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KT88s in an ARC D76

byoung334

byoung334

Active Member
So I have been thinking about putting KT88s in my Audio Research D76 in place of the 6550s. ARC has nothing on their site addressing this in older amps. So what do you think? What should I set the DC balance and bias to? For the 6550 its 50 ma.
 
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Unless you have the ability to set the bias by way of a THD analyzer, I would go for the same settings as used for the 6550. They are similar enough that any difference in quiescent bias current required for optimum performance will be rather small.

Dave
 
dcgillespie said:
Unless you have the ability to set the bias by way of a THD analyzer, I would go for the same settings as used for the 6550. They are similar enough that any difference in quiescent bias current required for optimum performance will be rather small.

Dave
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Dave I do not have a way to set the AC balance. Sot you think I should bias current at 50 mA?
 
50 Ma is a very good quiescent current to use. As for the AC balance control, without a distortion analyzer, the next best thing to do is to set it at its electrical center. Since this control is a linear taper control, its mechanical center will be very close to its electrical center, so either approach will produce a well balanced drive to the output stage.

Dave
 
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