[bonyjam]

Hi all,

Looking to seek any advice on this issue.

I bought a used Lite Audio E100 headphone amplifier about six months ago and recently noticed that the right channel had low volume from a cold start but after about 15 minutes of playing the issue disappeared.

This issue is repeatable and the only solution was to wait for 15 or so minutes.
Is the amp electronics dying?
I have also done the following to ensure it was not caused by other factors such as:

1. Replaced with two new Neutrik 6.3mm connector jack (NJ3FP6C) on the amp, The soldering and wiring were verified to be correct.
2. Use another DAC (Gustard X12) and another interconnect (Furatech) to connect to the amp

However, the issue persists. Anyone out there had a similar experience to share or know which part of the electronic is dying?
Thank you

 

[tomb]

Just a wild guess, but from online pics, it looks like a pretty good sized relay is protecting the power-on startup. That relay could be going bad on the right channel, but there may be enough capacitance between the contacts to allow a very low signal to get through. Of course, as a relay continues to operate, it heats up, possibly "un-sticking" the "sticky" contacts for the right channel.

 

[bonyjam]

Just a wild guess, but from online pics, it looks like a pretty good sized relay is protecting the power-on startup. That relay could be going bad on the right channel, but there may be enough capacitance between the contacts to allow a very low signal to get through. Of course, as a relay continues to operate, it heats up, possibly "un-sticking" the "sticky" contacts for the right channel.

Thanks, Tomb.

Your explanation does make sense.
I am not good with electronics but I can understand the relays are to protect the speaker/headphone.

With the attached picture, is the relay circled in green?
I searched Youtube to identify what is a relay.


The reason I ask about which components might be the culprit was to better estimate a repair cost.
If this is too expensive then I would just live with it, save up for another amp.

 

[tomb]

Yep - that's it. Plastic-cased PCB-mounted relays like that are fairly easy to replace, if you can solder. Simply look up the number at Mouser or DigiKey, order it and solder it in (after removing the original).

Like I said, though, it's still a guess, based on your symptoms.

Relays have metal contacts that are fairly close together, even in the non-contact position. That actually allows them to serve as a capacitor (often represented in schematics as two plates close together). Capacitors block DC, but not AC. Music in electronics is actually an AC signal. So, if the relay is sticking, you won't get a full connection - but there may be enough capacitance in the contacts to allow the signal to bleed-through at a much lower volume. As it heats up, maybe the sticking contacts unstick and eventually make the full connection.

 

[bonyjam]

Yep - that's it. Plastic-cased PCB-mounted relays like that are fairly easy to replace, if you can solder. Simply look up the number at Mouser or DigiKey, order it and solder it in (after removing the original).

Like I said, though, it's still a guess, based on your symptoms.

Relays have metal contacts that are fairly close together, even in the non-contact position. That actually allows them to serve as a capacitor (often represented in schematics as two plates close together). Capacitors block DC, but not AC. Music in electronics is actually an AC signal. So, if the relay is sticking, you won't get a full connection - but there may be enough capacitance in the contacts to allow the signal to bleed-through at a much lower volume. As it heats up, maybe the sticking contacts unstick and eventually make the full connection.

tomb, you were right. It was the relay.

I actually tried to remove the plastic covering cap by wiggling in hope that I can clean the relay contact but couldn't as I found out later that it was a sealed unit.
But surprisingly the problem went away. Now I can hear the relay click after a few seconds and both channel sounds came through.

Thanks for helping to narrow done the issue to the relay.