This and That:
I'd already owned the first generation in the past and only bought the second generation several years ago as the lower volume range without any channel imbalance wasn't quiet enough for me, so I ordered it with reduced gain.
The potentiometer and volume control implementation are fully analogue and therefore come with all the disadvantages of analogue volume control (channel imbalance in lower positions). That's why I sometimes used it with another DAC with variable line out for more precise volume control.
In fact, the Leckerton served me as my main stationary DAC-Amp for many years (before I replaced it with my RME ADI-2 DAC), and there's absolutely nothing wrong about that (excellent hiss performance, low output impedance, enough power for my less sensitive full-sized headphones, digital and analogue inputs - that's really all one needs). Upgrading to a device with precisely digitally controlled volume that still allows for quiet listening, at the same time with a low output impedance and perfect hiss performance, was the only reason why I even retired my UHA-6S.MKII, which also took quite some time as there wasn't any device that met my expectations, no matter in what price range, until the ADI-2 DAC was released.
For "modern" day standards, format support is rather "poor" and "outdated" on the DAC section that I think "only" supports sampling rates of up to 48 kHz and 16 Bit when fed by USB, and "only" up to 96 kHz and 24 Bit when fed by TOSLINK or COAX. As Red Book standard 44.1 kHz, 16 Bit is all I need and as I don't care about Hi-Res, DSD and all that crap that (imo) doesn't belong into personal audio anyway, my Leckerton never even saw its technical input format limits.
What's great about the DAC-Amp is that it features full-size digital inputs for coaxial and optical cables, so I've never needed an adapter for the optical input.
What I like are the feel and sound of the power and charging bypass (really convenient when the DAC is fed by USB) toggle switches on the back.
Oh yeah, build quality and design are great and a clear step forward from the first generation; it really doesn't look like a device coming from a small company that's basically just one person if I'm correctly informed. Battery life is good.
Sound:
I don't even remember what amp chips I chose, but I think it were the standard ones (yeah, the amp chips are exchangeable). Personally I really don't care what amplifier or DAC chips are used as long as the result of the implementation (output impedance, hiss performance, general measurements, frequency response output) is good.
Frequency response and hiss performance don't change no matter what input is used, and there's also no additional noise when using the digital inputs.
Frequency Response (no Load):
No surprise; it's as flat as it should be.
Output Impedance (loaded w/ Ultimate Ears Triple.Fi 10):
Based on the deviation, the calculated output impedance is commendably low with around 0.3, 0.4 Ohms, which also backs up Leckerton's specs of below 0.5 Ohms (they're trustworthy anyway given the company owner's educational and occupational background). Perfect.
Hiss Performance:
Even when using extremely sensitive in-ears such as my Campfire Audio Andromeda, the Leckerton is hiss-free. That's as good as it gets.
Switching to high gain, hiss becomes audible using sensitive in-ears but remains inaudible with less sensitive in-ears and full-sized headphones.
Subjective Sound Impressions:
I'm objective-minded and not into stupid subjective nonsense blah-blah.
Not surprisingly, the Leckerton sounds just as clean and transparent as a well-designed device should. It may appear subjectively a tad less transparent when used as a DAC than as an amplifier, but that's, if even actually present, only a nuance in critical listening when switching back and forth and nothing that would be relevant in everyday listening scenarios, even for critical listening. And it never really was for me.
Conclusion:
Very low output impedance, perfect hiss performance with extremely sensitive in-ears, high load stability. The only thing that would make it perfect is a digital volume control implementation (I don't like analogue volume control anymore).