ID Series - Noise in Emulated Output

[myk.robinson]

UPDATE Tonight,i tried a DI box with ground lift, a balanced cable,a 1/4" to XLR, and various combinations of all three, with no luck. The one thing that did work, is the infamous cheater plug.

Question is, why did this work, and what is the danger of running it minus the ground pin?

[cadblaster]

The cheater plug worked because you do indeed have a ground loop.
Next step is to plug/unplug each individual powered item one at a time with/without the cheater until you have located the culprit.
Don't forget to check your wall outlet too, and make sure neutral and hot are not reversed. Polarized plug/outlet= Narrow slot Hot, Wide slot neutral. (U.S)
These are cheap/easy for testing if your not comfortable with using meters (I keep one in the gig bag)
http://www.lowes.com/pd_292761-12704-61 ... facetInfo=

[myk.robinson]

I have a circuit tester. Bought one last week when I started trying to figure this out. My circuit is fine at home.

More food for thought... As I look at my things hooked up, the laptop adapter has a three prong adapter. The problem persists even with the laptop running on battery and not plugged in. I assume I can eliminate the laptop as being the cause. I can't run the amp without power so I can't do much to test it past knowing that it works fine running a cable with a three to two prong adapter. My audio interface is an Akai Pro EIE, and it's adapter has a transformer block built into the plug, and it is just a two prong polarized plug. My monitors are also a two prong adapter polarized plug, however the power source is built into the monitors, there is no transformer on the plug.

I can't control the power situation in other places, but when I get home today, I will disconnect my monitors and run headphones from the audio interface, and also unplug the laptop and run on battery power, with the Blackstar amp(s) using the proper three prong plug to see if I can isolate the issue to possibly being the audio interface's lack of a proper ground. The chassis of the EIE is metal, which probably doesn't help.... Something else I can try if that fails is to try using the Samson Studio GT by itself without the Akai Pro EIE. The Samson Studio GT can be used as an audio interface as well, it has two inputs on the front. This should help identify what in my chain is the problem...

But for live use in other locations, is there a reasonably affordable product you can recommend? I looked into the EBtech Hum Eliminator. Mind you, I am not an electrician... But with my limited research, it seems that the way this device works is potentially unsafe for equipment and has a high likelihood of damaging products by failing before a breaker would trip...

Your thoughts?

I know I'm thinking out loud here, but its worth a shot.

[myk.robinson]

Me again... I'll need to verify, but plugs may not be polarized. I'll verify when I get home. If not, I'll try one at a time and flip the plug to see if anything changes.

[cadblaster]

It's really not about transformers so much,,, it's about shared common grounds.
Keeping each ground separate is the key for noisy equipment. I.E. Plugging several AC items into the same surge protector can be a problem.
Check your outlet, as it's very common for the 2 wires to be reversed and not polarized.

Keep in mind tripping circuit breakers (wall panel) is really about protecting "You".
If you get have a dead short to the point that it trips the main power circuit,, you've probably already cooked your amp/laptop. That's why you normally use surge protectors or internal fuses/breakers to protect your equipment as they trip faster.

[myk.robinson]

@cadblaster, I used a circuit tester and found my outlets to be fine.

Will flipping non-polarized plugs make a difference? Will using different power strips and/or a battery backup make a difference?

[myk.robinson]

UPDATE: I have confirmed that the Akai is a non-poloarized plug and can be connected to an outlet either way you choose. However, digging a bit deeper yields some interesting results that may show that my issue is not quite as bad as it seems...

I think I may have found the culprit, looking for a second opinion. Yesterday, I tried the amp with the proper ground pin in place and ran it straight to the Samson Studio GT input, with the Akai Pro EIE totally out of the loop. Silence I connected to the Akai Pro EIE with it hooked into the Samson Studio GT to use as monitors (normal setup) and I get the noise. I disconnected the cables between the Akai and the Samson and hooked up headphones only, and it was silent as well.

So, at least at home, I think my problem may be the cables between the Akai and the monitors. The Samson Studio GT is an audio interface itself, but I have been using them as monitors only. The speakers have RCA jacks on the back, so I use a converter plug from the Akai to convert two 1/3" leads to RCA leads. I think I just need to get standalone monitors and use shielded speaker cables. Just guessing though..

Does this make sense?

[AscottAudio]

I was one of the first ID owners. I pretty much straight away noticed a digital clicking sound coming from the EO. It is pretty low level but enough be annoy anyone with good ears that wants a pristine recording.

I not only brought his to the attention of Jamie from Blackstar but also sent him recordings of the noise..his reply was that he said he could hear nothing..which I found very odd.

I love my blackstar amps .. but being digital the ID is bound to have "issues". ..the initial firmware upgrade was a "stress fest" and this low level noise spoils what is a very very good amp..

I still use the ID to record as with the noise being low level it is not noticeable while playing or in the mix but.. it would be nicer without it.


Cheers.


PS The cheater plug did nothing to get rid of my noise.

[myk.robinson]

AscottAudio, when I record directly to my Samson S StudioGT, I get no noise. But I can duplicate the problem of several other interfaces and mixing consoles so I have no clue where the root of the problem is. Just hope it can be addressed through firmware update