[Jukie]

While turning nob for in/decrease volume control, I'm boring with noise from
left channel.
That is my Melos' problem.
How can I fix it and kill the noise?
Do you have idea for it?
Using connect point spray is the best thing for it?

 

[ppl]

yes contact cleanner spray will work

 

[Zoide]

I hope this is not too OT, but is the main benefit of stepped attenuators to prevent this type of problem? Or do they have a more important benefit?

 

[Jukie]

I've solved this problem.
That was happened from wrong circuit mod.
Small resist was soldered wrong place that make unbalacing and
volume noise.
It was moved to right point and fixed all problems.
It maybe Carlos' tiny fault or mistake.

Anyway I know that the best way is replacing humble volume nob
to attenuator for example...DACt.
So I'm planning to replace it and willing to loose function of remote.

Thanks to all replys.

 

[Jukie]

Unsolved problems are...

Why Melos Audio did use humble headphone jacks and motor dirive volume?
While doing fix volume noise and circuit problems, headphone jack was
broken as biscuits and I'd found volume was the worst ever I'd seen before.

Did Carlo used too hot temperature soldering iron while modding?

 

[Chinchy]

I'm interested in the solution to this problem jukie. I recently had my Melos SHA-1 modded by Carlo, and I just recently (2-3 days ago) started having a hum problem in ONLY the left channel.

The history of my issue:
Prior to the mod, I was also having noise in the left channel, which Carlo told me was due to the original design of the Melos routing the left channel through the power supply, but I was told that his mods fixed this issue. At that time, the noise would come and go, and sometimes if I switched the input selector switch, the noise would go away.

When I first got the amp back after modding, everything sounded just fine. But all of a sudden the noise is starting to come back. I don't think the noise is caused by the tubes, but I'm at a loss to explain why the noise is there. So if you could tell me how you fixed it, I can check to see if that's the cause of my problem or if there is something else happening.

Thanks Jukie!

Edit: Oh yeah, and Carlo already switched out the original volume pot for a stepped attenuator, so I know it's probably not the stepped attenuator that's causing the noise.

 

[Jukie]

Yeah...left channel noise.....you got the point!
Hmmm..if you can see the back of main board of Maestrobator,
you can find tiny resistor alone.
My engineer had checked all of circuit board and check of it,
he found this resistor has soldered on wrong place that happened
left channel noise and balance problems.

It should never be a problem of only humble volume nob, I believe.
Please check Modded Maestrobator's circuit board seriously, I hope your
Melos will be fine and fixed the noise.

Thanks.

 

[Chinchy]

I don't know anything about electronics design or circuits. Anyone in the Bay Area want to take a look and see if they can find the errant resistor?