Dreaded tonearm hum

jmathers

Super Member
Well, I just HAD to rewire my tonearm on a Project 1.2 and now that it's done, it hums. Any ideas for troubleshooting?

I used the shielded Cardas wire and stripped the shielding off the wire (except for the colored stuff) that went through the arm tube itself. I left it twisted together.

As it comes out of the base of the arm pillar itself I bypassed the din and left the shielding on the wire and ran it out to two female RCAs. I left the original ground wires attached to the din (there's two coming out of the arm - one from the tube and one that's connected in the top of the pillar somewhere) since I would reuse the din anyway as a plug for the arm pillar and ran the original ground wire out to a post in my new RCA box and then on to the preamp ground.

I did nothing with the Cardas metal shielding other than to cut it off at the stripped ends of the wire - does this need to be grounded somehow? Could that be the problem?

I redid ALL of my solder joints last night thinking that maybe I messed up on one but that had no effect. Help!

Jeff
 
Did you make sure that the turntable is properly grounded to the amplifier (sorry if that sounds like a dumb question)?

When you retrace your work, do you see any chance that bare wire is touching something it should not?

I honestly don't know very much about turntables, and haven't noticed a lot of turntable questions on the DIY board. On the other hand, the turntables and tape message board would have many more people who could quickly answer that question.
 
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Jeff

Wish i had a definitive answer for you but about all i can think if is a bad ground somewhere. Make sure the cartridge and clips are clean. usually you get intermittent sound but Ive heard of them doing weirder things when dirty an old. Good luck.
 
i'm giving up

Well, came home and redid the cartridge clips -what a PITA! No effect and my third soldering job trashed the clips. Overheated, they now won't reclip...the only solution is new clips. So off they came!

Then I thought "Man, was I plugging the table into the preamp or the wall?" If it was the wall then I probably wasn't getting a good ground since all my wall sockets are ungrounded. Doh!

I'd gladly pay someone $100 to put the clips back on and check my wiring job - I will NEVER rewire a tonearm again:-( Glad the table's not a VPI or something.....

Thanks for the help anyway.

Jeff
 
Been a really long time since i soldered them small ass wires but I could probably help. Then again who knows :)
 
Grumpy:

Thanks for the offer of help. I was just super frustrated last night. I have to order new clips - this time I'll get something better than the cheapest Cardas CCCE clips - and that'll give me some cool off time.

You need very,very SMALL hands to solder these puppies on :D

Cheers
Jeff

By the way, I'll get the other table back to you this weekend - I'll call you.
 
jmathers said:
Grumpy:

Thanks for the offer of help. I was just super frustrated last night. I have to order new clips - this time I'll get something better than the cheapest Cardas CCCE clips - and that'll give me some cool off time.

You need very,very SMALL hands to solder these puppies on :D

Cheers
Jeff

By the way, I'll get the other table back to you this weekend - I'll call you.

The small hands part is definitely something i gotta work around. Its definitely a pita.

Maybe its the inner cheap ass in me coming out but I don't see any need to spend more cash the what the cheaper clips cost. IMO spend that money on the cart.

I should be around most of the day.

Grumpy
 
Second the smaller soldering iron, I was dealing with a fairly large iron a while back, and getting frustrated. So I went to a local store, and picked up a (no other word for it) dainty little Weller with tiny interchangable tips. The thing is a gem. It's only 30watts, but for tiny stuff it's quick and it's light, and makes small jobs a breeze.
BTW, I suffer from large hands syndrome as well. So I got one of those "Third Hand" magnifier/alligator clip dealios, thinking I would use it mebbe once or twice. Turns out I use it all the time. Very cool little gadget.
 
Thanks guys for all the advice. I redid the cartridge clips (again!) by scrouging around for some old sets and found some super cheap clips in an old box. NO HUM! I can't believe it but this time all the hum is gone and everything works perfect. I guess you just have to be persistant.

I probably wouldn't have considered the cheaper clips if grumpy hadn't chimed in and said don't waste your money on the fancy clips....thanks for being a cheap ass;-) Seriously, I'm so glad I went ahead and redid them today rather than waiting until next week - my Project TT is back and better than ever.

Plus I got rid of the old RCA cables and now can use any old cable I want. he box looks pretty cool too - almost as fancy as the Sumiko PIB.

Thanks again everybody for the help.

Jeff
 
I just ran acroos this Jeff, glad you got it fixed. I'd offer to help, as I have both small hands, (keep it to yourselves), and a 20 watt Weller and magnifing glasses, helping hands, etc.
Steve
 
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