MDAC First Listen (part 00100011)
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iansr
pfm Member
sam_cat
C'est Crounchifique!
For TDAC, it has to be full size imo. Gives you room to breath, allowing you more choices for it to be what you want it to be without being constrained by size.
I do like the small size of the MDac, sits nicely next to my mini pc.. But TDac is your statement design, a no compromise design to show just what is possible. Half width would give you a constraint that isnt needed (as most/all of us can certainly fit a 'normal' width unit)..
At the end of the day its your statement design, so the choice has to be yours!
Hi John,
As an MDAC owner I am starting to get very excited about the prospect of the MDAC2. A few points:
1) At least one person has asked for more output, which you found surprising. Well I have low sensitivity speakers, a low gain, low power amp and no preamp, so the MDAC's current gain is only just barely enough for me. Would it be possible for it to have higher gain without compromising anything, at least as an option?
2) On a related note, will it be possible to order it without the analogue gain reduction switch? I can only assume this will add extra unnecessary circuitry when not needed.
3) Would an i2s input be possible, at least as an option replacing an existing input?
4) I hope the SABRE's built-in filters will still be selectable - the slow roll-off filter is definitely my favourite in my system.
5) If you're struggling to fit everything into the current chasis, maybe you can withhold the ADC until the TDAC?
As an MDAC owner I am starting to get very excited about the prospect of the MDAC2. A few points:
1) At least one person has asked for more output, which you found surprising. Well I have low sensitivity speakers, a low gain, low power amp and no preamp, so the MDAC's current gain is only just barely enough for me. Would it be possible for it to have higher gain without compromising anything, at least as an option?
2) On a related note, will it be possible to order it without the analogue gain reduction switch? I can only assume this will add extra unnecessary circuitry when not needed.
3) Would an i2s input be possible, at least as an option replacing an existing input?
4) I hope the SABRE's built-in filters will still be selectable - the slow roll-off filter is definitely my favourite in my system.
5) If you're struggling to fit everything into the current chasis, maybe you can withhold the ADC until the TDAC?
JohnW
pfm member
The output level is limited by internal PSU supply voltages, with the +3dB over range then there's over 8V Pk-Pk voltage swing, this is already pretty excessive for a line level source - via the balanced output that's 16V pk-pk. Its not the DAC's duty to function as a power amp
The MDAC2 L1 comes without Analogue domain attenuation - but it also lacks the DSP, Advanced Clock & Digital expansion port (amongst other additional features).
Depending how many owners decide to go for the L2 / L3 level I'd like to discontinue the L1 option. The L2/L3 offer the highest SQ.
The Analogue domain attenuation is selected by high quality reed relays and when not enabled there are no extra components in the analogue signal path.
The MDAC2 L2/L3 will feature a Digital expansion connector which could be used at a later date add an I2S interface pod - but I2S offers no performance advantage, its only being promoted by those who fail to understand the fundamentals of Digital audio design.
In the native ESS mode all the existing filters will be supported.
The ADC sections are located in a different area of the PCB - I'm short of space in both lower corners of the PCB where the ESS DAC's are located.
I'm leaning towards L2.
Cheers and keep up the good work (without losing yourself too much in it...)
Johan
delange
pfm Member
The output level is limited by internal PSU supply voltages, with the +3dB over range then there's over 8V Pk-Pk voltage swing, this is already pretty excessive for a line level source - via the balanced output that's 16V pk-pk. Its not the DAC's duty to function as a power amp
I never understood why so many dac's insist on spitting out such high levels. Most power amps are clipping in the areas of 1 - 1.2 volts anyway, so what's the point?
sam_cat
C'est Crounchifique!
But is your name on the list? (JohnW setup a list aggges ago).. Things may have moved on/people dropped out since then.
Lowering power amp final gain and using a digital source closer to its max volume control lowers digital attenuation (for digital based volume controls) as well as increases dynamic range. Works for me anyhow.
JohnW
pfm member
Phil,
Basically, VFET amp owners will get the option to purchase a TDAC "At Cost" to compensate for the project delay, I'm not sure how much can be salvaged from the MDAC2 - but TDAC "build costs" will be affordable, maybe around GBP500 - GBP600, the "Solid aluminium chassis" will eat at a significant chunk.
I've got 600 tubes now in stock, after the VFET amps that will leave about 500pcs... TDAC will require 4 tubes per unit - so I can build about 100 TDAC's factoring in spare tubes.
Basically, VFET amp owners will get the option to purchase a TDAC "At Cost" to compensate for the project delay, I'm not sure how much can be salvaged from the MDAC2 - but TDAC "build costs" will be affordable, maybe around GBP500 - GBP600, the "Solid aluminium chassis" will eat at a significant chunk.
I've got 600 tubes now in stock, after the VFET amps that will leave about 500pcs... TDAC will require 4 tubes per unit - so I can build about 100 TDAC's factoring in spare tubes.
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