Review and Measurements of LH Labs Go2Pro DAC and Headphone Amp

[amirm]

Yes, the owner told me that it has much more juice through its balanced output. I am getting setup to create a test fixture for balanced headphone outputs so in the future should be able to measure them.

 

[Jimster480]

Yes, the owner told me that it has much more juice through its balanced output. I am getting setup to create a test fixture for balanced headphone outputs so in the future should be able to measure them.

I thought balanced was all the rage?

 

[sssn]

I thought balanced was all the rage?

Balanced connections for driving headphones are a huge marketing fad in my opinion. It already starts with the fact that there's no standard connector, making lots of aftermarket cables necessary and potentially binding customers to your brand.

Technically, balanced connections enhance crosstalk performance and noise rejection, which aren't really important in headphone applications. However, they increase hiss, distortion and output impedance, which ARE important in headphone applications. It's especially ridiculous that balanced connections are so heavily marketed in portable gear, where people often use (BA) IEMs. Those are especially sensitive to hiss and high output impedance.

 

[Jimster480]

Balanced connections for driving headphones are a huge marketing fad in my opinion. It already starts with the fact that there's no standard connector, making lots of aftermarket cables necessary and potentially binding customers to your brand.

Technically, balanced connections enhance crosstalk performance and noise rejection, which aren't really important in headphone applications. However, they increase hiss, distortion and output impedance, which ARE important in headphone applications. It's especially ridiculous that balanced connections are so heavily marketed in portable gear, where people often use (BA) IEMs. Those are especially sensitive to hiss and high output impedance.

Yes I am well aware, I have laughed for quite some time at "balanced" connectors for headphones.
There is already awesome crosstalk performance from single ended devices all over the market.

 

[amirm]

I hate them because they double my workload. As it is, it is bad enough that I have to test with so many loads. Then comes the balanced output and it starts all over again.

 

[Timbo2]

I confess I find the one on my portable DAC useful. I run my 300 ohm Sen 600s balanced and my Shure 535s on the unbalanced side. The Sennheisers do much better with the extra power.

It did involve buying a $20 official Sennheiser cable and $30 worth of XLR connectors and male jacks. Add in about 2 hours of soldering. But now I have 4 pin XLR, 2.5mm balanced and 3.5mm and 1/4 inch unbalanced capabilities on the 600s.

I wanted to just buy a cable, but good luck doing that for a sane amount. Only other option was wait a month and get them from China. But even there it was tough finding non exotic connectors and cables.

 

[amirm]

I had to do the same thing. Bought a cheap replacement cable for the HD-650 and XLR connector. Yet to connect them together though.

 

[Timbo2]

I had to do the same thing. Bought a cheap replacement cable for the HD-650 and XLR connector. Yet to connect them together though.

Heads up the Sennheiser cable uses epoxy insulation, it it a bit of PITA to work with. I burned it off with the iron, but it stinks and you have to clean the burnt residue.

I like the cable itself, it has low microphonics and is supposed to be OFC.

 

[amirm]

I was too cheap and bought a much cheaper replacement cable. Crossing fingers that they skipped the epoxy in making it.

Seriously, if it is the litz cable, they are an absolute pain to work with. You either need a heavy duty soldering iron or some kind of flame to burn off the insulation.

 

[Roen]

Switching from DAC testing to headphone testing, I measured the output impedance a very low 0.5 ohm.

View attachment 11745

This means that it should have no effect on the frequency response of the headphone even if that latter is pretty low.

Output Impedance on single-ended, balanced, or the same?

 

[amirm]

Output Impedance on single-ended, balanced, or the same?

Unless I say otherwise, it is unbalanced.

 

[Roen]

I believe you also ran the tests with firmware < 2.0.

Would be interesting if you re-ran the tests with the newer firmware and the new volume / gain control.

 

[amirm]

I believe you also ran the tests with firmware < 2.0.

Would be interesting if you re-ran the tests with the newer firmware and the new volume / gain control.

Unfortunately I no longer have the unit.

 

[Roen]

SINAD numbers?

 

[flipflop]

SINAD numbers?

Looks like it's 90 dB on low gain.

 

[mshenay]

I believe you also ran the tests with firmware < 2.0.

Would be interesting if you re-ran the tests with the newer firmware and the new volume / gain control.

Mhm, the firmware makes a difference subjectively, that said I would be very interested to see what you can measure without cheap cables ect...

 

[Roen]

Mhm, the firmware makes a difference subjectively, that said I would be very interested to see what you can measure without cheap cables ect...

I think I was mistaken anyway, re-reading the review, it seems like @amirm had a unit with the newer firmware, since he changed the gain via hard volume control, rather than the control panel in windows.

I'm curious to see if he wants to re-test my Infinity version, which has a third (medium) gain stage, with his new equipment.

 

[Roen]

FYI

Maximum Power Output: User switchable - 1000mW @ 16 Ohms, 100mW @ 16 Ohms 9 (Infinity model also has an 450mW @ 16Ohms)

I'll be interested in how my Infinity measures once you get it in your hands with the newer dashboard.