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CAYIN

Cayin RU9 Vacuum Tube Portable DAC and Amp

  • Based on 18 reviews
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Availability: In Stock.
Fulfilled by Amazon
Arrives Saturday, Jul 25
Order within 19 hours and 42 minutes
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Features

  • Tri-Mode Sound Customization Choose from Classic, Modern, or Solid-State modes to fine-tune your listening experiencefrom tube warmth to analytical precision.
  • Gen5 Nutube 6P1 Tube Integration Delivers authentic vacuum tube character with enhanced durability, clarity, and harmonic richness in a compact form.
  • Dual DAC + Discrete Class A Amp Features an in-house R2R DAC and fully balanced 4-channel Class A amplification for powerful, natural, and clean output up to 730mW.
  • High-Res Support & Versatile I/O Supports PCM 768kHz, DSD512, and DoP formats with 3.5mm SE and 4.4mm balanced outputs, plus the latest XMOS XU316 USB processor.
  • Premium Build with Smart Features Compact CNC-machined aluminum chassis, OLED display, magnetic mount, and audiophile-grade components for form and function.

Description

The Cayin RU9 redefines portable hi-fi by blending cutting-edge digital architecture with classic analog warmth. Featuring the Gen5 Nutube 6P1 vacuum tube, an in-house R2R DAC, and triple sound profiles, it offers an immersive, customizable listening experience. With support for PCM 768kHz, DSD512, dual DAC balanced architecture, and a powerful discrete Class A amplifier, the RU9 delivers stunning audio quality across headphones and IEMs alike. Housed in a sleek, CNC-machined body and engineered with audiophile-grade components, it is equally refined in performance and design. Whether at your desk or on the go, the RU9 brings studio-quality sound to your pocket. The RU9 features the latest Gen5 Nutube 6P1, developed by Korg and Noritake, offering improved durability, clarity, and microphonics. This vacuum tube delivers classic harmonic warmth and a uniquely rich, lifelike listening experience. RU9 features a fully discrete Class A 4-channel balanced amplifier with up to 730mW@32Ω output power in Turbo Mode. With three selectable power levels (Standard, High, Turbo), it adapts to everything from sensitive IEMs to demanding headphones. The latest XMOS XU316 USB interface supports PCM up to 768kHz and DSD512, ensuring compatibility with high-res files. With 3.5mm SE, 4.4mm balanced outputs, and optional Bluetooth 5.1 (SBC, AAC, aptX, LDAC), the RU9 is as versatile as it is powerful. Housed in a CNC-machined aluminum chassis, the RU9 weighs only 150g and includes a magnetic attachment system for convenience. Audiophile-grade components like the NJW1195 volume controller, anti-vibration brackets, and smart charging circuitry round out its premium build. Utilizing a dual DAC configuration and fully differential design, the RU9 ensures precise signal decoding with excellent channel separation. This results in improved dynamics, soundstage, and lower noise levels. Switch between three distinct playback signatures: Classic (tube warmth), Modern (refined tube clarity), and Solid-State (clean and analytical). These flexible modes allow users to tailor the sound to their personal taste or music genre. At the heart of the RU9 lies an in-house developed 24-bit R2R DAC known for its natural, musical sound. This architecture provides analog richness and precision often favored by audiophiles for its engaging sonic character. When Nutube is disabled, Hyper Mode activates a high-performance solid-state path that reduces power consumption and bypasses tube warm-up time. This mode ensures instant, clean playback with maximum detail.

Manufacturer: Cayin


Brand: CAYIN


Mfr Part Number: RU9


Model Number: RU9


Item Weight: 0.37 Kilograms


Built-In Media: DAC Amplifier


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Saturday, Jul 25

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews

    • Simply put: YES.
Do yourself a favor and hit buy now. This thing F****. The sound is rich, velvety, luxurious, everything you want it to be. The battery life is kind of meh, but that’s really irrelevant considering how fast and easy it is to charge up. Plus if you’re using it for long enough to deplete the integrated battery you’re probably also in a place where you could’ve been using it on auxiliary power anyhow and that unlocks the “Hyper” mode which is said to only increase the power output but to me it adds just that little bit more of velvety feel to the sonics. I really can’t say enough good about this thing. I use for EVERYTHING. Music, check. TV, check. Movies, check. It just makes the experience of everything better. But that may also be that my two daily cans are Clear MG’s and Stellia’s, so I’m not exactly starting with a low bar. This little “dongle” really makes them sing though. ... show more
Reviewed in the United States on May 9, 2026 by Collin
    • One of a kind !
Out of all CAYIN Dac Amps . The RU9 is the most Analog sounding . it’s the warmest .the most musical out of them . But , there all great in there own way . The RU6 (R2R) is my fav and the RU3 . Now the RU9 is my #1 . Then my #2 is RU3 then RU6 . The RU7 is too neutral .even though it’s good also and I do use it depending on what IEM I’m using . RU7 has great Mids and natural tonality . But I prefer warm sources . More musical sound preference. And this RU9 has that Warm tube Bloom that’s noticeable . Even on the modern mode it’s warm Analog sounding . And on the normal mode with AKM chips . It’s Analog with rich depth and very musical . Despite the battery only being 3-4 hours it doesn’t bother me cuz I use it connected to my phone via USB C and the battery doesn’t drain . But I love the triple timber choices . I like the magnet on the case and it works very nicely . The RU9 is well built and I love the Tube Bloom it gives to the music and vocals ! I’m a CAYIN Fan . And they make great products . My next buy is the CAYIN N7+ master quality DAP . Also thanks to Musicteck ! They have the best Audiophile selection of Dac Amps and Daps and IEMs and Headohones . ... show more
Reviewed in the United States on January 9, 2026 by REECE
    • This is the portable Bluetooth tube DAC/amp to get if you’re an audio nut like me..
Incredible audio quality in transistor mode as well as the two tube modes, classic and modern. I am a retired musician that has done his fair share of mixing and mastering in the day. The Classic mode really lets The.Nu-Tubes shine with the most tube like experience with more midbass punch and a nice glow and smoothing the highs and uppers without sacrificing detail. The modern mode is a nice mix of the classic mode and transistor mode combined. The Bluetooth connection has been rock solid, even when using.LDAC..Yes, this piece of kit is pricey at $500 but it is truly worth every penny if you’re into Audio as much as I am. I give this RU9 by highest recommendations. ... show more
Reviewed in the United States on November 28, 2025 by fiddler59
    • Small unit, big sound.
The more I use it the more I love it. I mostly use this unit plugged in with hyper mode but its not bad on battery only. If you're in the market for a small unit with big sound then give it a try. Excellent results using Arya organic headphones and 7hz timeless II IEMs. This got me curious as to what other products Cayin has to offer. I might have to explore one of their tube amps next! ... show more
Reviewed in the United States on June 27, 2026 by Jesse S.
    • Tubes Aren't for Me
I bought this because of the tubes and the fact that is had a coaxial output. I figured I'd be able to use this for my headphones and my car straight into my DSP. I loved how portable it is and the magsafe feature. The device sounds clean when tubes aren't engaged but unfortunately the tubes don't engage when using the coaxial. Also, the classic mode smeared things too much. The modern mode was the best, but it didn't dull sharpness enough for me to want to keep a tube in my signal chain. This kind of power can be had for much cheaper through the fiio qx13. ... show more
Reviewed in the United States on November 10, 2025 by Chi Guy
    • With Meze single ended With Meze single ended
Review Image by tyler
Review Image by tyler
Review Image by tyler
Using Meze Strada single-ended in low power and traditional tube mode. Many always go straight to balanced on everything but then they some of the musical aspects of music. They keep chasing what is unattainable and should consider chilling.
Reviewed in the United States on February 2, 2026 Reviewed in the United States on February 2, 2026 by tyler
    • Not a great value
This thing sounds awesome, love the magnet. For $500 it should have a PEQ function.
Reviewed in the United States on November 8, 2025 by Shopper6592
    • El mejor sonido portátil posible!!!!
Es más de lo que uno podría suponer.... Sencillamente fantástico!!!, hay que escucharlo para creerlo.
Reviewed in the United States on September 1, 2025 by Dhyan

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