Korg Nutube 6P1
A modern miniature triode for real tube sound in a portable DAC/amp.
CAYINPORTABLE DAC & TUBE AMPLIFIERCustomer reviews (0)
Cayin RU9 USB DAC Headphone Amplifier
Three sounds in one portable amp.
A portable Nutube DAC/amp with dual AK4493SEQ DACs, three timbre modes, Bluetooth 5.1 and 3.5mm and 4.4mm outputs.
Regular price
£449.00
Unit price
Including VAT
Free next day UK delivery
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Cayin RU9 USB DAC Headphone Amplifier
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MEET THE RU9
Three sounds in one portable amp.
A portable Nutube DAC/amp with dual AK4493SEQ DACs, three timbre modes, Bluetooth 5.1 and 3.5mm and 4.4mm outputs.
Three timbre options
Classic tube, Modern tube or solid-state, on both outputs at the same power.
Wired or wireless
USB up to 768kHz / DSD512, LDAC Bluetooth, S/PDIF and up to 1W in DC Hyper mode.
Read the full description
The Cayin RU9 is a portable DAC and headphone amplifier built around a Korg Nutube 6P1 valve. Choose Classic tube, Modern tube or solid-state sound, play from USB, Bluetooth or S/PDIF, and run it as a dongle, from its own battery or on external power, when its Hyper mode gives up to 1W per channel from the 4.4mm balanced output. Two AKM AK4493SEQ DACs, an XMOS XU316 USB processor, a magnetic back and a magnetic leather case make it a flexible upgrade for a phone, music player or computer.
A Nutube with three timbres
The Korg Nutube 6P1 is a modern miniature triode, and the RU9 can use it in two ways or bypass it. Classic tube gives the richest harmonic character (up to 3% distortion, by Cayin’s figures), Modern tube a cleaner tube sound (up to 0.6%), and solid-state, through OPA1662 op-amps and Nexperia transistors, the most neutral (0.008%). All three are available on both outputs, at the same power, and Cayin developed a vibration-reduction system for the tube.
Dual DACs and four-channel balanced amplification
Two AK4493SEQ DACs, fed by a third-generation 16-core XMOS XU316 USB processor, play PCM up to 768kHz/32-bit and native DSD512. A four-channel JRC NJW1195A controls the volume, and a four-channel, fully balanced amplifier drives the 3.5mm and 4.4mm outputs, both usable as headphone or line outputs, with three gain settings (0, −6 and −12dB).
Three ways to power it
Plugged in by USB alone, the RU9 works as a dongle. With its 2,000mAh battery it supplements the source and plays for up to 4.7 hours (3.5mm, solid-state), and it recharges in about 1.3 hours with a QC3.0 or PD2.0 charger. Set the mode selector to DC and connect a power adapter, and Hyper mode raises the 4.4mm output from 620mW to 1,000mW per channel into 32Ω (1,170mW into 16Ω), and the 3.5mm output from 310mW to 420mW.
Every way in
Besides USB audio, in UAC 2.0 or 1.0 mode, the RU9 receives Bluetooth 5.1 through a Qualcomm QCC5125 with LDAC, aptX HD, aptX LL, aptX, AAC and SBC, and has a 3.5mm S/PDIF port that works as a coaxial input or output up to 192kHz/24-bit. Mac, Android and iOS need no driver; Windows 10 or later may need Cayin’s USB audio driver.
Built to carry
The CNC-machined metal housing weighs about 150g, a 0.96-inch OLED screen shows the settings, and a magnetic back panel lets you attach the RU9 to a phone, tablet or player with the supplied magnetic ring; the magnetic PU leather case is included too.
| DAC and tube | 2 × AKM AK4493SEQ · Korg Nutube 6P1 · XMOS XU316 · JRC NJW1195A volume |
|---|---|
| 4.4mm balanced | 620mW (battery) / 1,000mW (DC) @ 32Ω · 1,170mW @ 16Ω (DC) · 1.0Ω · SNR 118dB (solid-state) · separation 105dB |
| 3.5mm | 310mW (battery) / 420mW (DC) @ 32Ω · 610mW @ 16Ω (DC) · 0.5Ω · SNR 118dB (solid-state) |
| Timbres | Solid-state: THD+N 0.008%, 20Hz–32kHz · Modern tube: 0.6%, 20Hz–32kHz · Classic tube: 3.0%, 20Hz–22kHz |
| USB | UAC 2.0/1.0 · PCM 44.1–768kHz/32-bit · native DSD64–512 · DoP64–256 |
| Bluetooth and S/PDIF | Bluetooth 5.1 in (QCC5125: LDAC, aptX HD, aptX LL, aptX, AAC, SBC) · S/PDIF in/out up to 192kHz/24-bit on a 3.5mm port |
| Battery | 2,000mAh · 3.1–4.7 hours by output and timbre · QC3.0/PD2.0 charging about 1.3 hours |
| Size and weight | 100 × 70 × 15mm · about 150g · 0.96-inch OLED |
Good to know
- For Hyper mode, set the mode selector to DC and connect a power adapter (not included).
- Windows computers may need Cayin’s USB audio driver.
- In the box: RU9, magnetic PU leather case, magnetic ring, L-shaped USB-C OTG cable and USB-C to USB-A adapter.
In the box
- Cayin RU9 USB DAC Headphone Amplifier
- Magnetic PU leather case
- Magnetic ring accessory
- L-shaped USB-C OTG cable
- USB-C to USB-A adaptor
Downloads
THE FINER DETAILS
Built for
better listening.
Know what you’re choosing.
Find the right fit for your setup.
- DAC
- 2 × AKM AK4493SEQ
- Headphone outputs
- 3.5mm single-ended · 4.4mm balanced
- Output power
- 4.4mm: 620mW @ 32Ω on battery, 1,000mW @ 32Ω in DC mode (1,170mW @ 16Ω) · 3.5mm: 310mW / 420mW @ 32Ω
- Hi-res support
- PCM 768kHz/32-bit · DSD512 native
- Battery
- 2,000mAh · 4.7h (3.5mm solid-state) · 3.5h (3.5mm tube) · 4.3h (4.4mm solid-state) · 3.1h (4.4mm tube) · QC3.0/PD2.0 charge about 1.3h
- Screen
- 0.96" OLED
- Bluetooth
- 5.1 receive (Qualcomm QCC5125)
- Bluetooth codecs
- LDAC, aptX HD, aptX LL, AAC, SBC
- Signal-to-noise ratio
- 118dB solid-state · 114dB modern tube · 104dB classic tube
- Output impedance
- 1.0Ω (4.4mm) · 0.5Ω (3.5mm)
- Size (H × W × D)
- 100 × 70 × 15mm
- Weight
- 150g
- Amplification
- Korg Nutube 6P1 · OPA1662 + Nexperia transistors, four-channel balanced
- Line outputs
- 3.5mm & 4.4mm (shared)
- Digital outputs
- S/PDIF
- Inputs
- USB-C (XMOS XU316) · S/PDIF · Bluetooth
- Power
- Dongle, battery or external DC mode
Specifications are based on manufacturer information and may change. Battery life varies with use and settings.
The press, on the RU9
Independent ears.
Their verdict.
A different perspective on your next listen.
03 / Expert reviews
impressive, yet very 'tweakable' sound, excellent power output, and all inside a low-profile yet extremely sturdy design
Marcus
Read reviewHeadfonia
in this price-range it might be one of the best solution on the market
NanoTechnos
Read reviewEar Fidelity
it is one of the best mobile DAC/Amps currently on the market
Wildly Recommended
Mateusz Chmura
Read reviewSelected excerpts from published reviews. Scores are each publication’s own. Follow the links for their full verdicts.
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