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Pops and crackles from Oracle Delphi

B

banjoman

pfm Member
I have recently refurbished an Oracle Delphi Mk 1 and set it up with a Fidelity Research tonearm.
All fine and dandy and sounding pretty good.
The noise floor is really low and there is no discernible hum.

But a strange thing happens when I put on a record on the spindle or take it off after a spin.
I get loud popping/crackling sound through the speakers - sort of like loud static electricity pops. If I touch the metal spindle on the TT, I get similar pops. Interestingly, once I've touched it, there's no further pops after that. And after a few record changes it does not seem to occur at all. But every time I start the deck after a period of no use, the pop happens again.

I am guessing its something to do with static electricity? Or something worse?

The tonearm cable is well grounded and there is no hum through it at all. There's no pops or hum when I touch any part of the tonearm either. So, it seems to be something to do with the body/spindle of the turntable itself.

Any thoughts? Do I need to have a separate ground loop from the body of the turntable?
 
banjoman said:
Any thoughts? Do I need to have a separate ground loop from the body of the turntable?
Click to expand...

That would be my guess. Should be a simple fix, and easy to try with a temporary earth wire from the "chassis" (might need an assistant to hold it) to the amp ground before working out the best permanent connection.
 
My Roksan has a ground lead from the bearing to arm, is/was there one on yours?

Pete
 
It's static. Try running a length of wire from the point where you are earthing the arm and touch it on various parts of the turntable to see where it needs to be attached.
 
Thanks folks. Will try a ground lead. There's no obvious place on the bearing or on the deck I can think of to attach the lead but will try different options and see how I get on
 
Also, worth double checking continuity of the current ground lead. I had this recently with one deck, no hum or issues but the odd small pop when touching the arm after a side - turned out to be a poor joint on the arm cable earth lead on the spade.
 
banjoman said:
Thanks folks. Will try a ground lead. There's no obvious place on the bearing or on the deck I can think of to attach the lead but will try different options and see how I get on
Click to expand...

Are you perhaps walking on a synthetic carpet/rug or plastic tiles? If so it may be you rather than the TT that is charged up! You can buy antistatic sprays that you can use on the floor near the TT.

Cheers,

DV
 
TPA said:
Also, worth double checking continuity of the current ground lead. I had this recently with one deck, no hum or issues but the odd small pop when touching the arm after a side - turned out to be a poor joint on the arm cable earth lead on the spade.
Click to expand...

That's an interesting possibility I hadn't thought of. Its a fairly new lead, but will check properly. Thanks!
 
Darth Vader said:
Are you perhaps walking on a synthetic carpet/rug or plastic tiles? If so it may be you rather than the TT that is charged up! You can buy antistatic sprays that you can use on the floor near the TT.

Cheers,

DV
Click to expand...

Its wooden floor all the way and being 'summer', no woollens in sight...
 
Just as a matter of interest can you ground yourself before touching the deck next time. Perhaps a metal radiator or copper gas pipe and then touch the spindle. If it doesn't 'pop' then its unlikely to be an earth problem. Just to check next remove the record from its sleeve and put it on the deck. Does it now 'pop'? If so its you that has become charged.

Cheers,

DV
 
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