Denon DP 59l buzz.

[Pacoloco]

My trusty Denon dp59l turntable has developed a sudden very noticeable Buzz from both channels. Wiggling the RCA connections on the back of the preamp does nothing to affect the buzz and it is equal in both channels. Each lead from the turntable cable carries the noise even if the other is unplugged . The buzz is present whether the turntable is powered on or not. However, powering on the turntable increases the volume and intensity of the noise. The noise increases with volume increase of the preamplifier. I have tried several preamps and receivers and two different sets of speakers to rule out those components. Disconnecting and reconnecting the ground wire makes no difference.
any suggestions?

 

[Tonoje]

Have you ruled out everything at the cartridge end?

A multimeter would make it easier to check your cables and connections. Too affordable not to own, and too useful not to use.

 

[Pacoloco]

Have you ruled out everything at the cartridge end?

A multimeter would make it easier to check your cables and connections. Too affordable not to own, and too useful not to use.

I think I will swap out cartridges tomorrow. Keep my fingers crossed. It's a nice old cartridge, but I would much rather have it be that than something electronic in the turntable.

 

[Pacoloco]

I think I will swap out cartridges tomorrow. Keep my fingers crossed. It's a nice old cartridge, but I would much rather have it be that than something electronic in the turntable.

Well hallelujah, it turns out it was just a broken wire inside of the ground lead of the turntable interconnect. It looked okay but a wire had broken inside right at the connection to the little Spade. Enough wiggling and it made contact and killed the buzz. I snipped off the Spade and exposed some bare wire and reconnected it. Problem solved. Oh by the way, I did check connectivity from the four colored cartridge leads through to the positive and negative of the L and R interconnect RCA's, and it was all good. So it's a good thing I wiggled the ground lead enough!

 

[Tonoje]

Oh by the way, I did check connectivity from the four colored cartridge leads through to the positive and negative of the L and R interconnect RCA

Glad to hear you found the source of the problem.

From this end, people will only know you've done what you say you've done, so if it's not mentioned in the first post, it may get suggested to you.

If you have the means to check connectivity (which I assume means you have a meter), you have the means to check the ground wire connectivity: that, I think (without being able to visualize exactly your turntable model) allows a more thorough check than what you first mentioned, which is connecting and disconnecting the ground wire. In effect, your ground was disconnected (because of the fault), whether you connected the wire or not. Your test showed no change, which sends you looking elsewhere - where you're not going to find it. A meter test would have no shown no ground connectivity, which indicates there's something amiss with the wire or its connection to the TT chassis. A nice, fast way to isolate the problem.

 

[Pacoloco]

Glad to hear you found the source of the problem.

From this end, people will only know you've done what you say you've done, so if it's not mentioned in the first post, it may get suggested to you.

If you have the means to check connectivity (which I assume means you have a meter), you have the means to check the ground wire connectivity: that, I think (without being able to visualize exactly your turntable model) allows a more thorough check than what you first mentioned, which is connecting and disconnecting the ground wire. In effect, your ground was disconnected (because of the fault), whether you connected the wire or not. Your test showed no change, which sends you looking elsewhere - where you're not going to find it. A meter test would have no shown no ground connectivity, which indicates there's something amiss with the wire or its connection to the TT chassis. A nice, fast way to isolate the problem.

 

[Pacoloco]

Ok, I get it, So how do you prove a ground wire is working with a multimeter?

 

[Tonoje]

Set to continuity mode, assuming it has one, which it generally will, and stick a probe at each end of the wire. That'll tell you if the wire has continuity. With a working wire/ ground connection, if you do this from, say, a screw in your turntable chassis where the wire is grounded, to the spade lug at the other end, you can show that you have ground from that screw to the lug. With your broken wire, your meter would show a continuity problem, though by the time you place the probe at that end of the wire, you may also have seen that the wire looked damaged where the lug is crimped on.

As I said, I can't visualize your (or every turntable), and it may require removal of the base to access the ground point for the wire. Even then, it may be faster to check that way than spend hours looking somewhere else after incorrectly concluding that the ground wire is sound. Your problem was probably visible, as it happens, but the advantage of checking with the meter is that it will also pick up those that aren't - internal breakage in a connector etc. I have RCA cables like that.

Edited: (connectivity -> continuity).

 

[Pacoloco]

Set to continuity mode, assuming it has one, which it generally will, and stick a probe at each end of the wire. That'll tell you if the wire has continuity. With a working wire/ ground connection, if you do this from, say, a screw in your turntable chassis where the wire is grounded, to the spade lug at the other end, you can show that you have ground from that screw to the lug. With your broken wire, your meter would show a continuity problem, though by the time you place the probe at that end of the wire, you may also have seen that the wire looked damaged where the lug is crimped on.

As I said, I can't visualize your (or every turntable), and it may require removal of the base to access the ground point for the wire. Even then, it may be faster to check that way than spend hours looking somewhere else after incorrectly concluding that the ground wire is sound. Your problem was probably visible, as it happens, but the advantage of checking with the meter is that it will also pick up those that aren't - internal breakage in a connector etc. I have RCA cables like that.

Edited: (connectivity -> continuity).

Ok, thanks.

 

[Tonoje]

Out of curiosity, I had a look at a photo of the underside of your Denon model. The tonearm wires connect to a circuit board, and the ground wire and phono cable also connect to the board. There's a shield plate covering the board. If you wanted to check continuity for the ground wire, you'd presumably remove the shield plate (1 screw) to access the ground wire connection point, or you could probably just leave the shield in place and measure from the screw (or the plate itself). But if you'd read no continuity, you'd still have needed to take the shield off to check more closely.

 

[Pacoloco]

Out of curiosity, I had a look at a photo of the underside of your Denon model. The tonearm wires connect to a circuit board, and the ground wire and phono cable also connect to the board. There's a shield plate covering the board. If you wanted to check continuity for the ground wire, you'd presumably remove the shield plate (1 screw) to access the ground wire connection point, or you could probably just leave the shield in place and measure from the screw (or the plate itself). But if you'd read no continuity, you'd still have needed to take the shield off to check more closely.

Could I just measure continuity from the ground lead to one of the ground shells on the interconnect cable RCA terminals? Presumably they have a common ground.

 

[Tonoje]

Sounds possible to me (I'm slightly reaching the limit of the little I do know), but there may be drawbacks in terms of narrowing things down to a problem in the ground wire or a problem in the phono cable. Though if you have the meter out anyway, you can do the check and just narrow things down as needed, depending on whether you read a fault or not.

 

[Pacoloco]

I tried the trick of testing connectivity between the ground lead and the ground shell of the RCA cable (which was suggested to me by a friend,) and it does NOT work.

 

[Tonoje]

Good to know. Well, no harm in the conventional method: connector to connector of the actual wire you want to check. I think the ground wire problem you had must be rather common, too, as I've seen a lot where the external lug and the wire at the point where it's attached to it are in poor shape. Its usually thin wire and that location subjected is to a lot of yanking and bending over the years.