strange behavior on Ref 40 ( or Soulution?)

[TOGA]

I noticed this twice.
While trying to find new disc player, I have been using loan Soulution 540 for a few days, I have 2 power cords to try with 540. When I wanted to change cord
I had to switch off main switch on the back of 540, doing this while Ref 40
was in Mute, after restart 540 and unmute the Ref40, I will lost right channel sound. I don't know what caused this, but the only way to bring back right channel was to restart Ref40. Can it be that switching off 540 main switch may cause some DC flow out from right channel and activated some protection circuit on Ref40, which I never knew they have one or not. Seems like in order to
swap AC cords in 540 I have to switch off Ref 40 as well to prevent this.
I thought at first that by activate Mute was safe enough.
Toga

[E-Stat]

Originally Posted by TOGA

I thought by activate Mute was safe enough.

The mute on my SP-9 works only on the output to prevent start up thumps and transients from reaching the power amp. In your case, the transient was on the input side.

I would recommend simply switching to an empty input before powering down any source while the line stage is active.

[microstrip]

I also have found that very strong mains transitory spikes, as due to switching on power amplifiers without soft start, can sometimes affect the volume control of my REF40, usually lowering the current level, without changing the display. When this happens I just reduce the volume to 0 and from that moment on everything works fine.

[TOGA]

Ok, now I tried,
By switching to other input before switch off and disconnect power from disc players as E-Stat suggested, now Accuphase, the result was different from when I do with Soulution. Now it was exactly like microstrip found, the volume level is much lower, like one leg of XLR input is gone, gain reduced. only power down Ref40 and restart will solve problem, so like Windows of old times . Both Ref40 and disc players were connected to RSA Maxim, which may have some energy storage from coil/cap that can cause some voltage spike when disconnect cable, may be, volume IC that Ref40 must be less immune to such disturbance than other preamp.
Lucky that it can be reset easily and no permanent damaged. Oh is this mean that RSA Maxim doesn't do it job well enough ? By letting some transient to
other equipments.

Toga

[TOGA]

ok, if it happen again I will reduce volume back to 0 instead of restart it, which I worried that it will reduce tube life.

[microstrip]

Originally Posted by TOGA

ok, if it happen again I will reduce volume back to 0 instead of restart it, which I worried that it will reduce tube life.

And you avoid the wait until the count up ends!