Noise problems

[Brian Mac V]

Hi all.

I have a brand new laptop with $cuffham's S-Gear in "Standalone", a decent Interface, a new guitar, new hq guitar leads, expensive cabling to monitors. @3ms 96000. All good

If I take the output of the audio interface and plug into my Tascam, then try playing the VST. the hum and noise is really bad. I've tried everything to eliminate it. The only thing in the mains is the Tascam. It's not just the laptop, my PC is the same.

Is it a mismatch in Signal voltage? Suggestions?

Thanks, Brian

 

[-mjk-]

I had to run a grounding wire from the chassis of my USB interface to the computer chassis to eliminate noise.

 

[Brian Mac V]

That sounds like a plan, I'm away from gear at the moment, I'll try it as soon as I get in.

edit, I missed that. From the Interface to the Laptop/PC?

At first I thought you meant from Interface to Tascam. I'll try anyway see what happens.

How did you attach the ground?

 

[Jim D]

Brian, I assume when you say "new hq guitar leads" you mean new high quality guitar pickups? Is it possible that they are not connected correctly to the switch? That would produce hum and noise no matter what you plugged it into. Does your guitar make the same noise through an amp? One thing you could also try is running through a DI box. Maybe an impedance issue? Just a thought.

 

[Brian Mac V]

Thanks Jim, yes the guitar fine, same thing using other guitar. no problem through my amp or into PC, it's only when I connect Interface Out to Tascam. Yes also, to the leads question. Do you mean going DI into Interface? It has Line and Inst switches.

And I'm afraid my Laptop is like 100% polymer, so that's ground leads out too.

 

[Findlay]

i guess you have tried disconnecting the power supply to the laptop and running on battery power? Those power supplies kick out all sorts of noise. If it is of any help I made an earth lead for my DP32sd from the Earth terminal on a Uk mains plug to a jack plug which I connect to the monitor out on the Tascam. I use this to eliminate buzzing on mic and guitar inputs. I only realised the other day what an effect dimmer switches can have on noise!

 

[-mjk-]

That sounds like a plan, I'm away from gear at the moment, I'll try it as soon as I get in.

edit, I missed that. From the Interface to the Laptop/PC?

At first I thought you meant from Interface to Tascam. I'll try anyway see what happens.

How did you attach the ground?

My Tasman DP-32 is connected to the computer with a USB cable, and everything I have is MIDI connected, plus I control my monitor send thru a Behringer Q502 and it's also a USB interface. Lots of opportunity for CPU hash noise. I'm also a professional broadcast engineer, and have spent many years designing and building grounding systems for radio stations and recording studios, as well as being an RFI investigator and troubleshooter. So,

I took one of the mounting screws on the Behringer out because it connects the plastic side to the metal casing and I put a ring terminal with a wire crimped on it, under the head of the screw. Since it is a machine screw into a threaded boss in the chassis, that is a solid electrical connection to the chassis of the Q502. Then I connected the other end of the ground wire to a screw that holds the computer onto the wall mounting bracket (it's an AIO form factor). The moment I touched that grounding wire to the screw connected to the chassis of the computer, the noise dropped by about 60dB.

 

[Jim D]

interface into DI then into DP