 which handles it like a champ i have to give it top credit there

So here is a quick summary the 9 majors in clarity and detail it is very analytical so much that it can rob your music of life it can turn a vocal performance into a treble only performance without any body this is not a good headphone amp for non pop tracks with vocals as top priority

the x7s is sooo much better in this genre of music its not even funny

The 9 is a detail monster it asks a lot of your recordings but if you find one that oozes in detail the 9 will eat it up and show you everything and lay it out right in front of you.. seamlessly! it has much better bass the one part were the x7s lack of clarity dont benefit is bass it just dont have the same power or clarity and clearly lags behind

The x7s though is a much more consistent performer i listen to music because well i enjoy it not to analyze it to death so for a lot of music the 9 just simply aint suitable the 9 would be perfect for someone working in a recording studio were accuracy and detail trumps everything else

This is crazy considering the 9 is meant to be class A amplifier without any biasing meant to embrace second harmonic distortion and be the most colored amplifier in the world but its not its incredibly neutral and honest to the source i bought this because i thought it might be fun to hear the "color " but that is not at all what this headphone amplifier is about it is about unrelenting truth

And when hearing a really well mastered tracks.. mostly acoustic classical musical... that is dripping with detail it is very enjoyable to plug in my headphones to the 9 if i want that power that kick listening to a great baseline the 9 is number 1 choice

but for 99 percent of my music.. vocals... it simply robs it off its life sucking out the mids like a tormented vacuum cleaner though for detail i have not heard anything that beats it and there is something to say for being able to bring a microscope to whatever song it is your listening to

 

[Jimbob54]

After now having listened extensively to the nuprime 9 i thought i would update some of my thoughts
First i want to mention a bug bear of mine with the nuprime which made me think i might had somehow broken if you change the volume from the front holding it.. it will scratch with the metal at the top if you change the volume by putting your finger along the volume control it wont happen but that is pretty bad design hopefully this aint the case with all units

i much prefer the aunex7s volume control also its much bigger and more comfortable to use even though it is analog

i also in my adventures opened it up this is not something Nuprime says you shouldent do rather they in the manual tell you
that you have to do this if you want to change the setting from MM to MC when using a turntable

i think the way the way attached the top case is kinda ingenious there is a kind of metal tab that gets to be inserted into the front but the screws for the case are way to small i have lost two permanently gone forever

i had enough left to firmly reattach the case which is important because the heatsink is designed to sit flat to the case to dissipate heat so make sure to make sure it is firmly in place when you are done

The white material you see in the above photo in my earlier post.. photo i got from the internet is actually a kind of sticky material that glues itself to the case it was partially stuck to the case when i opened it up as long as you make sure the case is back as normal the glued sticky piece should go back hugging the case

Otherwise the internals looked just like the photos i already seen on the internet nothing new to see here very tidy and pretty
I have done extensive listening before and after i opened it and here are some more impressions

There is definitely a character to the way the 9 sounds it became more and more obvious the more i listened and i will attempt to compare this character to the aune x7s

The 9 lacks body this is a consistent thing i noticed which ended up making certain music sound clinical and anemic vocal performances for example

it is strange because the bass of the 9 is very good it has more of a feeling than the x7s and you can more clearly differentiate it compared to the X7s But it lacks body it can sound tinny at times

Another thing is it is quite sharp there is a lot more treble now why that is i cannot say im not an audio engineer but you know how someone sounds when they have a cold? a bit nasally voices with the 9 sound a bit like that it lacks a body and it is quite treble happy

Sense of space is quite similar it is hard for me to say if anyone of these two is better they are both very good though you dont get that in your head sound that i hate and is why i usually avoided headphones

I watched inspector morse and that did give me a good observation about sound stage performance it was raining in this specific scene and i could clearly hear that on the X7S not on the 9 this because on the x7s the rain was not taking up the same place as the actors in the show which is to say inside my head... but inside the right and left earcups

The 9 because of its lack of space the rain had to share the same place as the actors which made it much harder to hear

There are things the 9 does great and things it does badly so i will make a couple examples of this in actual music i have listened too

The Traveling Wilburys - End Of The Line

Wow with my X7S i want to dance its such a catchy track makes me feel happy the 9 seems to have lost something there are highs and there are lows but nothing in the middle at all it as if the mids have been completely sucked out

Bob Dylan most foul

The 9 does a better job with representing the detail around bob dylans voice especially the bass the whole track is clearer but i prefer the fullness of bob dylans voice with the x7s though this is an early example of the 9 showing its strength which will become much more obvious with the next track this track made it obvious what the 9 is good at which is complexity it seamlessly shows you everything in the track no matter how layered it is never glossing over any part of the song the X7s just seems to want to make good music the 9 cares that you hear everything and wants to make sure you do even if this might hurt musicality

Clark Terry Skylark

Welcome to the one track i found were the 9 easily kicks the X7s butt listening to the 9 makes you suddenly notice so much more in the track as if the x7s had a veil over it it simply sounds higher resolution on the 9 and that might sound pretty esoteric but that is the best way i can describe it as if the 9 was playing the bluray while the x7s was playing the dvd

Coming back full circle to this question of body on the 9

Nathaniel Rosen Suite no. 1 in G major

If you to know what i mean when i say lack of body look up this track the 9 has no body at all the Cello strings aint attached to an instrument on the 9 on the x7s it is a whole instrument

Heaven is a place on earth Belinda carlisle
the bass stops faster on the 9 and it has more of a kick a feeling to it on the x7s its more like a constant baseline but on the 9 it is noticeably more distinct on my studio monitors it sounds like a constant droning in the background so its nowhere close to the x7s or the 9 but the 9 wins over the x7s

there is a portion of this song were it becomes really clear that the 9 has the upper hand at 3.07 to 3 22
This entire section is so much cleaner clearer on the 9 every bass hit is much cleaner and has more feel more power and this is clearly were the 9 wins and kicks the x7s butt it just cannot compete with the sheer amounts of clarity the 9 puts out every bass kick clean separate it has oceans worth of space and separation on the x7s it becomes less distinct and continuous and not at all the same amount of power

Does this part of this song sound distinct to you? does every bass kick live in its own space or is it more like a constant droning baseline? and i do mean everything.. in the part i posted there are very quick bass at 3.17 and it just speeds up .. every hit has to be crystal clear be distinct live in its own space everyone of them has to have separation air and a feeling of power even when it speeds up! that is the grade you have to pass if you want to aspire to do what the 9 does when it comes to out right clarity and the 9 dont do this only to bass but it treats all music as lego pieces belonging to a bigger picture rather than just treating it as a continuous " noise "

my studio monitors end up in sixth place my X7s at second place and my 9 a first place the 9 is the only one that can make what happens at 3.17 sound like every kick is it owns thing the sound belongs to the collection of multiple bass beats it becomes just one solid sound on my x7s and on my studio monitors a continued quick bass line without distinct components

when that quickfire bass line has reached max speed the baseline has become just a blur a single continuous noise on anything but my Nuprime 9 which handles it like a champ i have to give it top credit there

So here is a quick summary the 9 majors in clarity and detail it is very analytical so much that it can rob your music of life it can turn a vocal performance into a treble only performance without any body this is not a good headphone amp for non pop tracks with vocals as top priority

the x7s is sooo much better in this genre of music its not even funny

The 9 is a detail monster it asks a lot of your recordings but if you find one that oozes in detail the 9 will eat it up and show you everything and lay it out right in front of you.. seamlessly! it has much better bass the one part were the x7s lack of clarity dont benefit is bass it just dont have the same power or clarity and clearly lags behind

The x7s though is a much more consistent performer i listen to music because well i enjoy it not to analyze it to death so for a lot of music the 9 just simply aint suitable the 9 would be perfect for someone working in a recording studio were accuracy and detail trumps everything else

This is crazy considering the 9 is meant to be class A amplifier without any biasing meant to embrace second harmonic distortion and be the most colored amplifier in the world but its not its incredibly neutral and honest to the source i bought this because i thought it might be fun to hear the "color " but that is not at all what this headphone amplifier is about it is about unrelenting truth

And when hearing a really well mastered tracks.. mostly acoustic classical musical... that is dripping with detail it is very enjoyable to plug in my headphones to the 9 if i want that power that kick listening to a great baseline the 9 is number 1 choice

but for 99 percent of my music.. vocals... it simply robs it off its life sucking out the mids like a tormented vacuum cleaner though for detail i have not heard anything that beats it and there is something to say for being able to bring a microscope to whatever song it is your listening to

Am I right in taking from this you have bought a "dog"? We've all done it

 

[Aubergine]

Am I right in taking from this you have bought a "dog"? We've all done it

I would be disappointed if the 9 sounded just like the x7s depending on my mood i can now listen to music in two completely different ways and i do listen to a lot of classical music as well and i cant think of any better way than to listen to that on my Nuprime

It is amazing how much detail it can get out of a recording!

Didnt mean come off as wholly negative or anything like that just impartial making plenty of observations that people might find interesting

 

[Jimbob54]

I would be disappointed if the 9 sounded just like the x7s depending on my mood i can now listen to music in two completely different ways and i do listen to a lot of classical music as well and i cant think of any better way than to listen to that on my Nuprime

It is amazing how much detail it can get out of a recording!

Didnt mean come off as wholly negative or anything like that just impartial making plenty of observations that people might find interesting

Just out of interest , what headphones are you using it with ?

 

[Aubergine]

Just out of interest , what headphones are you using it with ?

Beyerdynamics 880s Beyerdynamics 990s Sennhesier 598 Shure 840s Sony 7506 just to name a few no in ears! not my thing mostly because i am quite careful about my hearing and i dont feel comfortable using them..

 

[Jimbob54]

Beyerdynamics 880s Beyerdynamics 990s Sennhesier 598 Shure 840s Sony 7506 just to name a few no in ears! not my thing mostly because i am quite careful about my hearing and i dont feel comfortable using them..

As long as you are happy, everything is good.

 

[Aubergine]

As long as you are happy, everything is good.

Same to you!

 

[Aubergine]

Here comes another post about the Nuprime 9 this time i took a more detailed look at the volume control how it performs across the range channel imbalance at lower gain how does it perform with more sensitive headphones versus harder to drive ones

There are " only " two gain settings low and high it is puzzling that there is a 3.5 for in ears on the unit when i firmly believe that there is to much gain even on low for those to be usable that is if not something happens inside the unit when you plug them in maybe the output impedance can change on the fly somehow? When plugging in two headphones i was surprised that the less sensitive headphone became a lot more quiet considerably so and performed closer to the more sensitive headphone in terms of output you could argue this is simply because they share the power but

On another headphone amp i used the volume using the same two headphones performed with the same volume no matter if another headphone was plugged in or not.. this makes me wonder if this is somehow a design decision Nuprime might have made maybe the output impedance is defined by the most sensitive headphone? if this is true then in ears might just be possible to use with this unit

the amount of gain is not necessarily that important because one headphone amp i own can output a lot of volume but it distorts like something fierce

The nuprime never distorted anyone of my headphones at even loud volumes which is good plenty of clean " power

the volume control also acts as an on and off switch and it turns prior to the phase were you switch it on so while the volume control starts at 6 a clock it the actual attenuation begins at 6.45 or 6.50 the amp dont shut the output down at very low attenuation like other amps i have used they mostly do this i i think to stay clear of channel imbalance issues

With my Beyers i can hear something even at the lowest volume position this is confirmed when i use my Senns i can clearly hear the audio playing through my sennheisers even at lowest attenuation

The weird part is that there is no volume imbalance at the absolute beginning of the volume control when then increasing the gain a little bit there is a brief period were the sound goes entirely over to the left and then it evens out again

But with the beyers the channel imbalance happens from the get go and vanishes about 7.30 same place as the Senns

Neither headphones use more than 40 percent of the volume control in real life use
12 a clock on the beyers at low gain is uncomfortably loud and these are 600 ohms

Interesting observation i made is that the high gain switch does nothing at the beginning of the volume control if you listen with the volume control prior to about 9.45 there is no difference in output after this the sensitivity of the volume control changes and volume increases more rapidly in high gain mode

there is like a specific moment a specific place on the volume control when the higher sensitivity from the high gain setting sets in its not immediately more sensitive from the beginning thats pretty ingenious because you could possibly leave it in high gain mode even with more sensitive headphones because it performs identical to low gain mode for the beginning portion of the volume control adjustment

Or maybe all volume controls work like this and im just giving them undeserved credit