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Parasound JC 3+ Phono Preamp Hum

I know hum problems have been discussed ad nauseam on this board, but after trying a few different things, I have been unable to find a solution. I recently purchased a used JC3+ to replace a PS Audio GCPH with Underwood Mods. Although the GCPH had some hum, the volume had to be turned up to past 50% before it was audible.

With the JC3+ I get a low hum at 25% and loud hum at 50% volume. What I am describing is with everything on, no record playing.

The SL1200G TT is grounded to the JC3+. I’ve tried the following: 1. Added a ground wire from the TT to the integrated chassis, a Cayin A-88T Mk II. 2. Changed cables from TT to JC3+. 3. Changed cables from Integrated to JC3+. 4. Plugged JC3+ directly to wall outlet. 5. Changed to AC polarity on the JC3+ via the switch on the back from normal to invert. 6. I’ve tried using no ground wires.

Due to my cabinet configuration, power cables and audio cables run parallel and close to each other. There is no way I can arrange them to be perpendicular to each other.

If I lift the tonearm and let it fall back on the cradle, I can hear the echo or bump through the speakers.

My cartridge is a Hana SL.
Cables: TT to preamp, Silnote Morpheus
preamp to Integrated, Morrow MA4 (and tried AQ King Cobra)

Everything is plugged into a rather inexpensive, basic Belkin PF30 power strip.
I have been considering upgrading to a AQ Niagra 1000. Not sure if that would help with the hum.

The JC3+ is definitely a better sounding preamp than the GCPH . I can’t hear the hum when playing music, but I’m quite disappointed that the JC3+ hums louder than the GCPH.

Again, I know hums have been discussed to death, but any ideas or suggestions for my specific problem would be appreciated.
Eric

ericsch
invictus005
597 posts
 
@ericsch Do me these two tests.

1.) Disconnect the turntable from the JC3+, but leave everything else connected. Short both RCA inputs (center hole to outer sleeve) on the JC3+. Now turn the volume up and report back if the hum is still present.

2.) Do you have Comcast cable in that room? Disconnect the coax cable by unscrewing it from the box’s cable in. Is the hum still there?

Unused balanced inputs will have no impact.
lancelock
625 posts
 
@ericsch 

I do have plenty of space between cables. I’m using RCA cables not balanced. Everything works as it should.
atmasphere's avatar
atmasphere
7,068 posts
 
OK this will sound a little weird, but if you can pick the phono preamp up and move it around, see if that affects the hum.
If it does, move the phono section to a different location- it could be too close to a power transformer, like the one in the Cayin.
Post removed 
ericsch OP
180 posts
 
@dweller  and others I will try the various things you suggested as soon as time allows. I will probably start with moving the JC3+ away from the rest of the system. I have visitors coming for the next 3 or 4 days. Thanks to all for your responses.
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