Connecting Hi-fi active speakers (XLR balanced) to a laptop

[dhg]

Hi!

I have purchased a pair of PMC-AML1 active speakers and am looking for an easy and relatively inexpensive way of connecting them to a computer (a new macbook pro running yosemite).

I have two options I'm considering: using a Dragonfly 12 DAC or an Apogee Duet 2

The Dragonfly would require converting a 3.5mm output to a balanced input (XLR) while the Apogee Duet has XLR output already. Both inputs are USB. The Dragonfly is marketed as a hifi component though the Duet has similar if not better specs (I'm not sure about the technical specs though) but is marketed to DJs/recording artists. I can find a used Duet for not much more than a new Dragonfly + volume control.

Does anyone have any views on the whole connection issue? Is the Duet just as good and better since it doesn't require going from 3.5mm to XLR and it's just a marketing thing maybe?

Thanks for your help!

 

[andyjm]

Line level balanced connections are great for running a cable around a studio or a stage, but don't really bring any benefit to a home installation unless your cable runs are very long or your grandmother has arc welding as a hobby. All other things being equal, for domestic use there should be no difference between balanced and unbalanced (for various reasons, over short runs unbalanced may be slightly better).

If both pieces of equipment already have balanced connections, you might as well use them, but if not, there are couple of ways to interface balanced and unbalanced.

To go from an unbalanced DAC to balanced speaker, the best way is to use a 'balun', this takes an unbalanced signal and balances it. These are available stand alone or built into adaptors and are generally based on small transformers (unpowered) or differential amplifiers (powered). Good ones are not cheap, and bass performance can be a problem.

The cheap and cheerful solution (used by most adaptor cables) is to ground one leg of the balanced connection at the speaker input (XLR). If you buy an 'unbalancing' or converter cable, this is what it will do. If you google 'how to unbalance an XLR' there are any number of pictures and diagrams of how this works. It isn't perfect, you lose any balancing benefit and the levels aren't quite right, but this is the generally accepted solution and should work just fine.

 

[davedotco]

Andyjm's summary is spot on but both of you are missing the obvious....

Buy a usb dac with balanced outs, simple. Plenty of choice, Matrix Mini I, Dacmagic, Teac UD H01 at the lower end going up to whatever you like pricewise.

Why bother with messing about with adaptors and sub optimal connections?

Though if you get the Duet you can get a 'Breakout Box' which will give you balanced outs for your monitors.

 

[Gazzip]

http://www.nakamichi.co.uk/products/nakamichi-7-1-power-processor

.....or you could go for the Nakamichi 7-1 processor. Optical in from your MacBook Pro or streamed via Bluetooth. Fully balanced output and remote control too! All that for £199. The best of all is that it also sounds pretty good AND it looks like a Hifi product, not a piece of computer equipment.

 

[davedotco]

http://www.nakamichi.co.uk/products/nakamichi-7-1-power-processor

.....or you could go for the Nakamichi 7-1 processor. Optical in from your MacBook Pro or streamed via Bluetooth. Fully balanced output and remote control too! All that for £199. The best of all is that it also sounds pretty good AND it looks like a Hifi product, not a piece of computer equipment.

I thought of that too but as it does not have USB input I discounted it.

You could use optical if the macbook in question has it or possibly even HDMI, stream via an Apple ATV, currently quite cheap, as I said, there are loads of options.

 

[rhk]

Few thoughts 1. Minor detail, but the Duet has balanced 1/4" jacks (TRS) not XLR out. You can still run balanced jack -> XLR easily enough. 2. With the Duet you are primarily paying for the recording side (ADC/Pre-amp), so unless you do recording you might get more bang for your buck elsewhere. 3. While I'm fairly happy with my Duet as a headphone amp I'm considering getting something better for the hifi. I dont have a dragonfly so can't comment on that.