Annoying buzzzzzzz

[needledrop]

When I send the outputs of my Teac 80-8 tape machine to my digital interface, i'm getting a buzz mixed in with the audio signal. Now, I know the 80-8 is unbalanced and doesnt buzz when i listen to it through my analog mixer, and I know the interface doesnt buzz when I record my guitar straight into my computer, but im not sure if it's unbalanced or balanced, but it does have rca analog inputs (emi 6/2).
When i run my 2 channel Ebtech Hum Eliminator between the tape player and the interface the hum goes away??? Do I have any other option but to drop $200 on an 8 channel Ebtech?

thanks

 

[Beck]

RCA jacks are unbalanced.

Maybe ground loop issues, or you have power and audio cabling running too close together… they should be separated. They can cross each other but shouldn’t run in parallel for any length. Same with the USB cable.

Your PC and 80-8 should all be running from the same outlet via a power strip. But often residential AC outlets are miswired so the hot and neutral wires are reversed. So first thing to do is make sure you AC is in order.

Get one of these (see pic) from Radio Shack, Lowes, Home Depot, etc, and check your outlets.

Even with the AC in order you might have to lift the ground on one of the devices (I can't remember if the 80-8 has a 3-prong plug grounded plug or not).

Are you using the EMI with a laptop? If so does it buzz when running laptop on battery? That’s another way to test for ground issues.

One thing you’ve got working against you is that little EMI 6/2 is all plastic, so it’s susceptible to all kinds of interference.

 

[needledrop]

Thanks for the reply Beck.
Yeah, I figured rca's were unbalanced. I dont see any cables crossing with the computer, but the tape machine goes into a patchbay in a rack that has a furman conditioner on top, so there are power cables near it. Its gonna take some work to change that....spaghetti! Everything is on the same powerstrip actually 3 chained together and no its not a laptop.

As far as the AC. if it was wired wrong wouldn't the units buzz on there own (when functioning) as well as when they are interconnected?

 

[Beck]

Yeah, you want to keep audio cables away from things like transformers and switching power supplies. Winning the war on hum takes some planning and rearranging if needed as the studio grows.

Whether a device hums/buzzes or not depends on how the manufacturer dealt with grounding. A lot of equipment has separate signal and earth grounds, and some older equipment has no chassis ground at all. But if it does and your house wiring is wrong the wire that’s grounded to the chassis won’t be connected to the grounding block at the fuse box because it’s on the wrong side (white wire is where black wire should be on the outlet). Tracking down ground loops and other hum producing sources can have you pulling you're hair out.

When I was younger I had a house or two with bad wiring. The first thing I would do (unbeknownst to the landlord) was rewire everything in the room for my studio. Now, in my house I ran a separate ground with 8-gage wire through my attic to the grounding block in the breaker box. I also pounded a second 8-ft grounding rod into the ground right outside the service box and connected it to the block. The AC to my studio room is isolated from everything else in the house and has the best ground... probably the best ground in town.

 

[needledrop]

Ahhh ok.
Yeah, Ive been trying to track this down for awhile now, can even tell you how many hours ive spent with headphones all the way up connecting and unconnecting.......

Thats pretty impressive what you've done for your studio, wish i could do the same but it would be difficult being on the 6th floor and all!!!!!

Im going to try a few things over the weekend...thanks again

 

[dgatwood]

When I send the outputs of my Teac 80-8 tape machine to my digital interface, i'm getting a buzz mixed in with the audio signal. Now, I know the 80-8 is unbalanced and doesnt buzz when i listen to it through my analog mixer, and I know the interface doesnt buzz when I record my guitar straight into my computer, but im not sure if it's unbalanced or balanced, but it does have rca analog inputs (emi 6/2).
When i run my 2 channel Ebtech Hum Eliminator between the tape player and the interface the hum goes away??? Do I have any other option but to drop $200 on an 8 channel Ebtech?

Do you have any devices in the chain with two-prong plugs? If so, try a grounding pigtail.

https://homerecording.com/bbs/showthread.php?t=207689&highlight=grounding+pigtail

 

[SteveM]

I've been struggling with a hum problem myself. My solution was to take the headphones off. It really works!

 

[The Ghost of FM]

Thanks for the reply Beck.
Yeah, I figured rca's were unbalanced. I dont see any cables crossing with the computer, but the tape machine goes into a patchbay in a rack that has a furman conditioner on top, so there are power cables near it. Its gonna take some work to change that....spaghetti! Everything is on the same powerstrip actually 3 chained together and no its not a laptop.

As far as the AC. if it was wired wrong wouldn't the units buzz on there own (when functioning) as well as when they are interconnected?

So you're saying the computer and the deck are on the same power bar or bars?

If so, put the computer on the closest outlet on the first bar and the deck's ac plug right next to it. I mention this because 3 power bars all connected together could still provide an 18 foot wire distance within that arrangement in a worse case scenario, which might easilly be long enough to cause the ground loop hum.

In my set up, I put my mixers on the first outlets of the bar and the recorders right next to those.

Cheers!