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USB Interface Tweak.

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USB Interface Tweak.

Postby Matt_A » Thu Jun 12, 2014 3:27 pm

Hi,
I've been reading SOS for a number of years and always find the forums a great source of useful information. Now it's my turn to repay the favour and let you know about a little device I came across recently.
I've been using an apogee Duet2 (SOS recommended!) along with my iMac for recording guitar and synths for some time with great results. I've often been a little worried about the reliability and performance of the USB connection from the interface to the mac. I came across this little device, the iUSB IPurifier.

http://ifi-audio.com/products/accessory/

Its a small pluggable device which sits inline along the USB cable and claims to improve the quality of data transfer. I've been using the IPurifier now for a number of weeks with good results. With the IPurifier inline there is always a consistent noticeable improvement in instrument seperation and top end. I guess its effects with other audio interfaces may be similar. Well worth a try!
Matthew
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Re: USB Interface Tweak.

Postby desmond » Thu Jun 12, 2014 3:32 pm

I'm sure I had some popcorn around here somewhere...?

With the IPurifier inline there is always a consistent noticeable improvement in instrument seperation and top end


Great! Record the same repeatable piece of audio, with and without the device, and do a null test. I would be interested to see the facts on the data...
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Re: USB Interface Tweak.

Postby The Elf » Thu Jun 12, 2014 3:34 pm

USB carries digital data. There is no way to 'improve' it.

Snake oil and twaddle.

Sorry!
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Re: USB Interface Tweak.

Postby Matt_A » Thu Jun 12, 2014 3:45 pm

I was also very sceptical being a DSP software engineer in digital electronics.
Its a cheap little device so I just thought I would give it a try. iFi audio say you can get a refund if not happy so no problem there.
Its not a massive difference but it is there.
It seems to have a larger effect on playback than recording.
Im assuming most of the effect is the Duet get a cleaner power source during recording/playback for its preamps as its powered from the mac across USB.
Try it and see what you think.
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Re: USB Interface Tweak.

Postby mooblie » Thu Jun 12, 2014 4:18 pm

Hmmm. I always thought this forum was remarkably free from snake oil merchants/fans. :frown:
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Re: USB Interface Tweak.

Postby DGL. » Thu Jun 12, 2014 4:25 pm

Harmonics in a digital system DO NOT MATTER! well so long as they aren't bad enough to misrepresent 0's as 1's and visa-versa.
On a baseband digital system all the computer is looking for is a plus voltage and a negative or 0 voltage. The fact that it may not be a perfect square wave has no effect on what is received.

i.e. if a 1 is understood to be between 3-6 volts with a nominal voltage of 5 then if the harmonics on that +5v signal make it slightly under/over +5v then it will still be detected as a perfect 1.
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Re: USB Interface Tweak.

Postby BJG145 » Thu Jun 12, 2014 6:26 pm

*throws rotten fruit and veg*
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Re: USB Interface Tweak.

Postby tim_obrien » Thu Jun 12, 2014 6:41 pm

10101010101010101010101

Please point out the 'electromagnetic incompatibility' there....

usb doesn't pass audio, just 1's and 0's.

Snake oil....
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Re: USB Interface Tweak.

Postby Richard Graham » Thu Jun 12, 2014 6:46 pm

Ha ha, brilliant, how much are they? Are they stocked by all good joke shops, or just a select few?
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Re: USB Interface Tweak.

Postby Matt_A » Thu Jun 12, 2014 6:46 pm

I guess it's nothing to do with the digital USB data lines and more to do with filtering probably CMR on the USB power lines effecting the Duets analogue sections.
The iMacs usb power lines probably aren't the cleanest supplies especially all the junk I have plugged in.
Anyway just thought I would let you know.
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Re: USB Interface Tweak.

Postby Kaw-Liga » Thu Jun 12, 2014 9:00 pm

I have a usb midi keyboard that's got some led's on it. When I use lots of usb connections, the led's grow dimmer, and/or start to flicker. This might be a clear sign of the unstable power you talk about. Of course, it could also affect the mic premps. What I did was to buy a powered usb hub.
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Re: USB Interface Tweak.

Postby chris... » Thu Jun 12, 2014 9:13 pm

Where can I get one ??

( the site cited in the OP doesn't seem to have an obvious "buy it now" button )
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Re: USB Interface Tweak.

Postby chris... » Thu Jun 12, 2014 9:16 pm

OK, Googling abit leads (ha) me here:

http://www.mains-cables-r-us.co.uk/

http://www.mains-cables-r-us.co.uk/computer-audio/862-ifi-audio-ipurifier.html

which looks to be an excellent value seller of various types of cables, all scientifically proven to improve the sound of your HiFi.
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