Hybrid Integrated Amplifier ACRH-1.2
The ACRH1.2 is an integrated and complete stereo amplification and
preamplification system. It offers the features of a high-end unit designed in a user-
friendly, convenient, easy to use system. Its tube-based preamplifier offers
outstanding detail in sound and scope. This, along with its semiconductor output
stage, creates a musically dazzling performance.
It is well known that a good preamplifier is the heart of a sound system. With this in
mind, Margules Audio fronted challenge of developing a hybrid integrated amplifier
combining an extraordinary tube preamplifier with excellent solid state amplifier.
Description:
Preamplifier
The preamp section of the unit is based on two dual triodes (12AU7) per side that
acts as coupling circuit from the signal source to the power amplifier. The circuit is
based on the knowledge and experience gained in the development of the acclaimed
Margules SF220 line stage.
This topology allows the frequency response to be further wider than the audio
bandwidth, maintaining the fase and amplitude constant with a very low distortion
together with an extremely fast transient response.
High Voltage Power supply
The Bias power supply of the preamplifier is fully regulated. Good regulation
reduces the loss of signal integrity.
The filament supply is also regulated and has active damping control to avoid noise
and microphonics.
Remote operation
The remote control is unusually versatile. Besides the input selection, volume, power
on and off
You will also be capable of switching the AC power any associated equipment having
load up to 15
amps (1800 watts). Additionally switching control can be accomplished by means of
the RS232 connection or with an external web server(optional)
All switching is made by mechanical high quality relays avoiding the audio signal to
go through semiconductor device, thus ensuring maximum signal purity.
Amplifier Section
The totally discrete semiconductor amplifier has Direct coupling topology, designed
so that the entire interstage is direct, avoiding capacitors , results faster transient
and lower distortion.
The output stage bias is designed with a proprietary circuit optimizes the operating
point of the semiconductor to avoid the typical overheating found in other designs
Class A while avoiding the problems of distortion in Class B.
The innovative design of ACRH-1.2 complements metal film resistors and printed
circuit silver coating.
Connections:
All inputs and outputs of the preamplifier are unbalanced RCA connectors.
The back panel is organized by blocks from left to right: the first RCA block contains
the inlets to the amplifier, the second is for the preamp, the third has four inputs,
which have the same gain and impedance; and the fourth section is direct avoiding
the volume control, so you can use the ACRH together with a 5 channel preamplifier
for a high end multichannel. It can also be used as an input and output circuit for a
processor.
The phono preamplifier is external and is not included.
The preamplifier has two outputs per channel, they are connected in parallel.
One will be connected to the amplifier input, completing the integrated system. The
other is available to connect an active subwoofer or perhaps an adapter multi-room
extension or surround system.
To wire the speakers, connect the 5 ways binding post of the amplifier terminals to
corresponding speaker, use a good cable with a 12 gage or more, it is
recommendable to avoid long runs, less than 10 meters.
Connect the speakers red to the red and the black to the black, it is VERY important
to avoid any short circuit, this will lower the life expectancy of the ACRH.
The output stage has big current capability and it is protected by fuses, if a fuse
blows, it might be because the ACRH was overdriven or the speaker cable has a short
circuit.
Check for proper connections before turning the ACRH on.
The minimum loudspeaker impedance is 4 Ohms, avoid paralleling speakers that can
lower the speakers below this recommended impedance.
When the power line is connected to the ac wall outlet the filaments of the tubes and
the remote control receiver will be turned on.
The filament will be on as long as the AC is connected, so the unit will be in standby
mode, and can be turned on and use immediately, also the life expectancy of the
tubes will be longer.
Avoid turning the unit on immediately after you connect the ACRH to the wall outlet,
let it warm the filaments for a couple of minutes.
