Topic: Setting up a laptop from across the room (Interconnect question)

[newbieforever]

hi! quick question... are there any fast and hard rules on maximum lengths for interconnects? im in the process of remodelling and would like to situate my laptop+USB DAC near the sitting area (instead of near the amp). i have two options:

1.  run a long interconnect (3.5mm to RCA plugs) from the amp to the laptop+USB DAC
2.  run a long USB cable so that the DAC and Amp remain close to each other (with the laptop at the other end of the room)

* not really sure about bluetooth and whether it can provide bit perfect transmission. any inputs would be most appreciated regarding this as well.

thanks in advance for your time!

[CoolTOYZPH]

Personally I use a longer USB cable and satisfied with the result.
More for economic reason, USB cable is cheaper thenn ICs.
I like testing ICs and seldom do I find long run factory terminated ICs.

[newbieforever]

Personally I use a longer USB cable and satisfied with the result.
More for economic reason, USB cable is cheaper thenn ICs.
I like testing ICs and seldom do I find long run factory terminated ICs.

thanks for the reply sir!

my initial research indicates the same (3 meters max for low speed devices and 5 meters max for high speed). how long is your USB cable, if you don't mind my asking?

another viable option would be to situate the entire audio stack (CDP, Amp, etc.) near the listening area and leaving the speakers up front... but that would mean investing heavily in good quality speaker wires. yikes. has anyone tried this?

[uvax]

The maximum length of a USB 2.0 interconnect is 5m according to the usb standards. You'll have to take this into account when you make your choice.

[Courage]

Ayaw mo sir i remote na lang yung laptop using Ipad or Android? Para di mo na sya aalisin sa pwesto nya?

[markcrenz]

1.  run a long interconnect (3.5mm to RCA plugs) from the amp to the laptop+USB DAC

Check DAC specs, if it outputs 2V pwede 10m or even more, basta mataba RCA cables. By mataba I mean the copper, not the insulator.

2.  run a long USB cable so that the DAC and Amp remain close to each other (with the laptop at the other end of the room)

I've used 5m (2.5m cable + 2.5m extension) for USB without apparent loss. Voltage drop from thin wires mostly contributes sa signal loss, so with thicker (DIY) USB cables longer distances (over 5m) can be achieved.

[newbieforever]

Check DAC specs, if it outputs 2V pwede 10m or even more, basta mataba RCA cables. By mataba I mean the copper, not the insulator.
I've used 5m (2.5m cable + 2.5m extension) for USB without apparent loss. Voltage drop from thin wires mostly contributes sa signal loss, so with thicker (DIY) USB cables longer distances (over 5m) can be achieved.

thanks sir! very helpful. will check my USB DAC for voltage output.  While the USB solution seems more viable (and economical), would be nice to have the laptop and DAC together since i'm also into headphones.

[newbieforever]

Ayaw mo sir i remote na lang yung laptop using Ipad or Android? Para di mo na sya aalisin sa pwesto nya?

haven't tried this, although was looking into it when i connected a PC to my TV before.  opted for a wireless keyboard and mouse instead. is there an app for this? i have an iPad 2. how does the iPad connect to the laptop/PC?

[newbieforever]

Check DAC specs, if it outputs 2V pwede 10m or even more, basta mataba RCA cables. By mataba I mean the copper, not the insulator.
I've used 5m (2.5m cable + 2.5m extension) for USB without apparent loss. Voltage drop from thin wires mostly contributes sa signal loss, so with thicker (DIY) USB cables longer distances (over 5m) can be achieved.

is this it?

Maximum Output Line Out 100K   2.1 VRMS

DAC is still in transit. got it from Massdrop (JDS Labs Objective DAC Rev B).

[Courage]

haven't tried this, although was looking into it when i connected a PC to my TV before.  opted for a wireless keyboard and mouse instead. is there an app for this? i have an iPad 2. how does the iPad connect to the laptop/PC?

I'm using an app called RD Client for both IOS and Android to remote Desktop the Laptop. You can actually see and control the screen of your Laptop with this app

I'm using Jremote naman to remote the Player from the laptop

Anong audio player sir gamit mo?

[uvax]

Check DAC specs, if it outputs 2V pwede 10m or even more, basta mataba RCA cables. By mataba I mean the copper, not the insulator.
I've used 5m (2.5m cable + 2.5m extension) for USB without apparent loss. Voltage drop from thin wires mostly contributes sa signal loss, so with thicker (DIY) USB cables longer distances (over 5m) can be achieved.

For usb it is not signal loss that dictates the maximum length but the time window when the host must receive an acknowledgement from the usb device. USB 2.0 specs has a max time delay of 1.5µs before the host times out the connection. This roughly translates to 5m.

[newbieforever]

I'm using an app called RD Client for both IOS and Android to remote Desktop the Laptop. You can actually see and control the screen of your Laptop with this app

I'm using Jremote naman to remote the Player from the laptop

Anong audio player sir gamit mo?

interesting! will look into RD Client. using Foobar on my laptop.

[newbieforever]

For usb it is not signal loss that dictates the maximum length but the time window when the host must receive an acknowledgement from the usb device. USB 2.0 specs has a max time delay of 1.5µs before the host times out the connection. This roughly translates to 5m.

good to know... so signal is unaffected no matter the length of the USB cable? are all USB cables essentially the same?

[Courage]

interesting! will look into RD Client. using Foobar on my laptop.

You can use ios Remote app to remote Foobar, research on it as its has some configuration and components needed to be setup sa laptop. I use that before when i'm using Foobar, i switched to Jriver thats why i no longer use Foobar as player, only as DLNA

[Gino]

In car audio, shorter ic and longer speaker runs is preferred over the opposite.

[newbieforever]

thanks for all the replies! from what i've gathered, probably the most viable and economical option would be a 5 meter USB cable (or an even longer USB repeater cable). seems better than a longer IC since there are less chances of degrading the audio signal.

that being said, are all USB cables essentially the same? should i look for the cheapest one or go for the more expensive (ie. "branded") ones? shouldn't make a difference.... right? :-)

note: my next viable option would be to situate the entire equipment stack near the sitting area and leave just the speakers up front. would be nice not having to walk across the room to adjust the volume. would make for a cleaner, more minimalist look too. will probably go this route when i finally am able to build a house of my own.

[CoolTOYZPH]

I am using a QED 5M USB Cable.
http://www.qed.co.uk/hdmi_digital/digital_data/performance_graphite_usb_a-b.html

From experience the DAC and IC has more influence on the Sound Quality than the USB cable.

[remington]

I use both long IC and USB cables as I have two configuration on my dac and are satisfied with the result. Kailangan lang maganda quality ng both cables.

[junbathan]

I just had the same concern since last weekend, my solution yesterday was use a 5m USB cable from Ace hardware for less than 400 pesos.

[Stagea]

hi! quick question... are there any fast and hard rules on maximum lengths for interconnects? im in the process of remodelling and would like to situate my laptop+USB DAC near the sitting area (instead of near the amp). i have two options:

1.  run a long interconnect (3.5mm to RCA plugs) from the amp to the laptop+USB DAC
2.  run a long USB cable so that the DAC and Amp remain close to each other (with the laptop at the other end of the room)

* not really sure about bluetooth and whether it can provide bit perfect transmission. any inputs would be most appreciated regarding this as well.

thanks in advance for your time!

How far apart are they? You can run a long USB cable (5M or so) without a problem for the far majority of DACs.

For even longer runs, active USB extensions exist. Some of them are 40M long (or longer), but really long ones may impact operation of isochronous devices (and may need a power injection at the end... such as using a powered hub).

[Stagea]

For usb it is not signal loss that dictates the maximum length but the time window when the host must receive an acknowledgement from the usb device. USB 2.0 specs has a max time delay of 1.5µs before the host times out the connection. This roughly translates to 5m.

Markcrenz is correct. 1.5µs is a sufficiently long time for longer lengths.

The USB 2.0 spec sets a 26ns (high speed) / 30ns (full speed) propagation delay threshold between connectors to allow the builder to string 6 cable runs through 5 hubs sequentially and still reliably run a device at the end (hubs are allowed upto 79ns of delay each to meet the high speed spec). The 26ns spec is where the 5m length "limit" on passive cables came from. The total round-trip time from the 6 runs, 5 hubs, and device would be below 1.5us if all of the components follow the USB 2.0 high speed spec. This results in a 30m maximum run length at 5m per cable if all the devices are at the upper limits of the spec.

You can choose not to follow the spec and there is still a big chance that it will work. USB extensions often span 10-20m between repeaters because their repeaters are designed to deal with the attenuation of the longer runs (and some use cables with better propagation properties). Their repeaters are also simple devices that do not take up the full 79ns delay allocated by the USB 2.0 high speed spec per hub. This allows them to meet the 1.5us round trip time even if they're hooked up to a hub (such as the internal root hub of a PC) and run a hub at the end to connect multiple devices (or to inject power). A 40m extension with a 5m passive cable connected to a powered hub which then connects to another 5m passive cable to the device will result in a 50m run from the PC, for example.

I've seen active USB extensions as long as 80m (4 repeaters with 20m segments). With the root hub on the PC and a 5m passive cable on the end, that gets it very close to the maximum of the USB 2.0 spec (giving a span of 85m from the PC).

https://www.youtube.com/watch?v=OQgLNCBPZE8

[newbieforever]

thanks for all the help! 

looks like im going with a long USB cable.