What we also get here is a custom outboard linear PSU unit which is actually AC (that is not that very common) that provides both 24V and 6V AC rails as well. We will also find four RCA input sets, one RCA output and one XLR output on the back. And the power switch as well – this is something that is common in many more affordable Schiit’s products and can take some time to get used to (even Gungnir 2 DAC has the power switch on the back, yet the bigger power amps have the standby buttons located on the front, which actually suggests that it’s more about the power usage than convenience). The last thing that you have is the Forkbeard slot, since it’s also Forkbeard-enabled.
That will allow you to control Saga from your mobile phone via Bluetooth connection and it might be especially useful when there’s no line of sight with the preamp. Moreover, the control app is now available for Android too. Not to mention the fact that you can actually control the whole Schiit stack from one app and it will show you some really interesting things in such a case. Like the Class A region of operation that it will present to you on the phone screen in realtime. The front panel is quite uncluttered and also has a phone output. So additionaly, the Saga 2 can be viewed as an headphone amplifier with quite extensive connection capabilities. And you also have the gain switch.
The above-mentioned functionality requires just a bit of an explanation: Saga 2 can work in passive mode, in a buffer mode with the gain equalling one/two and in active mode with the gain of four/eight. That also means that it can work as a completely passive volume control. One more thing: while the entire audio circuit of the preamplifier is indeed a discrete one, the headphone amplifier uses OPA1656 as a booster and has 150mW of output power. So, no those big planar headphones at high levels here. But even considering this, the feature level is truly an impressive one here and should be a benchmark at this price. And now let’s ask Jason Stoddard, one of the Schiit Co-Founders about the general idea behind this particular piece of gear, especially the no-feedback solid-state concept:
A lot of our designs have been trending towards lower feedback or no overall feedback, or switchable feedback, because less feedback tends to sound better. The difference in Wotan between feedback and no-feedback settings is very dramatic. So for a preamp gain stage it makes a lot of sense. We even use the same basic stage in Skoll, and it works very well there. The tradeoff, of course, is not-state-of-the-art measurements, but THD doesn’t seem to correlate very well with what we hear, and it’s like -100dB or so in any case.
Then we have the new topology that is called Equipose, which Jason also explains:
Equipoise, which I should just rename Poise™ or something more marketing-y, is a much simpler stage than Nexus™. It’s a single differential gain stage with a error-cancelling Class A buffer on either side. Nexus has two differential gain stages for much higher overall gain. And gain is what you need for feedback. Nexus’ additional gain makes it better to use for, say, speaker amps, or amps that need to have low output impedance and other qualities that you only get with feedback. Equipoise is much better suited for no-feedback applications, like preamps. The Freya+ was the first Schiit product to use this topology in its differential buffer stage.
And then there’s that passive mode which is also something that also needs jsu a bit more explanation at the source:
It can work very well, as long as the cables are short. Passive means variable output impedance as you noted, so you might have up to 5k ohms output impedance. With long, high-capacitance cables (cables are usually rated in pF/ft), you might get to a point where you’re rolling off the high end response of your system. Or, if your amp has a very low input impedance, it won’t work well. That’s why we always include a buffer or active mode as a switchable option. Some people like pure passive, some people like a buffer, some people like gain. Choice is best.