Review: Niimbus Audio US4+ Statement Amplifier (includes large high-end amp roundup)

[JeffMann]

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.

i am interested in learning why a relay-based volume control should produce better sound than an Alps RK 27 potentiometer when using a Nimbus US4+ amplifier. Could you please delineate the differences in sound quality? What about long-term reliability - as I read somewhere that the relays can malfunction with the passage of time?

Jeff.

 

[project86]

Jeff, anything in the signal path (and even some related things outside of it) has the potential to degrade sound quality. A quality potentiometer or other volume solution is a key ingredient in a really great sounding component. It's all about less stuff between you and the music.

A nice ready-made stepped attenuator from Goldpoint sells for $279 for the quad version (for balanced designs). The quad Khozmo ladder-type is $429, plus $200 extra for remote control capabilities. So these things aren't cheap in the least. The Niimbus solution is built from scratch and seems clearly more advanced than either of those.

I haven't heard a US4 with the RK27 to compare directly. But when I had a pair of V281s here, I did that exact comparison (RK27 version vs relay-based attenuator) and I heard improvements with the relay option. A bit more resolution, some imaging and soundstage enhancements, and just general clarity overall. It was subtle at first but under the right circumstances, the improved focus was very welcome. Night and day difference? No, but to my ears it was worth the upgrade money to know you have the best available sound out of your amp.

I imagine that applies even more so for a US4+ considering it is more resolving than V281, and the relay option is even more advanced this time around.

I can't speak for reliability other than to say my V281, seeing almost daily use, has no issues at all. All pots have the potential to get scratchy with age and I'm not sure relay-based solutions are inherently better or worse. Maybe someone else has data on that?

 

[smodtactical]

I like the white pcb on these amps, looks cool

 

[JeffMann]

Jeff, anything in the signal path (and even some related things outside of it) has the potential to degrade sound quality. A quality potentiometer or other volume solution is a key ingredient in a really great sounding component. It's all about less stuff between you and the music.

A nice ready-made stepped attenuator from Goldpoint sells for $279 for the quad version (for balanced designs). The quad Khozmo ladder-type is $429, plus $200 extra for remote control capabilities. So these things aren't cheap in the least. The Niimbus solution is built from scratch and seems clearly more advanced than either of those.

I haven't heard a US4 with the RK27 to compare directly. But when I had a pair of V281s here, I did that exact comparison (RK27 version vs relay-based attenuator) and I heard improvements with the relay option. A bit more resolution, some imaging and soundstage enhancements, and just general clarity overall. It was subtle at first but under the right circumstances, the improved focus was very welcome. Night and day difference? No, but to my ears it was worth the upgrade money to know you have the best available sound out of your amp.

I imagine that applies even more so for a US4+ considering it is more resolving than V281, and the relay option is even more advanced this time around.

I can't speak for reliability other than to say my V281, seeing almost daily use, has no issues at all. All pots have the potential to get scratchy with age and I'm not sure relay-based solutions are inherently better or worse. Maybe someone else has data on that?

John - thanks for the information.

I did a google search on relay-based attentuators and I found this page relating to Benchmark's version - https://benchmarkmedia.com/blogs/application_notes/benchmarks-256-step-relay-controlled-attenuator - and it seems that they have developed a very advanced version. I wonder how the Nimbus version compares to the Benchmark version.

Jeff.

 

[gebo]

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

Hi Fried,
would you be so kind to inform us about the „highlights“ of the (new) features the upcoming Niimbus DACs will be equipped with.

 

[Hellraiser86]

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

THX Fried
Sounds like a plan for my upcoming holidays because (like you mentioned) it is not the shortest route from Nürnberg to Konstanz
I am really looking forward to this.

 

[koven]

@fdg Is there US dealer for the Niimbus?

 

[project86]

I'm not Fried but I can answer that anyway - Arthur, the current Violectric/Lake People distributor for North America, will be handling Niimbus here as well. Not sure when he will have a full site up and running but you can certainly contact him via the Violectric USA site if you want to discuss.

 

[fdg]

Some words about the upcoming D/A converters under the Niimbus brand.

The cases will be as those from HPA US 4 /4+.
There will also be the prominent large illuminated volume knob.
A big point we thought about was to implement a display or not.
If yes, it would have been a black/white OLED display.
Finally we voted against a display out of the following reason:
The past showed that our gear lasts for at least 15 – 20 years of hassle free operation.
We cannot guarantee that for any display. What, if a display fails which is essential for operation after let´s say 12 years and we are unable to supply a spare part because its not produced anymore.
Shall we say to the customer: Sorry, put your DAC in the bin?
That’s not our way to deal and so we will employ some buttons to control the DACs.

The DACs will have “analog” generated supply voltages coming from two oversized toroidal transformers. Also there will be Nichicon capacitors in the power supply as well as mains voltage filters to keep high frequency noises away.

The digital architecture from both models will be the same.
Some PCM inputs, balanced, unbalanced, optical. One or two UBS inputs capable of at least 384 kHz sample rate and, yes, DSD. Most of you know that I am an admitted DSD hater because that format is good for nothing and most time the files are at least cheating if not fraud. But, give them people what they desire …
The activated input is then connected to a 32 bit resampling unit with over 170 dB theoretical dynamic range, The clock supply for the resampling is taken from our well introduced Femto-Clock from Lake People DAT RS 05. We will have 4 x D/A converter (32 Bit types) per channel to smooth the conversion process.
This is what we learned during the development from our DAC V800 to V850. An enhanced clock supply counts, as well as a converter array.

The lower positioned Niimbus DAC will have a digital 32 bit volume attenuator and re-engineered fully balanced analog output paths.

The higher positioned Niimbus DAC will have some additional analog inputs (1 x balanced, 2 x unbalanced) to use it as a combined analog and digital pre-amp.
Because of the analog inputs, the volume control is also analog and taken from HPA US 4+ (256 steps with reed relays).

The analog output signals will end in a balanced output (XLR) and an unbalanced output (RCA) which again can be used simultaneously due to independent drivers. Of course we will have the intelligent and low impedance adjustable output voltage know from DAC V800/V850, but with dip-switches on the back and not inside.

We hope to release the prototypes during the high-end show in Munich in May 2019.
Suggested prices are 3500 EUR/USD for the lower positioned DAC and 5000 EUR/USD for the higher positioned DAC (EUR prices including VAT, USD prices excluding VAT).

Cheers, Fried

 

[project86]

Thanks for the info Fried. I see your point about having a display on your products. Just recently, this very scenario played out for Cayin with their latest portable player. It had only been on the market for a year or less when the display supplier sold out of their entire remaining stock (nearly 30,000 units) virtually overnight. This left Cayin in a tough spot.

The older a device gets, the more chance of something like that taking place. Meanwhile buttons and regular LED lighting never goes out of style or becomes obsolete.

 

[jokostyle]

Yes, fore sure, it makes sense and talked very much to me.

Although i haven't -yet- discarded it for that, the touchscreen is the HPA4 feature which questionned me the most. Perhaps they did it to gain space*, but i still wonder what is the point of having it on a flagship -supposely durable- equipment.

The problem was simply resolved by turning the amp off and unpluging the power cord without Benchmark help ( the etc6849 input was enough ), but this experience represent very well one of my nightmares with any touchscreen featured on pricey gears

Got mine in... while it sounds great, my touch screen is not responding to almost any input . Really bummed out.

It has to be very special to be chosen by me against its competitors.

*

on it you get a nice graph showing your volume of both the headphone and the line output, independent MUTE buttons, -20dB dim button, input select arrows, user defined input name, BAL. button to take you to a Balance screen where you can dial in the balance for both the headphones and the line outputs independently, a brightness toggle (upper left corner) and a settings menu button!

The Balance of the Headphones and the Line outputs can be controlled independently of each other!

 

[neogeosnk]

Touch screen was software issue. Firmware easily fixed it. Also you can tell the display to go to sleep and it goes off to whatever u set. I don't see the display going out anytime soon. Benchmark products have 5 year warranty, I think I'll be fine for a while.

 

[Fegefeuer]

Sure but Lake People worry about more than 5 years after. People send in their amps to Lake Konstanz after even 15 years to have them fix a volume knob or whatever failed and imo it's great to have companies care about spare parts after such a long period instead of pointing to "buy new".

It's also why I prefer expensive Sennheiser headphones out of all others (well, Beyer has a great spare parts service as well but their headphones are not up to Sennheiser's level) because you can get your headphones fixed 20 years later.

 

[project86]

A buddy came through today with a few headphones I had never heard before - Kennerton Odin (MK1 I think), Audio Technica W1000Z, and AKG K872. Niimbus drove them all fantastically, and highlighted the strengths and weaknesses of each. My buddy was very impressed, and he is used to his very nice Trafomatic Head 2.

The Audio Technica was a bit disappointing. Very nasally and thin, much like the older AT woodies. They had gone in a somewhat different direction with W1000X and W3000ANV, and I quite liked those, but the W1000Z really needs a warm, colored tube amp.

The K872 is an odd duck as well. I really couldn't wrap my brain around them. Totally different from my K812 when it was stock, and even more different than my K812 after mods. These are supposedly very easy to drive but their owner said they sounded the best he ever heard out of the Niimbus. I'll have to take his word for it I guess.

Now, the Kennerton Odin.... that's something I could really get behind. Beautiful, rich sound, nice impact though lacking a bit of sub bass extension. Not the last word in accuracy but very enjoyable. Reminds me of my old Smeggy Thunderpants which I regret selling to this day.

The owner of all these was very very impressed with the Niimbus. His Trafomatic is no slouch and certainly adds some fun to the equation, but I think he fell in love with the honestly and resolution of the Niimbus.

 

[smodtactical]

Hey Lake People @fdg can you send out the Nimbus to other high end reviewers like @Hansotek (enjoythemusic), @grizzlybeast (earphiles), @Currawong etc to get more perspectives on this amp. Maybe a loaner program?

Thanks!