Original OPA-3A 300B Vacuum tube Amplifier HiFi Headphone Balance output Amp
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1. the input part
With balanced and RCA mode selection, the balanced input uses a high-quality op amp to convert the balanced signal into an unbalanced signal, which is adjusted by the AN audionote volume potentiometer and input to the amplifier circuit.
2. the output part
There are external speaker function and headphone output function, in which the earphone can select four-core balanced output and 6.5 single-ended output. The four-core balanced output is isolated and amplified by the output transformer, and the balanced signal of positive and negative waveform is output by special process. Push the balance headphones.
- The whole machine adopts high quality PCB welding to ensure stability and uniformity.
- EI type output transformer with two high-quality broadband high-quality sound quality Japanese Z11 iron core
- Use high-power Z11 iron core EI type power transformer specially designed for this machine
- the high pressure part uses 274B/5U4G for bile rectifier
- The front stage uses two 12AU7 vacuum tubes, and the latter stage uses two 300B vacuum tubes for Class A single-ended power amplification. Fully reflect the 300B's unique, smooth, transparent personality.
- the input has BALANCE / RCA selection
- the headphone output can choose four core balanced output and 6.5 output
- with an external speaker function
- boot mute delay function (about 30 seconds)
- power input selection Furutech (Furuhe) FI-03 with insurance power tailstock
- the power switch uses the British RS silver-plated contact power switch
- the signal input uses the US original CARDAS (Cadas) RCA signal socket
- the volume potentiometer selects the British original AN audionote
- Easy-to-install plug-in vacuum tube protection cover
- Rated output power: External speaker output: 8W+8W (when 4-8Ω load)
- Balanced headphone output: 4500MW+4500MW (at 32Ω load)
- Single-ended headphone output: 1000MW+1000MW (for 32Ω load)
- The whole machine frequency response: 20Hz ~ 50kHz (-1.5dB)
- Harmonic distortion: 0.5% (1kHz)
- Signal to noise ratio: 89dB
- Input sensitivity: 220mV
- Input impedance: 100kΩ
- Left and right output balance: <0.5dB
- Use vacuum tube: 12AU7 x2, 300B x2, 5U4G x1
- Machine size (WxDxH): 360mm x275 mm x170 mm
- Net weight: 20kg
- Working conditions: Temperature: 0 ° C ~ 40 ° C Humidity: 20% ~ 80%
- Storage conditions: Temperature: -20 ° C ~ 70 ° C Humidity: 20% ~ 90%
- Headphone output mode is variable voltage output
- Output impedance: speaker 6Ω headphone 64Ω
- Output impedance when the headphones are balanced: 64Ω 6.5 output 32Ω