Luxman MQ-80

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General information[contribute]

The Luxman MQ-80 is a power amplifier in the valve amplifier category. It was manufactured from 1976 to 1976.

Gina Lopes (March 31, 2010): Stereo power amplifier which used 6336A for the thermionic tube.

The duotriode 6336A used by MQ36 of OTL amplifier is adopted as an output tube. The push-pull circuit was made to constitute from one per channel of one side using this 6336A, and the output of 40W has been obtained in the time of an 8-ohm load intensity MQ80.

Although the thing of the appearance similar to the conventional OY15 type is used for an output transformer, in order to take out the effect of a cross shunt push-pull operation, the primary side coil was divided into the plate and cathode side, and the scheme which carries out the by filer volume of this is adopted.

It is possible to hold down to a low distortion to the Oide power with this scheme. Moreover, the high region frequency characteristic of an output transformer is extended to 200kHz, and since it is what was extremely excellent also in the phase response, the effect excellent also in the stability at the time of applying negative feedback to a modification of the nakedness property of amplifier and a concurrent is acquired.

As for the output stage of a cross shunt push-pull operation, 50% of an Output voltage returns as negative feedback, and also since 6336A is the low rp. quantity Gm, a big drive voltage is needed.

Then, adopt duotriode 12BH7A which has the power in which a plate loss is large in the drive stage, a cathode follower hardwired-connection circuitry is made to constitute, and it is considered as the powerful drive circuitry. Moreover, 6AQ8 of the duotriode was adopted as the phase inversion stage, the cathode coupled circuit was made to constitute, and the first rank has adopted 6267 of a pentode in order to earn gain.

Ove wikstroem (July 28, 2016): Bias
Pin one is ground. Pin 2and 3 are left Chanel bias is 0.85v
Pin 4 and 5 is right Chanel bias is 0,85v. Adjust when the amp is hot.


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