MDAC First Listen (part 00011110)
- Thread starter ChrisPa
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A consideration - how does that play with the idea of synchronizing with one of your amplifiers? I remember some class A / B switch on the amplifier side when the volume got below a certain level.
Is this something unrelated to the analogue attenuator, with MDAC2 being always at full output when running with your amps (attenuation done on the amp side)?
Thanks,
Jiri
JohnW
pfm member
Jiri,
Your 100% correct - in an ideal system the source should output at full level and the amplifier change its gain structure as required depending on level thus maximising the use of the amplifiers Open loop Gain.
The MDAC2 will disable its internal Analogue Gain scaling when it detects the MIMP / MAMP.
The MDAC2 analogue Gain scaling come into it own with conventional systems - especially those with excess gain where the MDAC is used with more then -40dB of Digital attenuation - I don't understand why they have so much gain.
JohnW
pfm member
Its good for any application where the listening level is used below -20dB as the Analogue attenuation reduces the level of Digital attenuation required.
Let say you listen at -25dB, then the Analogue attenuation takes care of the first 20dB and then you only need 5dB of digital attenuation.
The MDAC automatically select the attenuation mode as required, so will automatically bypass the analogue attenuation for levels above -20dB, so you can still reach full the output level of 2.2Vrms.
jansen
pfm Member
Sit back and enjoy the ride. This is up to John. We're all spectators. John's designs and his design process have always been entertaining and simply require a little patience 
[/QUOTE]
That is what I do since I'm into this project and why I support it. It entertains me so much more than hifi magazines or stores (even more than active listening sometimes)It puts me into an active process (without much understanding in technical issues) and I learn so much. It is also fun to read some pointed contributions of others here. And for sure I'm so very excited about an unique product with special features, developed in an ethos far beyond any industrial produced gear. We don't have so many opportunities to enjoy such in capitalistic reality. Go on John!!!
Regards,
Jansen
[/QUOTE]That is what I do since I'm into this project and why I support it. It entertains me so much more than hifi magazines or stores (even more than active listening sometimes
)It puts me into an active process (without much understanding in technical issues) and I learn so much. It is also fun to read some pointed contributions of others here. And for sure I'm so very excited about an unique product with special features, developed in an ethos far beyond any industrial produced gear. We don't have so many opportunities to enjoy such in capitalistic reality. Go on John!!!Regards,
Jansen
Regarding the -20dB attenuation on the MDAC2 side - assuming the switch is going to be software-controlled, it might be useful to allow setting the threshold value via later software updates, if possible. For example - I now listen via headphones at -16dB (balanced), which might become -19dB with the more powerful analogue stage on MDAC2, so I'd experience quite a lot of switches just by slightly adjusting the volume. This could be solved by disabling the attenuation for headphones, but then again - there are people with more efficient headphones (Hifiman?), who might run at, say, -28dB, and who would benefit from the attenuation.
This might not be a problem if the switch is done without mechanic parts and without pauses in the music (which were a consideration with the power amp, if I recall correctly).
Not something critical, but it could be useful to have it in the "todo" list for future firmware versions.
JohnW
pfm member
Yes - the attenuation relay is control via software - so there will be a software menu option to enable or disable the "Automatic" Analogue attenuation mode. We can also fine-tune how the Relay is controlled in use / with headphones etc.
For special uses (like Headphone only) we could offer custom output levels to optimise the listening levels - the attenuation could be set to say -10dB or some such... but really -20dB is the maxim attenuation I can apply with the MDAC2 circuit, with the -20dB attenuation, the feedback resistor is reduced to 10ohms, thankfully the MDAC2 has a REAL power output stage and takes the 10 ohm load within its stride.
JohnW
pfm member
Sit back and enjoy the ride. This is up to John. We're all spectators. John's designs and his design process have always been entertaining and simply require a little patience
That is what I do since I'm into this project and why I support it. It entertains me so much more than hifi magazines or stores (even more than active listening sometimes
)It puts me into an active process (without much understanding in technical issues) and I learn so much. It is also fun to read some pointed contributions of others here. And for sure I'm so very excited about an unique product with special features, developed in an ethos far beyond any industrial produced gear. We don't have so many opportunities to enjoy such in capitalistic reality. Go on John!!!Regards,
Jansen[/QUOTE]
Jansen -
Thank you for your valued supportIll just chime in an and say that I'm 100% behind JohnW. I'm supporting an artist here, and of course he need to have all the creative space he need, THAT will give ME the best product.
So John...Kep un dreaming and we will try to support you.
( and in the meantime ill try to decide if i relay need those b&w 801 s80, or that it would be possible to live with just my pair of Martin Logan Vantage....tuff one )
So John...Kep un dreaming and we will try to support you.
( and in the meantime ill try to decide if i relay need those b&w 801 s80, or that it would be possible to live with just my pair of Martin Logan Vantage....tuff one
)Yes, inserting headphones would enable a new DSP Profile - you have the option of crossfeed or Tone controls / EQ if desired - or just totally bypassed
Now we are talking!
fusion5
on the dark side of hifi...
Exactly! The more I think about this, the better it gets. I prefer a future-proof design.
Keep up the good work!
Michael
JohnW
pfm member
Ill just chime in an and say that I'm 100% behind JohnW. I'm supporting an artist here, and of course he need to have all the creative space he need, THAT will give ME the best product.
So John...Kep un dreaming and we will try to support you.
( and in the meantime ill try to decide if i relay need those b&w 801 s80, or that it would be possible to live with just my pair of Martin Logan Vantage....tuff one
Thank you and everybody else for the kind words of support and encouragement.
Those B&W speakers are going to be a very different beast to your Martin Logan Vantage - Vantages seem like a very good speaker - I really miss my ESL's. I look forward to the new lab being completed so I can set-up the listening room with my CLS's or the Aeons... The CLS's are very fussy about the room - they either work very well, or they are terrible, the Aeons are much more room friendly.
Its said that ESLs are best driven by Tube amplifiers (atleast the Quad ESL's) - not sure how this pans out for "hybrid" ESL's... I suspect the Bass section is best driven by a solid state amp - while the ESL section might be better driven by a tube Amp - but you would have a hard time matching output levels between two different amplifier types and I'd guess its not a good idea to mix and match amplifiers without being able to correctly match the units gain and phase etc.
The other day I found a Quad II Classic Integrated tube Amplifier under my Lab bench I'd completely forgotten about - its a Tim Paravacini design which also has a decent Phono stage - its had only a few hours use, if anyones interested in making an offer I'd let it go cheap as I have no need for it + I'd be able to stretch my legs after all this time
JohnW
pfm member
She has a 4 ohm tap - let me test her in the morning, if everything tests out OK, I'll send you some pics
(and the test results) Being a Tim Paravacini design she meant to be very good
- I've only heard good things about the design - its always been rated very highly Here the cheapest unit I could find on Ebay - I'd accept much less as its without original packaging... I'll first confirm that its in perfect condition both electrically and cosmetically
http://rover.ebay.com/rover/1/710-5...0001&campid=5338728743&icep_item=301133189122
This site contains affiliate links for which pink fish media may be compensated.
Really??? I am so excited. I don't post here much but I've read about 1000 pages and I never heard this before. An analogue "in" is the only thing that is missing from the MDAC 2. Now I really can't wait. I almost bought an Auralic Vega last week as it's getting hard to wait. I'm game for the best DAC that you can make...this year though, please!
JohnW
pfm member
Jim,
The Analogue input (Analogue bypass) is fixed level, so you will need a method to adjust the level of your analogue source (a simple passive pre-amplifier will do)
We will make an external Analogue attenuator available at a later date if your need a variable (adjustable level) input based on the extremely HQ Khozmo 48 step stepped attenuator - which will be controlled via the MDAC2.
Oh Yes - I can promise the MDAC2 will be out THIS year
Steven Toy
Accuphase newbie
Christmas!
I'm in no rush. L3 Toy is still thrilling.
I'm in no rush. L3 Toy is still thrilling.
JohnW
pfm member
Provisionally sold then.
Have you tried it with your ML's ?
Qual. Cab. email may be better.
Regards Paul.
Paul,
You have PM
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