Read the articleof our Canadian colleagues Brosseau.ca "BC Acoustique: EX-888, a first viewed" - August 2014.
See the EX-888 bench test from Canadian TED magazine - December / January 2014.

The EX888 is a tubes amplifier using KT88 power tubes and 12AX7/12AU7 for pre-amplification. We wanted to achieve with the EX-888 an amplifier with an exceptional sound that honours the legend of tubes but also benefiting from a reserve of power that allows easy association with the majority of speakers in the market.

To achieve our goals, we used a proven pattern but with some unpublished parts (including a so-called "anode follower"), which allowed us to reconcile a low rate of reaction against (ensuring maximum power) and a very low level of distortion (less than 1% with a gradient odd harmonics characteristic of achievements tubes).
 

HIGHLIGHTS
Pre-out
Optional board slot
Massive continuous power of 500VA transformer

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Power supply
It is based on a very high quality impregnated EI transformer capable of delivering a continuous power of 550VA. The diodes used in the rectifier bridge are broadband-like to ensure a continuous tension as pure as possible. Finally the filter is achieved by an innovative structure called CLC ie the equivalent of a third order filter for a perfect smoothing of the output voltage.

Output transformer
The winding of the output transformer uses a structure to achieve perfect symmetry output stages and the same minimal distortion. They use a deoxygenated copper wire. They are very generously sized to pass the entire dynamics of the output stage. They are wound in 3Ω and 6Ω (normed 4Ω and 8Ω) whereas the trend (long ago) prevailing in speaker manufacturers.

Components
The volume knob is a motorized with APLS potentiometer.
Capacitors links are aluminum insulated polypropylene sheet.
They come from renowned manufacturer SOLEN.
The resistors areall high power.
Double side soldering.
The circuit is printed on epoxy and 70 microns thick.

SPECIFICATIONS
Continuous output power: 2 x 40W (ultra-linear mode) or 2 x 20W (in triode mode)
Output Impedance: 4Ω, 8Ω
Bandwidth: 10Hz ~ 38kHz (-1 dB)
Distortion ≤ 1% (1kHz)
S/N ratio ≥ 93dB
Tubes: KT88×4 12AX7×2, 12AU7×2
Input Sensitivity: 360 mV (700 mV bypass)
Input impedance: 100kΩ

Dimensions (WxHxD): 430x200x405 mm
Weight: 25 kg

Connections
5x RCA inputs (gold plated) including: 1x RCA input (OPTION) can receive an optional board card
1x RCA input (AUX2/AV) for "by-pass" stages of gain control in the context of use in an A/V system.
1x RCA "Pre-Out" output for adding an amplifier power in the context of a bi-amplification.
Settings of Treble and Bass tone with "Direct" function to shunt circuits correction.
Switching between triode mode and Ultra-linear
Gold plated terminals isolated
Remote control