Ming-Da MC-300B845 schematic needed - diyAudio
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Old 9th June 2011, 05:47 AM   #1
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Default Ming-Da MC-300B845 schematic needed

Hello!

I was asked to help to repair broken Chinese High-End monoblock from Ming-Da. I've never seen such a beast, what it is inside. Does anyone have a schematic by chance?

Looks as weird selection of tubes to me, like 300B to drive 845 without proper interstage transformer.

Any info?

Anatoliy
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Old 9th June 2011, 12:44 PM   #2
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high end..... suuuuureeeee......
All you need to fix it is blue paint. As in "Paint it Blue and Throw it in The Sea".

Greek saying.

No offense to you, of course.
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Old 9th June 2011, 04:43 PM   #3
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Quote:
Originally Posted by Wavebourn View Post
Hello!

I was asked to help to repair broken Chinese High-End monoblock from Ming-Da. I've never seen such a beast, what it is inside. Does anyone have a schematic by chance?

Looks as weird selection of tubes to me, like 300B to drive 845 without proper interstage transformer.

Any info?

Anatoliy
Wondering if this is similar to the Liang which uses a 300B as a low current (!) cathode follower.
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Old 9th June 2011, 07:25 PM   #4
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Very probably, I have not seen it yet. I hoped to see some drawing before I get it. Anyway I read some opinion in the Net, and it looks like tube selected according to popularity ratings, and used in totally wrong for them regimes. Like, 300B instead of 6SN7, for more expensive appearance, resulting in all that hemorrhoid with directly heated cathodes. Also, looks like output transformers have wrong values of winding ratios.
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Old 9th June 2011, 08:52 PM   #5
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"hemorrhoid" oh man I almost spilled my coffee on the screen!

As a proud owner of a Ming-Da (different model), I support the decision to gut it and re-make it, including the power transformer! It is probably point-to-point anyway.
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