2 x Starkrimson Monoblock Amp

The Orchard Audio Starkrimson monoblock amps deliver excellent spatial imaging with detail and a sense of depth and width I’ve not had in my home before. Bass is impactful, midrange believable, and highs with no edge to them. Hard to believe these little guys do so much. GaNFET technology, in my opinion is going to rock the HiFi high end market. I rate them a solid FIVE STARS.

High value audio…well worth the money.

I had some high end class D before, the Ncore NC400, back when they were brand new. Monoblocks. Was an astounding leap over anything that I had ever heard. Then i felt like as an audiophile who likes to try new gear, that I go all in on AB just to see if *great* AB would match what I heard. I went through 4 AB amps ending in a Parasound A21+. Incredible sounding amp, extremely engaging. I listened to it very hard the night before the Starkrimsons showed up. I said, this will be a very hard act to follow. Without going into all the flowery words: the speed of these amps is incredible. You may take that as having a masterful vice grip on the recording. Nothing gets past these. Gobs of power, gobs, of control, on my CSS 1TDX Superior. I’ll give you a hint: with the Parasound I used inline FMOD 100hz filters with 12dB rollout to reduce bass output to really get performance out of that monstrous amp. With these little boxes in use, the filters are removed and I now have thwacking, riotous bass that starts and stops on a dime. These amps are superlative in any sound quality metric you are concerned with. Are they good at this? YES, whatever that is, they are fantastic. The MUSIC comes through, pure and ultra high end sounding. Ultra high end. Forget class this versus class that. There are awful AB amps and there are great ones. Same as class D. These starkrimsons are world class, a stunning achievement, and a stunning value. Be careful you don’t order something else and regret it.

Clarity and nice focus.

This small amps rock.

Outstanding clarity and openness are qualities that come to mind. Dead quiet background—perhaps the quietest amps I’ve owned. My only gripe is that the 5-way binding posts don’t accept all spade sizes, perhaps owing to a clear plastic protective cover over the spade lugs on the binding posts. I’m not sure if the clear plastic covers can be removed. But they don’t accept HAVE spade lugs.

These amps sound great with my bi-amped JBL 4344Mk2 speakers driving the three drivers that cover 340Hz up. (I didn’t try them full range, but have no reason to question their performance with the lower frequencies; I simply already had that covered with another amp.) I compared the OA amps with my Berning Siegfried 10W SET (the 811 version). There was no clear-cut winner here. On the one hand, the AO was clearly better than the SET in some important ways—lower distortion and more power. I spent a lot of time comparing them with different music. I ran a pair of balanced interconnects to get the best quality and to make switching amps fast and easy. On balance, I preferred the sound of the SET on most music, as it seemed to express nuances of tremolo and vibrato in instruments and voices more clearly. This difference was immediately obvious and not subtle. I have to wonder if I like the second harmonic distortion of the tube amp, which as an SET without negative feedback has far more than the essentially immeasurable distortion in the OA. Another explanation is that the SET has a damping factor that works more to my taste with my speakers; it’s output impedance is much higher than the OA. Very generally speaking, the dynamics of individual voices are more distinct with the SET. By contrast, the OA is far better at reproducing the collective crescendo of a whole section or orchestra. Either one is satisfying, just in a different way. For such a small, lightweight, efficient package, the OA is amazing. And for the TWO monoblock amps, an incredible value for excellent performance.

I love the amps, but I got the wrong input gain.

As a long time Magnepan owner, finding a powerful, resolving amp that didn’t cost over $4k and act like a space heater has been a challenge and long time search. After receiving and using the mono blocks for 72 hours, they are a home run. None of the issues I have had with past class AB and tube amp choices, just superb clarity and ease in handling demand in any part of the audio spectrum. I know earlier class D amps were criticized for treble but GaN behaves much better than the class AB amps I have owned for treble sweetness and clarity

I found the monoblocks good but not great. Reasons: They sounded “strident” on the high frequencies – massed strings sounded bright. Loud passages in classical music with full orchestra sounded stressed – not natural. I would like to return the mono blocks. Can I do that? I received them 2 weeks ago.

I have had the Starkrimson mono amps in my home for four weeks now. They are my first class d amplifiers. I use a very fine, purely analogue German transistor preamplifier and I use speakers with one coaxial driver for treble and midrange and two drivers each as dipole for bass. And the reproduction of the bass has always been the problem. I no longer have this worry with the Starkrimsons! It is amazing, almost unbelievable and crazy, with what force and control the bass now sounds from my speakers. The bass is not boosted, not mulled, but dry, almost slim and yet very profound.
But the highs and mids are also amazingly good. Quite different from my transistor amps before. I asked myself what is different now. The answer: the absence of any kind of artefacts. I had to get used to that at first, it sounded somehow…. naked. But also very clear and clean.

I listen to rock and pop, but professionally I listen to a lot of classical music, with strings, brasses, woodwinds, percussion with lots of overtones, sopranos, tenors, choir, etc.
This is now a great pleasure!

Big compliments to Leo!

Best regards from Lüneburg/ Germany,

Urs-Michael Theus

Very neutral. Seems to be particularly good at overcoming issues with existing long/high guage speaker wire and smallish drivers, as one encounters with in-wall systems. Because its physically small, and runs cool, its particularly well suited to be tucked away in a closet or cabinet, also something that happens with in-wall or in ceiling systems. IMO, its the ultimate solution for combining audiophile requirements with SAF (Spouse acceptance factor).

I was able to test my new pair of Orchard Mono blocks against a $6000 150w tube amplifier VTL ST-150. Not only did my pair of Orchards hold its own against this massive amplifier but they performed superior in the higher frequency ranges. A tad less bass than the tube monster but just a tad and that may be due to the orchards accuracy. A great addition to my set up!

Very impressed by the design.
Sounds great. There’s nothing more I can add another reviewers haven’t already said.
My personal experience beyond just fantastic sound has been with the in-line amp and external power supply design. Makes it easier to manage cables and hide the amp entirely.

I bought two Starkrimson monoblock amps to use with a pair of Klipsch Cornwall 4 speakers. The speakers are very efficient and tend to make a feature of any noise in the electronics. The Starkrimsons are super-quiet and my music now plays against a silent background. Not only that, but the sound is wonderful. Separation and clarity are improved and the bass is noticeably tighter and more forceful. They are a clear step up from the power amp in the GoldNote IS1000 I previously used and also a little better than the Luxman MQ-88uC tube power amp that is sometimes in my system. Despite the Cornwall’s much trumpeted affinity for low powered tube amps, surprise surprise it turns out they also love high powered, ultra-low-distortion, ultra-low-noise amps like the Starkrimsons.

The Starkrimson Mono Blocks are amazing. I am in love with my stereo system again. Every thing is better, bass, 3D imaging and control.

Used this in my biamped system for the low mids to high. Superb sound. More resolving than the 300b se amp that I was using earlier. Only difference is the slightly lower sensitivity

I have been impressed by the balance, clarity and rhythm of this amp, Bass is tight and controlled while highs are precise and detailed.
Performance matches amplifiers well above this price point. In short, great performance and fantastic value!

is this full bridge design

What about using it with unregulated power supply?

I dont see any datasets for the amplifier?

Power supply voltage? Specifications?

Nothing mentioned about that.

This is my second pair of BOSC Mono blocks. Clean crisp highs and mids, plenty of bass oomph for me and a low noise floor. Small form factor is a real bonus. I look forward to many years of listening enjoyment from these originals. Leo has been very quick in responding to any questions and his answers are always concise and to the point.

Alright, after some careful listening I can say it sounds amazingly precise, clear and tight.
There is not a hint of distortions even if I push the volume to the limit.
However there is a slightly disappointing facet to this refresh – suddenly it turned out
too much of my recordings are of a poor quality. Which became immediately obvious
with the new amplifiers. I don’t need to pay any special attention to hear all imperfections
of the old and many newer recordings (doesn’t matter if they were remastered recently
and/or sold in hi-res formats). It is just there for me to easily tell what exactly is wrong
with this or that. Which by itself takes away some of the joy. And it makes me a bit sad
the beloved oldies will never sound as good as modern hi-res recordings. Speaking of which
recordings of true quality sound so good and exciting! Deep tight articulated … well everything,
all the spectrum of frequencies. Superb balance. All instruments are apart and simultaneously
play together. And the voices, oh my.

So you can already tell I am very pleased with the purchase.
Congratulations on a great product, Leo!

Here is what my listening setup was:
DAP Shanling M5S (double AK4490 DACs) -> BOSCx2 -> Usher V-601 monitors.

The amps replaced Peachtree Decco65 (night and day really).

Fantastic sound in a small compact package.

Thanks to Leo and the AOS forum I managed to borrow a pair for a few weeks and have a listen.
Below are my thoughts.
Had a few good days listening to the amps using my Myryad preamp and various front ends – Orbe through the Firebottle Phono amp, Technics CD player and also the Raspberry Pi, using stored FLAC files and the CD player up sampling the tunes to 176.4Khz on the Pi.

Start with the TT first. Started with some simple music, not over produced with generally just voice and simple arrangements (David Sylvian being one) and found the amps to allow the music to flow without appearing to not add or subtract anything.
Found it very easy to get lost in the music and before you know it the LP had finished. Wonderful.

Next up was music with more going on, more electronic and a bit faster paced (such as later recordings by A Certain Ratio) – midrange was very good (valve like) but the bass seemed a bit more muddled compared to the Burson and the Pure Sound valve amp – no real issues with the high frequencies, perhaps a bit forward but not in your face.

Next up, let’s go digital so step forward Mr Pi. Again, started with some simple (in structure and instrument wise) using FLAC files (such as Ludovico Einaudi) and absolutely no issues – the music appears to come across with nothing added or taken away and found it enjoyable. Used the same music through the CD players and very similar to the FLAC file (apart from the Technics CD player seemed to add extra sparkle to the highs – not the amps fault!!)

Tried it using more electronic (Nine Inch Nails) and faster paced (808 State) music on CD and FLAC format. Similar to what I heard using the TT, the bass a little muddled at times but nothing too detracting and on CD, the highs sometimes brighter than using FLAC or the TT so not a fault of the amps.

Very satisfied with how the amps were performing.

Next few days I took the Myryad preamp out of the equation and used a passive preamp (thanks BigBottle) and also the Pi direct to the amps.

The main difference with the PI now going direct was the bass seemed to be grasped better than when using the Myryad so perhaps the synergy with this and the BOSC amps wasn’t quite there (will look into this later).

Using the Passive Pre, I tried the TT and found that the simpler music worked very well, although less impact from the bass than before but the rest of the audio spectrum sounded great then moved to digital music. Much as before with the same issue with CD and the highs.

Went back to the Myryad and dug out some older (not sure who made them or where I got them from) interconnects and replaced the ones from between the preamp and the BOSC amps.

Noticed a slight improvement with more complex and electronic music in the bass registers – not a massive change but a little clearer in the lower registers.

Summary.
In general, I found the amps to be very good (a slight step up on the Burson but I need to do some opamp rolling) and on par with the valve amp – perhaps better grip when the volume is cranked up.
Liked the small form factor but found the PSU’s sizes to be on the large size.
Didn’t find the sound to be ‘digital’ at all but did prefer them with more simple music (as you could probably tell with from the text above), but paired with the correct preamp and cabling I am sure will work a lot better for more complex tracks – the more I tweaked the better they sounded.

Hope the above helps anyone interested in these.