jolida JD9 hum...

midfi · « **on:** 2 Nov 2011, 11:00 pm »

just when all was right in the world for a few days, I received my new Audio Technica AT-F3/III in the mail today. Installed it on a sled, plugged it in, balanced arm, et cetera... Switched the RCA's over to HI out and hummmm!!!! I set the dip switch to 100 ohms per AT's specs. Tried all 3 gain settings to no avail. Rechecked ground, moved cables around, picked table up, blah blah blah... Still hums. On the MM side it has a hum but it's very low but with the MC it's very audible.

SteveFord · « **Reply #1 on:** 2 Nov 2011, 11:24 pm »

Mine was humming like crazy the other day and it turned out to be the interconnects. I reconnected them and all is right in Jolida-land.

midfi · « **Reply #2 on:** 3 Nov 2011, 02:03 am »

tried it and changed to another pair, still humming...

Jeff K · « **Reply #3 on:** 3 Nov 2011, 08:59 pm »

Try moving it. Mine is sensitive to placement. On top of a CD player it hummed. Under it, no hum.

SteveFord · « **Reply #4 on:** 3 Nov 2011, 11:25 pm »

Failing that there's only two tubes to change. I'm using Sovtek 12AX7-LPS with good results.

Æ · « **Reply #5 on:** 4 Nov 2011, 01:11 am »

Quote from: midfi on 3 Nov 2011, 02:03 am

tried it and changed to another pair, still humming...

Your problem started when you installed a new phono cartridge. You need to unplug your entire turntable/tonearm from your Jolida and see if the problem goes away. If it does, then obviously the problem is with the turntable/tonearm/cartridge. Typically most phono "hum" problems can be narrowed down to a bad ground, grounding issues.

midfi · « **Reply #6 on:** 4 Nov 2011, 01:28 am »

ok, unplugged RCA's from the TT to the preamp, then it has that "FM radio between stations" hiss. Plug RCA's back in, hiss gone hum returns.

I've got to get some longer RCA's to move it away from rest of system. And TT is grounded to the JD9, no other component in my system has a ground lug on it...

midfi · « **Reply #7 on:** 4 Nov 2011, 01:29 am »

changed power cord too, no change... Switched carts out and the part that's killing me is it sounds so good (esp. with a Shure M91ED with a hyper elliptical, go figure...) until you get to the quieter passages of music or no music playing and its very audible.

Æ · « **Reply #8 on:** 4 Nov 2011, 03:23 am »

Quote from: midfi on 4 Nov 2011, 01:29 am

changed power cord too, no change... Switched carts out and the part that's killing me is it sounds so good (esp. with a Shure M91ED with a hyper elliptical, go figure...) until you get to the quieter passages of music or no music playing and its very audible.

I would unplug your turntable/tonearm/cartridge from the Jolida and insert shorting plugs (RCA) into the Phono input jacks and listen. You Jolida should be dead quiet, if not then your Jolida has a problem.

midfi · « **Reply #9 on:** 4 Nov 2011, 04:34 am »

where do I get these "shorting plugs"?

Æ · « **Reply #10 on:** 4 Nov 2011, 06:38 am »

Quote from: midfi on 4 Nov 2011, 04:34 am

where do I get these "shorting plugs"?

Well, they are available at numerous places. Or you can even make your own.

http://www.tweakshop.com/Shorting%20Plugs.html

orthobiz · « **Reply #11 on:** 4 Nov 2011, 09:39 pm »

Caps? You can find them here:

http://www.cardas.com/content.php?area=products&content_id=7&pagestring=Accessories

I don't have any but it looks like they're good to have around.

Paul

Æ · « **Reply #12 on:** 4 Nov 2011, 11:39 pm »

Quote from: orthobiz on 4 Nov 2011, 09:39 pm

Caps? You can find them here:

http://www.cardas.com/content.php?area=products&content_id=7&pagestring=Accessories

I don't have any but it looks like they're good to have around.

Paul

I avoid the term "caps" when referring to RCA shorting plugs. Caps is more often used as an abbreviation for capacitors. Semantics.

midfi · « **Reply #13 on:** 4 Nov 2011, 11:48 pm »

Quote from: Æ on 4 Nov 2011, 06:38 am

Well, they are available at numerous places. Or you can even make your own.

http://www.tweakshop.com/Shorting%20Plugs.html

Question... would hacking an old pair of RCA's and tying the - and + together have the same effect?

Æ · « **Reply #14 on:** 4 Nov 2011, 11:54 pm »

Quote from: midfi on 4 Nov 2011, 11:48 pm

Question... would hacking an old pair of RCA's and tying the - and + together have the same effect?

Absolutely!

midfi · « **Reply #15 on:** 5 Nov 2011, 10:39 pm »

more news at 11...

midfi · « **Reply #16 on:** 6 Nov 2011, 06:18 pm »

gotta stoppage of the action. Put Adcom GFP-750 in da shop, DeOxIt didn't clean up the super scratchy sound in the volume and source selector pots.

A B&K CS-117 is in route for a filler until I get the ADCOM back.

midfi · « **Reply #17 on:** 13 Nov 2011, 07:27 pm »

okay a few things. 1st the CS-117 is pretty good little pre and its cheap too, but I digress...

Plugged the TT directly into the CS, very low hum, so low that you have to put your ear at the speaker to hear it low. So it gotta be in the Jolida but I can't send it back because I've monkeyed with it! (which is cool). Even with the hum the Jolida sounds livelier than the phono section of the CS but the CS ain't bad. The CS phono sounds comparable to my ADCOM 565 phono section in the bass and midrange but the ADCOM has a little more treble.
I don't even know where to start with the Jolida, I guess I'll have to take a day and try to put everything back to stock piece by piece and replay after each part is restored to see where I loose the hum (if I lose it at all!).

Ericus Rex · « **Reply #18 on:** 13 Nov 2011, 09:27 pm »

Did you put in any fancy-schmancy resistors? They can add lots of noise. If so, I'd start with replacing those then try it out again.

Æ · « **Reply #19 on:** 13 Nov 2011, 10:32 pm »

Quote from: Ericus Rex on 13 Nov 2011, 09:27 pm

Did you put in any fancy-schmancy resistors? They can add lots of noise. If so, I'd start with replacing those then try it out again.

Noise and hum are two different things. Why would replacing resistors cause hum? Better resistors usually have less noise. Look up "shot noise."
Hum can almost always be fixed. Hum is usually 60Hz or a multiple of. The problem can be locating the source of the him, but after that, most fixes are pretty well documented.