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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
atmasphere's avatar
atmasphere
11,841 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.
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ericsch OP
753 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.
last_lemming
639 posts
 
I have a JC3+ and I have had him issues in the past but never from the unit. Get a long grounded extension  cord. Like one you use for outside yard work. Plug it into another outlet in another room. For whatever reason this worked for me. If you had a hum in your previous phono pre it’s most likely not the pre. Also make sure your cart leads are tightly plugged in. And finally if you have a removable headshell it might not be making full contact on all 4 pins. This happened with my new Technics 1200 gr. Changed the shell and hum went away 100%. 
vdotman's avatar
vdotman
145 posts
 
Have you checked the tonearm leads at the cartridge? Might be a grounding issue at the source. Try slightly moving the lead wires and see if anything changes.
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