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"Ribbon", The 20/40W ALL-FET Class-A Power Amplifier |
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The EB-700/343 is a high-speed ALL-FET Class-A power amplifier driver with exceptional resolution, and dynamics. Its neutral sound makes it equally applicable in high-end home systems as in studio monitor and recording applications. Within its power rating, the EB-700/343 outperforms most high-end power amplifiers on the market in terms of sonic quality, irrespective of price.
Only FETs (JFETs and MOSFETs) are used as active elements in the amplifier. The input stage is using Cascoded dual low-noise monolitic JFETs, which are operated at 2mA. The second stage consists of two paralleled JFETs, each conducting 10mA. These are Cascoded with MOSFETs for linearity and reduced internal capacitance. The resistors are all high quality Caddocks and Vishay/Dale. The driver board can be operated with unbalanced input (input impedance: 100k) and with balanced input (both inputs: 2.2k).
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 |  | | EB-700/343 Schematic |
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The driver circuit is fed from discrete ALL-FET, wide-band, low-noise regulators (not shown) These are also using Cascoded dual low-noise JFET for the input, and MOSFETs in the driver and output stage. The electrolytics are ELNA CERAFINE.
The “RIBBON” driver can be used with 3 pairs of HITACHI MOSFETs for a 20W pure Class-A amplifier or with 5 pairs of HITACHI’s for 40W pure Class-A amplifier. The heatsinks need to have approx. 0.4K/W and <0.3K/W respectively. Recommended heatsinks are the SK56/150 and the SK139/150 or SK139/200, respectively.) The PCB is 120x130mm.
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 | | | The New RIBBON Driver Board |
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