Niimbus Ultimate Series US4/US4+/US5/US5 Pro Headphone Amps - by Lake People
Nov 22, 2018 at 1:07 AM Post #151 of 1,248

JeffMann

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many times it depends on the source...i am using roon nucleus with dave/blu2.....others using different sources report different volumes etc..the 281 is a really fine amp

It obviously depends on the output of the source and DAC. I also have a V281 => Susvara and I also set the dip switch to -12. However, my volume control on the V281 operates between 9-11 o'clock because my Wyred-4-Sound 2v2SE 10th Anniversary Limited Edition DAC has a fixed output (that bypasses its volume control) of 8.3V in XLR balanced mode. Fortunately, the DAC's output voltage in "fixed output" mode can be independently set and if I set the XLR output voltage to 4.6V then the V281's volume control will operate between 11-1 o'clock if the dip switch is set at -12.

Jeff.
 
Nov 23, 2018 at 2:02 AM Post #153 of 1,248

fdg

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As you can see from the block circuitry, Niimbus US 4+ is able to receive unbalanced signals
and output balanced and unbalanced signals on its headphone- and line outputs.
Same is true for the balanced inputs.
All this with maximum flexibility as the headphone rails and the line-out rails may have independent pre-gain setings.
Thank you, Fried
US 4+ block circuit.JPG
 

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Nov 23, 2018 at 2:10 AM Post #154 of 1,248

Arniesb

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As you can see from the block circuitry, Niimbus US 4+ is able to receive unbalanced signals
and output balanced and unbalanced signals on its headphone- and line outputs.
Same is true for the balanced inputs.
All this with maximum flexibility as the headphone rails and the line-out rails may have independent pre-gain setings.
Thank you, Fried
US 4+ block circuit.JPG
I really love my V280 Mr. Fried, but... For me it lacks Volume steps at 0 gain. More steps or 128 steps relay would be really nice...
P.S how it improves over previous amps? Better parts? More transistors or something? Thank you.
 
Nov 30, 2018 at 2:42 AM Post #155 of 1,248

fdg

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I apologize for the inconveniences with the remote control for Niimbus US 4+ and the missing manual in english.
Both will be delivered ASAP when they are available.
Meanwhile please see the software control of Niimbus US 4+ attached.
Thank you, Fried
US 4+ software-en.pdf
 
Nov 30, 2018 at 4:45 PM Post #158 of 1,248

zappazappazappa

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Dec 1, 2018 at 11:57 AM Post #159 of 1,248

fdg

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@ Arniesb

You will have more attenuator travel on your V280 when you switch the Pre-Gain to -6 or -12 dB

The technical improvements of Niimbus US 4 and US 4+ over the current Violectric models:
Due to the fact that we managed to create a stable amp with a gain of -4 dB (+2 dB for balanced outputs) we could expand the dynamic range and tailor it to a useful point.
Meaning, we achieve 135 dB dynamic range not by more output voltage swing on the top end (where you can hardly use it when driving low impedance cans) but a more silent amp through low gain on the low end. The noise figure is over 10 dB better compared to the Violectric series.
The opinions of all listeners are quite similar: blackest background, more open and transparent, enhanced stage ... and so on.
When you´ve got an hour or so of time just read here:
https://www.head-fi.org/threads/rev...r-includes-large-high-end-amp-roundup.886668/
 
Dec 2, 2018 at 2:49 AM Post #160 of 1,248

Arniesb

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@ Arniesb

You will have more attenuator travel on your V280 when you switch the Pre-Gain to -6 or -12 dB

The technical improvements of Niimbus US 4 and US 4+ over the current Violectric models:
Due to the fact that we managed to create a stable amp with a gain of -4 dB (+2 dB for balanced outputs) we could expand the dynamic range and tailor it to a useful point.
Meaning, we achieve 135 dB dynamic range not by more output voltage swing on the top end (where you can hardly use it when driving low impedance cans) but a more silent amp through low gain on the low end. The noise figure is over 10 dB better compared to the Violectric series.
The opinions of all listeners are quite similar: blackest background, more open and transparent, enhanced stage ... and so on.
When you´ve got an hour or so of time just read here:
https://www.head-fi.org/threads/rev...r-includes-large-high-end-amp-roundup.886668/
Thank you Fried i im sure i might buy atleast us4 1 day. P.S i always prefer gain of 0db i dont know why i just cant match impact and dynamics with lesser gain settings regardless of wolume...
 
Dec 2, 2018 at 1:20 PM Post #161 of 1,248

rgs9200m

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Hi Fried and thanks. I asked a question in the other thread for which you provided the link for an explanation instructions on setting the dip switches for input pre-gain and output gain. Thank you.
(It's an excellent sounding amp with fine texture and solidity and a nice humanity in the overall sound.)

And this amp runs nice and cool at all times! That's really important on your desktop. It's such a nice refined sound and has a great look and feel with great craftsmanship.
 
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Dec 3, 2018 at 2:21 AM Post #164 of 1,248

rgs9200m

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My Niimbus impressions:

What jumps out at me is that it is a detail monster, with much more plankton than I was used to from familiar recordings. It shows the complexity of the musical event.

It's strange, but it sounds like the kind of change I would expect from a new enhanced DAC rather than an amp. (I could have been fooled into thinking that I had a new DAC actually.)

There is just more clarity to the texture of each musical object, but it's not grain, it's just more focused.
And the images are nice and robust.

It's well defined, but it's not harsh at all. It's also not a thin sound. Strings and higher pitched voices and instruments like woodwinds are silky and continuous.

And related to this is image placement, with spatial aspects of sound sources and their boundaries more evident than I am used to.
The soundfield is very good, with air around things, so if something is on the left or right, it resists collapsing into the left or right driver.
I guess this is called transparency.

At the same time, things are not bright or shrill or subject to digital glare which always can make me cringe in fear. It is not at all clinical. In fact, it seems to tame digital glare.

I wouldn't call the sound liquid or dry or bloomy or trying to be tube-like, it's just there.

So this is not a rolled-off sound, but it's not a for-better-or-worse sound either, since I didn't hear anything painful even on pop/rock recordings.
And instrumental material really comes alive, full of drama.

Things ding and bang and shimmer and soar in very joyful way.

And the detail extends to the bass, which is very solid and deep with no hangover.
Percussion is also really nice, with great slam and thump.

Overall, the one word I would use to describe the sound is convincing, meaning that I was convinced the sound I heard was not covered up or over-processed in any way.

It's all about insight and discovery since I'm hearing more and more in my old familiar music in an unforced but dramatic way. It's quite a glorious sound I have to say. So I am very happy with it. I just can't turn away from the sound. There's a sort of new grandeur to it.

But again, if you are looking for a mellow, glowing, sugary or syrupy style sound, this is not it. But still, it is organic and lifelike and easy to listen to, and very compelling, so it's a keeper for me.
 
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Dec 3, 2018 at 2:42 AM Post #165 of 1,248

rgs9200m

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I've done my main listening for these impressions with a Chord DAVE feeding the Nimbus and a Hifiman Susvara using a balanced Dana Lazuli Reference headphone cable and a pair of Stealth Sakra single-ended interconnects.
I use a Shunyata Anaconda Alpha power cable on the Niimbus and a Telwire HC power cable on the DAVE.
Music is from my own pcm and dsd files on a Windows computer using USB input to the DAVE.

The Niimbus is replacing a Rudistor RP010B I've had (and been a big fan of) for 7 years.
 
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