{"product_id":"xduoo-ta-68-balanced-tube-headphone-amplifier","title":"xDuoo TA-68 Balanced Tube Headphone Amplifier","description":"\u003ch1\u003e\u003cstrong\u003etube amplifier with independent volume controls\u003c\/strong\u003e\u003c\/h1\u003e\n\u003cp\u003eThe TA-68 is a fully-balanced desktop tube headphone amplifier built around tube rectification, 12AU7 preamplification, 6C19 current amplification, and a capacitor-coupled output stage. It provides XLR, 4.4 mm, and RCA inputs alongside 4-pin XLR, 4.4 mm, and 6.35 mm headphone outputs. Independent left and right volume controls, isolated transformer power supplies, and a 45-second protection delay support precise, controlled listening with a wide range of high-impedance headphones.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eFully-balanced signal path\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eThe TA-68 uses separate tube circuits for the left and right channels from input to output. This fully-balanced architecture supports stronger channel separation, clearer spatial placement, and a quieter background when used with compatible balanced sources and headphones.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eTube rectifier architecture\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eTwo 5U4G tubes provide high-voltage rectification, with independent anode voltage supplied to the left- and right-channel circuits. The tube-based power stage contributes to the amplifier’s smooth, full-bodied tonal character.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003e12AU7 tube preamplification\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eTwo matched and screened 12AU7 dual-triode tubes handle voltage amplification. Their role in the signal path gives the TA-68 a warm, rounded presentation while retaining detail and clarity during extended listening.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003e6C19 tube buffer\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eEach channel uses two matched 6C19 power tubes for current amplification. This four-tube buffer stage supplies the drive required for headphones with impedances from 60 to 600 ohms.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eCapacitor-coupled output\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eA classic capacitor-coupled output topology preserves the tonal qualities of the tube circuit while isolating the headphones from direct current at the output stage.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003ePremium audio capacitors\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eVishay audiophile capacitors are used for signal coupling, while audio-specific Nichicon capacitors handle power-supply filtering. Together, these components support a smooth tonal foundation, controlled treble, and consistent signal transfer throughout the amplifier.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eDual transformer power supply\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eTwo low-noise, low-flux-leakage EI transformers provide separate power feeds for the left and right channels. Isolating the channel supplies helps reduce inter-channel crosstalk and supports the TA-68’s measured channel separation of up to 80 dB in balanced operation.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eIndependent channel control\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eSeparate volume knobs allow the left and right channels to be adjusted independently. This makes it possible to correct channel imbalance, compensate for recording differences, or fine-tune image placement without affecting the opposite channel.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eBalanced and single-ended inputs\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eThe rear panel includes stereo XLR and 4.4 mm balanced inputs, along with a stereo RCA input for single-ended sources. A front-panel selector provides direct switching between balanced and line-level input modes.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eThree headphone outputs\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eThe front panel provides a 4-pin XLR balanced output, a 4.4 mm balanced output, and a 6.35 mm single-ended output. These connections accommodate many full-size headphones without requiring an additional adapter.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eDelayed startup protection\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eA relay-based protection circuit applies a 45-second warm-up delay when the amplifier is powered on. The delay allows the tubes to stabilize before the headphone outputs engage, while also reducing power-on and power-off thumps and limiting inrush current to connected drivers.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eSwappable tube design\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eAll tubes are socket-mounted, allowing compatible replacements from different manufacturers to be installed. Tube changes can alter the amplifier’s tonal balance and presentation while preserving the original circuit design.\u003c\/p\u003e\n\u003ch2\u003e\u003cstrong\u003eAluminum alloy chassis\u003c\/strong\u003e\u003c\/h2\u003e\n\u003cp\u003eThe TA-68 uses an aluminum alloy enclosure with a sandblasted front panel and a ventilated protective tube cage. The metal chassis provides structural support and helps shield the internal circuitry from external electromagnetic interference.\u003c\/p\u003e\n\u003ch3\u003e\u003cstrong\u003eProduct highlights\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eFully-balanced left and right signal architecture\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eTwo 5U4G rectifier tubes\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eTwo matched 12AU7 preamplifier tubes\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eFour matched 6C19 buffer tubes\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eCapacitor-coupled headphone output stage\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eVishay coupling capacitors\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eNichicon audio-grade filter capacitors\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eIndependent left and right volume controls\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eDual isolated EI power transformers\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eXLR, 4.4 mm, and RCA inputs\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e4-pin XLR, 4.4 mm, and 6.35 mm headphone outputs\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003e45-second relay protection delay\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eSocket-mounted, swappable tubes\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eAluminum alloy chassis with tube cage\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eSpecs\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eModel: TA-68\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eProduct type: Balanced tube headphone amplifier\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003ePower supply: AC 100–120 V or AC 220–240 V\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eBalanced input connections: Stereo XLR and 4.4 mm\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eSingle-ended input connection: Stereo RCA\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eBalanced headphone outputs: 4-pin XLR and 4.4 mm\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eSingle-ended headphone output: 6.35 mm\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eRectifier tubes: Two 5U4G\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003ePreamplifier tubes: Two 12AU7\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eBuffer tubes: Four 6C19\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eBalanced output power: 120 mW at 75 ohms, 160 mW at 150 ohms, 200 mW at 250 ohms, 330 mW at 300 ohms, 240 mW at 600 ohms\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eSingle-ended output power: 60 mW at 75 ohms, 100 mW at 150 ohms, 130 mW at 250 ohms, 210 mW at 300 ohms, 160 mW at 600 ohms\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eBalanced gain: 24 dB\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eSingle-ended gain: 18 dB\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eFrequency response: 10 Hz–80 kHz, ±0.5 dB\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eBalanced channel separation: 80 dB\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eSingle-ended channel separation: 71 dB\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eBalanced SNR: 116 dB, A-weighted\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eSingle-ended SNR: 110 dB, A-weighted\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eTHD: 0.1% at 1 kHz into 300 ohms\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eRecommended headphone impedance: 60–600 ohms\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eStartup delay: 45 seconds\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eDimensions: 13.0 x 11.8 x 7.3 in (33 x 30 x 18.5 cm)\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eWeight: 24.3 lb (11.0 kg)\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003e\u003cstrong\u003eWhat’s included\u003c\/strong\u003e\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eTA-68 balanced tube headphone amplifier\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eTwo 5U4G rectifier tubes\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eTwo 12AU7 preamplifier tubes\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eFour 6C19 buffer tubes\u003cbr\u003e\n\u003c\/li\u003e\n\u003cli\u003eProtective tube cage\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"xDuoo","offers":[{"title":"Default Title","offer_id":48020455751916,"sku":"APS-1394-1","price":1299.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0225\/2721\/3642\/files\/IMG_3678.jpg?v=1785251308","url":"https:\/\/apos.audio\/products\/xduoo-ta-68-balanced-tube-headphone-amplifier","provider":"Apos","version":"1.0","type":"link"}