Installation of Tubes, Tube Cover, Location and Ventilation
Small Signal Tubes:
1.Locate a 12AX7A Tube.
2.On the top left side of the amplifier, locate the Tube Socket that has the nomenclature V1 12AX7A next to it on the chassis. Refer to figure 4 and 5.
3.Orient the Tube so the area where no pins are located on the base of the Tube is aligned with the corre- sponding area on the Tube Socket.
4.Carefully insert the Tube into the socket until the base of the Tube is fully seated in the Tube Socket.
5.Repeat the above steps for the remaining two 12AX7A Tubes at locations V2 and V5.
6.Locate a 12AT7 Tube.
7.On the top center of the amplifier, locate the Tube Socket that has the nomenclature V3 12AT7A next to it on the chassis.
8.Insert the Tube, following the same procedure as in steps 3 and 4.
9.Repeat steps
Tubes at locations V4, V6 and V7.
Caution: To prevent electrical shock make sure the MC275 Tube Cover is installed before connecting the AC Power Cord.
Before operating the MC275, locate the previously re- moved Tube Cover and perform the following steps:
Installing the Tube Cover:
1.The Tube Cover has a wide opening along one side of its longer dimension. Orient this wide opening so it is facing towards the three large transfomers.
2.Carefully place the Tube Cover onto the MC275 while at the same time aligning the two chassis mounted ball studs with the Tinnerman Clips in the cover. Refer to figure 6.
Location and Ventilation
The MC275 can be placed upright on a table or shelf, standing on its four feet. It also can be installed in a piece of furniture of your choice. Do not install the MC275 di- rectly above a heat generating component. Adequate venti- lation extends the trouble free life of the MC275. The sug- gested minimum space for operating the MC275 is 22 inches (55.88cm) in width, 18 inches (45.72cm) depth, and 21 inches (53.34cm) in height. Always allow air to flow through the ventilation holes on the bottom of the amplifier and a means for the warm air to escape at the top. If the MC275 is installed in a cabinet, a quiet running ventilation fan can be a definite asset in maintaining the coolest pos- sible operating temperature. Refer to figure 7.
KT88/6550
12AX7A | 12AT7 | 12AX7A | 12AT7 |
Figure 5
Ball Stud Fasteners
Figure 6
Warm Air
Cool Air
Figure 7
7
