CH Precision - A1 2-Kanal Endstufe

A1 - 2 Kanal Endstufe (2 x 100W RMS 8Ω) - Ein musikalisches Ausnahmegerät

Der CH Precision A1 ist etwas vom Feinsten der analogen Verstärkungstechnologie.


  • The absolut Highend
  • Made in Switzerland
  • 1A Neuzustand
  • original Verpackung
  • Neugarantie

Alle fantastischen CH Precision Musik Instrumente werden in der +Schweiz+ entwickelt und gebaut.

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21'500.00 CHF

-10'300.00 CHF

31'800.00 CHF

Auf meine Wunschliste

Technische Daten

Height120 mm
Width440 mm
Depth440 mm
Weight43 kg

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Der A1 bringt jedes Detail zu Gehör, integriert diese Einzelheiten aber zu einem musikalischen Ganzen

Panta rhei – Alles fließt

Er ist auch unendlich flexibel und konfigurierbar. Im MONO bridged Modus bietet er 350 Watt Dauerleistung unter 8 Ohms! Dazu ist der A1 ein High Tech Gerät mit einer Vielfalt an Anpassungsmöglichkeiten, wie sie wohl derzeit kein anderer Hersteller bietet. Er kann im Stereo-/ Mono-/ Bi-Amping und Bridge-Modus betrieben werden - die entsprechend der Hardware-Ausstattung zulässige Einstellung erfolgt unkompliziert über das Frontpanel (!). Die Ausgangsleistung beträgt 2x100W (<8Ohm) und 1x350W (<8Ohm) im „Bridge“-Modus.

Der A1 wurde zahlreich ausgezeichnet.

Technische Eigenschaften:


The A1 power amplifier has been developped with modularity in mind. It can be equipped with a single analog input board in case the A1 is used for a single channel but a second analog input board can also be fitted from factory if needed for stereo operation. This modularity ensures the following operation modes:

  • stereo mode
  • single channel mode
  • bi-amplification modes, both passive and active
  • bridge mode

Changing the A1 operating mode is easy and can be done on-the-fly from the front panel user interface. Only the available options are permitted depending of the hardware configuration.

Power Supply:

The central power supply is taking most of the internal space of the chassis. The huge 1'200VA transformer is mounted on silent-blocks to avoid at maximum its vibrations to be fed-back into the sensitive part of the circuitry. It is shielded both with a magnetic screen and an electrostatic one. The transformer's plate is also secured for transportation.

For optimum thermal performances, the output stage's diode bridges are mounted on the front panel's back and are of hyper-fast soft-recovery type.

The filtering capacitors are 4-poles type, which ensures that the current spikes needed from the rectifiers for refilling the capacitors are kept away from the central ground point.

Analog stages:

All analog stages inside the A1 are built only with discrete components, no operational amplifier have been used into these sections. This deliberate choice warranties the shortest path for the audio signal and allows the use of custom-made building blocks.

No capacitors have been used in the signal path, nor any output relay to ensure the maximum transparency.


A gain range of 24dB - with steps of 0.5dB - is embedded into each channel, for a perfect match with the loudspeakers' sensitivity and room size. A lower gain is typically preferred for high-sensitivity speakers into a small room while a bigger gain is sometimes needed for large room with low-sensitvity loudspeakers.

This gain adjustment can also be useful with multi-amplified loudspeakers to adjust the level of the various drivers.

Output stage feedback:

Unlike into all other CH Precision's analog stages, the A1's output stage can be configured to have some global feedback. The global versus local feedback ratio is adjustable on-the-fly from the front panel user interface, only a few relays are switched during this operation. Each step is 20%, going from 0% - local feedback only - to 100%.

In case the A1 is used in bi-amplification mode, the user can select a different feedback ratio for each driver.

Output stage bias:

In order to keep the output stage distortion constant over time, the output stage's bias must be kept as constant as possible. This value is very dependent on the output stage temperature - the transistor die - which can be known thanks to the ThermalTrak devices from On Semiconductor.

A very special circuit has been built around the output stage which is taking into account both the temperatures of the heatsink and the transistors dies. It allows to keep the bias constant into the output stage whatever the musical program and room temperature are.

In term of performances, the A1 class-AB design is outperforming a pure class-A design with usual bias compensation. This schematic is patent-pending.


Each channel's output signal is permanently monitored - both in voltage and current - into a DSP, which calculates in real-time the effective channel's output power. The same DSP is also monitoring the heatsink temperature and drives small fans in case the A1's internal temperature becomes too high.

In case where an abnormal condition happens, the amplifier is turned off to secure the connected loudspeakers. No output relay have been used into this amplifier, its symetrical structure allows a smooth turn-on and turn-off of the power supply without noticeable noise.

Analog inputs

Inputs typeBalanced (XLR), one connector per board
Single-Ended (RCA & BNC), one connector per board
Input impedanceBalanced: 94kΩ
Single-Ended: 47kΩ or 300Ω
Input stageJFET input stage
Ultra-low noise, discrete fully differential stage
24dB range adjustable gain in 0.5dB steps


Amplification stageUltra-low noise full discrete class AB design
5 pairs of complementary output transistors
Output Power2x 100W / 8Ω, 2x 175W / 4Ω, 2x 300W / 2Ω in stereo and bi-amp modes
1x 175W / 4Ω, 1x 300W / 2Ω, 1x 550W / 1Ω in monaural mode
1x 350W / 8Ω, 1x 600W / 4Ω, 1x 800W / 2Ω in bridge mode
BiasPatent-pending bias circuitry for constant bias operation
FeedbackUser-adjustable local vs. global feedback ratio, from 0% to 100% with 20% steps 
BandwidthDC to 450kHz (-3dB) at 1W into an 8Ω resistive load
Signal to Noise RatioBetter than 115dB in stereo and bi-amp modes
Better than 118dB in bridge mode
Total Harmonic Distortion + NoiseLess than 0.1% with 0% global feedback
Less than 0.01% with 100% global feedback

Analog outputs

Binding postsTwo pairs of Argento binding posts for loudspeakers connection
MonitoringNon-intrusive DSP-based protection of the amplifier
Instantaneous voltage & current values are permanently monitored for each channel
ProtectionsShort-circuit protected
Disconnected loudspeaker detected
Over-temperature of the heatsink
Over-temperature of the output transistors

Power supply

Transformer1'200VA single transformer, oversized for low-noise operation
Power capacitors 2x 47'000uF/63V 4-poles capacitors 
RegulatorsNon-regulated symetrical power supply for the power stages
Eight local regulation stages for input/driver stages
Seven local regulation stages for the logic/display


Display480x272 pixels, 24bits color, AMOLED
Mains operationSelectable 100V, 115, 230V AC, 47-63Hz
Fuses value and locationStandby fuse (white holder): 250mA T (230V AC), 500mA T (100V AC, 115V AC)
Main fuse (black holder): 10A T (230V AC), 16A T (100V AC, 115V AC)
Power supply consumption<1W (standby), 1200W max in operation
Remote controlEthernet based system control via the Android CH Control App

Options boards



Ethernet control board

General control board. Provides USB based firmware update and external ethernet control.

Factory built-in



Monaural analog input buffer board

Three analog inputs - XLR, RCA and BNC - are provided on a single board. A pass-through XLR male connector allows a direct connection to another A1 amplifier.

Can be factory ordered for Left or Right channel.

Factory built-in (1x), second board is needed for stereo operation


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CH Precision - A1 2-Kanal Endstufe

CH Precision - A1 2-Kanal Endstufe

A1 - 2 Kanal Endstufe (2 x 100W RMS 8Ω) - Ein musikalisches Ausnahmegerät

Der CH Precision A1 ist etwas vom Feinsten der analogen Verstärkungstechnologie.


  • The absolut Highend
  • Made in Switzerland
  • 1A Neuzustand
  • original Verpackung
  • Neugarantie

Alle fantastischen CH Precision Musik Instrumente werden in der +Schweiz+ entwickelt und gebaut.

Eigene Bewertung verfassen