Electrical popping

[scorpio333]

Bit of a rant - every time the furnace condensate pump turns on or off, the speakers POP. One more thing to fix! The stereo setup is on its own circuit and is about 30’ from the pump. Quick google didn’t turn up much. Time to pull out the aluminum foil and make a hat, or a shield for the pump. The colder it gets the more often it happens.

[rgpit]

How is the pump powered? Directly from furnace controller or is it connected to 120 VAC line? You can use a noise suppression filter.

[scorpio333]

The pump is powered with a standard grounded plug, I switched it to a different outlet and that didn't cure it.

I'm beginning to wonder if the Furman power conditioner is at fault. I attempted to plug in a second turntable last night while the rest of the system was up and running...POP...tried it again and no pop. I don't recall getting pops when I was using a surge protector for the rig.

The washing machine also causes noisy calamity.

Easy solution, unplug the pump and don't wash clothes while listening to records.

[Sir Thrift-a-Lot]

That sounds like your Furman could be defective.

[scorpio333]

That sounds like your Furman could be defective.

I have two others, going to swap one and see what happens.

The other thing I’m suspecting is the Jolida JD9, it’s a gain monster. Perhaps it’s picking up EMI. I switched over to my 2nd table with a MM cart that goes into a different pre. No pops.

Also, the tv/theater setup in the same room on a separate circuit with two Furmans never pops. Electricity is fun!

[scorpio333]

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

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.

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.

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. 

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.

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

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.

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]

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.

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]

Rolling op amps is cheap enough.   I hope they are socketed.

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.

[Sir Thrift-a-Lot]

Are they socketed?

[scorpio333]

Yes. Originals are OP37G. I’ve tried TI 627’s, Burr Brown 637 and TI LT1028, and a few others Jim had.

Just found AD797 will work and may be lower noise. Dunno, internet opinions are not always accurate vs my findings. They’re only $8 each, so easier to swallow if they don’t work out.

[Sir Thrift-a-Lot]

Were the originals noisy?    Maybe it's not the op-amp.

[scorpio333]

Were the originals noisy?    Maybe it's not the op-amp.

Yes.

I narrowed it down a bit now. It’s the moving coil section of the preamp. Up til today I’ve only used it for the OC9 cart. The AT SUT arrived today. Connected the table to the SUT then to a Yaqin tube pre and was impressed, very good detail and separation. Listened to a side of the JB’s through that pre then connected it to the JD9 at 47K, 50db and low outputs. Played the same side and BAM! this is why I bought the OC9.

The JD9 still has a hiss but not until the volume is at 75%. Up to about 12 hrs and no pops on the current Furman. Strangely the offending Furman is powering the tv, HTR, and disc players and no pops or noise.

Maybe if I plug the washing machine into a different outlet someone else will do the laundry?