{"product_id":"astell-kern-a-ultima-sp4000t","title":"Astell\u0026Kern A\u0026ultima SP4000T | Vacuum Tube Digital Audio Player","description":"\u003cp\u003e\u003cimg style=\"display: block; margin-left: auto; margin-right: auto; width: 40%;\" alt=\"Astell\u0026amp;Kern product logo red\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0023\/9255\/5595\/files\/astell-kern-horizontal-logo-cf203a-red.jpg?v=1676570802\"\u003e\u003c\/p\u003e\n\u003ch4\u003eDiscover the Astell\u0026amp;Kern SP4000T, the Ultimate DAP, Where Analog Warmth and Digital Precision Collide\u003c\/h4\u003e\n\u003cul\u003e\n\u003cli style=\"font-weight: bold;\"\u003e\u003cstrong\u003eCopper Finish Coming in the Near Future\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli\u003eIndustry-first DAP with MIL-Spec Vintage Vacuum Tube Raytheon JAN6418 in Quad Configuration\u003c\/li\u003e\n\u003cli\u003eIndustry-first DAP with Triple Tube Mode (Triode, Ultra Linear, Pentode)\u003c\/li\u003e\n\u003cli\u003eT Series Signature feature: Triple AMP System\u003c\/li\u003e\n\u003cli\u003eAdjustable Tube Current with Three Levels\u003c\/li\u003e\n\u003cli\u003eHigh Driving Mode, ESA, and Advanced DAR for superior sound quality\u003c\/li\u003e\n\u003cli\u003eFull Open Android\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cimg alt=\"AstellKern SP4000T DAP standing rear view center with notebook on wooden table\" height=\"1360\" width=\"2048\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0023\/9255\/5595\/files\/ak-sp4kt-banner.webp?v=1783964647\"\u003e\u003c\/p\u003e\n\u003cdiv class=\"bloom-take\"\u003e\n\u003ctable bgcolor=\"”#f6f6f6”\" width=\"90%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e\n\u003cp\u003e\u003cspan style=\"color: #a30e0b;\"\u003e\u003cstrong\u003eBloom's Take\u003c\/strong\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp\u003eAstell\u0026amp;Kern has never been shy about experimenting at the top, and the SP4000T might be their most flexible flagship yet. Rather than chasing a single “perfect” tuning, it builds on the SP4000’s technical foundation and adds a tube stage that lets you reshape the sound to match your preferences. It’s less about redefining performance outright, and more about expanding how you experience it.\u003c\/p\u003e\n\u003cp\u003eSonically, the SP4000T still delivers the detail, imaging, and expansive staging you expect from a summit-fi DAP, but the real story is how it presents that performance. In solid state, it leans clean and resolving, while the tube modes introduce varying degrees of warmth, body, and smoothness. Whether you prefer the lush, rounded character of Triode, the balance of Ultra-Linear, or the more energetic clarity of Pentode, each mode feels intentional rather than gimmicky, offering meaningful shifts in tone and texture.\u003c\/p\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/bloomaudio.mom\/blogs\/articles\/too-tube-or-not-to-tube-astell-kern-sp4000t-review\" title=\"Astell\u0026amp;Kern SP4000T Review\"\u003eRead our full review\u003c\/a\u003e.\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003cp\u003e\u003cbr\u003e\u003ciframe width=\"560\" height=\"315\" src=\"https:\/\/www.youtube.com\/embed\/G4kbSFVb7ks?si=Eq3SKgL9X2JMNVF3\" title=\"YouTube video player\"\u003e\u003c\/iframe\u003e\u003c\/p\u003e\n\u003ch3\u003eA New Standard in Tube Configuration\u003c\/h3\u003e\n\u003cp\u003eWith 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.\u003c\/p\u003e\n\u003cp\u003eThe four tubes in the SP4000T work in a differential configuration, with each pair facing the other in mirror symmetry. In this precise balance, music signals are amplified with twice the clarity, while common-mode noise is mutually cancelled and eliminated.\u003c\/p\u003e\n\u003cp\u003eWhen four hearts beat as one in perfect balance, the tube's signature rich harmonics resonate with the deepest, most resonant sound ever heard in the SP4000T.\u003c\/p\u003e\n\u003ch3\u003eTriple Tube Mode\u003c\/h3\u003e\n\u003cp\u003eThe SP4000T is the industry's first DAP to feature Triple Tube Mode. Combined with the T Series Signature Triple AMP Mode and the Tube Current level adjustment first found on the SP3000T, it offers up to 54 possible combinations tailored to any genre or preference, a true Analog Sound Palette.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eTriode Mode: The Purest Voice of the Tube\u003c\/strong\u003e\u003cbr\u003eThis mode brings out the richest harmonic texture unique to vacuum tubes, letting the breath of a vocalist and the trembling of strings gently dissolve into a lush, lingering reverb.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003eUltra Linear Mode: The Aesthetics of Balance\u003c\/strong\u003e\u003cbr\u003eA design that blends the tonal color of Triode with the output of Pentode. The sound fades softly at its edges, yet carries a firm, solid core.\u003cbr\u003e\u003cbr\u003e\u003cstrong\u003ePentode Mode: The Most Powerful Voice of the Tube\u003c\/strong\u003e\u003cbr\u003eMaximizing tube amplifier output and dynamic range, this mode retains the tube's signature warmth while stripping away reverb — delivering a clean, powerful presence that speaks with directness and force.\u003c\/p\u003e\n\u003cp\u003e\u003cimg src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0023\/9255\/5595\/files\/ak-sp4kt-lifestyle.webp?v=1783964709\" width=\"2048\" height=\"1360\" alt=\"AstellKern SP4000T DAP lying on open notebook closeup of side buttons\"\u003e\u003c\/p\u003e\n\u003ch3\u003eThe Perfect Harmony\u003c\/h3\u003e\n\u003cp\u003eA\u0026amp;ultima SP4000T, built on Astell\u0026amp;Kern's exclusive Teraton Alpha technology, achieves a perfect fusion of true analog sound from the Quad-configured Real Vacuum Tubes and the dynamic sound of the OPAMP.\u003c\/p\u003e\n\u003cp\u003eSP4000T offers TUBE AMP mode for the authentic analog sound of a tube amplifier, OP AMP mode delivering Astell\u0026amp;Kern's signature clarity and expansive soundstage, and HYBRID AMP mode combining the best of both analog warmth and high-resolution output.\u003c\/p\u003e\n\u003ch3\u003eAnti-Microphonic Noise Architecture\u003c\/h3\u003e\n\u003cp\u003eThe greatest technical challenge in applying vacuum tubes to a compact portable device is achieving low noise even at high resolution and high output. SP4000T introduces an upgraded 5-stage 2nd Generation Architecture (up from the previous 4-stage design) to suppress microphonic noise (noise generated in vacuum tubes from even minor external vibrations). \u003c\/p\u003e\n\u003ch3\u003eHEXA Audio Circuit Structure\u003c\/h3\u003e\n\u003cp\u003eThe SP4000T integrates dual AK4499EX DACs, AKM’s latest flagship, paired with dedicated AK4191EQ processors for each left and right channel, forming a fully discrete audio circuit architecture.\u003c\/p\u003e\n\u003cp\u003eUnlike conventional DAPs that handle both digital and analog signals inside the DAC, the SP4000T's audio circuit uses a dedicated digital delta-sigma modulator (AK4191EQ) to reduce noise in the digital signal before passing it to a completely isolated Analog DAC (AK4499EX) for independent analog signal processing.\u003c\/p\u003e\n\u003cp\u003e\u003cimg alt=\"AstellnKern SP4000t dap rear left 3 quarter in leather case whitebox\" height=\"1200\" width=\"2048\" src=\"https:\/\/cdn.shopify.com\/s\/files\/1\/0023\/9255\/5595\/files\/ak-sp4000t-case.webp?v=1781190116\"\u003e\u003c\/p\u003e\n\u003ch3\u003ePremium Leather Case\u003c\/h3\u003e\n\u003cp\u003eThe bundled leather case for the SP4000T was crafted using 'MINERVA' leather from 'BADALASSI CARLO', a renowned leather workshop located in the San Miniato district of Florence, Italy.\u003c\/p\u003e\n\u003cp\u003eVegetable tanning is an eco-friendly leather-making process, slow and time-intensive, that tans hides using only plant-derived tannin extracts. Badalassi Carlo leathers employ the Tuscan vacchetta technique, after removing the hair from the hide, bovine bone powder-derived tallow is added during the vegetable oil tanning process.\u003cbr\u003e\u003c\/p\u003e\n\u003ch3\u003eAdditional Features and Enhancements\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eAstell\u0026amp;Kern's TERATON ALPHA\u003c\/li\u003e\n\u003cli\u003eAstell\u0026amp;Kern Direct Path Customization Technology\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e99.9% Pure Copper Shield Can\u003c\/li\u003e\n\u003cli\u003eNative DSD512, 32-bit\/768kHz Support\u003c\/li\u003e\n\u003cli\u003eUSB PD 3.0 Fast Charging\u003c\/li\u003e\n\u003cli\u003eLarge 6\" Full HD Display\u003c\/li\u003e\n\u003cli\u003eEnhanced Battery Protection Mode\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"Astell\u0026Kern","offers":[{"title":"Silver","offer_id":42674487918667,"sku":"AK-SP4000T-SLV","price":3620.0,"currency_code":"USD","in_stock":true},{"title":"Silver - Open Box","offer_id":43182373830731,"sku":"AK-SP4000T-SLV-OB","price":3620.0,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0023\/9255\/5595\/files\/ak-0-sp4000t-thumb.webp?v=1781189645","url":"https:\/\/bloomaudio.mom\/products\/astell-kern-a-ultima-sp4000t","provider":"Bloom Audio","version":"1.0","type":"link"}