Line Magnetic LM-212PA, Руководство по эксплуатации

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212
Top view
Fine adjustement of plate current of tube 212.
Ampere meter of tube 212.
Bias current adjustment tube 212.
Hum adjustment (noise).
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1
2
3
1
2
3
4
Bias adjustment for 212 tube
Notes: You do not need to perform the bias adjustment when using the amplifier for the first time.
Turn on the amplifier and wait for about ten minutes.
WARNING : When making adjustments, be careful not to burn yourself with tubes that are very hot.
V1: Power stage
212 tube
V2: Driver
300B tube
310 tube
274B tube
V2 tube is auto-biased and you do not need to adjust the bias. Input, Driver and Power tubes (212, 300B, 310 tubes)
must be matched for the best results. If two vacuum tubes bias are not at the same level it means there are some working
current deviations of the power tubes.
Switch the BIAS ADJ to V1, switch is located on the front panel, to test plate current for 212 tube. Inspect the ampere
meter on the front panel and make sure the needle is in the area ia=70mA shown on this diagram (below). If it is not,
adjust the bias via the top screw to get close to this value, then use the fine adjustment for final setting.
To optimize listening to the amplifier, it is recommended to use about
150 hours, according to the above method to test the working state of
power tube.
Noise adjustment method: When the machine appear hum noise,
adjust the V1 HUM BALANCER potentiometer noise, and listen to the
corresponding channel speaker to minimize noise.
If you have any questions, please contact a local maintenance
service or your local dealer.
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