[bogiedr]

Greetings everyone. My Parasound Z ClearAudio Emotion set up had been working perfectly. After not listening to vinyl for a couple of weeks, I decided to listen to Miles Davis. As soon as I turned on my Amp and it started hummimg like crazy. After checking all the connections, I disconected the ground cable from the Parasound and evrything went, quiet, sound was good again. Does that make sense or do I have a sick preamp needing attention? My other preamp table set up is perfect. Any advise?
Thanks, Bogie

[neobop]

Hi Bogie,
" After not listening to vinyl for a couple of weeks, I decided to listen to Miles Davis."

Was it LIVE EVIL? Maybe Miles was just too much to start out with after 2 weeks. 

Really, even if we had more info, all we could do is guess. Is this the ground from your deck, or one going to the preamp from your Z? Any other ground wires?
At least it stopped humming.
Regards,
neo

[richidoo]

I have had situations where the ground wire hums louder than without it.

My guess is that there is some other change to the grounding of the TT which has made a loop when the grounding wire is connected. Or the connection quality has changed somewhere, the resistance of a connection has risen. Maybe an interconnect?

If possible, verify the source of the hum by running the amp by itself, (no source IC connected -mute the amp if possible) then add linestage by itself, then phono amp, then TT. When you hear the hum start, temporarily put a ground buster on that newest device to see if the hum goes away. Experimenting like this will help you find the exact cause.

You could also open up the Z if it's off warranty and look for anything weird, like burning marks on PCB, leaking caps, solder joints especially near the TT grounding lug. Twist all the IC connectors a little to break any corrosion. With 60dB gain, the slightest change in resistance can make a hum.

[neobop]

I wouldn't recommend turning on a power amp without the linestage being on. I almost blew up a giant pair of speakers once by turning off a preamp while the amp was still on. It was like a thunderbolt. You won't be able to tell anything anyway if the amp has protection circuitry. If not, an amp might hum like crazy or go into oscillation and it could have nothing to do with the phono ground. All the rest applies though.
neo

I forgot to mention that sometimes you have to run a ground from the phono to your linestage and another from the linestage to the amp. If it was OK before, I think it's probably a loose ground connection in the phono stage or table.

[Listens2tubes]

I have a Sumiko Talisman Ruby on loan while my Dynavector Karat D17-2 is out for repair. When time has passed since the last time I switched to phono on my preamp the Talisman will hum. Just touching the cartridge willl stop (disipate?) this.  Then everything is quiet and ready to play LPs.

As for amp/preamp turn on and off it is recomended to turn you preamp/frontend on first - wait 30 seconds - then turn on the amp. Shutdown is the opposite. Amp off first - wait 30 sec - frontend off. This allows the preamp to sputter to life before the amp gets a chance to amplify it and vice versa.