I will add my 2 cents in as this board has produced better results than I anticipated and I feel that with a few tweaks it will become very popular.
Here is the priority I would suggest:
External power supply while attached to VIM of Edge-V. Ideally power VIM/Edge from Tone Board through GPIO so that a quality power supply could be used. Good clean power is critical for high end audio so a DIY (Salas) or off the shelf (iFi) would be a huge benefit.
I2s input to Tone Board. There are several “isolator” boards that improve the audio by having better clocks and/or signal/power cleaning features. Most of these are I2s and having a functional I2s would again open more markets.
Hardware volume control. Software volume control is less than idea (it works fine in most cases but I am looking at the high end applications). Yes it is better to have the volume control on the preamp but the ESS has the ability built in for hardware volume control so itis a good solution for those wanting to keep components to a minimum. There is a reason audio players such as Mood and Volumio give you the option to use hardware or software for volume control.
Balanced out for me is not a priority. Sure they look great and you have bragging rights but how many amps require balanced input?
I am no expert but I do fit the market segment that you are selling to and I am involved in a market that you are not reaching as much as I think you can.
Forgot to mention input priority.
SPDIF has highest priority, then usb then I2s. Imagine running high end audio through I2s, computer/laptop running usb and plug your phone into Spdif (with inexpensive adapter). Phone calls would take priority, then video/video chat/gaming, then high end I2s audio. You would virtually eliminate the need for a switch/selector board. No need to swap cables.
i love khadas toneboard, could someone give me a hint on how to make it the basis of a dac+4ch headphones amplifier ? it would then be ideal as an in car infotainment solution instead of the shitty and over priced car manufacturers old tech offers nowadays
Will there someday be a KTB with 2 mono DAC chips and balenched output? Personally I don’t think adding a volume control knob would be a great succes as many potentiometers will decrease the soundquality and most people have pre-amps with (much better) volume contol knobs. Also having the option to add a lineair power supply would be great!
it is the ESS chip that does the volume control, and in the digital domain, and they did whatever is good so that the sound quality is not affected by that, so please suggest other audiophile oriented upgrades than removing the remote volume control
Analogue volume control is much better than any digital volume control. Also as I said, almost any preamp comes with a volume control knob so adding one would for me (and most people who are into High End Audio who own a preamp) pointless…
because the shorter/simpler the path (in term of components) from the dac output to the final transducers, the better;
if you add a preamp, it will cost a ton of money to make it as transparent as the perfect simple wire with perfect variable attenuation that it is supposed to mimic, and you’ll also need to spend valuable money in perfect interconnect wires between the dac and the preamp, between the mains and the preamp, etc…
I even think that the most satisfying architecture is something like the d-note technology from Trigence where a single stage transforms the digital stream directly into transducer oscillations !
It is very true that how shorter the path is the better it will be! I myself use the ToneBoard as a Dac for my Raspberry Pi wich runs on Roon. I use a Rega Elicit-R amp with a pair of Totem Arro’s. To me this is not far from perfect sound quality (altough it sometimes lacks a bit of lowbass). I have used multiple preamps in the past but to me there where no noticeble changes in sound quality.
the TB is a relatively very good DAC; an rpi is somewhat noisier piece of electronic for a very serious hifi setup, and the TB does not accept (afaik) I2S inputs but only unbalanced coaxial spdif (and USB which has its issues)
For all my compunents I have build separate lineair power supply’s. I use a HifiBerry Digi+ Pro with an Allo Isolator to keep noise as low as posible (since you cannot filter all the noise out). I am currently thinking of buying an DDDAC 1794 (really worth looking it up), to connect to the Digi+ Pro via I2S
back to some suggestions on how better could the next TB :
I suggest it will accept balanced AES-EBU inputs and toslink; and it should do some DSP crossovering and eq to be able to output balanced analog audio signals to separate SUB, BASS, MIDS and HIGH pure analog amplifiers