07X er en ren forforsterker og ingen ting annet. Ingen RIAA er innebygget i 07X.
Her er det kun fokus på å gjøre akkurat det den skal gjøre - å klargjøre audiosignalet til det perfekte utgangspunktet for en effektforsterker å ta tak i.
2 XLR Innganger
2 RCA Innganger
Med 2 par XLR innganger kan man f.eks kople opp 2 av hovedkildene med balanserte kabler - for høyest mulig støyreduksjon.
2 XLR Utganger
1 RCA Utgang
Processor In / Ut
- Latest variant of the 07 preamplifier, featuring substantial active and passive component
- Balanced and unbalanced inputs and outputs
- Extremely low-noise circuitry with no overall feedback
- May be operated with included Coda universal remote control
- System logic remembers the most recent volume and balance settings for each input
- Wide bandwidth regulated supply with AC EMI and RFI line filter
- Double-sided gold plated circuit
- All anodized
The circuitry used in the FET PREAMPLIFIER 07x is the result of an advanced and complete design process combining innovation and prove fundamentals. This process avoids both the limitations of total adherence to convention and the flaws resulting from inappropriate applications of clever circuit gimmicks. Impedance isolation and matching is derived from FETs. While careful design can yield good results from any device type, FETs consistently have the edge in voltage gain, low noise, low interaction, and interface applications. FETs are inherently transconductance devices, meaning that an input voltage controls an output current. Unlike conventional transistors, FETs have extremely high input impedance (about 10 meg ohm - similar to vacuum tubes). The FET "senses" the audio signal without drawing current from the source. This eliminates complex interactions with the source, allows maximum performance from each system element, and greatly reduces the chance of cable characteristics altering the sound. The absence of input current in FETs allows high bias currents for linearity and speed without sacricing DC parameters.
Noise is kept low by multiple paralleling of input devices, careful selection of circuit impedances, and pre-screening of devices. The Class A complimentary followers used to drive the preamplifier output are of such speed, linearity, and low output impedance that no feedback correction is required or used. The advantage of this is that the circuit´s perfect stability and transient response are preserved into a wide range of dicult and unpredictable loads. Variation in sound, which could occur through interactions with interconnect cables and other system elements are thus avoided.
Until recently, perfect volume controls (attenuators) did not exist. This is because conventional stereo potentiometers have serious channel mistracking (20% typically), become noisy with age, wear out, and have poor resolution of level - particularly when operated by a motor as required for remote operation. In an attempt to solve these problems, many manufacturers have been using "switched attenuators", which are discrete, resistor ladders built on rotary switches. But while these eliminate channel mistracking, they introduce new problems, including limited resolution, stepping transients, and cannot be operated remotely. And they still wear out.
They limit resolution because the most contacts available on rotary switches are thirty-one. This requires two or three dB steps in order to get enough range out of the attenuator, which isn´t a fine enough resolution for most listeners. Switched attenuators also introduce switching transients (a "click" or "pop") each time they change positions.
This noise comes from two sources. The first is mechanical noise from the switch itself as its ball-detent mechanism moves from detent to detent. But a more troublesome source is the voltage difference caused by the change in the musical waveform during the time it takes the switch to move from one position to the next. The greater the voltage difference, the louder the transient.
1. Finishes - All exterior and interior metal parts are anodized. While paint may be more impact resistant, the anodized surface is more resistant to solvents and prevents corrosion. Moreover, the anodized parts´ appearance can be enhanced by either graining or beadblasting the surface.
2. Circuit Board - Circuit boards are fiberglass epoxy with gold plating over a tin/nickel barrier. This gold layer will not corrode, while the barrier plate prevents the gold from migrating to the lower copper layer and detracting from its appearance.
3. Resistors - All are high reliability metal film 1% resistors.
4. Capacitors - All capacitors are of high quality. The only electrolytics used are in the power supply where large numbers provide enormous filtering capacitance for the supply.
5. Semiconductors - There are no integrated circuits (IC) to be found in the circuit path. Very high quality dual FETs are the only source of voltage gain and were selected for their superb noise performance and precision matching. The remaining semiconductors are also of very high quality, each possessing parameters ideally suited for the specific application.
6. Connectors - Coda employs a standard RCA configuration with a gold plated case. The balanced connectors are Neutriks from Switzerland.
7. Wire - All signal wire has been eliminated whenever possible. Where wire is used, Coda employs silver plated copper, 141 strand, 18 gauge wire with a silicone insulation.