Buying a 400A - Page 2

dave_gerecke · 22nd April 2008, 02:03 AM

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

Mywing · 22nd April 2008, 10:55 AM

Thanks of the signaling Dave,
I will talk about that with to the seller.
Cheers

dave_gerecke · 22nd April 2008, 03:35 PM

Prego MyWing!

Mywing · 11th May 2008, 09:30 PM

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.

Nelson Pass · 12th May 2008, 12:23 AM

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.

Mywing · 12th May 2008, 08:35 AM

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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22nd April 2008, 02:03 AM	#11
dave_gerecke diyAudio Member Join Date: Dec 2007 Location: Vermont	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

22nd April 2008, 10:55 AM	#12
Mywing diyAudio Member Join Date: Mar 2007	Thanks of the signaling Dave, I will talk about that with to the seller. Cheers

22nd April 2008, 03:35 PM	#13
dave_gerecke diyAudio Member Join Date: Dec 2007 Location: Vermont	Prego MyWing!

11th May 2008, 09:30 PM	#14
Mywing diyAudio Member Join Date: Mar 2007	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.

12th May 2008, 12:23 AM	#15
Nelson Pass The one and only Join Date: Mar 2001	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.

12th May 2008, 08:35 AM	#16
Mywing diyAudio Member Join Date: Mar 2007	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