Phonoland

Hi everybody--

Just got a fantastic Dual in reasonable shape, works pretty well, and the little rubber jiggies in the spindle are even intact. I had to reconnect one of the tiny hairthin cartridge wires, as it broke loose from the solder. Got a new cartridge and plugged it in, but I've got slightly-bad sound. Its one of those instances where the background is clear, but the foreground is muddy and not so clear, and a little 'echo-y'. This seems like it should be a simple fix. If anybody has any ideas, I'd surely appreciate it.

Thanks
Duane

Check on two things:

1. Is the stylus force correct?

At least on that Dual, the force is easy to set, as long as someone hasn't messed up the spring.

- Turn the stylus force control on the arm to 0.
- Adjust the counterweight so the arm is perfectly balanced with the cartridge installed.
- Turn the stylus force dial to9 the correct force for the cartridge (in gram-equivalent force).
- Set the antiskating dial to the same value on the scale for the stylus you have.
- Double check the force with a stylus force gage.

2. Check for acoustic feedback. If the speakers are shaking the pickup, you will get those symptoms.

The only fix for this is to isolate the pickup from the speakers. Don't put the speakers on the same shelf unit the turntable is on. Put a soft pad under the turntable base.

Hey Record Changer, as always, thanks for the good info. I have balanced the arm, The bad sound issue seems to have cleared up. Now the main issue is the background sounding clear, the 'foreground' (ie Loretta Lynn) is a little distant.

Okay, I've made some further observations. STEREO records don't sound distorted, but as though the vocals are in the background. But MONO records, especially 45s, sound distorted. Why would that be? I also notice, even after balancing the arm and setting the anti-skate, the arm wants to slide back towards the rest. Even with the anti-skate at zero it does this.

It is quite likely that either the speakers are out of phase, or one channel on the cartridge is wired backwards.

Use the mono switch on the amplifier to find out which. (If the amp has no mono switch, use a Y cables to connect both turntable outputs to one preamp input.) If the centered main vocalist on a stereo record disappears with the mono switch on, or if all sound on a mono record but quiet distortion disappears, one channel on the pickup is wired backward. If the sound is permanently disoriented with the mono switch on (it sounds like it is stuck to the back of your head), no matter what record is played, one speaker is wired backward.

If the cartridge is wired wrong, check the connections. The pickup wiring is as follows:

White: Left hot
Blue or Black: Left ground
Red: Right hot
Green: Right ground and headshell ground

I got this off an actual Dual headshell I have in my hand as I type.

If you have a Shure cartridge, the correct order of wires, top to bottom is:

Left hot
Right hot
Left ground
Right ground

If the speakers are wired wrong, check the wires. There should be a marking that tells which wire is the ground wire - a color stripe, silver tinning, or a molded ridge. Connect the marked lead to the - terminals on both ends. But I was upset several weeks ago, because the wire I bought had no markings at all. I had to use an ohmmeter and mark the ends. #&$%#*&!

Also note that mono records made before stereo was introduced DO sound awful when played on a stereo player. There was no quality control over what the groove sounded like when played with a cartridge sensitive to vertical motion. Before stereo, it was not necessary to check that. That's why stereo amplifiers have mono switches

One other thing to check in the indistinct sound area:

When you play a record, is the tonearm constantly bobbing up and down, causing the stylus assembly to flex? (I don't mean the motion caused by a warped record.) If so you have an arm resonance problem. This usually means the arm and the cartridge are mismatched. I never had this problem with any Dual, but it might be that you have a pickup that doesn't like the mass of that tonearm.

If the arm is trying to move while you are balancing it, check the following:

1. Is the turntable level?

2. Are the pickup leads trying to move the arm? If so, they might be caught on something, or the insulation might be hardening.

3. The antiskate on that unit doesn't ever fully turn off. You might be seeing the residual force when the arm is not on a record. It means the bearings are in excellent shape.

4. The arm tries to pull away from the spindle right at the rest post because it is activating the power switch there. But it should not do this when over a record.