As a headphone / preamp companion to my upcoming dCS Rossini, I am seriously considering the Niimbus US 5 Pro Headphone Amplifier.
The US5 Pro adds an additional balanced headphone connection. Since the 4.4mm Pentaconn connector has gained popularity as a new balanced headphone connection standard we have decided to add this feature and renamed the the product the US5 Pro. All other features and specs remain the same as the US4+.
The Niimbus US5 Pro will ship mid June, 2021.
Any headphone amplifier from HeadAmp is highly recommended. The GSX Mini - or better yet the GSX MK2.
Focal used the GSX MK2 together with the Naim nDAC during the development process of the Utopia headphone.
As for Violectric I found the V550 to be better than the previous V281. I have not had the chance to demo the Nimbus other than a quick listen 2 years ago at CanJam NY.
Moon 430 HA and Benchmark HPA4 - stay away from the Moon, the Benchmark while technically proficient, was not my cup of tea.
Best
Gregg
PS - there is always STAX - however that is a topic for a new thread. HIGHLY recommended
I have both, and will test them, and the new Niimbus, with my upcoming Abyss 1266 TC (and maybe Hifiman Susvara). All three can drive them well - on paper- but the proof is in the pudding.
I cannot wait 
This is an intriguing offering. I need another headphone amp like I need another . . . . . (fill in the blank). But I have always like the Lake People approach and product lines,.and at less than half the cost of a Primavera, this might be a very good option.
I have two of Fried Reim’s amps that I really like (Lake People HPA RS08, Violectric V200). My favorite remains my trusty Bryston. Needs to be fed with 2V through XLR, 6V is a bit too hot for its liking.
Not yet, I am waiting for dCS to make announcements about near future changes to their programme, to see if these will affect my choice. Vivaldi successor? Vivaldi 3.0? Rossini 3.0? Headamp offering, or Rossini with headamp?
I’m in the same boat as yours!
Personally I am extremely satisfied with the WooAudio 3ES-Elite edition amplifier in combination with the very good Takatsuki 300B tubes.
Yes indeed I would bet that is superb. However it is in an entirely different price league ( !!) especially with the Takasuki 300Bs. It is also for electrostatic cans which places it in another category
Incidentally I heard the new Cossor replica WE Royal 300Bs last weekend in my friend’s monobloc push/pull amps driving Quad ESLs. Outstanding sound. Maybe not quite as good as the Takasakis but fabulous and fabulous value too.
To Gregg and other headphone users.
I’m new to using headphones and also a headphone amp. Largely based on Gregg’s review, I’m considering purchasing a HeadAmp GS-X Mini. I originally thought that I’d connect the GS-X Mini to the XLR outputs of my Rossini and realized I wouldn’t be able to listen to my turntable and CD player as these 2 sources don’t go through the Rossini. The other option I’m considering is to connect the GS-X Mini to the XLR outputs of my Gryphon Pandora preamp as all my sources are connected to the Pandora preamp.
My question is will this Pandora preamp to GS-X Mini connection method compromise the SQ of the GS-X Mini and ultimately the headphones? If this is an acceptable connection method, what gain level should I set the Pandora preamp to so I’m not under driving or overdriving the voltage level fed to the GSX-Mini?
Thanks in advance,
Brian …
The standard way of connecting a headphone amp to a preamp is to use the tape loop. That is not always supplied but looking at a picture of the Pandora, and if correct ,this appears to have a tape loop via RCAs. Tape loops do not apply any processing to the signal i.e. they are effectively unity gain. So there us no gain level consideration needed as it is just a connection and no amplification etc. is involved.
It’s how my headphone amp is connected to my preamp (then to my Vivaldi.) The main consideration you then need to make is about a decent RCA/RCA wire.
Thanks for the quick reply Pete. Yes, my Pandora preamp has a tape loop. I may have misunderstood some of the posts here thinking that some people suggested connecting a headphone amp via XLR (Balanced) connections for optimum SQ.
Thanks,
Brian …
You did not misunderstand. Connected with XLR almost always sounds better. In that case, however, you need to invest, in extra XLR cables, and in something like this:
I run my headphone amp directly from the xlr’s on the vivaldi dac. I use the RCA’s into my naim 552.
I found this worked slightly better than going through the pre amp. That might be because it’s all balanced right the way through ? Not sure but it sounds good.
Set up is violectic 281 headphone amp in standard trim, running balanced xlr’s in, and balanced cable out to my sennheiser 800s
I’m running the Headamp GSX-Mini (looped through from a Headamp Blue Hawaii) on 7m-long XLR leads from an Accuphase preamp. The preamp serves to connect all sources and to control volume; the GSX-Mini and Blue Hawaii both have stepped attenuators which I’ve turned to the max 
(The Accuphase preamp also drives a power amp, the preamp has two sets of XLR outputs so no cabling issues there.)
@ermo Emo, thanks for your reply re: an XLR connected headphone amp sounding better than using RCA cables. The cost of the cables is a wash as XLR and RCA cables are approx the same cost. I don’t understand the need for a 3in x 3out switch as my Gryphon Pandora preamp has 2 sets of XLR outs, one currently used to feed my Gryphon amp and I would think I could use the other XLR out to feed a headphone amp.
Am I missing something?
Thanks,
Brian …
@Paul_Bemelmans Thanks Paul. I think you may have answered my question as your setup is similar to what I’m considering. Your Accuphase preamp and my Gryphon preamp both have 2 sets of XLR outs, one for the amp and the other can be used for a headphone amp. You may have also answered my other question by setting the GS-X Mini attenuator to the max and use my Gryphon pre-amp to control the volume to the headphones.
Please excuse my ignorance but I don’t understand why you use a Blue Hawaii and a GS-X Mini. I’m only planning to use a GSX-Mini. Is the Blue Hawaii for special types of headphones?
Thanks,
Brian …
