268C: Includes complete audio section, linearized EQ, ARC acoustic environment processor

268: Includes complete audio section, linearized EQ

Directly engraved Swiss FM268, 268C preamp; contains complete audio part, linearized EQ, ARC acoustic environment processor (268 not included), standard remote control, completely cracked original module, double shielding transformer consistent with the original machine, using 4700uf Mondolph audiophile capacitors. Strictly follow the original machine testing, production links. Components strictly aging, testing, pairing; module pairing before each group of modules installed, all work points refer to the original machine; factory and then after 100 hours boiler; each independent number, module parameters archived for future maintenance. Sound field is open, rich in detail, sound loose and natural at the same time rich in flavor. 6 groups of balanced input, 1 group of balanced output, 1 group of recording input and output, 1 phono amplifier power supply output. Adjustable left and right channel balance, phase reversal.

Note: Because the pre-stage gain is high, be sure to wait for the warm-up is complete, the indicator light is always on before adjusting the volume of use

Technical parameters.

Gain: 20dB

Maximum input level: 7.75 V

Maximum output level: 18.5 V

Input impedance: 100kΩ

Output impedance: 20Ω or lower

THD+N: 0.003% or more

Signal-to-noise ratio: 95 dB or more

Input terminals: Balanced (XLR) x 6

Output terminals: balanced (XLR) x 1

Recording input and output terminals: balanced (XLR)

Power supply: 230V/220V/115V/110V AC, 50 / 60Hz

268C front panel, preheat stage indicator flashes after power on, always on when preheat is complete

Power switch, power indicator volume knob (remotely controllable), left and right channel balance potentiometer

6 groups of input switching buttons, 4 function buttons (recording monitor, mono monitor, phase inversion, attenuation 20dB), linearization EQ knob

268C backplane: 6 sets of balanced inputs, 1 set of balanced outputs, 1 set of recording inputs and outputs, 1 phono power output; ARC acoustic environment processor (268 not included)

268C internal structure: the upper green PCB is the linearized EQ circuit, the core preamplifier circuit is in the lower layer (see 266 preamplifier)

Double shielded transformer and Mondolpho 4700uf capacitor in line with the original machine

Professional test instruments: AP SYS-22, Kikusui signal generator, 3012b Tektronix oscilloscope

Product Description.

After an in-depth understanding of the FM268 preamplifier circuit to make a 1:1 replica, the input amplifier circuit using the latest hr input module, to achieve high resistance into the low resistance out, with a variety of different signal sources. Input module THD + N up to 100dB or more, with excellent anti-interference ability. hr is high-precision adjustment, including the output amplifier module are precision adjustment, correction of hot and cold end waveform and output swing consistency.

FM268 has a linearized EQ function, which can adjust the music very important frequency range. The frequency band is not arbitrarily determined as in the case of general equipment, but is set to the frequency at which human hearing has been proven to include the basic elements of music reproduction. In 50HZ, 200HZ, 800HZ, 3.3KHZ, 12.8KHZ set linearization circuit control band is divided into five frequency bands, the module we use the bridge for precision matching and the use of AP for frequency adjustment, to achieve the true indicators and the original factory consistent. eq adjustment plus or minus 6dB and 12dB. the linear EQ is different from ordinary EQ, linearization circuit is not a filter but in The signal path is placed in parallel rather than in series to control the amplitude characteristics of each frequency band. The absence of phase interference allows high-performance frequency control to be performed for the first time in the analog domain without affecting the quality of the signal system. Music restoration can be optimized to the entire system and to the software and environment.

Linearization of parallel EQ

The filter capacitor uses 4700uf Mondolfo fever capacitor, decoupling and coupling use and the original consistent Nikon PW and ELECTEL film capacitors. Transformer use the same transformer as the original, which is a double shielding transformer.

The unique ARC (Ambient Acoustic Processor) circuitry enhances listening pleasure and realism by eliminating or reducing room standing wave patterns and other resonances. Each machine we will refer to the original test diagram, the replica machine test for comparison and sent to customers. Guarantee equipment reproduction reliability.

Input module bandwidth up to 1M, input and output module using transistors are precision aging pairing test, amplification module to ensure that the positive and negative output swing and square wave consistent, that is, to adjust the amplification precision. The adjustment is also a relatively high degree of adjustment of the amplification module, both positive and negative square wave consistent with the same output amplitude, is a relatively difficult to adjust the core technology, in the playback of the positioning level transparency will be very large performance.

"FM268" can reduce (or eliminate) the unpleasant sound of CDs, LPs and tapes, and can also strengthen the weak part of the music signal. All this is done in the analog domain, fully preserving the character and transparency of the original signal. The linearizer's improvements range from subtle nuances to incredible areas.

Look at the linearization controller on the front panel of the FM268, it looks like just an equalizer, but the FM268 Line Level Linearizer works on a completely different principle than an equalizer. Equipped with a full aluminum remote control, you can volume, mute, linearization EQ switch.

The company replica 268C production process throughout the actual test will be sent to the subscriber video, to ensure that the test indicators reach the original value.

268 original EQ and replica 268 EQ actual test curve comparison (black and white chart for the original, color AP chart for the replica version)

THD+N is only 0.00232% at 3V output as measured by 268 preamp

268 pre-stage measured frequency response curve