
 - JD90 - Current-Mode Tube Power Amplifier 
- Introduction to the Characteristics of Products - 1. The current-mode circuit architecture eliminates the intermodulation distortion inherent in traditional long-tail phase-split driving circuits, which is the primary factor degrading sound quality. - 2. The current-mode circuit features a wide frequency bandwidth, high slew rate, and unlimited voltage swing, offering a large dynamic range. - 3. The minimal use of vacuum tubes in the amplification path significantly reduces phase distortion. - 4. The adaptive constant-current and constant-voltage hybrid biasing of the JD90 power tubes ensures push-pull arm current balance, minimizing DC magnetization of the output transformer. - 5. The independent balanced feedback structure guarantees stability across the entire frequency spectrum and dynamic range. - 6. The low-noise DC-regulated power supply for the driver stage achieves high power supply noise rejection and stable driving capability for the power tubes, overcoming the influence of Miller capacitance on the slew rate and delivering sharp dynamic performance. - 7. The application of power tube temperature equalization and high-efficiency flat heat pipes significantly reduces the operating temperature of the vacuum tubes. The temperature of the power tube glass envelope decreases by over 100°C, greatly improving the lifespan and reliability of the vacuum tubes while achieving ultra-low background noise. The overall system achieves a signal-to-noise ratio (SNR) of 95dB or higher. 
- Amplifier technical specification - Stereo Output Power: 25W - Frequency range: 6Hz to 60kHz±1dB(at 1W into 8Ω) 0dB at 1kHz - Frequency range: 8Hz to 35kHz (-3db); 30W at 1kHz, 8Ω - THD+N: - ≤ 0.3% (1W,20Hz-30kHz,8Ω).typically 0.07% at 1kHz - ≤ 1% (15W,20Hz-30kHz,8Ω). - Circuit Mode: Current-Mode A Mode - Bias adjustment: Auto Biased - The amount of negative feedback: 6dB - Input impedance: RCA 100kΩ,XLR 55KΩ - Input sensitivity: Max 1.4Vrms at 1kHz for 25W - SNR: 100dB (A-Weighted) - Rated output impedance: 4-6 Ω / 8-16 Ω - Input Channel Isolation:10-100kHz>70dB,1kHz> 85dB - Channel Separation: 10-20kHz>70dB,1kHz>85dB - Tubes Used:4 x KT90;2 x 6922 - Machine size: - 17(W) x 14(D) x 9.6(H) inches - 43.6 (W) x 36.4 (D) x 24.5(H) cm - Weight: - 78 lbs (33kg) N.W. 86 lbs(39 kg )G.W. - Fuse:- 230 VAC/50HZ,T3.15A. 110VAC/60HZ,T6.3A- Maximum Power:- ≤ 400VA
- FRE-1W  - FRE-15W  - FRE-30W  - THD-1W  - THD-15W  - THD-30W  - SNR  - Sensitivity  - R-Channel Separation  - L-Channel Separation  - Channel Isolation  
- List of Tubes Used - This machine uses two 6922 vacuum tubes and four 6SN7 vacuum tubes for the front stage of amplification. The rear stage uses four Russian KT88 vacuum tubes for push-pull amplification. - TF* is Tube Fidelity Company's special pure thickness sound processing Tube, which has the effect of pure thickness and pure sound, eliminating noise, and improving sound quality.- Vacuum tube model for this machine - 6922EH - SVKT90 - Alternative vacuum tube options - E88CC 
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沪公网安备 31011402001758号