
MRC SYMPHONY 77 SOUND SYSTEM
Congratulations! You have just purchased one of the most
advanced digital model railroad sound systems available
today. The MRC Symphony 77 will bring you the sounds of
railroading whether or not you have a train layout. Just plug it in
and enjoy. The sounds are divided into two independent
groups, emanating from their own speakers. There are also
two modes of operation depending on the era you like- Steam
or Diesel.
Operational Information:
1. A wall transformer is included in the box, please plug
into the rear jack of the right hand speaker prior to
plugging it into your wall outlet. Turn the power switch
on, the pilot LED should light, and sounds will come
from the speakers depending on which mode you have
chosen.
2. Use the mode switch to pick your mode, either steam or
diesel, (D=diesel/S=steam), and the idling sounds of
that type of loco will play from the right side speaker,
with the associated type of random noises playing from
the left speaker. (Both modes can not be played
together).
3. Use the speed buttons to make that type of locomotive
go from idle to full speed and anywhere in between by
repeatedly pressing the up or down buttons.

4. The volume knob controls the volume of the right side
speaker sounds only. You can adjust the volume, while
operating the speed up/down buttons to emulate the
sounds approaching or fading away.
5. All sounds associated with the sound push buttons can
be re-triggered. You can repeat the same sound before
the sound ends to make it seem longer. Or you can start
a new sound to cut off the current sound.
6. You can play one sound from each group at the same
time.
7. Only one slide switch sound can be activated at one
time, (right side position). The unit may not operate
properly if more than one slide switch is activated.
8. The mode switch, speed up/down buttons and the
volume control knob operate independently of the sound
buttons, and do not interfere with the playing of the
sounds.
9. There are numerous choices for either the diesel horn
or the steam whistle. Use the select button for that group
to change the sound of the horn/whistle to the one you
prefer. The current horn/whistle selected will play first,
and then keep pressing the select button to find the one
you like. Then every time you press either the horn or
whistle button, the one you selected will play.
10. The diesel horn or the steam whistle will always be
ready to play regardless of which mode you are in.
11. Just activating the rail clack slide switch will not make it
play. It is synchronized to the speed of the locomotive,
(either mode). Of course if the locomotive is at idle,
there are no rolling wheels clacking over rail joints.
12. There are also two types of coupling sounds. If you do
not like the one playing you can change it to the other.
2

Simply turn the power switch to “off ”. Hold down the
coupling button, as you turn the power switch back to
“on”, and the new coupling sound will be programmed
in. Repeat the process again to change it back to the
original sound.
13. The pump and fan sounds will only play in the diesel
mode, while the water and coal sounds will only play in
the steam mode, hence the “D” and “S” lettering by the
buttons.
14. The right speaker plays the following slide switch
sounds;
• Bell- steam or diesel depending on the mode
switch.
• Crossing gate.
• Rail clack.
• Dynamic brake, (can also be played in either
mode).
• Steam chuff or diesel rumble.
15. The left speaker plays the following button activated
sounds:
• Diesel horn.
• Pump/water.
• Fan/coal.
• Steam whistle.
• Coupling, (2 programmable).
• Uncoupling.
• Conductor, (can also be played in either mode).
• Air release.
• Brake.
• Associated random sounds for the type of
locomotive picked.
3

For further enjoyment:
The MRC Symphony 77 can be combined with another one to
give you double the sounds, or it can be combined with the
MRC Sound Station 312 (AA550), or the MRC City and
Country Sound Station (AA555), to fill your train room with all
the sounds you would need to bring your layout to life.
Warranty:
The unit is checked and tested prior to shipping to make sure it
is defect free. The warranty covers any factory defects for the
period of 90 days, and does not cover; abuse, misuse, or any
modifications made to the unit. If the unit is returned during the
90 day period there is a small shipping and handling fee of
$7.00 required to have the unit repaired under warranty. If there
is no warranty on the unit, please include a fee of $18.00 total.
Return procedure:
If you experience any trouble with your new MRC Symphony
77, please call 732-225-6360 first before sending it in.
If you are asked to return the unit in, send it to:
Model Rectifier Corp.
80 Newfield Ave.
Edison, NJ. 08837
Attn: Parts and Service.
Include a letter with your name, address, daytime phone
number, a copy of your receipt of purchase, and a detailed
description of the problem you are experiencing.
Model Rectifier Corp.
80 Newfield Avenue, Edison, NJ. 08837-3817
Tel: 732-225-6360