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S201 Amplifier Users Manual
A Simple Approach
The S201 provides a simple but effective approach to good sound. An amplier does two things, it increases the voltage of an audio
signal and it increases the current. Class A ampliers completely overlap the positive and negative signals providing great performance
but with huge power losses. Class A-B overlap only a little with much lower power use but compromised performance. The MSB
amplier uses a fully CLASS A stage to increase the voltage signal, and a CLASS A-B stage with no voltage gain to increase the current
supplied. This unique hybrid gives the best of both - a great performance with reduced power requirements.
Burn-In
The concept of burn-in is little understood. Does it take your ears some time to get used to the incredibly
detailed and life like sound of an MSB product or is something actually changing. The feedback we
receive leads us to recommend at least 100 hours of burn-in on this amplier. Customers generally
recommend one month.
Input Setting
A switch is located between the RCA single-ended and XLR balanced inputs. If using the RCA input
set switch to RCA. If XLR is being used try setting DOWN rst to the XLR - 6 db. If you have enough
gain in your system this is the best setting. If you cannot get enough output level, try putting the switch
in the center position. You will get 6 db more gain.
Heat
These ampliers will get quite warm. They should be used in an open air-conditioned room with nothing
covering them. Operation in extreme conditions will cause thermal shutdown. When they cool down
they will again operate. Heat is not reduced in stand-by mode. If your listening room is subject to high
temperature when you are not using these ampliers, please turn them off.
Fuse and Voltage
To meet the world-wide AC power specications, two different internal congurations have been
used. These are not switchable so Ampliers cannot be moved between regions.
• Japan Model requires 100VAC +/- 10V, 50 or 60 Hz (The voltage switch shown is removed)
• Switchable model requires 110 to 120VAC +/- 10V or 220 to 240VAC +/- 20V, 50 or 60 Hz
The amplier uses a 15A SLOW BLOW fuse. It is an input fuse only. The amplier does not
have output fuses.
12 Volt Remote Trigger
This power supply is equipped with a remote trigger for use with other MSB
products. The trigger uses a headphone jack. When any MSB product is
turned off, the other products connected will also turn off and vice-versa. The
connector is wired as shown. If you connect “signal” to “ground”, all MSB
products will turn off. If you connect “signal” to “12 V”, all MSB products
will turn on.
Warranty
All MSB products carry a one year warranty in the country of origin. No
returns accepted without an RMA. Upon receipt, MSB will repair or replace
any defective product. All product shipped FOB Aptos. Shipping and shipping
damage is the responsibility of the consignee.
12 Volt Remote Trigger wiring.
If the signal is pulled low:
Unit will turn off.
If the signal is pulled down with a 50K resistor:
Unit will go to standby.
If the signal is left oating:
Unit will remain on.
If the signal is driven with 12 V:
Unit will turn on and switch will be ignored.
Power LED Color Table
Green: The unit is on and operating
Amber: The switch for the unit is on, but the 12V trigger has turned it off, OR, the switch for the unit is on, but the protection
has shut if off because of overheating or over voltage.
Red: The switch is in the Off position.
Off: There is no power due to a blown fuse or no power connection.