![JBL Junior 320BT Wireless Bluetooth On-Ear Headphone with Mic for Kids - Blue [Open Box]](https://d30ek1sgwm2r4c.cloudfront.net/sites/files/treoo/images/products/202411/600xAUTO/jbl-junior-320bt-blue_2.jpg.webp "JBL Junior 320BT Wireless Bluetooth On-Ear Headphone with Mic for Kids - Blue [Open Box]")
![JBL Junior 320BT Wireless Bluetooth On-Ear Headphone with Mic for Kids - Blue [Open Box]](https://d30ek1sgwm2r4c.cloudfront.net/sites/files/treoo/images/products/202411/600xAUTO/jbl-junior-320bt-blue_1.jpg.webp "JBL Junior 320BT Wireless Bluetooth On-Ear Headphone with Mic for Kids - Blue [Open Box]")
Astell&Kern A&ultima SP4000T Digital Audio Player -Stainless Steel
- Four Raytheon JAN6418 Vacuum Tubes
- Two AK4499EX DACs
- Two AK4191EQ Processors
- Triple Tube Modes & Triple AMP System
- Tube Current Adjustment
- 6" 2160 x 1080 Display
- Multicolor LED Volume / Bit Rate Knob
- Native DSD and 32-Bit / 768 kHz Support
- 256GB Built-In microSD Card Slot
- One 4.4mm and Two 3.5mm Outputs
What’s in the Box
- Astell&Kern A&ultima SP4000T
- Premium Cognac Leather Case by Badalassi Carlo
- USB-C Cable
- Documentation
The A&ultima SP4000T, available first in Stainless Steel and later a Copper body option, is the culmination of approximately two years of multifaceted effort following the launch of the SP3000T in 2024, crafted together with the SP4000 from the very beginning stages of planning and development.
The SP4000T is the industry's first DAP to feature the RAYTHEON JAN6418 MIL-Spec vintage vacuum tube in a Quad configuration.
With independent dual-tube structures dedicated to the left and right channels respectively, the channel-separated design, once exclusive to home audio high-end tube amplifiers, has finally been brought to the world of DAPs.
Each of the four tubes is precisely measured for its noise and gain characteristics before being paired, then fully isolated from noise through independent modular flexible PCBs and a multi-layered architecture, a design that only Astell&Kern, with its long experience in analog circuits and vacuum tubes, could bring to life.
Triple Tube Mode in the SP4000T is a first in the industry for a DAP. Combined with the T Series Signature Triple AMP Mode and the Tube Current level adjustment, it offers up to 54 possible combinations tailored to any genre or preference, a true Analog Sound Palette.
The Astell&Kern SP4000T offers three distinct tube sound modes, each delivering its own unique sonic character. Triode Mode emphasizes rich harmonics and lush, lingering warmth, creating an emotional and immersive presentation ideal for vocals and acoustic instruments. Ultra Linear Mode balances the tonal richness of Triode with the power and control of Pentode, producing a refined yet authoritative sound suited for a wide range of music genres. Pentode Mode focuses on maximum output and dynamic impact, preserving tube warmth while delivering a cleaner, more direct, and energetic presentation.
Combining Astell&Kern’s exclusive TERATON ALPHA technology with Quad-configured Real Vacuum Tubes and advanced OPAMP design, the SP4000T delivers both authentic analog warmth and ultra-high-resolution clarity. Users can choose between dedicated OP AMP Mode for powerful dynamics, expansive detail, and low-noise precision, or TUBE AMP Mode for the rich, emotional character and natural soundstage unique to true vacuum tube audio.
An advanced 5-stage HYBRID AMP Mode that blends the strengths of both amps, allowing listeners to fine-tune the balance between analog warmth and high-resolution transparency to match their personal listening preferences.
The SP4000T introduces an upgraded 5-stage 2nd Generation Anti-Microphonic Architecture (up from the previous 4-stage design) to suppress microphonic noise (noise generated in vacuum tubes from even the most minor external vibrations).
The Astell&Kern SP4000T is designed for modern streaming-focused listening, running Android 15 with full Google Play Store support while maintaining Astell&Kern’s flagship analog sound quality. Its proprietary ADP (Astell&Kern Direct Path) technology bypasses Android’s standard sample rate conversion limitations to enable true lossless, bit-perfect playback from streaming services. The SP4000T also introduces Astell&Kern’s first dual Wi-Fi antenna design, delivering significantly faster and more stable wireless streaming and downloads, with internal testing showing up to twice the 5GHz download speed of previous models.
The Astell&Kern SP4000T combines Astell&Kern’s most advanced audio technologies to deliver a deeper, more refined analog sound experience. Its fully discrete circuit architecture separates digital and analog signal processing using dual flagship AK4499EX DACs and dedicated AK4191EQ processors for each channel, reducing noise and enhancing clarity, depth, and purity across the entire signal path.
Building on the SP4000 platform, the SP4000T also incorporates High Driving Mode with parallel OPAMP configuration for greater dynamic range and more detailed, immersive sound reproduction. Proprietary ESA (Enhanced Signal Alignment) technology minimizes group delay and frequency distortion, while Advanced DAR technology restores lost harmonics before applying upsampling for more natural, lifelike playback.
Additional refinements including Any Layer HDI PCB technology and a 99.9% pure copper Shield Can further minimize signal loss, noise, and electromagnetic interference, resulting in exceptionally clean, vivid, and highly resolved audio performance.
The SP4000T is packaged with a premium leather “Cognac’ colored case crafted using 'MINERVA' leather from 'BADALASSI CARLO', a renowned leather workshop located in the San Miniato district of Florence, Italy.
The Astell&Kern SP4000T combines flagship-level connectivity and high-resolution playback capabilities with advanced wireless and user-focused features. It offers 256GB of internal storage with microSD expansion up to 1.5TB, supports native playback up to 32-bit/768kHz PCM and DSD512, and features a 6-inch Full HD touchscreen alongside dual-band Wi-Fi, DLNA networking, USB audio output, and USB DAC functionality for Mac and Windows PCs.
Wireless performance is enhanced through support for aptX Adaptive and LDAC codecs, while BT Sink mode allows the SP4000T to function as a high-quality Bluetooth DAC for external devices such as smartphones. Features like ReplayGain, AK File Drop wireless transfers, USB PD 3.0 fast charging, and customizable battery protection further improve everyday usability.
For extended listening comfort, the SP4000T also includes advanced Crossfeed controls that recreate a more speaker-like listening experience through headphones, allowing users to fine-tune spatial presentation and reduce listening fatigue over long sessions.
Pricing and availability for the SP4000T Stainless Steel and Copper will be announced soon.
Two additional premium leather cases will be available for the SP4000T. A black color case, crafted from soft cowhide by GRUPPO MASTROTTO, delivers an exceptionally soft touch, with a uniform surface quality and a distinctively vibrant Italian coloration. An olive-colored case, crafted from premium vegetable-tanned leather by BADALASSI CARLO, is crafted through a proprietary tanning and dyeing process. Both cases feature a standing mechanism on the back to provide greater convenience in use.
| Product Availability | Available (current model) |
| Product Type | Digital Audio Player |
| Style/Type | Portable |
| Features | WiFi, Bluetooth, Expandable Memory/Storage, Internet Radio, Dual Headphone Output, High-Res Audio Certified, DSD, MQA (Master Quality Authenticated), 2.4GHz/5GHz Dual-Band WiFi, roon ready |
| Connectivity | Wireless & Wired |
| DAC | AKM4191EQ x2 + AKM4499EX x2 |
| Op-Amp / Amplifier | RAYTHEON JAN6418 x4 (Quad Tube) |
| Internal Storage Capacity | 256GB |
| Expandable Storage | Yes |
| Expandable Storage Capacity | 1TB (1024MB) |
| Bluetooth Version | v5.2 |
| Bluetooth Codecs | SBC, AAC, aptX HD, LDAC |
| Waterproof Rating | IPX0 – No protection |
| Sampling / Bitrate | PCM: 8kHz ~ 768kHz (8/16/24/32bits per sample), DSD Native: DSD64(1bit 2.8MHz), DSD128(1bit 5.6MHz), DSD256(1bit 11.2MHz), DSD512(1bit 22.4MHz) |
| Frequency Response (Hz) | PCM: 8kHz ~ 768kHz (8/16/24/32 bits per sample) |
| Signal-to-Noise Ratio (SNR) | 124dB |
| Voice Assistants | - None - |
| Streaming Services | Roon |
| Mic for Calls/Communication | None |
| Input Connectivity Options | microSD [External Storage], USB Type-C (USB-C) [Charging], WiFi |
| Output Connectivity Options | 2.5mm (4-Pole) [Balanced], Optical mini-TOSLINK (SPDIF), 3.5mm Stereo, 4.4mm (5-Pole) [Balanced], Bluetooth |
| Network Device Output Options | WiFi |
| Driveability (Output Impedance) (Ω) | Unbalanced Out 3.5mm (1.5ohm) │ Balanced Out 2.5mm (1.5ohm), 4.4mm(1.4ohm) |
| Battery Life (Hours) | About 10 hours (Standard : FLAC, 16bit, 44.1kHz, Unbalanced, Vol.50, LCD Off, LED On, OP AMP Mode) |
| Product Dimensions | 3.34” (85mm)[W] x 5.89” (149.8mm)[H] x 0.76” (19.5mm)[D] |
| Product Weight (g) | approx. 544g–565g |
| Colour | Silver |
| Package Contents | What’s in the Box
|
| Warranty | 1 year warranty (local) |
If you're based in Singapore,
- spend $300 or more for free doorstep delivery1.
($250 for Silver/Gold/Platinum VIP members) - add a few more bucks, for delivery during the night/weekend, or quicker prioritised delivery options2.
- self-collection is possible at our Showroom, based in Ubi (nearest to MacPherson MRT). Find out where, and how to get to us here.
- and yes, you may arrange your own 3rd party logistics to pickup your purchases on your behalf.
GrabExpress, Lalamove, GoGoX, RydeSEND services are welcome.
View additional Terms & Conditions associated to local doorstep delivery service.
Friends from Overseas,
- we do ship internationally.
- certain brands impose cross-country supply restrictions, so we may not be able to ship to such countries for restricted brand(s).
- shipping fees are calculated according to total gross actual or volumetric weight of all item(s) in cart, whichever higher.
- shipping fees will vary depending on international carrier(s)3, and will be displayed during checkout.
- do be aware of additional import tax/VAT that may apply.
Due to recent changes in U.S. trade regulations, additional tariffs are being imposed on products manufactured in China and imported into the United States. As many of our audio products are made in China, orders shipped to U.S. addresses may be subject to an added tariff charge at checkout, reflected as a "U.S. Import Tariff Surcharge". Please note that this surcharge amount is determined by U.S. import policies and may vary significantly depending on product categories and any future policy adjustments. These charges are necessary to ensure compliance with U.S. customs requirements and to allow us to continue serving our U.S. customers reliably. We strongly encourage you to review the total cost at checkout before placing your order.
This surcharge is temporary but necessary during this period of significantly increased operational pressure as a result of the ongoing geo‑political situation in the Middle East.
Orders shipped to Gulf Cooperation Council (GCC), Africa, US and EU regions may be subject to an added surcharge at checkout, reflected as a "Temporary Emergency Situational Surcharge". Please note that this surcharge amount is determined by our freight partners, and may subject to adjustments according to situational updates. We strongly encourage you to review the total cost at checkout before placing your order.
View additional Terms & Conditions associated to international door to door shipping service.
1 Terms and condition do apply for free delivery. For more information, click here to view.
2 View our updated list of local delivery options.
3 View our updated list of international carriers.
No Reviews Available for this Product Yet. Leave Your Review
The A&ultima SP4000T, available first in Stainless Steel and later a Copper body option, is the culmination of approximately two years of multifaceted effort following the launch of the SP3000T in 2024, crafted together with the SP4000 from the very beginning stages of planning and development.
The SP4000T is the industry's first DAP to feature the RAYTHEON JAN6418 MIL-Spec vintage vacuum tube in a Quad configuration.
With independent dual-tube structures dedicated to the left and right channels respectively, the channel-separated design, once exclusive to home audio high-end tube amplifiers, has finally been brought to the world of DAPs.
Each of the four tubes is precisely measured for its noise and gain characteristics before being paired, then fully isolated from noise through independent modular flexible PCBs and a multi-layered architecture, a design that only Astell&Kern, with its long experience in analog circuits and vacuum tubes, could bring to life.
Triple Tube Mode in the SP4000T is a first in the industry for a DAP. Combined with the T Series Signature Triple AMP Mode and the Tube Current level adjustment, it offers up to 54 possible combinations tailored to any genre or preference, a true Analog Sound Palette.
The Astell&Kern SP4000T offers three distinct tube sound modes, each delivering its own unique sonic character. Triode Mode emphasizes rich harmonics and lush, lingering warmth, creating an emotional and immersive presentation ideal for vocals and acoustic instruments. Ultra Linear Mode balances the tonal richness of Triode with the power and control of Pentode, producing a refined yet authoritative sound suited for a wide range of music genres. Pentode Mode focuses on maximum output and dynamic impact, preserving tube warmth while delivering a cleaner, more direct, and energetic presentation.
Combining Astell&Kern’s exclusive TERATON ALPHA technology with Quad-configured Real Vacuum Tubes and advanced OPAMP design, the SP4000T delivers both authentic analog warmth and ultra-high-resolution clarity. Users can choose between dedicated OP AMP Mode for powerful dynamics, expansive detail, and low-noise precision, or TUBE AMP Mode for the rich, emotional character and natural soundstage unique to true vacuum tube audio.
An advanced 5-stage HYBRID AMP Mode that blends the strengths of both amps, allowing listeners to fine-tune the balance between analog warmth and high-resolution transparency to match their personal listening preferences.
The SP4000T introduces an upgraded 5-stage 2nd Generation Anti-Microphonic Architecture (up from the previous 4-stage design) to suppress microphonic noise (noise generated in vacuum tubes from even the most minor external vibrations).
The Astell&Kern SP4000T is designed for modern streaming-focused listening, running Android 15 with full Google Play Store support while maintaining Astell&Kern’s flagship analog sound quality. Its proprietary ADP (Astell&Kern Direct Path) technology bypasses Android’s standard sample rate conversion limitations to enable true lossless, bit-perfect playback from streaming services. The SP4000T also introduces Astell&Kern’s first dual Wi-Fi antenna design, delivering significantly faster and more stable wireless streaming and downloads, with internal testing showing up to twice the 5GHz download speed of previous models.
The Astell&Kern SP4000T combines Astell&Kern’s most advanced audio technologies to deliver a deeper, more refined analog sound experience. Its fully discrete circuit architecture separates digital and analog signal processing using dual flagship AK4499EX DACs and dedicated AK4191EQ processors for each channel, reducing noise and enhancing clarity, depth, and purity across the entire signal path.
Building on the SP4000 platform, the SP4000T also incorporates High Driving Mode with parallel OPAMP configuration for greater dynamic range and more detailed, immersive sound reproduction. Proprietary ESA (Enhanced Signal Alignment) technology minimizes group delay and frequency distortion, while Advanced DAR technology restores lost harmonics before applying upsampling for more natural, lifelike playback.
Additional refinements including Any Layer HDI PCB technology and a 99.9% pure copper Shield Can further minimize signal loss, noise, and electromagnetic interference, resulting in exceptionally clean, vivid, and highly resolved audio performance.
The SP4000T is packaged with a premium leather “Cognac’ colored case crafted using 'MINERVA' leather from 'BADALASSI CARLO', a renowned leather workshop located in the San Miniato district of Florence, Italy.
The Astell&Kern SP4000T combines flagship-level connectivity and high-resolution playback capabilities with advanced wireless and user-focused features. It offers 256GB of internal storage with microSD expansion up to 1.5TB, supports native playback up to 32-bit/768kHz PCM and DSD512, and features a 6-inch Full HD touchscreen alongside dual-band Wi-Fi, DLNA networking, USB audio output, and USB DAC functionality for Mac and Windows PCs.
Wireless performance is enhanced through support for aptX Adaptive and LDAC codecs, while BT Sink mode allows the SP4000T to function as a high-quality Bluetooth DAC for external devices such as smartphones. Features like ReplayGain, AK File Drop wireless transfers, USB PD 3.0 fast charging, and customizable battery protection further improve everyday usability.
For extended listening comfort, the SP4000T also includes advanced Crossfeed controls that recreate a more speaker-like listening experience through headphones, allowing users to fine-tune spatial presentation and reduce listening fatigue over long sessions.
Pricing and availability for the SP4000T Stainless Steel and Copper will be announced soon.
Two additional premium leather cases will be available for the SP4000T. A black color case, crafted from soft cowhide by GRUPPO MASTROTTO, delivers an exceptionally soft touch, with a uniform surface quality and a distinctively vibrant Italian coloration. An olive-colored case, crafted from premium vegetable-tanned leather by BADALASSI CARLO, is crafted through a proprietary tanning and dyeing process. Both cases feature a standing mechanism on the back to provide greater convenience in use.
| Product Availability | Available (current model) |
| Product Type | Digital Audio Player |
| Style/Type | Portable |
| Features | WiFi, Bluetooth, Expandable Memory/Storage, Internet Radio, Dual Headphone Output, High-Res Audio Certified, DSD, MQA (Master Quality Authenticated), 2.4GHz/5GHz Dual-Band WiFi, roon ready |
| Connectivity | Wireless & Wired |
| DAC | AKM4191EQ x2 + AKM4499EX x2 |
| Op-Amp / Amplifier | RAYTHEON JAN6418 x4 (Quad Tube) |
| Internal Storage Capacity | 256GB |
| Expandable Storage | Yes |
| Expandable Storage Capacity | 1TB (1024MB) |
| Bluetooth Version | v5.2 |
| Bluetooth Codecs | SBC, AAC, aptX HD, LDAC |
| Waterproof Rating | IPX0 – No protection |
| Sampling / Bitrate | PCM: 8kHz ~ 768kHz (8/16/24/32bits per sample), DSD Native: DSD64(1bit 2.8MHz), DSD128(1bit 5.6MHz), DSD256(1bit 11.2MHz), DSD512(1bit 22.4MHz) |
| Frequency Response (Hz) | PCM: 8kHz ~ 768kHz (8/16/24/32 bits per sample) |
| Signal-to-Noise Ratio (SNR) | 124dB |
| Voice Assistants | - None - |
| Streaming Services | Roon |
| Mic for Calls/Communication | None |
| Input Connectivity Options | microSD [External Storage], USB Type-C (USB-C) [Charging], WiFi |
| Output Connectivity Options | 2.5mm (4-Pole) [Balanced], Optical mini-TOSLINK (SPDIF), 3.5mm Stereo, 4.4mm (5-Pole) [Balanced], Bluetooth |
| Network Device Output Options | WiFi |
| Driveability (Output Impedance) (Ω) | Unbalanced Out 3.5mm (1.5ohm) │ Balanced Out 2.5mm (1.5ohm), 4.4mm(1.4ohm) |
| Battery Life (Hours) | About 10 hours (Standard : FLAC, 16bit, 44.1kHz, Unbalanced, Vol.50, LCD Off, LED On, OP AMP Mode) |
| Product Dimensions | 3.34” (85mm)[W] x 5.89” (149.8mm)[H] x 0.76” (19.5mm)[D] |
| Product Weight (g) | approx. 544g–565g |
| Colour | Silver |
| Package Contents | What’s in the Box
|
| Warranty | 1 year warranty (local) |
No Reviews Available for this Product Yet. Leave Your Review
What's better than this
Calling All Audiophiles!
Experience Sound Rewards Today.
A reimagined shopping experience for our loyal customers awaits.
