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Hi Paul,I received the Monica 2 about a month ago and thought it would be something different for Dmason to try in the Reali-T since he already has the SN DacKit. Regarding a shift in my direction, I see it like this:The custom SN DacKit board installation that I currently offer (see: http://www.redwineaudio.com/SN_DacKit_Installation.html) caneasily accept either the SN DacKit board or the Monica 2 board. Either bard can be used in that enclosure, which already contains the 12V SLA battery. ...
Do you have a preference sonically?
Just a thought about the phase inversion. Why not just reverse the + and - leads on the RCA's, directly on the DAC board. Then you don't have to play with your speaker cables at all and worry about switching them for this component vs another component every time you use it.Thanks,Bob
Would going from the 80 Mhz to say a 100 Mhz ocillator reduce the 8 nsec jitter to 6?
Ulas, Your analysis of the Monica 2 dac is making me rethink its purchase. But, for less than 150.00 I get to try a NOS dac, dc power, and reclocking. It should be easy to spit the power and power the analog from one supply and the digital from another. I had this is mind anyway, got a nice dual 7 volt 35 watt transformer. It should be fine for powering this unit. I listened to either an ACKDACK or a dactit once. Also the AN kit 1 dac. There were okay, but I like the sound from using a 3.00 micrp ...
100MHz doesn’t buy you much. Yes, it adds only 6ns rms jitter but that’s only 30 times higher than the natural PLL jitter. You would have to reclock at 8GHz before the reclock jitter was the same level as the PLL jitter. But what’s the point of doing that? All you’ve done is replaced Gaussian jitter with linear jitter. Also, my calculations assumed ideal components and conditions. I did not include the intrinsic jitter of the reclock crystal/oscillator (~100ps), the intrinsic jitter of ...
"hi vinnieappreciate if you could post this on audiocircle. thx!thx to ulas for his comments. i'll try to add in some.> From a strictly technical viewpoint, the Monica 2 is a poor design. First, all asynchronous reclocking adds jitter equal to the period of the reclocking frequency. In this case, the 80MHz reclock adds approximately 8ns rms jitter. i would suggest the measurements done by pedja on this page.http://users.verat.net/~pedjarogic/audio/tda1541a_dac/tda1541a_dac_rev_meas2.htmthe overall jitter does indeed increase but more interestingly, look at the spectrum. it's "spread out" further away from the clock freq.> Monica 2 is a budget design. It uses a single power supply that is shared by all the digital and analog circuits in the chips on the board. Putting everything on a single shared power source reduces the cost at the expense of increased noise. the pcb is built for separate supplies. there are separate power supply inputs. i test them by sharing the same supply but it is up to the user to use separate supplies if they wish to. if you hv bones to pick with the pcb design, let me point out that it is built double sided with one huge ground plane with the digital/analog grounds separated by a ferrite bead. some folks may not like the ferrite bead. well, just short it. > Speaking of noise~ The reclock latch appears to be a 74ACT374. AC/ACT logic is notorious for its high noise characteristics. The consensus at diyAudio.com is it should be avoided at all cost. The last thing I want in a DAC is noisy power and a noisy clock.you can draw any consensus on any diy audio forums. and talking to various people, there are so many things to avoid when it comes to diy. i don't know at the end of the day if anything ever gets built. more on this later.but enlighten me on this. with the asynch reclocked dac, how come i hear better overall definition/image? i don't know much about audio but a few things tell me i'm on the right track.1. music doesn't get more detailed than it is. if you hear more detail, it shows that something is masking this detail previously. so whatever you are doing gets more detail, this is the right path.2. if the system is quieter now, has lower background noise, then the system is doing it right.> If you thought reclocking somehow reduced or eliminated jitter, think again. If you prefer the sound of a reclocked DAC, enjoy.the question is, hv you listened to one?it's not that i prefer the sound of a reclocked dac. i listened to one with reclock and another without and everyone i could get hold of prefered the sound of the reclock. i'm not putting out asynch reclocked dacs just for fun. it's because i listened to it and clearly prefer this version over the rest. i appreciate your comments but i'm not going to try to explain technically any more as when it comes to sonics, very often being technical doesn't help.non-oversampling filterless dacs measure horribly but to my ears and lots of music lovers' ears, they sound right!single driver speakers measure horribly at the freq extremes but they sound right!even the "compact amp" on my website - the simple el84, is widely derided by some on diyaudio and audioasylum. but those folks who hv built it and listened to it, find that it sounds right!so at the end of the day, who is right and who isn't? typically i find those who put down these works are mainly those who have not listened to these circuits. just because "feeling" that it shouldn't work, doesn't make it sound bad.the internet is a wonderful place but with so much information, a diy newbie will not build anything. if he wants to diy with tubes, there'll be so many against him. like wise with solid state amps, class-t amps, upsampling dacs, non-os dacs, multi-way speakers blah blah blah.if you listen to everything, you will never get anything built.the monica and other non-os dacs on my site is meant to illustrate a few points.1. a lot of stuffs in audio is made to sound a lot worse than it is. yeah 7805 isn't a great regulator, but when used in conjunction with a battery supply, i think it's fine! that's why i don't build the power supply into it. it's up to the user to build whatever supply he prefers. i clearly prefer batteries!2. good sound can be had with simple circuits for very little cost. if you talk to experienced diyers, it seems good sound is so hard to get. everything seems not right, not suitable, not good enough... at the end of the day, nothing is right! you think tl431 is good? someone will tell you it isn't. and the list goes on and on...3. lastly, these dacs are also meant to show that it doesn't cost that much to build good gear. now compare this with the dacs on the market. you may wonder why my customers prefer monica over some audio note, yba, micromega blah blah blah dacs. maybe they are not bothered by all the technical stuff and prefer to listen. last point i want to make is that, i generally find non-technical diyers accomplish more than technical diyers. the non-tech guys just build and listen. if it sounds good, this is the right path! the tech'd guys think too much and don't build enough. worse still, their prejudice is so set, they don't even listen enough. and when they do listen, something in the back of their head says... this won't work.enough said. yeo...
I don't want to be spending more money getting yet another dac, but I think I may have to try this one out. I guess the only thing I've got going for me is that I do have an excellent sounding tricked-out Nixon DacKit which I really enjoy, so I can wait a little while to see how it all pans out.
the pcb is built for separate supplies. there are separate power supply inputs. i test them by sharing the same supply but it is up to the user to use separate supplies if they wish to.
you can draw any consensus on any diy audio forums. and talking to various people, there are so many things to avoid when it comes to diy.
the overall jitter does indeed increase but more interestingly, look at the spectrum. it's "spread out" further away from the clock freq.
but enlighten me on this. with the asynch reclocked dac, how come i hear better overall definition/image?
the question is, hv you listened to one?
so at the end of the day, who is right and who isn't? typically i find those who put down these works are mainly those who have not listened to these circuits. just because "feeling" that it shouldn't work, doesn't make it sound bad.
last point i want to make is that, i generally find non-technical diyers accomplish more than technical diyers. the non-tech guys just build and listen. if it sounds good, this is the right path! the tech'd guys think too much and don't build enough. worse still, their prejudice is so set, they don't even listen enough. and when they do listen, something in the back of their head says... this won't work.
enough said.
