RH1 mains hum?

[allend]

My new mz-rh1 is fantastic... i love it, but i have noticed something:

i have tried to record sound from my laptop. this is not possible while it is connected with the usb cable: the unit display flashes "pc-md" when record button is pressed on the unit.

so to overcome this, i disconnected the cable, put the battery in, and then connected a male/male jack to jack lead from the laptop's headphone socket to the rh1's line-in socket. the problem is there is mains hum on the unit. this hum is "earthed" when i touch the unit and so disappears, but as soon as i release my touch - it's back. so recording in this way is not possible. i have also noticed that the hum is present when i am recharging the battery from a mains outlet and listening to music at the same time. and yes i have all ferrite cores attached.

Has anybody any advice for me?!?!

[A440]

Why not transfer the sound to the unit via SonicStage? Just import the file and send it over via USB. If it's some sound from the computer itself that you're trying to get, you could record it with Audacity (free) or TotalRecorder ($12).

All MD units get the hum when recording while using AC, and this sounds like a similar flaw. The best thing to do is probably to figure out a way to ground it using something other than your hand.

[Sparky191]

I didn't know about the mains hum. But then I almost always use batteries.

[allend]

Why not transfer the sound to the unit via SonicStage? Just import the file and send it over via USB. If it's some sound from the computer itself that you're trying to get, you could record it with Audacity (free) or TotalRecorder ($12).

All MD units get the hum when recording while using AC, and this sounds like a similar flaw. The best thing to do is probably to figure out a way to ground it using something other than your hand.

thanks ever so, but the sound i want to record is streaming radio from the net. i usually record from satellite digitally, but there are times that i want to record from the web.

I already use sony soundforge 8 - the absolute dog's for editing.

but what about earthing out the hum - or is it something i'm just going to have to live with??

thanks

I didn't know about the mains hum. But then I almost always use batteries.

the rh1 doesn't have battery add-on (AA or AAA style). there is only the internal rechargeable. hmmmmmmmm.....

[Sparky191]

Some people made AA powered USB chargers/power units. Would using one of those solve the problem? Theres a few threads on those DIY USB chargers. Heres one I posted before. I know theres others though.

http://forums.minidisc.org/index.php?showtopic=17681&hl=

[Sparky191]

...the problem is there is mains hum on the unit. this hum is "earthed" when i touch the unit and so disappears, but as soon as i release my touch - it's back. so recording in this way is not possible. i have also noticed that the hum is present when i am recharging the battery from a mains outlet and listening to music at the same time. and yes i have all ferrite cores attached.

I've been thinking about this. What have the ferrite cores got to do with the hum? You don't need the USB cable when recording, or when listenting to music, so its got nothing to do with the USB cable.

....

All MD units get the hum when recording while using AC, and this sounds like a similar flaw. The best thing to do is probably to figure out a way to ground it using something other than your hand.

This has been bothering me. Is there a hum in the recordings? when you use AC? That sounds like a serious flaw to me! Can't believe I didn't notice this before!

[A440]

Here's a longer discussion of this same problem.

http://forums.minidisc.org/index.php?showtopic=11523