Note that this is a discontinued product. You may want to visit the brand's page here to browse their newer products.
What reviewers think
Bloggers and YouTubers have tried this product—so we've summarized their strongest opinions below. Links to full reviews follow.
What are hifi reviews useful for? (1) Identifying products you should demo in person at a dealer. (2) Learning which products reviewers unanimously praise as the best they've heard (this means they probably are legitimately great). (3) Identifying a product's attributes that satisfy your idiosyncratic needs and tastes. Beyond that, we often discount what reviewers say because they heap praise on most products—and are often apprehensive about publishing strong criticism or comparisons between products. Further, they seldom have more than a few products on-hand, often relying on their memories to compare past products. Always listen for yourself.
All
MPA I Neptune PP
reviews
Video Review
Manufacturer details
Features
Specifications
- Output Power: 9W
- Input Sensitivity: 1V
- Input Impedance: 47K or 100K Ohms
- Output Impedance: 4 & 8 Ohms
- Max Power Consumption: 200W
- Output Noise, Unweighted: < 0.5 mVrms
- Dimensions (without tubes and feet): 200mm x 250mm x 440mm (Height x Width x Depth)
- Weight: 40kg (pair)
- Tubes: 2 x 6SJ7, 2 x 6SN7, 4 x 6V6G, 2 x 5U4G
Description
MPA I Neptune is a Pure Class A, Zero Negative Feedback, Fully Valve Rectified, Push Pull, 3 Gain Stage, Mono Power Amplifier. The powerful & grungy character of the triode connected 6V6G output tubes in combination with 6SJ7 and 6SN7 input and driver tubes offer the articulate presentation with a powerful & full bodied sound. Combined with the finest Materials & Components, MPA I is refined & musical sounding, especially when combined with higher sensitivity speakers. (91-93dB/W/1m sensitivty is recommended).
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Manufacturer Site
Brand highlights
Taking a step back to look at reviewers' thoughts of the brand's entire lineup—not just this product—what stands out most is the following:
- SW1X uses classic circuit designs, often inspired by Kondo and Audio Note UK, reimagined with modern enhancements and a focus on harmonically matched components.
- A key element is the use of non-oversampling (NOS) DACs and a lack of digital filters, aiming to eliminate digital artifacts and achieve a more analog-like sound reproduction.
- SW1X offers a wide range of models and versions within each product line, allowing customers to tailor the sound to their specific tastes and system synergy through component and material choices, such as copper or silver wiring and different capacitor types.
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Select product comparisons
SW1X DAC I Special 2
- Positioning: Entry-level line, designed for affordability and compactness.
- Description: Offers a pure NOS R2R design, providing a musical and organic sound that is rare in its price range. It features a simple yet effective valve amplification topology. Compared to higher models like the DAC II, it lacks the more advanced power supply and output stage configurations, making it suitable for smaller setups and those with a limited budget.
SW1X DAC II Balanced Special
- Positioning: Mid-range model with enhanced features for balanced audio output.
- Description: Combines the digital side of the DAC II with the power tube output stage of the DAC IV, offering a dynamic and engaging sound. It features a balanced signal output transformer and active I/V conversion, providing a more refined audio experience than the DAC I.
SW1X DAC III VSB
- Positioning: Mid to high-end model with USB connectivity for versatile use.
- Description: Integrates a USB interface, making it versatile for modern digital setups. It offers a pure NOS design with a valve output stage, providing a rich and detailed sound. Compared to the DAC II, it includes larger power supplies and a more robust output stage.
SW1X DAC IV
- Positioning: High-end model with advanced power supply and output stage.
- Description: Features directly heated diodes and a power valve output stage, offering a mature and large-scale sonic presentation. It surpasses the DAC III in dynamic range and musical refinement.
SW1X DAC X
- Positioning: Flagship model, representing the pinnacle of SW1X engineering.
- Description: The ultimate endgame DAC, combining technologies from the entire SW1X lineup into one chassis. It features a non-oversampling R2R design with a directly heated power triode valve output stage, delivering a musical and natural sound.
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Avg. Product Price
$10,001-$20,000
Used For Sale
5
Available (Scroll Down)
Brand Popularity
302
of 900+
Badges
Top 50 Brand
Top 250 Brand
Products Listed
46
Founding Year
Our take on the brand
SW1X Audio Design creates DACs that use a non-oversampling approach and vintage TDA1541 chips with tube output stages, avoiding digital filtering to maintain a more natural, analog-like sound. Their products feature separate power supply chassis designs and harmonically matched vintage components, including directly heated triode tubes and AB resistors, which are carefully selected for their distinctive sonic qualities.
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Our interview with the brand
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Used
SW1X
All of the Brand's Used Products
What if you spend more?
Trafomatic
Glenn
25456
25456
/
1
Reviews
Trafomatic Audio is unique for crafting its own transformers in-house, which gives them complete control over their amplifiers' sound quality. The brand stands out for using uncommon materials like Panzerholz (hyper-compressed plywood) for resonance control and rare tube types like the Elmac 250TL direct heated triode power tube in their designs.
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Product Strengths
- Highly customizable, allowing users to request specific configurations and tube types
- Offers a wide range of tube rolling options to pinpoint the desired sound signature
- Price-to-performance ratio is excellent, competing with amps costing around $5,000
- Can drive high impedance headphones like ZMF, HD 800, and T1, as well as planars and low ohm headphones with specific tube configurations
- Can sound very good with inexpensive tubes, but can be elevated to a ridiculous performance level with higher end tubes
- There is a HeadFi thread to help with connectivity options
Product Considerations
- Ordering process is unconventional, requiring direct communication through a HeadFi thread
- There is a wait time for builds, potentially around six months
- Tube rolling can become expensive due to the variety of options and the cost of some tubes
Takeaway: The Glenn is a highly customizable amplifier that provides excellent performance for the price, especially for those who enjoy tube rolling and experimenting with different sound signatures. It is a versatile amp that can drive a wide range of headphones, making it a great choice for many audiophiles.
Video review
Our take on the brand
Trafomatic Audio is unique for crafting its own transformers in-house, which gives them complete control over their amplifiers' sound quality. The brand stands out for using uncommon materials like Panzerholz (hyper-compressed plywood) for resonance control and rare tube types like the Elmac 250TL direct heated triode power tube in their designs.
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SW1X
AMP V Titan
22295
22295
/
1
Reviews
SW1X Audio Design creates DACs that use a non-oversampling approach and vintage TDA1541 chips with tube output stages, avoiding digital filtering to maintain a more natural, analog-like sound. Their products feature separate power supply chassis designs and harmonically matched vintage components, including directly heated triode tubes and AB resistors, which are carefully selected for their distinctive sonic qualities.
Expand Details
Product Strengths
- Alluring and sophisticated midrange with a tonal and textural directness
- Class-leading differentiation of dynamics and tonalities between instruments
- Engineering feat so thorough in forging a signal path of the purest as to be fanatical
- Brings a whole new level of sophistication to the art of music reproduction
- Exerts complete control of speakers with high sensitivity
Product Considerations
- The RCA jacks are closely spaced, necessitating the use of thin interconnects
- Eight watts may not be enough for speakers with lower sensitivity in larger rooms, potentially leading to dynamic compression and distortion
- Low output limits the range of suitable speakers compared to solid-state amplifiers
Takeaway: The SW1X AMP V 'Titan' Special is a handcrafted, ultra hifi amplifier from the United Kingdom, offering definitive performance, beauty of sound, and functional options. It stands apart in the field of the most exalted directly-heated triode amplifications, especially when paired with high-efficiency speakers.
Video review
Our take on the brand
SW1X Audio Design creates DACs that use a non-oversampling approach and vintage TDA1541 chips with tube output stages, avoiding digital filtering to maintain a more natural, analog-like sound. Their products feature separate power supply chassis designs and harmonically matched vintage components, including directly heated triode tubes and AB resistors, which are carefully selected for their distinctive sonic qualities.
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Balanced Audio Technology
Rex 500
25000
25000
/
5
Reviews
Balanced Audio Technology (BAT) designs all their components with fully balanced circuits and dual-mono power supplies, which deliver better channel separation and cleaner sound reproduction. BAT's signature approach includes zero global feedback and their Unistage circuit design, which amplifies the signal only once through a short signal path to preserve the original audio characteristics.
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Our summary
Product Strengths
- Powerful, able to drive any speaker at any level with ease
- Delivers a new dimension in realism at any volume level, exposing the timbre of bass instruments unlike ever heard before
- Reveals harmonic quality of instruments and voices
Product Considerations
- Heavy, weighing 140lb (63.5kg), requiring assistance for moving and unboxing
- High running temperature (55-65oC across the chassis) and draws 500W from the wall when idle
- When speaker cables are terminated with spade lugs, caution is advised as the posts are close together
- Output is floating—it should not be connected to any loudspeaker with a grounded 'black' terminal
- BAT components take a long time to "break in" (400-500 hours of use)
Takeaway: The BAT REX 500 is a very powerful amplifier that drives speakers with ease and reveals new levels of realism in familiar recordings. It is a must-audition for those seeking reference-level power amplification.
Video review
Our take on the brand
Balanced Audio Technology (BAT) designs all their components with fully balanced circuits and dual-mono power supplies, which deliver better channel separation and cleaner sound reproduction. BAT's signature approach includes zero global feedback and their Unistage circuit design, which amplifies the signal only once through a short signal path to preserve the original audio characteristics.
Product Page
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McIntosh
MC3500 Mk II
30000
30000
/
4
Reviews
McIntosh is one of the most iconic amplifier brands in the world, recognizable for its signature blue LED displays and distinctive industrial design. With a legacy spanning decades, McIntosh is known to many, even outside the audiophile community, and is sold in both mass-market retailers and specialized hifi stores. Their amplifiers are characterized by a warm, tube-like sound that enriches the midrange and smooths out the overall tonal balance.
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Our summary
Product Strengths
- Delivers 350 watts into 2-ohm, 4-ohm, or 8-ohm loads
- The design has a purity that is quite amazing
- Effortless power
- Soundstage is big
- Transparent
Product Considerations
- Not necessarily suitable for pairing with extremely cold sounding, sterile or bright speakers
Comparisons (according to reviewers)
- MC3500 is more open and airy, with base not as hard fisted, compared to Krell KSA 250
- It compares with brands like soulution, big Audio Research, and CH Precision, but at a lower cost
Takeaway: The MC3500 is an impressive amplifier that delivers a natural and pure sound, able to drive almost any speaker. If you're in the market for a McIntosh amp, this is the one that makes music sound pure, simple and unadulterated.
Video review
Our take on the brand
McIntosh is one of the most iconic amplifier brands in the world, recognizable for its signature blue LED displays and distinctive industrial design. With a legacy spanning decades, McIntosh is known to many, even outside the audiophile community, and is sold in both mass-market retailers and specialized hifi stores. Their amplifiers are characterized by a warm, tube-like sound that enriches the midrange and smooths out the overall tonal balance.
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What competes at this price?
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ampsandsound
Bryce
16000
/
Released
2021
The story of the Bryce was an extension of our work with the Nautilus integrated amp. The Nautilus integrated how special single ended amps could sound. Where the Zions represent ultra bandwidth push pull mono blocks the Bryce monos our are Ultra wide bandwidth single ended amplifiers with an output that opens them to most speakers with moderate efficiency. The Bryce’s mono layout allowed room for innovative thinking with the inclusion of a fixed bias structure and moderate feedback. The Bryce exacts the maximum output from a single power tube through high bias and gentle feedback. Wired as true Tetrodes feedback was used to extend the frequency response and maintain operation closely mimic triode curves.
ampandsound specializes in high-end, handcrafted tube amplifiers made in the USA. Their low-wattage amps pair perfectly with high-efficiency speakers and headphones. The company is known for classic, minimalist designs and a focus on delivering natural sound.
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Our Summary
Product Strengths
- Impressive bass response, dynamics, and power for a 12-Watt single-ended tube amplifier
- Dense, tactile, and sweet harmonic color with a clean and clear sound
- Robust build quality with point-to-point hand wiring and exceptional parts
- Easy biasing with a switch for KT88 to KT120/150 mode
- Proprietary transformers that contribute to a flatter response and deeper low bass
Product Considerations
- Careful speaker matching is required, ideally with speakers that have at least 94dB/W efficiency and a stable speaker load
- Must be turned off for at least 10 minutes, preferably 30, before turning it back on, or the rectifier tube could blow
- The correct tube type must be selected on the back of the amp, otherwise performance could be lackluster or tubes could be damaged
- The XLR input involves a slight reduction in detail due to using an input transformer to convert the incoming balanced signal to single-ended
Comparisons (according to reviewers)
- The Bryce eliminates the shortcomings of ampsandsound Nautilus when used as a speaker amplifier, adding dynamics, bass, and an extended top end
- The Bryce monoblocks are more romantic in execution, with single-ended construction—compared to the push-pull output of ampsandsound Zion
Takeaway: The Bryce Monos are high-quality amplifiers with a surprisingly powerful and detailed sound, providing an engaging listening experience. They are great for audiophiles looking for a tube amp that delivers both emotional connection and technical performance.
Video review
Our take on the brand
ampandsound specializes in high-end, handcrafted tube amplifiers made in the USA. Their low-wattage amps pair perfectly with high-efficiency speakers and headphones. The company is known for classic, minimalist designs and a focus on delivering natural sound.
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Thöress
SE-300B
10581
/
Released
2023
The SE300B Mono Amplifier is an all-tube power amplifier employing the famous classic 300B filamentary triode in single-ended operation mode for an output of up to 10 watts into a 4, 8 or 16 ohm loudspeaker load.
Thöress is a hifi brand known for its unique EHT Topology, which combines single-ended triode tubes with MOSFET output stages in Class-A mode, setting it apart from typical tube amplifiers through its transparency rather than warmth. The brand's products feature a distinctive vintage laboratory aesthetic with German labeling, and include the Phono Enhancer, which lets users adjust equalization curves on-the-fly without conventional tone controls.
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Our Summary
Product Strengths
- Pure sound, free of coloration while retaining musical detail, allows a graceful and effortless listening experience
- Natural and tangible sound due to accurate reproduction of details, creates a believable presentation
- Solid and controlled bass performance, unusual for a 300B single-ended triode amplifier
- Excellent sense of touch and tactile sound, making instruments like plucked strings and bowed violins sound very convincing
- Wide and deep soundstage with good 'air', providing a transparent and 'hear-through' sound, especially with complex music
Product Considerations
- Careful matching with partnering equipment is required, especially speakers with high efficiency
- Relatively low overall gain requires a source with a high output voltage
- Output transformer links need to be correctly set for speaker impedance, requiring dealer assistance
- Some reviewers found the top end sounding a bit rolled off before use of appropriate high efficiency speakers and source gain settings
- Changing the EL803S driver valves requires carefully matched pairs supplied by Thöress
Comparisons (according to reviewers)
- Vs Shindo Haut-Brion/Corton-Charlemagne, Thöress has more treble extension and transparency, Shindo has better upper-bass/lower-midrange substance and body—and more drive
Takeaway: The Thöress SE-300B offers a supremely musical and detailed listening experience with a focus on accuracy and sonic purity. When paired with the right speakers, this amplifier could be an excellent choice to bring out the best in music.
Video review
Our take on the brand
Thöress is a hifi brand known for its unique EHT Topology, which combines single-ended triode tubes with MOSFET output stages in Class-A mode, setting it apart from typical tube amplifiers through its transparency rather than warmth. The brand's products feature a distinctive vintage laboratory aesthetic with German labeling, and include the Phono Enhancer, which lets users adjust equalization curves on-the-fly without conventional tone controls.
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Thöress
EHT Power
14109
/
Released
THÖRESS introduces the EHT Mono Amplifier, the most powerful amplifier model of their product line, providing 30, 40 or 50 watts of output power into a 8, 6 or 4 ohm load respectively, combined with very low output resistance (high damping factor).
Thöress is a hifi brand known for its unique EHT Topology, which combines single-ended triode tubes with MOSFET output stages in Class-A mode, setting it apart from typical tube amplifiers through its transparency rather than warmth. The brand's products feature a distinctive vintage laboratory aesthetic with German labeling, and include the Phono Enhancer, which lets users adjust equalization curves on-the-fly without conventional tone controls.
Expand Details
Our Summary
Product Strengths
- The EHT combines tubes and transistors to mate the most desirable characteristics of both
- Amplifiers provide fullness and density, even at low listening volumes
- The EHT creates a natural sound with incredible saturation
- They are fully short-circuit proof at the outputs without any sound-degrading protection
- A switch-on delay is omitted because switching on/off develops no disturbing noise or dangerous signal in this circuit
Product Considerations
- Sound is focused on timbre rather than detail
- Their sound is soft rather than focused, rather warm than open, and rather close to us than presented in a perspective
- The devices are quite large, as they measure 434 x 184 x 434 mm (W x H x D) and weigh 14 kg each
Takeaway: The Thöress EHT monoblocks offer a holistic view of the musical material and its reinterpretation that can be very enjoyable for long listening sessions. They create events in their own acoustic environment, which is completely transferred to the listening room, creating a beautiful, organic, comprehensive, and internally properly arranged sound for those who value tonality above all else.
Video review
Our take on the brand
Thöress is a hifi brand known for its unique EHT Topology, which combines single-ended triode tubes with MOSFET output stages in Class-A mode, setting it apart from typical tube amplifiers through its transparency rather than warmth. The brand's products feature a distinctive vintage laboratory aesthetic with German labeling, and include the Phono Enhancer, which lets users adjust equalization curves on-the-fly without conventional tone controls.
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Fezz
Audio Lybra 300B
10306
/
Released
2023
One of the finest parallel single ended 300B tube amplifier made by Fezz Audio. It provides openness and spatial sound. Powerful, sublime, very involving and uniqe to itself.
Fezz Audio distinguishes itself by being the first to implement toroidal output transformers in single-ended tube amplifiers, a design choice that enhances efficiency and reduces noise. Their Evolution series, developed in collaboration with the KABO & PYDO design studio, has been recognized with prestigious awards such as the Red Dot Design Award.
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Our Summary
Product Strengths
- Delivers an incredibly rich, flavorful midrange and a sweet, relaxed treble
- Has a more sophisticated presentation than the utilitarian bent-metal chassis sported by most integrated tube amps on the market, and the smooth lines of the chassis help the amp stand out from the crowd
- Has a clever tube cage design with a clear Plexiglass front panel that delivers an unobstructed view of the tubes and is easy to install and remove
- Is seriously quiet, and there was effectively zero noise through any of the speakers
Product Considerations
- Can sound wildly different, depending on the impedance of the speakers
- The four slightly squishy feet underneath the amp may cause stains
- The power switch is on the rear of the chassis, which may be problematic if installing the amp in a cabinet with limited access
- Needs a good 20 minutes to warm up, and on initial startup, the amp sounded a bit thin, bright, and constipated, but after one album, it opened right up
- Limited power output (15Wpc) may not be sufficient for all speakers or listening preferences, especially when wanting to play music very loud
Takeaway: The Fezz Audio Lybra 300B is a well-designed tube amplifier that delivers a rich and flavorful sound. It can bring out the best in your speakers, offering clarity and great sound.
Video review
Our take on the brand
Fezz Audio distinguishes itself by being the first to implement toroidal output transformers in single-ended tube amplifiers, a design choice that enhances efficiency and reduces noise. Their Evolution series, developed in collaboration with the KABO & PYDO design studio, has been recognized with prestigious awards such as the Red Dot Design Award.
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ampsandsound
Black Pearl
14000
/
Released
2023
Much like its namesake, the Black Pearl is made of the stuff of legends: the Western Electric 300B. The most famous audio tube ever made, and for good reason - it’s low distortion, clarity and purity of tone set it apart from even other triodes. In the right amplifier the 300B is fast, dynamic and tight, qualities we often associate with larger, more complex pentode topologies. Like the Calypsos, the Black Pearl started as a personal project with the goal of maximizing the potential of the Western Electric 300b reissue. This is among the very best 300B replicas one can buy, and to many ears, the closest one can get to originals.
ampandsound specializes in high-end, handcrafted tube amplifiers made in the USA. Their low-wattage amps pair perfectly with high-efficiency speakers and headphones. The company is known for classic, minimalist designs and a focus on delivering natural sound.
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Our Summary
Product Strengths
- Simplicity mixed with extreme refinement delivers something special that is unforgettable
- Amazing bass control, even over speakers with notoriously floppy bass
- Solid-state quiet, with no noise or hum present even with ears pressed up to the speakers
- Calmly pulls one into the presentation, taking one further into the music
- Excels with music featuring a lot of inner detail or acoustic instruments, resolving textures and attacks with precision
- Sheer physical quality, both inside and out, is the best of the best
Product Considerations
- If new to the 300B tube, note these tubes have no central locator pins like other power tubes, one can put these tubes in their sockets wrong and blow the amplifier up
- Requires no setup other than installing the tubes
Comparisons (according to reviewers)
- Attention to detail is not seen on a McIntosh
- Only the BAT REX Power Amplifier delivers bass grip and resolution at the same level
Takeaway: The ampsandsound Black Pearl amplifier offers a unique and immersive listening experience with exceptional detail and bass control. It is a destination product worth the investment for those who truly appreciate high-quality audio.
Video review
Our take on the brand
ampandsound specializes in high-end, handcrafted tube amplifiers made in the USA. Their low-wattage amps pair perfectly with high-efficiency speakers and headphones. The company is known for classic, minimalist designs and a focus on delivering natural sound.
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