HPA-nxV200 R2 based dual mono amplifier
(2 x 500 VA), separate supplies for input stage (2 x nx Volt One) and output
stage (90.000 uF per channel).
The amp was
easy to build and worked as expected “out of the box” The nx Volt Ones needed
adjustment, but if you give them a proper input voltage, they behave exactly as
described. The questions I had during building were promptly answered by
Anthony. And had I bought the right secondary trafos right away, I would not
have needed his support at all.
To set my
personal bias straight: I have been passionate about Hi Fi for + 40 years, I
have heard a lot of gear, including top of the line amps from Audio Research,
Naim, McIntosh, Classe, PassLabs, etc–
and I am lucky enough to have a pair of very capable speakers (Audiovector
SR6AA), so below I am not implicitly comparing to budget gear.
power on, it sounded edgy and veiled, but that changed gradually over the
following 6 weeks to transform itself
into probably the best amps I have ever heard. Since the difficult start it has
been growing on me. But it does need some serious burning in – and it would be
unfair to judge it before that has taken place. I had it turned on 24/7 for several
weeks but kept getting better over time.
signal, it is dead silent. It depicts a large 3-dimensional soundstage- very
broad, extending well outside each of my speakers, and so deep that some of the
musicians seem to be playing from behind the rear wall. It is very detailed and
will let you in on even the tiniest sounds and details – without even the
slightest trace of sounding analytical, thin or “naked” . It combines the
ability to place each sound source precisely on the stage with the ability to
integrate everything into an organic scenery. With good live recordings, the
soundstage is huge and it is as if you could walk up there blindfolded aand
still know precisely where the players are.
my speakers are now much more easy to place in my room – this amp seems to
maintain the tonal balance much easier than its predecessor that needed much
more support from the rear wall - or the low end weight would be lost.
probably has enticed me the most is the perfect tonal balance – electric organ,
trumpet, cymbals,l etc. - are rendered
with body, warmness ( if called for) detail and nuance. It renders perhaps the
only quality of a tube amp that I have been missing hitherto : the low midrange
“ juiciness” of voices, winds drums.
difficult for an amp (and speaker too, for that matter) is to render the “body
part” of cymbal, hi hat etc with the
proper sense of weight and dimension,
and at the same timecommunicate the fine
nuances of the decay as the sound travels towards the walls of the room in
which the sound was recorded – the aussie masters this discipline.
with a vengeance, but at the same time it retains all the detail and delicacy you
could ever ask for - so macro and micro dynamics are in perfect balance, it
seems. And it is infull control, whatever the music and the sound level.
All this is
delivered in a very natural, spacious
and coherent way, a way that lets me
focus on the music, that comes to life end blooms in my room.
This is an
amp that does everything important right.
compared their “Aussie” with some very renowned gear, concluding that their Aussie
was better. If I remember correctly, comparing to the gear that I have heard, I
totally agree. I believe it must be up
there, among the very best.
I know I
sound less than objective - but there is a reason for my enthusiasm: My Aussie is an exceptionally communicator of music. I
really do believe that something special is going on here.
707ES, heavily modified with ZapFilter
PC with Sound Blaster X-Fi Titanium HD Audiophile Sound Card (I know, but surprisingly good)
Preamp: Own design, with DACT attenuator, relay switched signal and ground paths
and selectable passive or active (AMB labs α20) line stage) Houses a separate DAC (NewClassD).
Speakers: Audiovector SR6AA (4 way
speaker with Audiovector Avantgarde Air Motion Transformers)
Cassidy: Live at Blues Alley, Songbird
Miles Davis: Kind of Blue, Sketches of Spain, Porgy and Bess, Bitches Brew, Dark
Magus, Get Up with It, Cellar Door Sessions, Agharta, Pangaea
Dire Straits: Private Investigations
Hans Theessink, Terry Evans: Visions
Grateful Dead: The Closing of Winterland
Nick Bärtsch: Ronin Live
Jan Garbarek Bremen
Keith Jarrett: Sun Bear Concerts
Eagles: Long road out of Eden
Anuar Brahem: The Astounding eyes of Rita
Cat Power: The Covers Record.
Gustavsen, Josefine Cronholm, Zawinul Syndicate, Joni Mitchell, Rickie Lee
Jones, Ane Brun, Massive Attack, Faithless, Primus…
I've installed the nxV200 R2 amplifier modules and I have to admit that they sound very well!
First thing one notices is that the modules will happily deliver a lot of tight
and clean bass. Next thing, is the wide bandwidth. Using a descent source, all
the detail will be easily noticeable. Mids are realistic especially if one
plays some jazz music, and high frequencies can be really sweet and clear.
However, as many others have already mentioned one can easily tell a good
quality from a not so good quality recording. Overall, I am very pleased with
Here goes a pic of my amplifier finished. The amplifier is built in dual mono
configuration with a 2*28V, 300VA toroidal transformer, two 35A/200V rectifier
bridges, four 6800uF/63V/105C filtering capacitors per channel and 100nF/630V
mkp bypass capacitors. I used 4.7uF/450V mundorf coupling capacitors in the
input stage although my source has no dc offset. At the rear I installed a
simple delay relay for the speaker connection in order to avoid any annoying
noise from the power switch and/or the charging of the filtering capacitors.
Thank you for a excellent product (nxV300R2) and one more
in the making, My choice fell on a 300 and I am very satisfied with that, I
used a lot of time (about 9months) but when the amplifier was conceived it was
all worth the Wait.
Powering it up for the first time on my modified HF-275
speakers the sound was crystal clear tight an powerful yet gentle when needed,
The nxV300 was replacing a LC Audio Zapsolute 42W (pure) Class A. After a short
while I had to admit I was missed some of the soothing warmth of my 15 year old
I soon realised that the sinner was the attenuator in the
preamp, the distortion that it produced when installed in my old amplifier was
never detected at the time.
Luckily I got myself a new Seiden 23 pos attenuator with
Takman Carbon resistors and it gave me the long wanted soothing sound,
Now when I play music I soon forget about the different
sounds coming from the stereo, I rather quickly start to enjoy music.
Today I had a fellow Hi-Fi addict visiting me, we played
many records, both good productions and bad, ending at some badly produced pop
records from the 1980s, we both agreed that the music was in focus and most of
the time messed up our analytic session.
When you don't want to change record for a new one to be
tested you know that the sound is excellent.
Dear Mr. Anthony,
I'm extremelly satisfied with your amp modules, so I
decided to build another, more powerful amp.
My friends are surprised with the sound and with Yamaha
NS-1000Monitor it sounds simply heavenly. They want to see is there any
subwoofer installed behind Yamahas, but...
So, I would like to inform you that I'll order new
HPA-nxV500 R2 modules from you.
Thank you for all support, regards,
Dear Mr. Anthony,
Now your amplifier is in nice setup.
Source is Sony NAC-HD1E, loudspekers are Yamaha NS-1000
Monitor and please, don't ask for interconnect and speaker cables. All wires
are custom made, perhaps I can add some money to improve wires, but at this
moment it seems that is not necessary to change them.
Now, what to say...?
Previous setup was with KEF CS5. Not bad at all, but pure
renaissance this amp have with Yamaha NS-1000M.
You know what Yamaha made before almost 30 years.
Compression cabinet, berrilium, good crossover network and that's it. Magic
With nxV300 you can hear piano as piano and sax with all
noises of air turbulences in instrument. I cannot compare your amp with any
other amplification in my home because it cannot be compared. You can compare
only similar devices which can be different in a few minor things, but in my
case differences are too big to establish any good and fair observation what is
Simply - amp is fantastic. I have never been jazz lover.
Now I cannot stop to listen jazz...
So - what's wrong?
Nothing is wrong, now finally I can hear all sweetness
and detail of each instrument. Now I have all, now I have music.
Thank you for this. Good job!
I have benchmarked the amps to a couple of expensive amps
like Krell KSA-300, Luxman M-600A, Dynamic Precision and some other amps that’s
regarded to be in the higher level, and none of them had anything on the nxV500.
None of the amps where better in any area, control, bass
depth, clarity, separation, airiness. nxV500 is probably one of the best amps in
I recently bought some nxV300 amplifier modules from a good friend in Denmark.
I have played with Hypex Ucd400HXR for about 1 year,
but yours nxV300 improves in the whole frequency area, i'm very impressed...
are planning to build an active speaker with your amp's in near future...
An little update : For 2 days ago, we made a battle between
an Nelson Pass XA30.5 and my Nvx300 with Smps dual mono supply, all 3 of us
did choose the Nxv300, more powerfull/dynamic, midrange was more clear and
defined, but the top was even more detailed and still as friendly sounded
as the Pass, indeed very impressing...
We where all very surprised, and i'm a very happy man.......
Just listened to my new NXV 500 R2 . Its amazing -- sounds wonderful. Much better than the earlier modules. Has the missing warmth in lower
midrange upper bass. Transparens is so much better also. This amps is
way better than the NCore 400 I made for a friend some weeks ago. The
N Core 400 sounds like a clock radio compared to this.
Erlend Sæterdal, Denmark
have a shoot out between the UcD180AD vs Pass-Lab Mini Aleph vs nxV200, all DIY
amps driving a pair of Coral Flat 8. nvX200 sounding to best to 2 of us, more
"weight", details and very good soundstage, it is really a good
| Klark Teknik | Clair Brothers Audio Systems
We have now had the opportunity of carrying out extensive listening test with
your NXV202ps modules and pleased to say this performs extremely well on
a wide range of different genre of music, but seems to be quite ruthless in
sorting out the poor recordings from good ones. We felt that the bass was
particularly well presented and is well extended. The mid and high range
is equally good with excellent clarity and detail.
Female voices show no hint of sibilance and the dead quiet background is
impressive - even though the module was bread boarded with no special attention
given to the layout of the connecting or signal wires.
We compared this to a Parasound 300W/ channel class A power amp and would say the
NXV202ps is certainly up there
and in certain areas exceeds the performance of this behemoth.
The other comparison was conducted vs our Glowmaster KT88 65W /ch class A
power amp ( which has a 5 globes rating from Hi Fi World) and can
honestly say there is very little to chose between them apart from a slightly
warmer sound from the valve amp, but with a more extended bass from the
NXV202ps . ( We used a 500VA transformer). This result is more or less
what we expected. So there is little to chose between a
"£600" NXV202ps based power amp and a £2500 Glowmaster KT88.
We would certainly agree with some of your other users who have posted
reviews that these offer Krell / Bryston performance - but at a fraction of the price
Acoustic Perfection, UK
I have been playing for two weeks now the nxV500 and im absolutely blown away with the
performance. Not just the dynamics and the total control, but also the level of
details and how it paints up the soundstage. Really impressive work and had a
real guru over this weekend. He is the number one audiophile i would say in
Sweden, but that might sound a bit steep. However he was really impressed and
wanted to try it and build one himself. My father will soon order a similar
Best regards from a very happy man.
Jonas of Sweden
I'm now using nxV500 to drive my MG12.
Thanks Anthony, you did a good job, the modules performance is very very good! Relaxed but no lost of details, especially the silky high-freq, no
harshess, very smooth, pin point focus, wide open sound with very good
Kenneth Lau, Hong Kong
Well I finally
have my stereo upgrade finished and it sounds sensational.
Your nxV500 lived up to every dream held and
exceeded all expectations. I am extremely satisfied with my purchase, it
was money well spent. And I'm not just referring to the quality of the
sound reproduction, it is truly a craftsman build piece of equipment both in
internal construction and in the professional external appearance. Thank you for your efforts!
replaced a custom made DEX amp which was in itself is a superb amp but it
simply doesn't compare to the bite of the nxV500. The nxV is so clean
& crisp, I'm now hearing definition and harmonics, owing to the massive
distortion free head-room, which creates
perfect sound fidelity and imagery across a full range of music genres. I
spent all day yesterday listening to music. First time in a long time.
has created a problem in that the brilliance of the nxV is now overshadowing my
bass power amp, which although has a higher power rating, cannot compete with
the dynamics and punch of the nxV.
I know it would
be a waste of time searching for a comparable power amp that will drive my JBL
bass bins with the same energy of an nxV.
I also doubt I would be satisfied with anything less than the
performance of the nxV, so in order to balance my system, I have decided to
order a second nxV500 from you.
Cheers Rik (ex sound engineer HSV7)
Warrandyte, Victoria, Australia
As a very happy owner of an Arcam AV300 receiver, I was looking to intoduce a dedicated poweramplifier to my setup to enjoy a superior musical experience. I'm a big music
lover and didn't feel the Arcam was providing adequate power to the two font
speakers. After reviewing the testimonials for Holton Precision Audio, I took a
chance (without auditioning the amp) and purchased the NXV500. The aim was to
to buy an amp that would provide a world class solution at an affordable price,
and I must say, this NXV500 amp is one of the best things I've ever bought!
The configuration I purchased included dual power supplies to provide a no
comprimise solution, housed in an elegant custom built chasis provided by
Holton Precision. The NXV500 is connected to my Arcam and drives the the two
main speakers (KEF Q7) whilst the Arcam drives the rears.
And how does it sound? Simply awesome! Power, precision, poise, drive - this
amplifier makes me smile! And thanks to the high damping factor, the way it
drives bass with such precision and control is truly astonishing.
Nearly all my audio equipment will be recycled over time - my Arcam, my Kef
Q7's, my Squeezebox Touch. I do not intend to recycle the NXV500.
On a side note, Anthony's service is excellent. Aside from designing an
outstanding amplifier, he always is available to take calls and has integrity.
I cannot recommend Anthony's designs, quality and service enough.
Congratulation's Anthony on developing a wonderful product. I wish you and your
business continued success.
Melbourne, VIC, Australia
At first thanks for your kind support in the whole phase
of my AMP III project.
After a long search to a High End Amp module, which suits
to the rest of my electronics and replace my Audionet AMP V multichannel
amplifier, i am glad that I found your perfect build nxV201PS & nxV202PS
Because I have replaced my main speakers in the past to a
set of Avantgarde Acoustic Duo Omega Horns and build therefore a set of 300B SE
mono blocks, i only need three of the five channels in my old Audionet AMP V.
So a new DIY project was born.
To make it short, your modules are absolutely awesome. With
my use of the Mundorf M-Lytic AG power caps, I
missed nothing to my old amp, quite the contrary.
The so important mid tone for the center channel is so
Also the very precise bass is fantastic. Please keep
going on with your wonderful stuff.
Best regards from Germany,
The HPA-nxV201ps modules got here in great shape.
I'm very surprised by the bass performance! I was fully expecting outstanding midrange and HF performance and was not disappointed (you're being compared head to
head with Krell and Bryston) but the bass was completely unlike any
mosfet output stage I've ever heard, and honestly the first listen have me so excited that I could go out to my roof and yell... What great amps!
3 cheers for HPA!
North Carolina, USA
I've been testing a pair of your nxV500's in my current reference system which comprises of:
B&W 800D Floorstanding speakers ($35,000 a pair)
2 x Classe CA-M400 mono block amplifiers ($22,000 a pair)
Classe CDP-202 CD player with inbuilt volume control ($11,000)Kimber Select Interconnects and Speaker Cables ($7000)
And previous systems consisting of Mcintosh, Mark Levinson and Krell electronics.
I decided to put the nxV500's head to head with the Classe M400's,
even though the nxV500 only has 300W/8 which is 100W less than
the M400, the sound quality is second to none. Right after hooking them up
and pressing play on my reference track of Diana Krall - Live in Paris -
Track 1. I Love Being Here With You, it was clear when the bass
rolled into the room, it didn't jump or snap into the space like it
was a leashed animal, and when Diana's voice is first heard it bloomed
beautifully and was sensationally convincing.
The build quality of your product is excellent and it uses high quality capacitors too! I always like to know what the almightly dollar really buys you,
and closer inspection of the M400, shows cheap capacitors and internal wiring,
including the XLR/RCA interconnect wiring.
In summary the nxV500 is smoother and has greater overall coherence that the hugely expensive mass produced Classe CA-M400 and because of this
the M400's have been given the boot and sitting in their place
is your very own nxV500 mono blocks!
Nicholas H Canberra, ACT.
The NXV 500 together with a DAC I
have modded and an old Philip CD Player and a Nelson Pass Balanced
Bride of Zen delivered the best sound ever in the HIFI club. Sometimes we have some
very expensive stereo in the club. 1 month ago only the AR 610 mono amps
had a price of $100.000 AUD
So we are extremely satisfied with
Cheers from E.Sæterdal
I completed my 2ch amp using your NXV200 modules a few months ago, and I must say that the sound quality is absolutely fantastic. Thank you for bringing
this level of quality to an affordable level.
Bartek M, Victoria, Australia
I have finished my amplifier using your NXV200 modules. Let me tell you
something, I am very picky with sound quality. I have had so many
amplifiers that I lost count lol just to name some of them:
Panache, Adcom, Marantz, Bryston, Acurus etc and I have also build
many kits including gain clones, chip amps LM3875/LM3886. let me tell you, I am
still waiting for the input sonic caps 3.9uf from Sonic craft. But
I could not resist waiting so here I am listening to music. Well let’s
start with the quality of your boards, they are top notch, yeah, yeah now you
want to know if I like the sound right? Well I have good and bad news....The
bad is I lost a lot of time looking for a great amps and amp kits! Ok so
what is the good news? I just found you and your wonderful kits! As I
mentioned before I had many good amps but, I was never happy with the sound and
details. There was always something. well let’s start with these
"small tanks" They are small, I had it for a couples of hours playing
with my Polk audio A1 really loud and the heat sink got barely warm. The
sound is awesome! I try to listen if I could hear some back noise and I though
the amp was unplug so I checked it...but the amp was on! No back noise at all;
boy! There is one thing I can say to you............ Very well done! You know
me I will get more for sure. Now I only have to wait for these input caps
to arrive and I will install them. So far I do not have words to thank you
enough for these top notch products.
service and products are the best!
you so much Anthony.
I compared the nxV300's
with my Threshold 450 listening on the Relco Mantis loudspeaker.
In my opinion the nxV300 is more detailed and I will sell
After building my new power amp. (HPA-nxV200 modules)
The result is an amplifier, which is, afterabout one week of burn in, able to deliver a very wide soundstage, a powerful,
controlled and well articulated low frequency range, smooth and liquid mids and
very detailed but never fatiguing highs. But much more important, this amp has
a very own but yet very natural sound signature. It really shows me something
about my source equipment, but remains playing everything in a very musical
manner. I think this is an outstanding product. It has its own signature, not
trying to copy any other amp, and it plays just tuneful, full-bodied and
convincing. I really searched for some drawbacks here, but wasn't able to find
My reference for comparison are some Rotel integrated amps (RA-935, RA-931mkII)
and some Naim Audio power amps (NAP 140 and NAP 160). My speakers are some MM
Serie Master by Reference 3a, an early version of the current model MM de Capo
Thanks for offering such a great product to the diy-oriented!
Full comments and photos found in the web site Gallery!
I have been using your amp (nxV200)for
over a month now, and have made my decision on its sound quality. It is now my
main amplifier and I have sold my Duevel amplifier (I see the new price for these
amps is now nearly US $5K)
In my system it gives my
speakers a bit more control on bass lines. I listen to a lot of female
vocals and the treble is just that bit better suited to my hearing. So you
have developed a stunning unit in my view.
All the best
Andy, New Zealand
Hi there Anthony!
..well, the modules (Nxv200) are simply astonishing!
the expected control and resolution on the whole bass region
(sub bass to mid bass) is amazing , especially considered that I use the"old"
psu from my NAD C325B (one toroid, say 230 W ,one integrated rectifier,
two (unknown) 15000 electrolitics) for both the two modules.
even the rest of the spectrum reveals far better resolution,
one of the amazing thinks that I hear is the "life like" sound of metal clash
(in movies effects for example, or cymbals..)
however absolutely non fatiguing sound!
Very well done Mr Anthony E Holton !!!
a satisfied customer.
Massimiliano Colarusso, Italy
I would just like to point out that I think your build quality is far superior to the Classe Audio, I've been doing some A/B testing of the 2 x Classe CA-M400
) and the nxV500's.
I think the nxV500 are better, the M400's are $10.9k each!
have made some fine amplifiers :)
Having upgraded my speakers I
was looking for something a little better then my monobloc chip-amps,
but wanted to keep the chassis as there a good fit with the rest of my
So using 45V rails and 20,000uf per
unit, in went the HPA-nxV200 modules.The first thing that struck me was
the improvment in the bass, very quick and tight.The treble was smooth and detailed,
and the resolution just outstanding!
I'm very happy with the results.
I have a pair of stereo amplifiers using
your 4X NXv200 modules which were assembled by Mark
Houston. I have to say that they are the best amps I ever heard.
With experience from a few other amplifiers, yours simply decimate all others.
Clarity, soundstage, transparency and speed of bass simply eclipses any other
amp that ive heard. They are so crystal clear that they do great justice to my 2 way
floorstanders using Scanspeak 18W8531G00 and Vifa tweeter.
The amp is dead quiet. I had to strain myself to hear the slightest stirring of
noise but it was coming from my hair that was rubbing against the cone of the
speaker! I have thrown all my passive components away and set up my active
crossover, with each driver independently powered by your modules.
The sound is so natural and filled with emotion that I challenge anyone to feel
nothing after listening to them.
A truly exceptional module you have designed.
Guitar string resonances reveberate with authority! Walls are vibrating though
the sub is off. So far this kills my Marantz amp in all aspects;
warmth,clarity,soundstage,coherence and speed.
The slightly bright nature of the amp is neutralized by the mellow sounding
Vifa tweeter. What emerges is absolute listening pleasure!
Dinesh, Melbourne, Australia
Congratulations on very fine
amplifier Anthony, it exceeded my expectations. You should be very proud of
The grip it has controlling a speaker is quite remarkable and smoothness is outstanding. 4 hours
straight, no bleeding ears, fatigue or head ache.
Full review found in Gallery section, a must read !
Peter from RZaudio (aka rabbitz) . NSW, Australia
Preliminary listening impressions - no background hum or buzz, very
quiet. Amps sound extremely nice! Nice clarity and soundstage, bass is quick
and tight.... my goodness. I would say after about 6 to 8 hrs of
play time, the sound really came into its own. The bass improved significantly,
sound stage is staggering, highs are sweet and the mids are right where I want
them. Listening to this amp play was pure pleasure. I am really looking forward
to more "seat time".
You really are able to pick
out subtleties on a CD that you have not heard before - even with my modest
Dan Dearlow, Edmonton Alberta, Canada
Wow. Everything was there. Crystal highs, space, tight and deep bass. Everything was so nice balanced, no matter what type of music we were listening. After few hours and a few beers, my brother almost started to cry when we were listening Peter Gabriel's first album
Anthony made a Stereo HPA nxV200 Amplifier for me , the improvement over the Arcom AVR300 is mind blowing More detail and bass control in movies [war of the worlds] .
Jeff William SA, Australia
is super sound. I am so happy…:-), Huge detail. In the whole audio spectrum, tight
and controlled bass, The middle range is so forward and clean without any
harshness, No harshness in the top end, Super high end sound. Perfect for me. A
little about myself I am 39 years old. I have been interested in HIFI since I
was 12 -13 Years old. And I have heard so many amplifiers in my time.
you very much for good product…