Interesting.
Yeah that is very risky, I did have one small accident where I was blasted with 50-60 in PO for a second or two when I forgot that I switched to high gain but not enough to cause damage thankfully.
The thing that I found most interesting and also very confusing to myself as much as others is this
True Line Out by PreAmp function.
Even though logically this is the only way it can explain it, together with Paul confirmations that Gain is before Line Out. I still have hard time accepting it as a fact.
I was so used to other DACs, and even as 1 bit discrete claimed, makes me thinking of Hiby, and was confirmed/corrected by Joe that R8ii is indeed a 1 bit discrete, and that Line out is typically 2Vrms and 4Vrms respectively.
The way 340 works is mind boggling. As I read and tried with my technical mind, explaining to myself, that the DAC implemented by Ibasso
This brought me back to the very first Manufacturers that brought this tech to the portable world, Cayin, the N7
Analyzing N7 blocks as Cayin states. I circled 3 parts.
Yellow part is where the Resistors arrays acting as analog filters and summing up voltages into voltages line level.
Yellow levels is so very very low, that it needs another buffering stage which is Blue circled. It is Line Driver under technical term.
Teal part is where the Line in toward Amplifying stage is taking stages. It amplifying the first stage of the Line Driver (all gains on the 340 including DC super gain).
This is what so different to N7. It appears that the Amp15, combining Line Driver together with Preamp stage into 1. Unlike N7, which allows you the options for Line Level directly by the Line driver.
Is this true Line out though ? Well...Preamplified signals is still a line level , just so long as it doesnt cause Double amplifications, then it is. This is also what we have been having from other devices as well.
From these instances, we got swallowed into the debate of Phony Line Out or True Line Out. Well, True Line out is Line Driver and nothing more than that. N7 allows that while our 340 doesnt.
It appears that according to Cayin blocks, there are ways to tap into and from the discrete line level, separating into Pure Line Driver toward Line Out and then amplifcations later. Under this layouts, my assumptions about 340 as it is now with 15 as a true Line Out was wrong. While it is said to have a max of 1-2Vrms,
the Amp15 only allow PreAmp Line Out, which is different than True Line Out (pure Line voltage level only). Preamp level out will have it voltage changes due to gain factors, which isnt listed on Ibasso site.
Phony Line Out is where the input buffer stage of amplifications are playing a role of amplifying voltage/current before going toward output (which other DAPs can incorporate) with locking DAC volumes or so, and appears to be Line Out. It is another trickery part.
But in conclusions, as I said before, The 340 with amp15 Line Out is Preamp level. It isnt True Line driver Line out stage which all gains should not have been applied. No double amping will be a thing though.
However, I think future amp modules
May be designing discrete Line driver stage and allowing True Line Out instead of Pre Line Out as additional option
Furthermore, I can observe that logically previous amp modules had different build. The Line buffer were just pure Gain and pure buffering architects toward Amp out. No preamp level. Therefore, even with LO as an option from 340DAC, they had slight hiss, and also cant perform the way the amp15 do. This was due to the facts that previous DX320/300 was using IC Chips which had powerful Line Level off the Bats.
What does this say ? Well....using off the shelves is easier than building a proper discrete 1 bit like Cayin and Ibasso. But at least they are leading the market and making them.
Also, once again, a properly designed preamp signals could be even better than just Pure Line Driver Line Out.
. This is the closest to Ibasso as the first time I started loving their players and signature, the 220TiTanium
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