[sdiy] Looking for advice about powered reference monitor problem

[Michael E Caloroso]

Odd volume changes can be caused by HF oscillation in a circuit
somewhere.  You won't hear it, but a 10x probe with a scope will
reveal it.

MC

On 11/19/20, Shawn Rakestraw <shawnrakestraw at gmail.com> wrote:
> Thanks for the comments and general direction. I believe you and genuinely
> hope that it is a solder joint. That would be a simple fix by relowing the
> joints. I can't help but wonder, would a cold solder joint suddenly form
> after 15 years of use and also never being moved for 10 years? I tried
> checking the noise floor (with my ears) and it seemed the same for both
> monitors. Maybe it is the input signal. I will investigate more!
>
>
>
> On Thu, Nov 19, 2020 at 3:34 PM The SynthiMuse <synthimuse at gmail.com>
> wrote:
>
>> If you listen to the monitors with no input signal and check if the small
>> amount of noise is the same for both monitors then that implies that
>> there's a bad connection or solder joint on the input signal. On the
>> other
>> hand, if you hear the backgtound noise profile tracks the previously
>> heard
>> behaviour on the suspect monitor,  that might suggest an issue further up
>> the chain on the power amp end.
>> Jimmy Moore's suggestions are good and it helps to have a known good
>> working channel to compare measurements with.
>>
>>
>