plantingclaymore
Joined: 28/06/11
Posts: 7
|
Strange interference from mac usb ports...?
#976523 - 18/03/12 11:15 AM
|
|
|
|
Hello, I've got an old macbook I use as a DAW. I use it with a UA-25EX soundcard. I
knicked a nice Quad amp off my dad so running it all through that. The problem is when I
try and plug extra usb things like keyboard and mouse through a USB Hub I get this ticking
interference through the speakers. Very annoying, any ideas? Do you think a different
hub would be the answer or would it be the same prob with any?
Cheers
|
Tartaruga
Joined: 04/09/10
Posts: 195
|
Re: Strange interference from mac usb ports...?
[Re: plantingclaymore]
#976524 - 18/03/12 11:21 AM
|
|
|
|
Hi
I did have this problem too,but only on the USB port near the power supply
plug,not on the other USB/FW ports.And I use no Hub.Try changing it from USB port,hope it
helps.Fo me,it did…
Cheers!
|
ef37a
Joined: 29/05/06
Posts: 5669
Loc: northampton uk
|
Re: Strange interference from mac usb ports...?
[Re: plantingclaymore]
#976533 - 18/03/12 12:41 PM
|
|
|
|
Hi,
You have the classic earth loop laptop problem I am pretty sure (I know macs are
made under the Pope and are infallable but they can't beat the laws of electricity can
they?).
Do you get the problem with the macbook on battery and the charger
unplugged?
Quad what? The full rig or just the power amp? If just PA is it DIN
in or RCA? If the former it might just be very simply a matter of snipping the earth off
the DIN, pin 2, one end.
Dave.
|
Scope
Joined: 03/07/06
Posts: 2160
|
Re: Strange interference from mac usb ports...?
[Re: ef37a]
#976537 - 18/03/12 01:05 PM
|
|
|
|
Just to clarify, thats the AUDIO earth, not the MAINS earth ( ! )
( We don't
want any accidents )
|
Exalted Wombat
Joined: 06/02/10
Posts: 4323
|
Re: Strange interference from mac usb ports...?
[Re: ef37a]
#976538 - 18/03/12 01:10 PM
|
|
|
Quote ef37a:
Hi,
You have
the classic earth loop laptop problem I am pretty sure (I know macs are made under the
Pope and are infallable but they can't beat the laws of electricity can they?).
Difficult to see how plugging in
a self-contained device such as keyboard or mouse could create an earth loop?
First off, I'd try swapping the Quad amp for something else. They were great units, but
not designed in an era when it was assumed audio gear would be sitting next to a computer.
|
ef37a
Joined: 29/05/06
Posts: 5669
Loc: northampton uk
|
Re: Strange interference from mac usb ports...?
[Re: Scope]
#976539 - 18/03/12 01:10 PM
|
|
|
Quote Scope:
Just to clarify,
thats the AUDIO earth, not the MAINS earth ( ! )
( We don't want any accidents
)
A timely warning never
hurts Scope but I DID say " DIN/ RCA" and "pin 2"
Hard to read "thirteen amp
plugtop" into that?
Dave.
|
ef37a
Joined: 29/05/06
Posts: 5669
Loc: northampton uk
|
Re: Strange interference from mac usb ports...?
[Re: Exalted Wombat]
#976552 - 18/03/12 01:50 PM
|
|
|
|
E.W.
The earth loop (if that is what it is, nobody really knows jack at this
stage!)is formed by the earthed laptop via its charger and the earthed Quad amp.
That the setup does not make a noise until some data is shunted about is classic!
Quad kit has always been very well RF proofed and P.Walker stood firmly to the
principle of designing audio gear for people not bats and cats even tho' he was out of
favour with the great beardy tweaks who castigated his kit at the time, now the
"cogniscenti" pay silly money for it!
Dave.
|
buggymusic
member
Joined: 30/09/02
Posts: 236
|
Re: Strange interference from mac usb ports...?
[Re: ef37a]
#976737 - 19/03/12 11:14 AM
|
|
|
|
I had the same issue (and gave up)
MacBook Pro -> Mbox2 -> QUAD power
amp
One suggestion was to put something between the o/p of the soundcard and
the input of the QUAD such as a stereo DI box with earth lift?
I've not tried
it myself although should work in principle and not impact the sound quality too much
I don't get the issue with my NAD amp
|
ef37a
Joined: 29/05/06
Posts: 5669
Loc: northampton uk
|
Re: Strange interference from mac usb ports...?
[Re: buggymusic]
#976751 - 19/03/12 11:54 AM
|
|
|
Quote buggymusic:
I had the same
issue (and gave up)
MacBook Pro -> Mbox2 -> QUAD power amp
One
suggestion was to put something between the o/p of the soundcard and the input of the QUAD
such as a stereo DI box with earth lift?
I've not tried it myself although
should work in principle and not impact the sound quality too much
I don't get
the issue with my NAD amp
A
good deal of later hi fi amps and other kit is class 2 insulation, i.e. no earth and a two
core mains lead. The NAD could be one such.
Dave.
|
Previous
Topics
Next
Threaded
Edit
Reply
Quote
