36-50 : 3-Zone Mixing Amplifier
482.6mm / 19"
/ 3 1/2"
Cloud 36-50 front view
Cloud 36-50 rear view
General Description
The Cloud 36/50 is a three-zone (two primary zone outputs
plus a third utility output), rack-mounting (2U) audio mixing
amplifier. It combines simple control of background music, power
amplification and versatile microphone paging in a single unit.
It is suitable for use in many types of premises, including pubs,
bars, clubs, shops, offices, hotels, etc.
The 36/50 has six stereo line inputs and a microphone input
which can be configured for use with paging mics; each has its
own preset sensitivity control on the rear panel. It has two
mono primary zone outputs, plus a third “utility” output; each
of the three outputs being driven by a 50 W (nominal rating)
power amplifier stage. The main outputs have HF and LF EQ
adjustments for zone optimisation during installation. The utility
output is useful for secondary areas such as toilets or corridors;
its source is user-selectable, and it may follow Zone 1’s source,
effectively doubling the amplifier power available for the area.
Music and mic level controls are provided for the utility output.
Any or all of the outputs may be configured as high impedance,
to drive 70/100 V-line loudspeaker systems, using either internal
or external transformers.
The front panel provides separate controls for music source
selection, music level and mic level in each zone. EQ cards to suit
popular installation speakers from various manufacturers may
be fitted to any or all outputs. Line 6 input may be set to have
priority over any other selected music source in either zone, to
facilitate connection of a jukebox, digital sound store or similar
device. The priority feature has selectable release times, to allow
a smooth return to the original music source.
The 36/50 is directly compatible with Cloud PM Series paging
microphones; alternatively, the paging mic input can be configured
to suit most OEM paging systems. Zone selection for paging is
via short-to-ground access connections; and Automatic Voice
Over (music ducking) may be selected by a rear panel switch if
mic-over-music priority is required.The paging level to each zone
is set with a front panel control.
Music level only, or music level and source selection may be
controlled remotely in either zone if wished, using standard
Cloud RL or RSL Series remote control plates. As with all Cloud
commercial audio products, a remote Music Mute facility is
provided, which may be used to satisfy the requirements of the
Local Fire Officer.
• Mixer/amplifier for two zones, plus separate utility output
• Selectable LINE 6 priority per-zone, with choice of release times
• Provides flexible music, paging and announcement facilities in
each zone
• Optional CL-3120 3-channel 70/100 V transformer can be
fitted internally
• 3 x 50 W power output
• Optional CXL-40T 70/100 V toroidal transformers available for
external connection to any or all outputs
• Dynamic clip limiting (all outputs)
• Utility output can be used for a third zone, secondary areas,
or can double power output available for Zone 1
• Selectable 65 Hz high-pass filter per-output (for use with
70/100 V transformers)
• Front panel user controls for music source, music level and mic
level in each zone
• Music Mute control input (N/O or N/C) to interface
to emergency system
• Rear panel level adjustments for music and mic level at
utility output
• Compatible with standard Cloud remote control plates:
RL Series (music level) and RSL Series (music level and
source selection), per-zone
• Six (unbalanced) stereo line inputs with individual gain
trim controls
• Balanced mic input; 15 V phantom power selectable
• Contact closure access port for paging zone selection
• Switchable mic-over-music priority (Automatic Voice Over)
• Optional EQ cards available to suit various popular installation
loudspeakers may be fitted in any or all outputs
• 2U 19” rack-mounting unit
• Convection cooled – silent in operation
• Sensitivity and HF/LF EQ adjustment for mic input (rear panel)
• HF/LF music EQ adjustment on each zone output (rear panel)
Block Diagram
System Example
The example above shows how the 36/50’s various features
may be used.
• Six stereo music sources are connected to the line inputs. Note
that the jukebox is connected to Line 6; if this input priority
option is enabled, any jukebox selection will automatically be
replayed through both zones, overriding the local selection for the
duration of the track(s).
• The larger area and the “corridor” have been depicted as using
70/100 V-line loudspeakers, hence the optional external transformers.
In this case, these would be Cloud type CXL-40T, typically mounted
on a CXL-800 rack tray. Alternatively, two of the three transformers
on the internallyfitted CXL-3120 module could be used.
• A paging microphone may be connected to the mic input; the 36/50’s
access port allows paging to any or all of the 3 outputs (including the
utility area) by simple contact-closure.
• The system also shows a Cloud RL-1 remote control plate installed
in Zone 2 to allow local volume control, and an RSL-6 in Zone 1 to
allow local source selection as well as volume control.
Technical Specification
Line inputs
Frequency response
20 Hz to 20 kHz ±0.5 dB
<0.05%, 20 Hz to 20 kHz
195 mV (-12 dBu) to 2.0 V (+8 dBu)
Input Gain control
20 dB range
Input impedance
47 kohms
>20 dB
-90 dB A-weighted (0 dB gain)
HF: ±10 dB @ 10 kHz
LF: ±10 dB @ 50 Hz
Microphone input
Frequency response
<0.05%, 20 Hz to 20 kHz
Gain range
0 dB to 60 dB
Common Mode Rejection
>70 dB @ 1 kHz
Input Impedance
>2 kohms (balanced)
>20 dB
-126 dB EIN (22 Hz - 22 kHz, 150 ohms)
HF: ±10 dB @ 5 kHz
LF: ±10 dB @100 Hz
Power Rating Low Impedance
4 ohm load(s)
8 ohm load(s)
1 channel driven
60 watts
2 channels driven
52 watts
3 channels driven
45 watts
1 channel driven
37 watts
2 channels driven
34 watts
3 channels driven
30 watts
100 V-line Output*
100 V balanced – 250 ohm minimum load
70 V-line Output*
70 V balanced – 125 ohm minimum load
VI Limiting, DC Offset, thermal & switch-on delay
Power input
230 V ±5% (115 V ±5% available)
Fuse rating
230 V: T3.15AH; 115 V: T6.3AH
Fuse type
20 mm x 5 mm 250 V
482.6 mm x 88 mm (2U) x 300 mm / 19” x 3.5” x 11.8”
Shipping (Gross)
610 mm x 200 mm x 460 mm / 24” x 8” x 18”
6.7 kg / 15 lbs
Shipping (Gross)
8.9 kg / 20 lbs
Architect’s and Engineer’s Specification
The mixing amplifier shall have three mono output channels; each
channel shall be capable of driving 50 watts into a 4 ohm load.
Two of the output channels shall be configured as primary zones, with
front panel controls for selection of music source, music level and
microphone level in each; the third output channel shall be configured
as a utility output, and have controls of the pre-set type for adjustment
of music and microphone levels.
An optional module shall be available to allow all channels of the
mixing amplifier to drive 70 V or 100 V-line loudspeaker distribution
systems.The module shall be retrofittable and be contained within the
chassis of the mixing amplifier.
The mixing amplifier shall be equipped with six unbalanced stereo
music inputs on rear panel phono sockets (RCA jacks) and one
electronically balanced microphone input on an XLR socket.
The microphone input shall be configured to operate with paging
microphones. Each music input shall have a rear panel input gain trim
control with a range of 20 dB. Two-band equalisation adjustment shall
be provided on the rear panel for the music signal in each primary
zone. Two-band equalisation adjustment shall also be available for
the microphone input; phantom power shall be available at the
microphone input when selected by internal jumper. A gain control of
the preset type shall be provided for the microphone input; this shall
have a range of 60 dB.
A control input shall be provided to activate the microphone input
by external contact closure, and route its signal to any or all outputs,
replacing the music signal while the contacts are closed. It shall
also be possible to configure the mixing amplifier to perform the
following functions: i) detection of a signal at the microphone input
will automatically reduce the music level by 30 dB, ii) one line input
will automatically override all others in either of the primary zones,
even if unselected; it shall be possible to set the time over which the
selected sources fade back up after the override input ceases to one
of least three values of up to 12 seconds.
Optional remote control plates shall be available to permit control of
i) music level in either primary zone; ii) music source selection and
music level in either primary zone; it shall be possible to retrofit these
to the mixer at any time. The remote control plates shall connect
via a rear panel multipin connector. It shall be possible to disable
either the front panel music level or the music level and music source
selection controls by rear panel switches. An external control input
shall be provided to allow muting of the music source by a fire alarm
or other external emergency system via isolated, ‘volt-free’ contacts,
and this input shall be configurable to respond to either a short or
open external circuit.
The mixing amplifier shall accept a range of plug-in equaliser cards
to permit use with compatible loudspeakers. It shall be possible to fit
these in any or all of the outputs.
The mixing amplifier shall be built in a 2U steel chassis for mounting
in a standard 19” rack. The mixer will be fitted with a front-panel
power switch with internal indication. Two mains supply variants shall
be available: 230 V or 115 V. Mains supply shall be connected via a
detachable IEC cable.
The mixing amplifier shall be the Cloud 36/50; the optional remote
control plates shall be the Cloud RL-1 Series (music level only) and the
Cloud RSL-6 Series (music level and source selection). The optional
70/100 V transformer module shall be the Cloud CL-3120.