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500W Ultra-high performance state-of-the-art audio power amplifier modules utilizing gallium nitride (GaN) transistors.
Product Documents
Rev 3.0 Instructions
Rev 2.0 and Earlier Instructions
All About The Orchard Audio Starkrimson Ultra Amplifier Module …
The Starkrimson Ultra 500W Amp Module brings Orchard Audio’s flagship GaN amplifier technology to the DIY and OEM world, delivering reference-grade performance in a compact,integration-ready format. Built on the same architecture as the award-winning Starkrimson Ultra monoblocks, this module offers exceptional resolution, lifelike dynamics, and effortless control — all while giving builders the freedom to design their own chassis, power supply, and system layout.
Switching at 0.8 MHz, the Starkrimson Ultra 500W Module achieves speed, transparency, and transient accuracy far beyond traditional Class‑D designs. Its fully balanced signal path and proprietary dual‑feedback architecture ensure ultra‑low noise, low distortion, and stable operation even with extremely difficult speaker loads.
Whether you’re creating a custom stereo amplifier, a multi‑channel home theater system, or a high‑performance active speaker, the Starkrimson Ultra 500W Module delivers true high‑end sound in a flexible DIY‑friendly package.
What Makes the Orchard Audio Starkrimson Ultra Amplifier Module Special?
This module is engineered for builders who want the full sonic benefits of GaN technology without the complexity of designing an amplifier from scratch. Every aspect — from the high switching frequency to the balanced topology — is optimized for transparency, speed, and musical realism.
Here’s a snapshot of the key highlights:
- 500 W into 4 Ω / 250 W into 8 Ω — serious power for demanding speakers
- GaN transistor technology for ultra‑fast switching and exceptional transient response
- Fully balanced signal path from input to output
- Proprietary dual‑feedback architecture for stability and accuracy
- 2‑ohm capable and 1‑ohm stable for extremely difficult speaker loads
- Compact, integration‑ready module ideal for DIY and OEM applications
- Ultra‑low noise and distortion for high‑resolution audio systems
The result is an amplifier module that behaves like a “flat wire with gain,” preserving the nuance, texture, and spatial detail of your recordings.
Designed for Real-World Music-Loving DIY Builders, Engineers, and System Designers
While some high-end gear prioritizes looks and/or specs over musicality, Orchard Audio’s approach balances both. The Starkrimson Ultra’s GaN-based Class-D design delivers extremely low noise, combined with low distortion and impressive transient response — giving you clarity and control without heat or wasted power.
Because it’s fully balanced from input to output and built with a modern proprietary dual-feedback design, the Starkrimson Ultra doesn’t just produce power — it preserves the nuance and texture of your recordings. Reviews and listening reports highlight its ability to bring out micro-detail and layering in music that can get lost in lesser amps.
Whether you’re listening to jazz, classical, rock, or electronica, this amplifier stays composed and musical through complex passages.
The Starkrimson Ultra 500W Module is built for enthusiasts and professionals who want high-end performance with complete design freedom. It’s ideal for:
- Custom stereo or mono amplifier builds
- Multi-channel home theater amplifiers
- High-performance active speaker systems
- DSP-driven or crossover-integrated designs
- OEM integration into commercial products
- Compact or space-constrained enclosures
Its balanced input stage and robust output section make it easy to pair with modern DACs, preamps, and DSP platforms.
How the Orchard Audio Starkrimson Ultra Amplifier Module Fits Into Your Audiophile System
This module integrates seamlessly into a wide range of DIY and professional applications:
- Pair it with your preferred power supply
- Linear or SMPS — the module is designed to accommodate both, depending on your goals for noise, efficiency, and enclosure layout.
- Pair it with your preferred power supply
- Its compact footprint allows for creative mechanical layouts, short signal paths, and optimized thermal management.
- Build multi-channel systems
- Perfect for home theater, active speakers, or bi-amp/tri-amp configurations.
- Combine with balanced sources
- Its fully balanced architecture ensures clean, noise-free operation in high-resolution systems.
The Reviewers Are Raving About the Orchard Audio Starkrimson Ultra Amplifers
The audiophile press is raving about the Orchard Audio Starkrimson 25 GaNM Power Amp. Here’s what they have to say…
Mark Marcantonio – Audio Pursuit (September 2025)
"Therefore, if you’re looking for terrific clarity, top notch, resolution, point point wiring, in high power, especially for speakers, such as Magnepans, I cannot encourage you enough if you’re in the market get in touch with Leo at Orchard Audio and give yourself some time with the Starkrimson Ultra or another one of his amplifiers, they are the real deal. My highest recommendation."
John Hoffman – Positive Feedback (September 2025)
"The Starkrimson Ultra Mono Premium amplifiers possess stellar vocal reproduction, and I was mightily impressed with how capable this affordable set of amplifiers is.” and “The reproduction of Branford Marsalis’ soprano saxophone on Mary Chapin Carpenter’s piece “John Doe No. 24″ is similarly impressive."
Mike Prager – Future Audiophile (January 2025)
"If you’d rather put every audiophile dollar towards performance, you and Orchard Audio’s Leo Ayzenshtat are on the same track (as am I), because for sound, these Starkrimsons rival or surpass any amp I’ve heard at anywhere near the price. They are perfect for any audiophile whose top priority is outstanding sound at a fair price.“Additional reviews can be found here:"
Who is the Orchard Audio Starkrimson Ultra Module Best Suited For…?
This module is ideal for:
- DIYers seeking flagship-level GaN performance
- Builders who want serious power and control in a compact module
- Systems requiring balanced signal paths
- Projects where speed, clarity, and neutrality matte
- OEMs looking for premium audio performance in a modular format
- Enthusiasts building amplifiers for difficult-to-drive speakers
If you want the sonic benefits of GaN technology in a flexible, high-power module, the Starkrimson Ultra 500W is the perfect foundation.
Want to Learn More?
The Starkrimson Ultra 500W Amp Module brings Orchard Audio’s cutting‑edge GaN engineering to the DIY and OEM world. With its high switching frequency, balanced architecture, and serious power delivery, it gives builders access to true high‑fidelity performance — without the limitations of off‑the‑shelf amplifier boards.
Product Specifications
Full product specifications at this link:
Read more here
Warranty / Return Policy
One (1) year warranty included.
Return / Refund Policy
Customs Disclaimers (for non-U.S. customers):
Any customs fees are the customer's responsibility.
We won't under-value merchandise or mark the item as a gift on customs forms. Doing that is
against U.S. and international laws.
Shipping Information
| Weight | 1 lbs |
|---|---|
| Dimensions | 8 × 8 × 7 in |
David S. –
These are replacing DIY 25 watt per channel class A amp. In looking to upgrade to get more power for dynamics, I was considering a class A/B stereo amp the consumed 500 watt at idle and did some math on the electricity cost. Going class D was not something I was considering, but I saw a convincing YouTube review of the Starkrimson Ultras. So, I purchased the amps, individual power supplies, and the capacitor upgrades; I also added solid copper binding posts. The monoblocks have a defined bass, more instrument separation, more realistic sounding instruments, and a natural sound. It was a shock to hear all of the extra detail when I first set them up. I have noticed many songs (not all) that I did not think were recorded very well sound much better than on my old amp. The cliche audiophile jazz recordings used to sound very good on my old amp. Now, with the Starkrimsons, I really understand why they are rated so high. I am really enjoying the amps. It was not planned, but being able to see the LEDs on the power supply through the vent holes eliminates the need for a front panel LED.
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Leo A. –
Thanks for the great feedback. I’m thrilled the Starkrimson Ultras brought out such depth and realism in your setup. It’s especially rewarding to hear they surpassed expectations. Appreciate you trusting my amps to take your system to the next level.
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Mike H. –
After upgrading to a PMC MB2se, our existing class AB amp couldn’t drive to speaker satisfactorily. The Starkrimson Ultra had no issues in this regard, maintaining absolute control and grip, with no perceptible distortion at all volumes. All the while, it was cool as a cucumber, so no more need for big, heavy heatsinks. Very happy!
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Leo A. –
Wow, that’s fantastic to hear! Thanks for sharing your experience with the Starkrimson Ultra modules. Glad you ditched the bulky heat-sinks too – keeping cool is a big perk!
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Eric S. –
Well built and sound great. Excellent customer service from Leo!
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Leo A. –
Thank you.
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Gregory L. –
They have not shipped yet , can not comment.
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Leo A. –
Thank you for the feedback. I am working to get orders shipped as quickly as possible. I am sure you will be very happy with the product.
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David J. –
From the first moment playing music with the ultra-amp modules, I was blown away. You could defiantly hear the difference coming out of my speakers and I’m still enjoying My music
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Leo A. –
Thank you.
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Gordon R. –
I am not an electronics pro. Had a few goofs building it and Leo helped me. The Starkrimson Ultra still came out great. Sounds open, clear and quiet. Gobs of power and great dynamics. Orchard audio A+
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Leo A. –
Thank you.
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Jeffrey B. –
Received kit from the US 2 days after it was shipped and found it very easy to assemble using Leo’s video series and a couple of email exchanges with Leo. All parts look very good quality and everything needed to complete the amp was contained in the kit. Leo’s support is outstanding.
This amp sounds superb. I am using it with The Orchard Audio Pecan Pi streamer/DAC and the clarity and soundstage are better than most systems I have heard. This is true for the whole frequency range. Live recordings, especially with acoustic instruments have a 3D staging. A superb amplifier!
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Leo A. –
Thank you.
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Dante K. –
It is not a secret that if we want the best sound quality and the best performance we need to go to separate components. Wives might not like it because it can be messy and a bit complicated to listen to music.
I didn’t go with the best of best for each component, because I had a limited budget, but tried to select the best value for each one.
Following is the configuration for my sound system:
Raspberry Pi 4 with Pi2AES hat for music streaming
Denafrips Ares II DAC
Topping PRE90 preamplifier
Schiit Vali II tube preamp
Orchard Audio Starkrimson Ultra GaN HiFi amp
Heco Aurora 1000 / Polk R200 speakers
Vintage Velodyne CT100 subwoofer
I will be limiting this review to Orchard Audio’s Starkrimson Ultra amplifier, and I am not sponsored or linked with any of the manufacturers described here.
I’ve tried different brands and models for each component, but the one that made a huge impact on the overall performance was when I tested the Orchard Audio’s Starkrimson Ultra amplifier. I have decided to order the DIY kit, in order to save some money and also because I enjoy building equipment.
I had excellent communication with Leo from Orchard since when I was configuring the Starkrimson kit. I’ve received the kit earlier than the estimated availability date, and I don’t want to get into details here, but the assembly was not as smooth as I would desire. Again, Leo helped me to resolve the issue, and it took longer than predicted to have it fully working.
Starkrimson product was designed with premium components in order to deliver a system with refined sound quality. Starting with the enclosure. I knew it was good because it uses the same source company as Nelson Pass products.
Power supply is a switching PSU, and even though several people still think that a linear PSU is better for audio equipment due to its lower noise, the traditional linear PSU requires a bulky transformer and large filter electrolytic capacitors. Besides its weight, they are relatively expensive and not very efficient. Regulated power supplies are more efficient, smaller and lighter, but are relatively complex and expensive.
Starkrimson’s switching PSU is a modern, efficient and high current capability one, with small footprint and light. It has also an inrush current limiter module, which is normally required on equipment with large transformers. I personally don’t think it is required on switching power supplies, but it doesn’t hurt, and for sure it will somehow improve reliability and life.
I had never tried a Class D amplifier, because of its drawbacks, which I don’t want to bring up here. All my amps were either class AB or A. Sound quality on class A amplifiers is excellent, but they are good ones to be used in the winter…. They are not very powerful and extremely inefficient. Then I’ve started hearing about GaN transistors used on HiFi amps, but the regular commercial amps with GaN were extremely expensive, much over my budget. A friend of mine suggested trying the Orchard’s amp, and after reading several positive reviews about it, I’ve decided to give it a try. It is not the least expensive component in the system, but I can tell that it is worth every single penny on it. Leo has designed it very carefully and I don’t see anything that could be modified to improve it. Using GaN transistor is not just replacing the MOSFET in a regular class D amplifier, due to the much faster switching, you can imagine what happens if both transistors on the output switch to ON state at the same time!
All components connected and listening to music for the first time. What a surprise!!! Bass is firm, strong, very solid, at a point that I had to reduce the volume on the sub, and change the cut-off frequency. Vocals are superb, pure, super natural. Highs are much more pleasant to listen to. In summary it has improved the whole range of frequencies. Transients are clear and perfect. The sound quality is like a class A amplifier, but with much higher power and extremely efficient. Even after playing music for more than 10 hours at a reasonably high volume, the temperature of the enclosure is almost at the same as the ambient temperature; maybe a few degrees over. Besides everything I’ve mentioned, Starkrimson is an extremely quiet amplifier.
I personally like a bit “rounded” sound, that’s why I have added a Schiit’s tube preamp between the Denafrip’s Ares DAC and the Topping’s PRE90 preamp.
I’ve tried a few different speakers like Elac, JBL, Klipsch, Polk, Heco, and Starkrimson can drive any with no problems. My final configuration is with the Heco’s Aurora 1000 speakers, which provided the best sound at least for me. It matched perfectly the Starkrimson’s excellent product . I guess most of the people never heard about Heco, but it is a traditional audio equipment manufacturer in Germany.
If you are seeking for a near perfect sound fidelity, Starkrimson is the way to go, without hurting your pocket. Price/performance is unbeatable. Highly recommendable!! Nobody will regret it.
Even some songs that I didn’t appreciate much before, listening with Starkrimson, I like them now.
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Leo A. –
Thank you for the feedback and very detailed write up.
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Frans N. –
Have received the fully assembled Starkrimson Ultra. It sounds like a curtain has been removed for my music. It started as an experiment but will for sure replace my 60 Watt Class A high-end mono’s. The level of detail and control over the bass is simply superior. This is my first positive experience I have had with Class D. I’m not really sure what a next step could look like. Also appreciate the swift feedback from Leo when I have any questions. Highly Recommended
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Leo A. –
Thank you.
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Joe G. –
Another test case and great for my “Forever Speakers”. The mighty Klipsch Cornwall IV’s !
Wimpy little flea bag 2W Tubes ain’t gonna do for that 15” Woofer. Great for the mids/highs but then so is the Ultra Amplifier.
Rock solid Phantom Center with a soundstage to die for ! Bass kicks in when required and shakes my living room. Both the Speakers and the Amplifier.
If there is out of phase material within the recording. You’ll think you surrounds are on ! Both a great attribute to Speaker/Amplifier pairing.
So don’t be scared. Give those Klipsch’s some power that they deserve. And dump the flea bag Amplifier while you’re at it.
As I’ve mentioned before . Leo’s Ultra Amplifier will drive ANY Speaker that’s out. You’ll forget about the Amplifier and just focus on the music.
After all, that’s what this hobby is all about.
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Leo A. –
Thank you. I am glad you are enjoying the amp.
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David F. –
Purchasing them was a gamble as I have used and lived with good valve amps (AB push pull) for decades and honed these to achieve really excellent performance. I have until now not ever liked any of the class D amps I’ve heard. While the Ultras are never going to sound like a good tube amp (which costs so much more than anything you are currently offering), they are better in so many ways in my system that I am happy to make your amps the mainstay in my set-up. Thanks for making such powerful and decent sounding amps for relatively very little money
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Leo A. –
Thank you.
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Tamara K. –
Great engineered amp, very accurate and very well sounding!
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Leo A. –
Thank you.
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Steven H. –
I have purchased and assembled the Ultra Modules and Hypex power supply. I have now listened to this amplifier for over 3 weeks every day and with every genre of music in my collection.
The Starkrimson Ultra amplifier is simply superb in every way. The music is wonderful! I highly recommend this amplifier.
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Mario Z. –
The modules are well designed and quite easy to assemble into a final product. When I first turned on the assembled amplifiers (I made two monoblocks) I was stunned. The first thing I noticed is how clean these amps sound, not analytically but just very clean. My previous amp (a rather expensive amp of a very famous brand) after these sounds like I covered the speakers with a thick bag and I’m not exaggerating. The other thing I noticed right away was the details in the bass area, I haven’t had this on a previous amp so I was amazed at how many details I didn’t hear with the old amp. The third thing that came to my notice was that for the first time I heard an obvious difference in the sound of the equipment before the amplifier (DAC, Premap). I am currently still testing these amps and will send more details when I catch some time for myself.
Leo thanks for your patience and for answering all my questions, great support even better product.
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Leo A. –
Thank you. Looking forward to hearing from you when you have have had more time to enjoy these.
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Phillip S. –
I am always interested in new amplifier designs that are available as PCBs for the DIY community. I pre-ordered a pair of Starkrimson Ultra boards when I discovered that PCBs are available. This is my first DIY class D amplifier. I particularly appreciate the included protection circuits, especially over current protection. I am also a fan of the fully balanced topology with BTL outputs and a high damping factor. I am generally a fan of low gain, but in the case of this amp, it is just a touch low for my (XLR) 4v DAC, mathematically speaking. Realistically speaking, this amplifier has plenty of output power, so it is not an issue, and I can enjoy a bit of headroom. I currently have the amp configured with both RCA and XLR inputs. In my case, shielded wires were required for all signal leads inside of the amplifier chassis. Even with the shielded wire, I detect a *very* low level of noise in the left channel (due to close proximity of signal wires to power wires in my layout.) To achieve the lowest noise level, it may be required to use a single input (RCA or XLR) with the other input shorted on the amplifier board. Overall, I am very satisfied with the Starkrimson Ultra amplifier. It is a great sounding amp, small in size, but big in power, efficiency, and hopefully long term reliability.
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Leo A. –
Thank you.
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David T. –
Modules and power supply arrived earlier than expected, well packaged and in perfect physical condition. The Starkrimson Ultra modules appear very well made and all power supply cables in the box. I was a bit late getting my enclosure, switch and accessories but hope to have my amp mounted, wired up and tested in the next few weeks. Looking forward to hearing how it works out with my system and doing a proper review at that time.
David
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Leo A. –
Thank you for the feedback. Looking forward to your full review.
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