The 2170 is gone. In its place sits a 3400, and I am still working out whether I traded up or just traded.

I did not decommission the TDAI-2170 because it failed me. It didn’t. It was, by any measure I trust, a fine piece of equipment. But somewhere between writing about it last time and today, the itch came back. Not for warmth this time, I had already made peace with the 2170’s neutrality, or told myself I had. The itch was for headroom, for a cleaner path from source to speaker, for fewer boxes doing the job of one. So the 2170 came off the shelf, and the 3400 went on.

It did not stop there. The Cambridge, a piece I praised without reservation not long ago, turned out to be redundant the moment the 3400 arrived. Streaming was one of the long list of things the 3400 picked up that the 2170 never had, and it does that job on its own, no help required. So the box I once wrote up as a small triumph came out of the rack anyway, and the signal path got a little shorter. I did not plan for that. I went shopping for an amplifier and came home having also solved a problem I did not know I was carrying.

I should also admit the whole thing was a bit of a steal. I bought this one second hand, and whoever owned it before me clearly wanted for nothing: it came fully loaded, USB, HDMI, and analogue modules all fitted. That analogue module is what has me most curious right now. It carries a dedicated MM phono input with proper RIAA equalisation built in, which means the turntable can go straight into the 3400 instead of through the small dedicated preamp I have relied on until now. I have not made that swap yet, but I am genuinely excited to hear what happens when I do.

On paper, this is not a subtle upgrade. More power. A cleaner amplification path, since the 3400 skips the usual DAC-then-amplifier handoff and keeps the signal in the digital domain until the very last moment before it reaches the speaker terminals. A noise floor low enough that the spec sheet reads like a rounding error. Streaming, inputs, and control options the 2170 never had. RoomPerfect is still there, doing what it always did, but everything around it is newer, faster, and, this is the word Lyngdorf themselves would use, more transparent.

And that is exactly where I paused.

Because here is the thing I never quite said out loud in the last post. I called the 2170 neutral, technically superior, less emotionally involving, and left it there, as if that were the whole explanation. It wasn’t. I never actually got comfortable with that move from the SDAI-2175 to the TDAI-2170. On paper it was a clear step up. In the room, with my Dali Helicon 800 Mk2s, something was missing, and I could never quite name it. The goosebumps I’d gotten used to just weren’t showing up anymore.

I have a theory now, one I did not have when I wrote about the 2170. I suspect the 2170 was underpowered for the Helicon 800 Mk2, but that is a suspicion, not a given. Big cabinets, demanding low end, the kind of load that wants current on tap, not just clean voltage, so power is the obvious first suspect. But the 3400’s output stage is different from the 2170’s in more ways than raw wattage, and any of the following could be doing just as much of the work:

• an improved power supply
• lower output impedance
• a different implementation of Equibit
• better clocking
• lower distortion at higher output levels
• improved RoomPerfect algorithms

I do not have a clean way to isolate which of these mattered most, and I am not sure it matters for the story I am telling here. What I know is that something changed, and the result is what I care about.

Transparent is a strange goal for something that is supposed to move you. The first evening with the 3400, before I had even run RoomPerfect, I noticed the same thing a few other owners have written about: it is unmistakably a very good amplifier, and it is not, out of the box, an emotional one. It sounds correct. Correct is not the same as alive. I sat there wondering if I had just repeated the exact mistake I made with the 2170, chasing a number on a spec sheet and arriving, once again, at a component that vanishes rather than one that sings.

Then I ran RoomPerfect properly, gave it a few days, and stopped comparing it to memory. And then, on a track I must have played a hundred times on the 2170 without much reaction, it happened: the goosebumps, unannounced, exactly where they used to be. That told me more than any spec sheet did. Whatever the 2170 was quietly failing to deliver to the Helicon 800 Mk2, the 3400 had it to spare.

Here is what I think is actually happening, and it took me a while to see it. Power and personality are not the same axis, but on the 2170 they may have been tangled together, whether through current on tap, output impedance, clocking, or some combination I cannot fully separate. It wasn’t just that the amp was neutral in the way a well-lit room is neutral, even, correct, a little clinical. It’s that neutral and underpowered, on a speaker like the Helicon 800 Mk2, can sound almost identical. Both hold back at the exact moment the music wants to lean forward. Whatever the exact mechanism, the 3400’s newer output stage has something in reserve the 2170 didn’t, and with that sorted, it turns out there was a second thing going on too: once the amp stops straining, it also stops adding its own opinion to the signal. Where the 2170 sometimes felt like it was politely holding the music at arm’s length, the 3400 gets out of the way completely. Once I stopped listening for character and started listening for what my other sources, the turntable, the tube CD player, were actually putting into the chain, the picture changed. The vinyl still sounds like vinyl. The tubes still bloom the way they always did. The 3400 is not adding warmth of its own, but it is no longer subtracting anything either, and it is no longer running out of breath when the Helicons ask for more.

That is the part I did not expect. I assumed a more powerful, more digital, more “correct” amplifier would flatten the differences between my sources even further, that everything would start converging toward the same clean, slightly bored sound the 2170 sometimes gave me. Instead, the opposite happened. With less of the amplifier’s own signature in the way, the character of each source came through more clearly, not less. The tube CD player sounds more like itself. The turntable sounds more like itself. Tidal sounds, for the first time, like it has a personality of its own rather than a personality borrowed from whatever amp it happens to be running through.

If there is one thing keeping me from unqualified enthusiasm, it is the My Lyngdorf app. It gets the job done, eventually, but “eventually” is doing a lot of work in that sentence. It is slow. Menus lag. Simple changes take longer than they should for a company that otherwise seems to sweat every detail of what happens after the signal leaves the box. For an amplifier this considered, the app feels like an afterthought bolted on to satisfy a checklist. I do not need it to be beautiful. I would just like it to keep up.

So maybe I did not trade warmth for headroom after all. Maybe I traded a component with its own quiet opinion for one with almost none, and in doing that, I gave the rest of the system room to have opinions of its own again. And the strange, satisfying part is where that lands me: back with the feeling I had on the SDAI-2175, the one the 2170 never gave back to me, except now with sound quality the 2175 was nowhere near. Not a return. Not a compromise between the two. The thing I liked about the 2175 and the thing I respected about the 2170, both, at once.

Still, I find it peculiar, that specific feeling, the goosebumps, coming back after all this time, on a completely different piece of equipment years apart. But who knows. We tend to remember romantically. Memory has a way of sanding down whatever it did not like about the past and polishing the rest, and I am not naive enough to trust mine completely on this. Maybe the 2175 was never quite as good as I remember, and the 3400 is simply good enough to fill in the gaps memory left behind. Or maybe the feeling really is the same, and I have just been lucky enough to find it twice. I do not think I will ever know for certain, and I have decided I am fine with that.

I still do not think there is a perfect source, or a perfect amplifier. I am not sure I want one. But I am starting to think the real upgrade was never about getting closer to some theoretical neutral. It was about getting things out of the way, first the amplifier’s own opinion, then a whole box that turned out to have no opinion left to offer, so the parts of the system that do have character, the ones I chose on purpose, finally get heard clearly, with enough current behind them to mean it.

The 2170 taught me what I was missing. The 2175 taught me what I was chasing, or what I remember chasing. The 3400 is the first time in a while I’ve had something that feels like both at once, memory or not.