My M-dac has inbuilt digital volume and it sounds very good hooked up direct to my mono blocks but i run the M-dac full gain through a AS passion pasive preamp because it sounds better that way because it gets full resolution of the music.
The M-Dac has a 32 bit processor, which if properly implemented allows you to 'throw away' 16 bits before impacting the resolution of a CD standard data stream.
This is a volume reduction of 96db, the music would be effectively inaudible at this level so any difference you are hearing is being caused by something else, most probably the 'buffering' effects of your preamp.
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My preamp is passive and uses input direct which bypasses the selector switch.
I told JW the designer of the m-dac this is how i use it and he agreed with me.
JW will be launching his own brand soon and the amp he has designed to be fed direct by the m-dac will auto adjust its sensitivity so that the m-dac is always playing at full resolution.
Go ask the M-dac designer if you dont believe me.
No need to get so defensive, the Passion is a fine device but like all passive preamps it will alter the transfer characteristics from the dac to the power amplifier. Audio Synthesis are well aware of this which is why, in the link you provided, they offers guidance as to the impedance matching of the other components.
I have no idea what is going on in your system but if the differences you are hearing are real it is unlikely to be the loss in resolution caused by the digital volume control, 40 db attenuation represents a reduction of resolution from 32 to 25 bits, hardly significant given that the actual resolution of the M-dac is unlikely to more than 17-18 bits.
Have you got a M-dac and passion and tried for yourself.
JW the designer of the M-dac understands and agrees with me and is building his new power amp to adjust its sensitivity as the volume on the m-dac is turned up and down so that the M-dac is always running full resolution.
I can hear the difference so can JW.
If you read the M-dac thread over on PFM JW helps and updates M-dacs he also makes or tells them how to make inline attenuators so guys can use higher volume settings on the M-dac because it sounds better that way.
The sound going through my passive only passes through 2 resistors same as using attenuators.
You make it sound like the retail product isn't properly finished.
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Its the way digital volume controls work they throw away resolution at low volume.
You make multiple changes to a system, introducing an extra component, changing the impedance of the interface, use the amplifier in a different part of it's operating range and find that you can hear differences to the way it sounds.
That is hardly surprising, what is surprising is that you can identify the use of the digital volume control as the only cause of these changes.
Interesting how you know how my system works and sounds without hearing it.
Interesting you know more than JW the designer of the M-dac.
My mono blocks are 150 watts and only need 413mV for full power and my speakers are 90db and i dont play loud so when run direct the volume on the m-dac is turned way down low so outputs lower resolution.
Run it through a transparent passive like the Passion at its full volume the M-dac plays at its highest resolution.
Have you tried it yourselve before you post on here that im wrong ?
Ive run the m-dac direct into 3 different power amps and run it direct into the Passion into my TVC passive into my Tom Even active preamp and into my Glasshouse preamp same result the m-dac sounds better running full output into a preamp.
As I have said before I have no reason to doubt what you say and I have never suggested that you are wrong.
I have simply pointed out that a properly implemented digital volume control operating within the context of a 32bit processor should not be audible.
If you are hearing a clear difference then most likely it is caused by something else. I was simply suggesting what the causes of this difference might be by applying some simple scientific logic to the issue.
If you want facts and numbers and detailed description of how the volume works on the M-dac join PFM and ask in the M-dac thread where Mr Westlake the designer can tell you all you need.
Link him this thread and ask away how and why he is designing his own power amp to self adjust its input sensitivity so that the M-dac when run direct into it will always be at optimal volume.
Unlike the ADM 9.0 9.1 9.1T 9.1RS 9.1RSS, obviously.
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Yes the original ADM were perfect in every way and as good as good gets and if anyone said they are bass light well they dont know what real bass sounds like because the small ADM produces perfect bass and cant be bettered even by large floorstanders.
The then perfect ADM got even more perfect with every new version and the latest also have warmer fuller bass than the original that was said to be perfect.
The perfect bass thats better than floorstanders is then bettered by the ADM40 floorstanders but thats only because AVI are the only company in the world that can make floorstanders with perfect bass.
There is a big difference in selling a newer and improved product when advances in technology and design become available rather than suggest that owners tweak with some form of DIY mod. If the product is genuinely not as good as with the modification, shouldn't the retail product then be updated to include the improvements?
Continuing to sell a sub par product and not include the upgrade doesn't seem very forward thinking. In addition, if the designer is aware of a problem and believes that the units digital volume attenuation is defficient in some way, even just the principle of digital attenuation, then why wasn't the unit fitted with an analogue volume control, such as the previously mentioned 'Passion' preamp?
Interesting. So the original ADM9s were below par? Great to see you guys admitting that, takes guts.
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