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Old 10th May 2016, 08:59 AM   #1
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Default Problem with needle on XA30.5, help!

Hi,

I'm new on the forum. My name is Domenico and I write from Italy.

I recently bought an XA30.5 power amp and I have a question related to the needle on the front panel.

Infact I noticed a strange behavior of the needle:

it is almost always positioned on the left side and it does not move (or move just a little bit) when playing music at a very high level.

I know the needle is supposed to move in case of transition from class A to class AB.

The strangest thing is that the needle moves if I hit with my hand the top panel of the amplifier.
(I made a video clip about this, I will try to share it if I understand how to do it! )

Is the behavior of the needle of my amp normal? Or there is a problem with it?

Anyone experienced similar issues or has an idea which could be the root cause?

Thank you in advance for your help!

kind regards
Domenico
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Old 10th May 2016, 09:28 AM   #2
Zen Mod is offline Zen Mod  Serbia
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open upper lid of case and observe is there some spider activity around needle mechanism

if yes , try to remove it

you can also use gentle breeze of air

regarding amp's general condition/setting - read this, for general info about PL amps setting : Pass Labs X150.5 , checking/adjusting offsets ,Iq and gain | Zen Mod Blog

what's temperature of heatsinks and are left/right side temperatures the same ?

NB that needle movement isn't great in amount ; it;s static as long amp is in A class domain , slightly moving when you approach and in AB/B class domain

(video - you must upload it somewhere (youtube ? ) then put link here)
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Last edited by Zen Mod; 10th May 2016 at 09:31 AM.
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Old 10th May 2016, 09:37 AM   #3
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I've been able to upload video clip on Youtube. You can found it typing: "Pass XA30.5 strange needle behavior"

Thank you all for your help!
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Old 10th May 2016, 09:48 AM   #4
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Default Video clip

I've been able to upload the video clip on Youtube
You can find it typing "Pass XA30.5 strange needle behavior"

Thank you all for your help!
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Old 10th May 2016, 10:05 AM   #5
Zen Mod is offline Zen Mod  Serbia
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bellow your user name on youtube , click on "share" arrow , you get link for sharing here:

https://youtu.be/9kbCCJnDBTg

now - answer on those questions , I asked in my previous post

we need to find (and to be sure) is there a problem just with a needle , or with amp biasing
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Old 10th May 2016, 10:23 AM   #6
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Thank you for your quick feedback!
I will try to take a look into the amplifier and see if there is any strange thing next to the needle mechanism or some dust.
I'll let you know the result!
About the temperature of heatsinks, last time I checked it seems to be more or less the same on both sides, but I will check again to be sure.
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Old 10th May 2016, 10:45 AM   #7
Zen Mod is offline Zen Mod  Serbia
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observe temperature on heatsinks considering Papa’s Palm Rule

you have picture in my blog
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Old 16th May 2016, 08:37 AM   #8
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Hi,
here update:
the problem seems to be caused by the movement (sliding) of the needle mechanism inside the housing.
A guy from Pass customer service told me that the first version of the needle mechanism used to have this problem (it is not well blocked inside the housing).
The solutions are:
- glueing
- replacement with new version of the mechanism

Anyone heard about this issue before?
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Old 16th May 2016, 10:06 AM   #9
Zen Mod is offline Zen Mod  Serbia
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I believe you got all needed info from a guy from Pass customer service
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