Distorted sound from speakers when headphone amp is switched off

Hi,

I got a strange behavior after I added a headphone amp to my system: when I switch it off, my floorstanding speakers start sounding quite distorted. My setup is:

M2Tech Young MkIII -> Roksan Caspian Integrated amp (used as preamp only) (pre out) -> Roksan Caspian Power Mono blocks.

Roksan Caspian Integrated amp (tape out) -> M2Tech Marley headphone amp.

Sound is clear when M2Tech Marley amp is switched on, but when I switch it off, I get distortion in my speakers.

Did anyone experience this or has ideas what can be wrong?

 

Sometimes tape outputs aren't buffered, sounds like that's the case for you, so you can't leave something connected that is powered off since the powered off electronics can load down the signal. Often there is a switch so you can disconnect that output.

 

Yep; good call.

 

It's unusual, but what Davey suggests can happen with some components. Many, perhaps most tape outs are not buffered. It could be that or even that the connected device has some noise from the power supply bleeding through common ground. Either way, disconnect the headphone amp from the preamp and see if it stops that behavior.
-Bill

 

Thanks for your replies.

Yes, when I disconnect Headphone amp from the tape out, the distortion stops, regardless if Headphone amp is connected to power or not.

Unfortunately, I did not find any way to switch tape out off on my integrated (used as pre) amp.

I'm wondering if this could be a fault of headphone amp input stage? There're 2 inputs in the headphone amp, an both behave in the same way.

I also tried to connect my old Marantz AVR to tape out my Roksan AMP, and there were no issues with the distortion.