Turntable Help

[Richard the one in Texas]

Dual 1229 with new Ortofon super OM40. Absolutely new Dual motor installed with overhaul.

Problem: needle engages record and a high frequency "ring" at constant level and pitch is heard on silent passages, ends upon needle disengaging record.

sounds almost like a wire is touching the metal platter and is being fedback through cartridge, but upon inspection, nothing seen.....could the idler wheel be inducing this?

any ideas on troubleshooting this problem?

It hasn't really hindered any enjoyment, since it is not heard during the music, and feint at best during silence. but would like to eliminate it.

thanks

[BillWX]

Yikes! I had something like this happen years ago when I did college radio. Being the technical director, it wasn't a nice phone call from a DJ at midnight. I tuned in and sure enough, there was a weird high pitched "buzz" on one of the turntables. But it didn't sound like a typical "ground buzz". Like you say, it only happened during silent/quiet passages or if the needle wasn't engaged. The DJ was having a time because after cueing a record, he'd turn the level up and there would be that noise.
Here's what happened - and it may or may not be your problem. I checked everything from cables to ground wires. All good. Then, when I was about to give up, I simply tapped the headshell and the noise stopped - but a second later, it returned. :eek: It turned out one of the little wires connecting the cartridge to the headshell had a short. By slightly wiggling each wire with the level turned up (while we were off the air of course :shh: ) with a jewelers screwdriver, I found the offending wire. Talk about a beast to figure out! Luckily, we had a spare headshell and I just swapped the wire and all was happy.
Now, don't ask me which wire it was! (Probably one of the grounds.)
On the other hand, check ALL your grounds first, that's usually an easy thing to do.
Also, your preamp might be acting up. I've heard weird things when they have a loose wire or burned out circuit.
Good luck!
-Bill

[JBStephens]

Any way possible you could upload a sample of the noise? Easier to figure out what's going on if we could hear it.

[Don C]

The contacts in the headshell are a common problem spot. If I remember correctly, the 1229 also has a set of contacts that serve to mute the output when the arm is not over the record. It's another spot that might benefit from some contact cleaner.

[MikeyH]

Dual 1229 with new Ortofon super OM40. Absolutely new Dual motor installed with overhaul.

Problem: needle engages record and a high frequency "ring" at constant level and pitch is heard on silent passages, ends upon needle disengaging record.

sounds almost like a wire is touching the metal platter and is being fedback through cartridge, but upon inspection, nothing seen.....could the idler wheel be inducing this?

any ideas on troubleshooting this problem?

It hasn't really hindered any enjoyment, since it is not heard during the music, and feint at best during silence. but would like to eliminate it.

thanks

Hmm.. I'd bet on the idler being hardened due to age. It might soften with some 'rubber revitalizer' that you can get from electronic stores. The ringing is probably the platter. You might be able to damp the actual platter underneath - a ring of blu-tack around the very rim, away from where the ldler runs.

You can have idlers rebuilt now; NOS ones are VERY expensive.

[Richard the one in Texas]

are there bearings in the idler?

I will do the contact cleaner.....again

blu-tack? explain....is it a caulk-like material?


thanks for the replies :wave:

[dmckean]

are there bearings in the idler?

I will do the contact cleaner.....again

blu-tack? explain....is it a caulk-like material?


thanks for the replies :wave:

It's that stuff they hang posters up with.

http://en.wikipedia.org/wiki/Blu-Tack

[MikeyH]

are there bearings in the idler?

I will do the contact cleaner.....again

blu-tack? explain....is it a caulk-like material?


thanks for the replies :wave:

There is a simple sleeve bearing. I am sort of guessing at the cause; my old Duals seem to run fine but my Garrard 301 does make a 'singing' noise when spinning - but this doesn't come through the speakers. A friend told me it was the idler wheel, and one day I guess I'll spend more than the whole unit cost me to get a new one (at least someone's still making them for that turntable)..

I was just thinking that if it is the platter ringing that damping it may get rid of your problem. The thin, bonded mat on the Duals isn't really very good at doing this.

Another possible cause could be the motor mounting; if any vibration is getting into the main structure it may have the effects you describe. If you're able to post a recording, we'll diagnose further...

[Chad Etchison]

You can also use Moretite or any othr rope chaulk in place of blue tack, it is of higher quality and never dries out.

Here's the stuff:

http://www.goodcommonsense.net/ropca.html

[JBStephens]

Remove the idler wheel, then replace the platter. With the idler wheel gone, put on a record and lower the tonearm onto the record and then turn on the turntable. If you still hear the noise, then the noise from the motor is being transmitted into the turntable chassis. If the noise ceases, then look to the idler wheel. Before messing with damping the platter and things, you might could try a decent turntable mat.

[luckyman]

The contacts in the headshell are a common problem spot. If I remember correctly, the 1229 also has a set of contacts that serve to mute the output when the arm is not over the record. It's another spot that might benefit from some contact cleaner.

Those contacts might need a very slight adjustment. Roof flashing tape
around the rim is available at Home Depot. Great stuff to dampen the platter.

[Richard the one in Texas]

thanks all.....


any recommendations for a good TT mat for these Duals?


Cleaned contacts, same "ring" :(
Checked leads, OK

Now to Home Depot for some damping material

[Rolf Erickson]

The contacts in the headshell are a common problem spot. If I remember correctly, the 1229 also has a set of contacts that serve to mute the output when the arm is not over the record. It's another spot that might benefit from some contact cleaner.

Yes this is correct.. My Duals have "shorting leaf switches" which during automatic play will cut off any signal unless the arm is playing the LP. Nothing will be heard until the stylus is in place to play a record in that case. So you will hear the noise stop when the arm lifts. This may "Mask" a problem in the wiring or elsewhere in the table and make it possibly seem like it's caused by the motor or platter. This is not to say it can't be that, but it may not be also.... Just be aware of this. Good luck.