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Electrical popping

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scorpio333:
copy/pasted comments from other thread for clarity/history...


--- Quote from: scorpio333 on December 11, 2018, 01:06:08 PM ---Nope, this is just one of those not so great quality records. It happens. It's in the 'to be cleaned' stack along with a few others.

As for the noise issue, I swapped out the Furman the vinyl rig was on and that seemed to help. I'm still having random issues when powering the system up and down. Sometimes I get a thud or pop when I turn the Furman on (with pre and amp off) and again after I turn it off (amp off first, then pre). Using an outlet tester everything checks out ok. The amp has a ground lug, but I didn't connect it to anything...yet.

I ordered a Audio Technica AT630 SUT so I can test using the moving coil table into my MM pre which has a much quieter noise floor than the JD9, the JD9 hisses like crazy and I never found the culprit. Once the SUT arrives I'll test it out and see what happens, maybe the JD9 gets put somewhere else or out to pasture.

--- End quote ---


--- Quote from: Jim Pittsburgh on December 11, 2018, 06:19:52 PM ---I don't have the hiss problem with my original JD9... quiet as can be. I did replace the op amps in mine to good effect, but even with the originals had no hiss.

--- End quote ---

We've talked about this in the past and I'm still shaking my head about it. I've swapped OP amps every which way of Sunday, moved cables, different cables, different tubes, etc...nothing changes. So I've been going over the internals this afternoon looking for anything out of place. I made a discovery. Seems when I replaced the coupling caps I simply snipped the old ones off and soldered the new right to the ends of the old. NO! They are supposed to be soldered to different points. Time to get the iron hot. 


--- Quote from: MacGeek on December 11, 2018, 09:10:46 PM ---Does any of the gear in the signal chain have a three prong plug?  If so, try lifting the ground.  Although I usually try ground lifts with hum problems, one never knows.

--- End quote ---

The pre and amp both use 3 prong plugs. Last night I had no pops for 3 hours, maybe the Furman swap worked.


--- Quote from: Sir Thrift-a-Lot on December 11, 2018, 02:27:31 PM ---If at some point you want to test that Jolida in another system/environment, I'd be happy to give it a test drive for a while.   That could be fun.

--- End quote ---

If the AT SUT performs the same/better than the JD9, you're welcome to borrow it. The SUT should be here Friday so stay posted for an update.

Sir Thrift-a-Lot:

--- Quote from: scorpio333 on December 12, 2018, 05:07:06 PM ---So I've been going over the internals this afternoon looking for anything out of place. I made a discovery. Seems when I replaced the coupling caps I simply snipped the old ones off and soldered the new right to the ends of the old. NO! They are supposed to be soldered to different points. Time to get the iron hot. 

If the AT SUT performs the same/better than the JD9, you're welcome to borrow it. The SUT should be here Friday so stay posted for an update.

--- End quote ---

I think you will want to see if you can correct the issue first.   That sounds very promising.

scorpio333:
Put the caps in the correct position, basically just shortened the signal path. Powered everything up, dead silent. The bad kind of dead silent, no music. Doh! I forgot to reattach power to the op amp board. Plugged it back in, still hisses. Fairly certain the op amps are the cause. I either have to live with that or order different ones.

Sir Thrift-a-Lot:
Rolling op amps is cheap enough.   I hope they are socketed.

scorpio333:

--- Quote from: Sir Thrift-a-Lot on December 13, 2018, 12:22:16 PM ---Rolling op amps is cheap enough.   I hope they are socketed.

--- End quote ---

That’s debatable.  There’s six of them. From China on eBay they are cheap, I think I got all six for about $20. But are they fakes? From US/Canada they start about $20 each.

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