GamuT M250i User Manual

M250i

Mono Power Amplier

Userguide

Contents:

Safety instructions 3

Unpacking 4

Connecting the input cables 4

Warming up 4

Sensitivity (Gain) 4

Cleaning the cabinet 5

The protection circuitry 5

A second of silence 5

Connecting your loudspeakers 5

Loudspeaker impedance 6

A lifetime of enjoyment 6

Normal use 6

What you can check if there is no sound 7

The service 7

A few useful specications 8

Interesting trivial facts 8

Recommended CDs 9

SAFETY INSTRUCTIONS:

Never let children (or grownups) push anything into holes or slots in the case - this could result
in an electric shock and could cause damage of the set.

Never guess or take chances with electrical equipment of any kind - it is better to be safe than
sorry.

Warning: To prevent re or shock hazard do not expose this appliance to rain or moisture

No user serviceable parts inside. Refer servicing to a qualied technician. Never remove covers
unless qualied to do so. This unit contains dangerous voltages.

DO read the user’s guide before you attempt to use this equipment.

DO ensure that all electrical connections are properly set in accordance with the manufacturer’s

instructions (this includes the mains plug, extension leads and interconnections between pieces
of equipment).

DO check that the mains fuse rating is set correct for your local mains voltage.

DO NOT obstruct the necessary all-around ventilation: Especially DO NOT place the set close to

curtains or on soft furnishing such as carpets. Overheating can cause unnecessary damage and
shorten the life of the set.

DO NOT switch the amplier on, then o, then on again quickly. The blue light must disappear
completely before you switch on again. Only switch on and o using the power switch.

DO NOT unplug the mains cables while they carry current. This will corrode and damage the
surface of the metal of the mains plugs and sockets. This can cause reduced sound quality and
electrical res.

The mains switches have special metals in the contact points selected for handling high in-rush
currents, as well as to break large currents. Plugs and sockets are not made of such metals.

DO NOT use the ‘direct’ speaker output for tests with square waves or sine waves and a capacitor
across the output terminals, as you may damage the amplier.

DO NOT connect output ground to input ground. Do not connect any output grounds together.

DO NOT connect headphones to this amplier without using protecting resistors.

Make sure that you do not let any tiny part of the speaker cable going to a terminal touch the
other terminals. Only connect this amplier to loudspeakers, and only one loudspeaker on each
channel. Do not connect the output of this amplier to another ampliers outputs or inputs.

DO NOT connect a red terminal to another red terminal.

Unpacking

Open the inner box, remove the 2 top blue foam parts
Lift the amplier up and place it on its feet. Be careful not to damage the gold plated connectors
on the rear panel. Keep the box and the blue foam, it is specially made to protect the amplier well,
and you may need it some day, when you move or if you want to upgrade the amplier.

Connecting the input cables

The main input is the 3-pin XLR socket. This is electronically balanced, and it will
therefore reduce hum pickup in the input cable. So the best choice of cable is a balanced
XLR cable, coming from a balanced output on your preamplier.
In case you have a preamplier with only RCA outputs, you can use the RCA input. Remember to
plug in the XLR Terminator plug, when you use the RCA input. It connects the negative
input to ground, making sure that the input is not “oating” with the risk of noise or oscilliation
comming in to the amplier circuits.

You release the XLR connector by pressing on the release button next to the XLR socket, and
pulling the XLR plug out at the same time. Do not pull on the cable, only on the plug.
The XLR connector: always connect Pin 1 (the ground) rst and disconnect it last. This way,
XLR connectors can be plugged and unplugged while the amplier is switched on.
However, some DC from the preamplier may still cause loud clicks, so it is recommended to
wait 10 seconds and then switch the power amplier on as the last precaution. If you use a tube
preamplier, please wait several minutes the rst time you use it. Always switch o the power
amplier rst before switching o your preamplier or any source. Always remember to turn down
the volume before switching on of o the poweramplier, if you fail to do so, the output relay
will ware down faster.

DO NOT CONNECT LOUDSPEAKER WIRES OR OTHER HIGH VOLTAGE CABLE TO THE INPUT.

Warming up

The GamuT power amplier will play sound a few seconds after you turn it on. However, please
allow minimum 30 minutes before you start serious listening, as the sound quality will slowly
improve, because all the parts need to reach their optimum operating temperature.
You may also note a slight improvement in the rst months of use. This is caused by the
capacitors, which do improve with use.
A CD player in repeat mode can speed up the process while you are not at home.
Do not play too loud.
After this break-in period is over, simply switch the GamuT on when you get home, and it will be
ready to perform at its best after dinner.