Tascam us-144 mkii RCA noise

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MarfSalvador

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Hi guys - my first thread on here after weeks of lurking in the backgrounds!

I bought a Tascam us-144 mkii; installed fine.

However, I've noticed that through my monitor speakers there is alot of noise....static interferance type noise (which gets worse after opening Cubase). The Tascam is connected to my amp via RCA cables.

The noise is not noticeable in headphones via the headphone out on the Tascam.

I tried some alternative speakers, hooked straight through a hi-fi with RCAs and the noise is still there.

When I did a test and switched back to my Audiophile 192 on board card - connected via jack cables to the amp>speakers, there is no noise whatsoever.

I've tried a few solutions I've seen on the net/forums....like using the same / different wall sockets; using drivers for different windows platforms; disabling virus / wireless etc etc but to no avail.

I'm running Windows 7 64bit with 4gb ram and a duo core 2.5gb processor.

The noise is there no matter what level I set the latency buffer to in the Tascam control panel.

I'm really new to all the techno stuff so any help or advice would be greatly appreciated!
 
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Well, I tried the interface with a laptop - and cut the mains power, so ran from the battery.

Magic - all bad noise disappeared!

So, how to resolve with my main PC. Well, I tried running the amp on a different circuit by using a 50+ foot extension cable. No bad noise...

So then I brought said extension cable back into my music room - plugged same wall outlet as all other devices. No bad noise...

I rang my pa-in-law (retired electrician) who said the long extension lead could be dissipating the noise along itself (as its soooo long)...but also suggested a filter / conditioner socket / extension so I don't have to use this maaasssssive 50ft lead.
 
Turns out, that extension didn't have an earth.

So my next stop was a DI box.

The US144mkii has unbalanced RCA outs. So I had to get jack adapters to go into the DI box, then balanced cables to come out of the DI. The noise has reduced considerably, even more with the ground lift switch in on the DI.

It's definitely workable now - the problem was with mixing - far too much noise to concentrate.

So, a couple of weeks after purchase, I finally have a workaround for the US144mkii.

I hope these small bits of info come in useful for anyone googling about such problems!
 
One of these will fix the problem completely. Put between the laptop and the monitors. You have a ground loot via the computer cable connecting the US144 to the computer, happens all the time.

Alan.
 
One of these will fix the problem completely. Put between the laptop and the monitors. You have a ground loot via the computer cable connecting the US144 to the computer, happens all the time.

Alan.

Thanks for the reply Alan!
Is it something that will be detrimental to the sound quality?

I've read people suggesting using ground loop isolators like these - Xitel Ground Loop Isolator: Amazon.co.uk: Electronics - but that they remove the frequency range that the hum is in.
 
Thanks for the reply Alan!
Is it something that will be detrimental to the sound quality?

I've read people suggesting using ground loop isolators like these - Xitel Ground Loop Isolator: Amazon.co.uk: Electronics - but that they remove the frequency range that the hum is in.

Not at all, they are isolation transformers, not filters, the transformers lift the earth completly (and the + and - connections) and also can balance an unbalanced signal. No change to signal quality.

I also use them when doing a live recording at gigs to isolate ground loops from the PA system.
Cheers
Alan
 
That's great, thanks a lot for the info
Think I'll head over and grab myself one of those :)
 
So I recorded some demos for somebody yesterday and I can get a really good signal on the guitar tracks - using a pair of MXL 603s mics.

However, when I record vocals, using a Rode NT1-A, the signal is quite weak in comparison.

Am I right in thinking that I need a pre-amp when recording vocals to get by this? I know the Tascam has pre-amps, but perhaps they just aren't that great / or powerful enough for the Rode NT1-A.

Or, is it that the phantom power on the Tascam doesn't have enough beef to power the mic.

The sound I get with the Rode NT1-A is pretty good...it's just really quiet!
 
It's not unusual for different mics to have different volume levels, The mics could have a different impedance, the NT1A has 100Ω impedance, the MXL603 has 200Ω impedance, so the position of the gain will be different.

The main thing is that as long as the actual pre-amp is quite enough at the higher gain there is no problem. The self noise of the NT1A is very low.

Cheers
Alan.
 
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