Boulder’s 861 delivers pristine, weighty bass alongside an exceptionally lucid, fluid midrange, bringing surprising scale to compact and refined loudspeakers. HiFi Turtle found its presentation wide, deep, and clearly imaged, while the compact CNC-finished chassis retains the brand’s premium feel. It is a poised, powerful route into Boulder’s distinctive musical authority.
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Nicely Roasted
Sound Quality
90/100
Build Quality
91/100
Value for Money
85/100
Pros
Full, pristine bass adds satisfying body without sounding bloated.
Exceptionally clear, smooth, and refined midrange reproduction.
Wide, deep soundstage with clear imaging and convincing panning.
Premium compact build, including CNC-finished chassis and unusually high-quality binding posts.
Cons
Its elevated bass balance can overwhelm a room or prove less ideal with already full-range speakers.
Balanced XLR inputs only, and the speaker terminals require spade connectors rather than banana plugs.
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What Reviewers Are Saying
SOUND QUALITY PERFORMANCE 90/100
The 861 is described as unusually clear and refined through the midrange, with a smooth, fluid presentation and a notably substantial low end. It also preserves a wide, deep spatial presentation rather than trading scale for its compact output rating.
Transparency Resolution
93/100
HiFi Turtle found the midrange "absolutely sublime," citing crisp, clean and exceptionally clear reproduction with a refined, buttery smoothness. The review particularly praises its ability to make both bookshelf and floorstanding speakers sound more open and articulate.
Tonal Balance Musicality
90/100
The presentation has a definite emphasis toward the bass region, delivering more bass presence than the reviewer's comparison amplifiers. Crucially, this added weight was not heard as bloated: bass quality remained "absolutely pristine," while the midrange stayed beautiful, fluid and musically inviting.
Dynamics
84/100
The review reports that the 861 scaled speakers impressively and gave a compact bookshelf design a fuller, more elevated presentation. Its 50W/8-ohm rating rises to a claimed 200W peak into 2 ohms, but the listening comments offer limited direct detail about large-scale transient slam or sustained high-level control.
Soundstage Imaging
92/100
HiFi Turtle describes the stage as "super wide" and "super deep," with clear images and convincing panning across the soundfield. The amplifier was also said to convey the depth and expansiveness of recordings very effectively.
Assessments of Build Quality, Usability, and Overall Propositions.
Build Quality
91/100
The 861 is hand-built in Colorado, with CNC-finished detailing that the reviewer considers consistent with Boulder standards. Its in-house 6mm binding posts were singled out as exceptionally premium-feeling, and the compact Class A/B chassis includes balanced XLR input and a load-tolerant output design.
Value for Money
85/100
At approximately $9,250, the 861 is presented as Boulder's least expensive amplifier rather than as an inexpensive product in absolute terms. The review notes that it retains the firm's hand-built execution and presentation without Boulder’s more substantial cost, but does not directly compare its value against competing amplifiers at the price.
Reviews & Sources
Professional reviews and sources for this product's Watt'n Potatoes analysis.
Online Reviews & Mentions
YouTube Reviews
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Specifications
- Continuous Power, 8 Ohms
- 50W
- Peak Power, 8 Ohms
- 75W
- Continuous power, 4 Ohms
- 90W
- Peak Power, 4 Ohms
- 110W
- Peak Power, 2 Ohms
- 200W
- Balanced Analog Inputs
- 1 pair balanced via 3-pin XLR
- Outputs
- .25" (6mm) Binding posts
- Distortion, THD
- 0.01%
- Equivalent Input Noise (EIN), 20 kHz
- 2.6 μV
- Input Impedance
- 100kΩ Balanced
- Frequency Response, 20 Hz to 20 kHz
- +0.00, -0.04 dB
- Frequency Response, -3 DB
- 0.015 Hz, 150 kHz
- Maximum Analog Gain
- 26 dB
- Power Requirements
- 100V, 120V, 240V, 50-60 Hz
- Power Consumption
- 550W Maximum
- Dimensions
- 12"x12"x3.5"
- Weight
- 22 lbs
Manufacturer's Description — Boulder Amplifiers
There is a solution for those in smaller living spaces, for those that have efficient systems, or for those who like the 866 Integrated sonically but prefer separates. The 861 Stereo Power Amplifier checks all these boxes. The 861 being the newest expansion of the 800 series is the same exact size as the 812 DAC Preamplifier it makes for an attractive combo both visually and audibly. All the boards and chassis are still made in Boulder’s dedicated facility in Colorado. You get the high performance, the expertise and craftsmanship in a manageable package.
The 861 is Boulders first amplifier in its size and it punches well above its weight class. Don’t believe us? You should really listen for yourself.
If you are curious of where you can hear one, reach out here
75W peak power per channel into 8 ohms, 110W peak power into 4 ohms, 200W peak power into 2 ohms
New protection circuitry enables the 861 to deliver greater current at maximum output without fear of damage to the amplifier's electronics
Space saving design is the same footprint (width and depth) as the 812 DAC Preamplifier
In-house manufacturing efficiency improvements have made the 861 an incredible value in comparison to previous amplifiers
Smaller carton packaging means easier transportation, unpacking, and installation
Along with assembly and testing, every circuit board and piece of metalwork is produced in-house at Boulder's dedicated facility for unparalleled quality assurance
Boulder's traditional in-house 0.25" (6 mm) thumbscrew binding posts are included for secure speaker cable connections and optimal sound quality
IP control, and networked HTML page
Software updates to the internal control and housekeeping systems available as needed with automated online downloads or manual USB port installation
Verified Dealers
Online Dealers
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Authorized dealers for Boulder Amplifiers 861
- 3mA Audio — online and in-store — Houston, Texas, United States (website)
- Absolute Hi End — in-store — Ormond, Victoria, Australia (website)
- American Sound — in-store — Richmond Hill, Ontario, Canada (website)
- Ana Mighty Sound — online and in-store — Paris, Île-de-France, France (website)
- Audio Advisors — in-store — West Palm Beach, Florida, United States (website)
- Audio Element — in-store — Pasadena, California, United States (website)
- Audio Gallery — online and in-store — Las Rozas de Madrid, Comunidad de Madrid, Spain (website)
- Audio Y Cine — online and in-store — Sevilla, Andalucía, Spain (website)
- Class A Audio — in-store — Notting Hill, Victoria, Australia (website)
- David Lewis Audio — in-store — Philadelphia, Pennsylvania, United States (website)
and 35 more verified dealers
