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TT hum

Sorry for starting my first activity with a question. I recently got VPI prime TT with Ortofon quintet black (MC).
Since day 1, it's been making background hum. I hear it even when the volume is about 20% of max, but it gets pretty loud when it's over 50%. I have Parasound halo p5 which supports MC cartridge and it's pretty new too.
TT and Pre are connected by monoprice RCA cable and separate grounding wire.
Here's what I did.

I disconnected and turned off all other equipment (TV, amp, CDP).
I simply kept power on only for TT and Pre, and connected these two as usual.
Then I evaluated hum with headphones. It's still there.
It does not happen when Pre is set to other input (CDP, when it's connected) but only happens with phono.
When TT is disconnected, no hum.It happens even when TT motor is off.
Touching anywhere of the ground wire does not affect it.
I tried switching monoprice RCA cable to something else (not a very good one though) but still happens.
What could be the problem?
sohnwh
3 responses Add your response
mattmiller's avatar
mattmiller
1,497 posts
 

1. Try and take away the ground wire. All of these pieces should have 3 prong plugs on them already. So, everything should be grounded fine.

2.  Is the turntable plugged into the wall directly or...?

3. what settings are available for cartridges on your preamp/phono preamp? And what are they set at?


Matt M

sohnwh OP
1 posts
 
1. I took off ground wire between TT and pre but no change.
2. I tried different power outlets, directly to the wall, multi tabs, but made no difference.
3. Pre has 3 settings : MM, MC 47k ohm, MC 100 ohm. I tried all of them. With MM setting, I get less hum but volume's too low. With the other 2 I get same loud hum. It is now set at MC 100 ohm.

thanks for response!!

mattmiller's avatar
mattmiller
1,497 posts
 

The Ortofon cartridge you have is only putting out .3mv! That is very low. This is a great cartridge, but it needs a phono pre amp with proper settings to dial it in. The Parasound does not provide the nessesary settings. Either change your cartridge to a MM or HOMC so you can use it with your P5, or you can get a external phono pre amp like a Musical Surroundings Phonomena II and use one of the linestage inputs on the P5. I think the buzz your hearing is because you are unable to properly set the Impedence and gain settings for the ultra low MC cartridge your trying to use. 


Regards,


Matt M 

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