Pin One Problem on DL1608

[nottooloud]

No different than the hundreds of million Laptops and LCD panels currently using these supplies.

Those don't have FUBAR grounding systems like the DL1608 .

On the contrary. A very large number of laptops with three wire supplies produce exactly the same kind of noise when their headphone output is hooked up to a sound system. Ground lifting them beats it, or selecting an alternate supply with only two wires.

[RoadRanger]

+1 - I've experienced that also.

[WK154]

No different than the hundreds of million Laptops and LCD panels currently using these supplies.

Those don't have FUBAR grounding systems like the DL1608 .

On the contrary. A very large number of laptops with three wire supplies produce exactly the same kind of noise when their headphone output is hooked up to a sound system. Ground lifting them beats it, or selecting an alternate supply with only two wires.

You know this how?
Not sure what that has to do with CE certification. A little out of context. But while were on the laptop subject I have yet to have a problem with one that is also connected to AC. For the most part I deal with Toshiba's, nor have I had a desktop pose this problem. TV's and DVD players have. It all depends on the equipment. Mackie hasn't cornered the market on poor engineering. Knowing Mackie they probably also did self certification on the CE mark. I have a DL that is non-conforming to the FCC consent degree as do most of you. As of late Dec. 2012 all units should have FCC certs. If you return the DL for repair they have to mark it FCC cert.. Yes a label! That and other violations netted Mackie a "Donation" of $85,000.00 to the gov.. Part of the gov. economic recovery program I'm sure.

[nottooloud]

I must have built my hummer wrong somehow. I got nothing, which really surprised me.

Now for one of the solutions. The first is a three prong AC connector but no pass thru safety ground. The  Model #1206 LCD AC supply no manufacturer given by Amazon. The measurement without the chassis ground are 5.1mV @ 187uA which drops to <= 0.1mV @ 1.4 - 1.5uA with the chassis ground connection. No safety ground noise dumped onto the DC return line and yes no hummer noise. Pin one problem gone.

Solution two a two prong plug model ST-C-075-12000600CT from e-bay adaptermonsters again no manufacturer name. The non chassis ground values are 7.1mV @ 195uA that gets reduced to <0.1mV @ 1.9 - 2.0uA with the chassis ground. Again no hum and no noise with and without the hummer. Reversing the AC plug has no effect. Great for mis-wired AC outlets.

The Amazon supply that comes up now searching "1206 LCD AC supply" is 14v 3A.
ebay seller  Adaptermonsters doesn't list a ST-C-075-12000600CT at the moment, but the sellers that do call it 18V 3.5A.
The Mackie supply I have is 12V 4.2A.
What are the specs on the supplies you're testing?

[RoadRanger]

http://transition.fcc.gov/Daily_Releases/Daily_Business/2012/db1213/DA-12-2009A1.doc

[WK154]

Re-read the post! The 3 prong supply is a 12V 6amp and there are plenty out there. I will repeat again it's pot luck. The model# are off the actual units but are never advertised as such. The 2 prong is a 5amp unit. RR should have his 3amp by now. waiting to hear from him.

[nottooloud]

On the contrary. A very large number of laptops with three wire supplies produce exactly the same kind of noise when their headphone output is hooked up to a sound system. Ground lifting them beats it, or selecting an alternate supply with only two wires.

You know this how?

My own experience. HP, for instance, used to sell both 2 wire and 3 wire supplies for Thinkpads. The 3 wire supplies frequently gave me buzz issues. The 2 wire supplies never do. Compaq, Dell, Motion, I've seen this a lot of times. It's not a concern for the manufacturers, because pro audio is not their normal application. Mackie, however, should obviously have known better.

[nottooloud]

Re-read the post! The 3 prong supply is a 12V 6amp and there are plenty out there. I will repeat again it's pot luck. The model# are off the actual units but are never advertised as such. The 2 prong is a 5amp unit. RR should have his 3amp by now. waiting to hear from him.

I guess I'm asking the wrong question. Searching on the model information you've given us is only finding me inappropriate supplies. What searches are you using to find appropriate ones?

[WK154]

Google 12V 6A Amazon

[nottooloud]

thnx

[WK154]

http://www.ebay.com/itm/NEW-12-Volt-DC-Power-Supply-5-Amp-5A-12V-Adapter-LCD-CB-/280869637201?pt=Laptop_Adapters_Chargers&hash=item4165228c51
AdapterMonster supply

[nottooloud]

Bought that one. 2 wire AC cable. Mackie's digital hash is gone. On the other hand, this supply makes it's own noise, and radiates like crazy. Very position sensitive. Noise goes up when I touch it and become an antennae. Still a dramatic improvement.

[WK154]

Did you run the chassis ground to safety? Without it you missed the boat.

[nottooloud]

Did you run the chassis ground to safety? Without it you missed the boat.

Tried the screws next to the ethernet jack, and tried the ground nut of the 1/4". Noise increased slightly. Granted, this was a worst case hookup, 1/4" ts to an unbalanced input high gain device, cranked up. At normal operating levels, the noise is easily acceptable with the adaptermonster supply. Reviews of these supplies on Amazon by people using them for their intended purpose, powering LCD monitors, do talk about noise in the image frequently, though. It doesn't suffer from Mackie's ground issue, but it's certainly not a quality piece of kit. Still and all, I'll use it. I'll also carry the Mackie supply.

Thanks for finding this.

[WK154]

You definitely don't want to use the 1/4 nut and the screws by the power/net plugs may miss the chassis shield that's why I used spade lugs to squeeze between the plastic case and the chassis for a good connection.