JJ 828 Integrated power tube stereo amplifier

High Class-A Stereo Amplifier

Ultralinear, 8 x KT88, 2x 70 W

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4 308,00 € excl. shipping

  • Red maple/24 carat gold platted
  • Black/Chrome
  • Gloss ivory/Chrome

    The basic design criteria for amplifier JJ 828 were as follows:

    • - integrated amplifier with remote control
    • - minimum 50W output power per channel
    • - sufficient damping factor at minimal global feedback
    • - great sound

    Our designers have chosen this solution:

    • - high quality components
    • - inputs switched by signal relays
    • - independent power source for each channel
    • - ultra linear circuitry with KT 88 tube
    • - high operational current of KT 88 (75mA)
    • - KT88 cathodes feedback (CFB) via output transformers
    • - output transformer unique design

    For the first time, tube ECC 99 is used as a driver for KT 88. This is a tube specifically developed by JJ Electronics for application as a unique linear driver for high power tubes KT88 and 300B. Concertina with ECC 82 parallel was chosen as a phase inverter in front of the ECC 99.

    There are two feedbacks in this design: one is a global feedback from OT (–6dB) and the second is from the KT88 cathodes through OT (5dB).

    Output transformer is based on C-core made from 0.13-0.15 mm sheets, with air distance 2 x 0.05 mm. The air distance provides linearization of electrical parameters within the entire power range. The manufacturing of C-core, similarly as in the case of the JJ 322 amplifier, is under complete control of JJ Electronic. There are two OT coils: each has four primary, four bifilar secondary and two feedback windings. This OT design yields 3mH at Lp 35H lsp.

Tube Complement 8 x JJ KT88
2 x JJ ECC99
4 x JJ ECC82
Circuit type Push-Pull Ultra Linear AB with CFB
Output power 2 x 70 Watt RMS
Load impedance 4 Ohm, 8 Ohm
Input impedance 25 000 Ohm
Input sensitivity 0,775 V for full output
Input sensitivity 20 Hz - 25 000 Hz (-1 dB)
S/N Ratio - 88 dB bellow full output
Input connectors 5 x Line (unbalanced)
Output connectors Tape out: For tape recording
Power Supply 230 V (120 V, 100 V) AC 50/60 Hz
Power Consumption 400 W max.
Dimensions 480 x 350 x 180 mm
Weight 35 kg
Finish chasis: black, gold antique or silver antique (pulver lack)
top plate: gold or silver (pulver lack)
cover: gold or silver (pulver lack)
wood: brown, natural (glossy) or black (dull)

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JJ 828 Integrated power tube stereo amplifier

JJ 828 Integrated power tube stereo amplifier

High Class-A Stereo Amplifier

Ultralinear, 8 x KT88, 2x 70 W

Write a review