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Old 22nd April 2008, 03:03 AM   #11
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Join Date: Dec 2007
Location: Phoenix, AZ
Hello MyWing, Perhaps it's just me, but when I look at the first picture, it appears that the second fuse socket from the right in the row of four is broken. I can't say for sure, but you may want to take a closer look at the picture. If that's busted, then what else may be wrong?!

Peace,

Dave
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Old 22nd April 2008, 11:55 AM   #12
Mywing is offline Mywing  Italy
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Thanks of the signaling Dave,
I will talk about that with to the seller.
Cheers
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Old 22nd April 2008, 04:35 PM   #13
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Prego MyWing!
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Old 11th May 2008, 10:30 PM   #14
Mywing is offline Mywing  Italy
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My "new" old 400A has arrived .
But I had a bad surprise. It sounds arsh, woody, dry, with absent highest frequencies absent, annoying mids...
This happens with both my preamps (a restored Threshold Sl-10 and an AR SP10).
The situation improves slightly with low volume...
What may be happened? The seller assured me that the unit is totally original and any component has been changed.
The only explanation I can give this sonic degradation is the ageing of capacitors and other internal components. What do you think about?
Who has had the opportunity to restore a 400A, has noticed a similar deterioration sound which I heard before the restoration?
Has someone an opinion about that? Nelson ... ?...

Another question: I came in mind that all this could be caused by a probable incompatibility with my Snell A. Perhaps does 400A suffer 4 ohms speakers?

Any suggestion and opinion are well accepted.
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Old 12th May 2008, 01:23 AM   #15
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It looks like you will experience the pleasure of making the amplifier
much better.

A number of people in the forum have worked on these. Obvious
candidates is replacement of capacitors, replacement of connectors,
fuse holders and whatnot, and bias adjustments.

As a rule the semiconductors do not need replacement unless there
is an obvious problem.
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Old 12th May 2008, 09:35 AM   #16
Mywing is offline Mywing  Italy
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Thanks for answer Nelson,
could you suggest a caps' brand/kind for the replacement? And above all, how to adjust the bias?...

Besides I would like to know the opinions of whom has materially completed a similar restoration .

Cheers
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