recently picked up an Akai AM2450 and has issue of audio in either channel fading out and sounds distorted while it does. When this happens its only to one channel and can be either.
turning up the volume temporarily fixes it.
I thought it'd simply be dirty volume pot and or dirty contacts in the speaker relay. However the issue persists.
oh and wow what a relay! the thing should have a clear casing to show off it's internals lol
The caps look original, unless they were replaced long ago and in entirety.
The volume pot had a ton of oil residue, it has a particularly open design. but I don't think the issue is either of those components. its been cleaned.
Particularly because the issue can be one channel or the other.
all other adjustments sound and work fine; balance, bass, treble. switches sound fine too; input, Loudness, Mono / Stereo, A/B speaker.
It has watt meters, which work when speaker switch is off...however when the fade out issue happens
it can be seen in the watt meter...it slowly decreases in magnitude.
The pots for bias look rather suspect / are completely open design.
Any ideas?
turning up the volume temporarily fixes it.
I thought it'd simply be dirty volume pot and or dirty contacts in the speaker relay. However the issue persists.
oh and wow what a relay! the thing should have a clear casing to show off it's internals lol
The caps look original, unless they were replaced long ago and in entirety.
The volume pot had a ton of oil residue, it has a particularly open design. but I don't think the issue is either of those components. its been cleaned.
Particularly because the issue can be one channel or the other.
all other adjustments sound and work fine; balance, bass, treble. switches sound fine too; input, Loudness, Mono / Stereo, A/B speaker.
It has watt meters, which work when speaker switch is off...however when the fade out issue happens
it can be seen in the watt meter...it slowly decreases in magnitude.
The pots for bias look rather suspect / are completely open design.
Any ideas?
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Strange its one channel or the other as that would point to the power supply for the fading channel.
Is it a common supply or dual ?
Is it a common supply or dual ?
it is a single power supply.
I see from research of other posts that just as you say this can be caused by power supply; in the case I had read the person replaced the PS caps and resolved the issue.
I'll give that a try as there are not many caps in the PS section.
I wonder if it's possible / likely that transistors could cause this; if it's a transistor issue is beyond me for finding a suitable substitute.
One thing I noticed this morning, if I try the temporary fix of a burst of volume, while the speaker selector switch is set to off even though the watt meter needles register it does not resolve the issue. I need to have the speaker selector to A /B or both A&B. not sure if that narrows down the path were the issue is.
I see from research of other posts that just as you say this can be caused by power supply; in the case I had read the person replaced the PS caps and resolved the issue.
I'll give that a try as there are not many caps in the PS section.
I wonder if it's possible / likely that transistors could cause this; if it's a transistor issue is beyond me for finding a suitable substitute.
One thing I noticed this morning, if I try the temporary fix of a burst of volume, while the speaker selector switch is set to off even though the watt meter needles register it does not resolve the issue. I need to have the speaker selector to A /B or both A&B. not sure if that narrows down the path were the issue is.
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It is an old amp; I believe it is from'79 - '80 or so.
New revelation! So I left the amp on and after a number of hours it stopped.
Does that further support capacitors drying out?
I figure the increased heat is reducing resistance somewhere.
New revelation! So I left the amp on and after a number of hours it stopped.
Does that further support capacitors drying out?
I figure the increased heat is reducing resistance somewhere.
Sometimes the capacitors can heal themselves a bit if left on.
I would replace the power supply caps still.
I would replace the power supply caps still.