DLK Model 2 Crossovers

[westermac]

I picked up a pair of DLK model 2 on CL recently (later model with the stainless mid/tweeter panels)... Got them hooked up today, and they rock! A touch "honky" in the 1-2kHz range compared to my Adam A5X's but very well-balanced otherwise and a fun listen.

The only problem I've run into is that the knobs on the rear panel are a little screwy... I cleaned them up with some faderlube but one of the speaker's tweaters is a good deal more sensitive than the other, to the point where the other's tweater has to be turned up all the way to match the first one at 12 O'clock.

The drivers and tweeters are all original, but the serial numbers are separated by a good 7,000, so not sure if that's the factor, or if the crossovers need some attention (recapping, perhaps)?

Thanks in advance for any help!

 

[spark1]

Were you able to spray deoxit directly into the pots, and then work them back and forth 30-40 times?

You can use an ohmeter to verify the pots are working correctly and that they have the same range of resistance.

You might also want to check the DC resistance of both tweeters...it should be close. If widely different, that may be the reason for the output difference.

Once you've verified that the pots and the drivers themselves are working correctly, recapping them certainly won't hurt....though I think your problem is in the pots or the drivers.

Good luck with them.

 

[westermac]

Were you able to spray deoxit directly into the pots, and then work them back and forth 30-40 times?

You can use an ohmeter to verify the pots are working correctly and that they have the same range of resistance.

You might also want to check the DC resistance of both tweeters...it should be close. If widely different, that may be the reason for the output difference.

Once you've verified that the pots and the drivers themselves are working correctly, recapping them certainly won't hurt....though I think your problem is in the pots or the drivers.

Good luck with them.

I did work the pots back and forth a few dozen times, and it cleared up the scratchiness but not the imbalance between tweeters.

I haven't tried measuring the resistance of the pots or tweeters yet, thanks for the suggestion!

 

[westermac]

@spark1 I finally got around to measuring the tweeters, and it looks like there's a mismatch with one measuring 8ohms and the other measuring 6ohms. Based on what I've found I think they're supposed to be 8ohms, so would you recommend buying a single NOS phenolic tweeter to replace the 6ohm one, or should I buy a pair to ensure they are closely matched? I'm not sure what the tolerances of these tweeters were (or how well they maintain performance over time). I see that there are new reproduction units available as well. Thanks!

Side note: I did perform a recap and the tweeter level mismatch persisted.

 

[spark1]

They should be measured at the tweeter terminals. Sounds like you are measuring with the caps in the circuit?

 

[toxcrusadr]

A nominal 8 ohm driver often reads about 6 ohms or even 5.5. Because the rating is based on AC impedance and the measurement is in DC resistance. So the one measuring 6 ohms is more likely correct. The other one would have lower output.

As mentioned above you should measure right across the driver's terminals with no components in between.

When a speaker does this there could be a bad solder joint somewhere. If you're measuring at the tweeter right the terminals, the only place is right where the tinsel leads from the voice coil connect to the lugs on the tweeter. You could reflow those solder joints.

 

[spark1]

@spark1 I finally got around to measuring the tweeters, and it looks like there's a mismatch with one measuring 8ohms and the other measuring 6ohms. Based on what I've found I think they're supposed to be 8ohms, so would you recommend buying a single NOS phenolic tweeter to replace the 6ohm one, or should I buy a pair to ensure they are closely matched? I'm not sure what the tolerances of these tweeters were (or how well they maintain performance over time). I see that there are new reproduction units available as well. Thanks!

Side note: I did perform a recap and the tweeter level mismatch persisted.

After verifying that your readings are correct, and swapping the speakers right to left and left to right to verify no problem with the amp, I would replace both. If the spread is really 2 ohms, the difference in output would be fairly noticeable...but perhaps not as dramatic as seems to be your case. For that reason, you might want to use your ohmeter to assure that both pots show the same resistance range before pulling the trigger on new tweeters.