Review: Niimbus Audio US4+ Statement Amplifier (includes large high-end amp roundup)
Aug 19, 2018 at 1:55 AM Post #16 of 153

gebo

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Tough to say, as it really depends on what I'm in the mood for at that particular moment. As I mentioned in the write-up - the Niimbus really lets you hear the true character of the source, even highlighting the differences in transport quality (which can be tough to discern in many other situations).

I spent a lot of time with the Resonessence Signature DAC, along with a modded HD800. That combo is about as transparent as it gets without resorting to Stax. Supremely neutral and revealing of every little detail, without being overly bright or boring. A true reference sound that works best with exceptional recordings, very unforgiving on lesser material.

The W4S Anniversary Edition is nearly as revealing, but also a bit thicker, more tonally dense, more impactful. I like it best with Susvara and a few others too. Excellent for electronica of all types, beautiful with classic rock, and a lot more tolerable with mediocre material.

The Assemblage DAC is rich, creamy fun. Better than the Sonic Frontiers which is also fun but a bit too dark for my tastes. This is my choice, paired with the original HE1000 or Abyss, for playing modern recordings that aren't exactly audiophile quality, as well as grimey hiphop and rock like Bad Brains etc.

The Exogal comet Plus is actually very close to the Assemblage. The Niimbus let me hear the improvement made by the upgraded WyWyres umbilical between DAC and PSU. Anyone searching for that classic Assemblage PCM1704 sound from a modern, reliable package that can also do hi-res/DSD, this is your machine.

The new iFi Pro iDSD is actually very similar to the Resonessence Labs sound, for 3x less money. It's not quite on the same level, but goes pretty far in that same direction. Also you can easily tweak it to sound warmer/smoother/etc. Very impressed with it thus far.


I could go on and on. Basically all of these sound great, while some other DACs (my Esoteric D-07x for example) show themselves to be lacking considering the competition.
project86: Thank you very much!
One additional question: What are the differences between the „Standard“ Resonessence Labs Mirus Pro and the „Signature Series“?
 
Aug 20, 2018 at 8:51 AM Post #17 of 153

tonyo442

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[QUOTE = "project86, post: 14426259, member: 51179"] Tout d’abord, je veux évoquer ce thread existant qui a commencé il ya environ 6 mois. La menace a commencé par une sorte d’aperçu, et le PO a fait un excellent travail en gardant le premier message mis à jour au fur et à mesure de la disponibilité des informations. Je publie ceci ici afin qu'il ne soit pas enterré dans les nombreuses pages existantes, mais aussi parce que je pense que les comparaisons d'amplis peuvent intéresser les lecteurs de Summit-Fi.

Maintenant, pour mes réflexions sur l'ampli casque Niimbus US4 +.

 
Aug 20, 2018 at 8:52 AM Post #18 of 153

tonyo442

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hello, try all these materials had to be a huge job, all notes, passages of music, take landmarks and many others, .... its counting the connections of each material, and especially to get to always make the difference between two products, very good and very big work, ......

on the other hand, if you allow, are you an enlightened amateur or a professional with any interest on certain products which you rename permanently,

like you and many other fans of headphone amps and headphones, I could make comparisons, and for the moment I stopped on the Moon 430 HA (no dac) for me the card is not delivered not too bad, but a map not very elaborate a troubleshooting card that can wait to have a Dac better quality, so you are questioning the Moon 430 HA, is it the sound amp headphone who is veiled or the built-in headphone amp with the small dac card, why not have chosen a top-level Dac, a reference, ...... and then do some tests with each separate headphone amp,

personally i have the lcd4 plugged into the ifi pro ican, and T + A dac8 with a very nice analysis in the low medium, and asymmetrical connection that brings a more beautiful transparency, much more than the symmetrical or one doubles the components , as the mains treatment with a direct line of the counter and inverter double conversion, I am therefore permanently connected to batteries, at 50 Hz and 230 volts, +/- 1% of variation,

it is true that the Moon 430 HA headphone amp does not go too well with the lcd4, but the Moon has never been veiled, after course some will have prestige helmets and dac 30 or 50 €, of course the resolution will be dull or veiled, ...... and honestly for me there is no built-in, headphone amp and dac and have been wonders, it's just pure commercial, no purist believes it,

many other helmets or headphone amps may seem very flattering in the high frequencies, maybe you prefer the simplistic systems, as it also depends on the music you listen to, on lyric, masses, choirs, maybe even the lcd4 goes further than the Susvara, simply it is necessary to know how to appreciate the differences and to listen to them, of course that the effect of mode of the lcd4 is passed, and each owner of helmet wants to evolve and in spite of the technology, the research which is justifies a € 6000 headset, as the fashion effect was on the focal Utopia, you knew that many headphones have sold themselves without even being listened to, and yes the ad, ..... the ad, .. ... and believe that the ideal headphone amp exists, like the ideal headphone, ...... thank you
 
Aug 20, 2018 at 11:22 AM Post #19 of 153

project86

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Great review, John. Appreciate you taking the time to do it.

Thank you!


project86: Thank you very much!
One additional question: What are the differences between the „Standard“ Resonessence Labs Mirus Pro and the „Signature Series“?

The Signature Series upgrade involves a new custom toroidal transformer, new opamps, and possibly some other "secret sauce" that hasn't been fully explained to me. It's not a massive revolution in sound, but more like an evolution over the already superb Mirus Pro.


hello, try all these materials had to be a huge job, all notes, passages of music, take landmarks and many others, .... its counting the connections of each material, and especially to get to always make the difference between two products, very good and very big work, ......

on the other hand, if you allow, are you an enlightened amateur or a professional with any interest on certain products which you rename permanently,

like you and many other fans of headphone amps and headphones, I could make comparisons, and for the moment I stopped on the Moon 430 HA (no dac) for me the card is not delivered not too bad, but a map not very elaborate a troubleshooting card that can wait to have a Dac better quality, so you are questioning the Moon 430 HA, is it the sound amp headphone who is veiled or the built-in headphone amp with the small dac card, why not have chosen a top-level Dac, a reference, ...... and then do some tests with each separate headphone amp,

personally i have the lcd4 plugged into the ifi pro ican, and T + A dac8 with a very nice analysis in the low medium, and asymmetrical connection that brings a more beautiful transparency, much more than the symmetrical or one doubles the components , as the mains treatment with a direct line of the counter and inverter double conversion, I am therefore permanently connected to batteries, at 50 Hz and 230 volts, +/- 1% of variation,

it is true that the Moon 430 HA headphone amp does not go too well with the lcd4, but the Moon has never been veiled, after course some will have prestige helmets and dac 30 or 50 €, of course the resolution will be dull or veiled, ...... and honestly for me there is no built-in, headphone amp and dac and have been wonders, it's just pure commercial, no purist believes it,

many other helmets or headphone amps may seem very flattering in the high frequencies, maybe you prefer the simplistic systems, as it also depends on the music you listen to, on lyric, masses, choirs, maybe even the lcd4 goes further than the Susvara, simply it is necessary to know how to appreciate the differences and to listen to them, of course that the effect of mode of the lcd4 is passed, and each owner of helmet wants to evolve and in spite of the technology, the research which is justifies a € 6000 headset, as the fashion effect was on the focal Utopia, you knew that many headphones have sold themselves without even being listened to, and yes the ad, ..... the ad, .. ... and believe that the ideal headphone amp exists, like the ideal headphone, ...... thank you

Sorry but I can't make out what you are getting at here.
 
Aug 21, 2018 at 10:25 PM Post #22 of 153

JeffMann

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Jeff:

No doubt John can answer your question better than I can.

However, elsewhere in the review he says, "The result is an amp...topping out at 7W per channel at 50 ohms." Compare that to the V281's balanced output rating @50 ohms of 4,200 mW (4.2 W) from the Violectric USA website. So clearly the Nimbus is more powerful than the V281 in absolute terms.

I believe that paragraph addressed the fact that the Nimbus has a drastically lower noise floor than other amps (by design). This brings back a faint memory of reading descriptions elsewhere of Violectric's amp design philosophy, which emphasizes high output power with the lowest overall circuit gain.

That's inherently confusing to this non-electrical engineer or circuit wonk--but if true, it suggests the Nimbus comes even closer than the V281 to meeting Violectric's design objectives for amplifiers.

How does that lower noise floor translate into better sound - considering the fact that I am not aware of any background noise when listening to music with my present audio system based on the use of a V281 headphone amplifier (PS Audio PWT => Wyred-4-Sound 2v2se 10th Anniversary Limited Edition DAC => V281 => Susvara headphone)?
 
Aug 23, 2018 at 3:53 PM Post #24 of 153

smodtactical

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Thank you. Glad you enjoy your V281.

I personally like the V281 a tad better than the GS-X mk2. While the GS-X is very detailed, it sometimes exhibits a tonal balance which I don't much care for. Just a bit too analytical I guess. One could certainly build a great system around it though.

I have not heard the Well Headtrip. But from pics I can find, the internals don't inspire a lot of confidence.

Thanks for your fantastic review. Hey please don't dismiss the HT just based on that picture. People I have talked to have been supremely impressed with the HT comparing it favourably to the EC Studio. Also staff members from Wells audio like @piperfect have reported that picture is from one of the early units and that the new units are much better.

So if you could get a chance I'd love if you could listen to the HT or HT reference to compare it.
 
Aug 25, 2018 at 12:14 AM Post #27 of 153

fdg

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Just chiming in to answer a few questions.

Is Niimbus the V284 we talked about some time ago?
Yes and no. We had plans to relase an amp over V281.
As V281 turned out to be our most successful amp we analised customers demands and wishes the past years.
The results - even to questions never asked before but significant enhancements for us - is Niimbus US 4 and US 4+.
As all this turned out to be more costly than intended we also created a new brand name under which features are covered which are, well, more than standard ...

Also we wanted the owners of Niimbus amps to not any more open the case to install options or set dip switches.
The result is:

Niimbus US 4 which can be seen as the enhanced Violectric HPA V280.
- Two inputs, unbalanced and balanced, to be activated from the back.
- Volume control via Alps RK27 attenuator
- balanced and unbalanced line-out connectors on the back, switchable to pre- or post-fader operation.
Thats all - a headphone amp with some basic features but outstanding sound signature.

Niimbus US 4+ can be seen a the enhanced Violectric HPA V281 with remote control and relay attenuator.
- three inputs, 1 x balanced, 2 x unbalanced, switchable from the front
- motorized volume control via 256-step reed-relay attenuator
- balanced and unbalanced line-outputs on the back, switchable to pre- or post-fader operation via software
- headphone outputs and line outputs can be de/activated from the front panel
- remote control for volume, input select, output select, mute

Despite the outstanding sound you get much more features you maybe have never thought about or asked before:
- delayed switch on, instant switch off during power on/off to protect your expensive headphones from DC issues during powering on and distortions during powering off.
- DC control of the outputs to protect your headphones from unhearable DC currents which may come from the amp itself (malfunction) or the inputs
- Overload control to avoid heavy distortions generated by the amp due to too large internal signals
- enhanced Pre-Gain settings with a range of 36 dB (-12 ... +24dB) to cover virtually all possible input voltages and all headphone impedances / sensitivities and provide a large travel of the volume control
- line-output voltage adaptable within a range of 24 dB (-12 ... +12 dB) to ensure a matching output voltage to the following gear
- adaptable brightness of the LEDs and the illuminated gap of the volume control (only US 4+)

... and yes, after the launch of the upcoming Niimbus DACs and 2 or 3 other nice analog items which are a bit secret by now ... there will be probably even more.
But if and when this will come true is surely not to be answered in 2018 or 19 or 20.

Cheers, Fried
 
Aug 25, 2018 at 5:40 PM Post #28 of 153

project86

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Thank you Fried. That brings out a difference between the US4 and US4+ that I had somehow missed - the US4+ has the fancy volume control, whilst US4 has a more standard RK27.

From my prior comparisons of V281 with RK27 vs V281 with the relay-based solution..... it makes a sonic difference. Not massive, but it's there. I imagine on the more transparent Niimbus it would be even more of a substantial improvement.

All this to say: in my very humble opinion, it seems like the US4+ is really the one to go for.
 
Aug 25, 2018 at 7:46 PM Post #29 of 153

Hellraiser86

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I am looking for a amp in this price range quiet a while. I really like the sound from the v281 (the best I have heard today) and it would be a great match for my adi-2 pro. but after i have stumbled into this thread ... :D
Now I want to hear the US4+ too!!! But unfortunately I do not know where I can do this :frowning2: It is so unsatisfying to live nowhere nearby a shop that has this brand...
 
Aug 25, 2018 at 8:56 PM Post #30 of 153

fdg

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I am looking for a amp in this price range quiet a while. I really like the sound from the v281 (the best I have heard today) and it would be a great match for my adi-2 pro. but after i have stumbled into this thread ... :D
Now I want to hear the US4+ too!!! But unfortunately I do not know where I can do this :frowning2: It is so unsatisfying to live nowhere nearby a shop that has this brand...

No problem, as I can see you are from Germany.
Just come by to have a listen. Konstanz is a nice place to be - although far from any other place in Germany.
From October on there should be some dealers having the Niimbus line.

Cheers, Fried
 

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