[doggie]

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) can
easily 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?

[Vinnie R.]

Do you have a preference sonically?

Hi Paul,

I haven't done a "shootout" yet, and I just sold my last Monica 2 installation to a customer, who bought it with custom Clari-T monoblocks and a Puri-T!  He should have 'em on Monday...

Back to the comparison, to be fair, I'll have to do more listening to them both side by side.  The Monica 2 uses blacks gates, which in my experience, have a long break in time.   Also, the Monica 2 output voltage (around 0.7V) is lower than the Scott Nixon, so level matching needs to be done if I were to A/B test them.  

Both DACs are non-oversampling with passive I/V conversion stages (no opamps), and sound great with battery power!  

Once Dmason burns his in, I'd love to hear about his impressions of the Monica 2 vs. SN DacKit.  He can switch between the built-in Monica2 in the Reali-T, and his external SN DacKit feeding one of the inputs of the Reali-T.  

[duff138]

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

is this a possible alternative?   this seems like a good way to do it, at east for me because I have several other things hooked up to the stereo.

[randytsuch]

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

I think most circuits tie the RCA minus to ground, so I don't think this would work.  You can do it at the speakers since they are floating.  It would also work if you had differential outputs/inputs, like with XLR jacks.

Randy

[Ulas]

Would going from the 80 Mhz to say  a 100 Mhz ocillator reduce the 8 nsec jitter to 6?

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 the reclock latch (~10ps), nor did I account for the setup and hold times of the reclock latch (~5ns). Had I done so, the numbers would have been a lot worse.
 
I made this Excel spreadsheet to calculate asynchronous reclocking jitter.

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. 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.

[Panelhead]

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 micrphone transformer as an output stage just as much.
  Alas, I have never owned a dac. Always used a modified one box. Yet to hear a player and dac that is better. This goes back to the Pioneer PD-91 I used for close to 10 years. been a lot of SACD player through the system since.

                             George

[randytsuch]

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 ...

Hi george
I ordered the dac described here
http://www.diyaudio.com/forums/showthread.php?s=&threadid=51381&perpage=10&pagenumber=17
made by Peter Daniels

It is more expensive, a kit, does not run off batteries, and is just coming out.  I bought it based on Peter's reputation, so I could try a NOS dac.

Randy

[Vinnie R.]

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  ...

All,

Yeo of diyparadise just emailed me and mentioned that he lost his audiocircle login/password, and the site doesn't seem to be allowing him to create a new accout.

Here is his email, which he asked if I could post:

"hi vinnie

appreciate 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.htm

the 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

...

Based on Yeo's post, all I can say for now is that IMHO, Yeo has the right attitude towards this hobby.  Nice post Yeo!  

To my ears, and to Dmason's ears, the Monica 2 is one beautiful sounding dac!  I wasn't thinking about measurements, clocks, jitter, etc when I was listening...I was too drawn into the music.  This has THE MOST meaning to me!    

All you can do is give it a listen for yourself....you may end up liking it a lot more than dacs costing > $1,000... wouldn't that be a pleasant surprise  

[Dmason]

So how does it sound?

I don't know if the above question is pertinent to this techno-debate; I have had a Monica II DAC cycling almost full time for three days now and it is beginning to show itself to be unusually musical. The midband coherence is really very special, and the palpability and texture in the two octaves on both sides of Middle C are becoming extraordinary, despite the totally green state of the component parts. ie: this is one very promising design. Sorry to let you naysayers down, and you know who you are. I know, it shouldn't work, or maybe it is just plain "wrong," but I write this based on what Mr Yeo has to say and wanted to reflect on his healthy attitude, and salute that attitude.

"Those who can, do. Those who can't, teach."        -Rudyard Kipling

I am always impressed by the negativity that crops up in these damn audio boards. I thought it was supposed to be about music, after all. I can tell you this: apparently the Monica DAC is doing its thing connecting me to the music, because every tune I listen to I can easily, and I mean, EASILY identify the key signature. This is a phenomenon I attribute to the level of musical coherence inherent in the system. Ask yourself if that is a material point in this discussion.

[Horizons]

I bought an assembled Monica (original, no reclocker) and I love it to death. Powered by a 12V battery, it does sound better than the Nixon DAC I replaced it with.

Monica DOES have low output. I'm running mine into a tube pre and I have to goose the gain pretty high.

Yeo is a straight-up guy too.

[Dmason]

There. Someone said it before I did.

I didn't want to be the first, and it's very early on WRT the evolution of the Monica II, but I would have to say that the lower midband on this thing is SO smooth, despite all the green-ness, that my gut impression is that, yes, I agree with Horizons, and I am beginning to prefer the presentation of the Monica to my beloved Nixon DAC, which is no slouch either, and isn't going anywhere, anytime soon...

Synergy

I will also say that which I had concluded months ago, and that is that in my thirty years of tweaking audio, cursed-with-perfect-pitch, humble, musician's opinion, battery powered non-oversampling DAC's offer an unusual synergy with equally battery powered T amps. When careful attention is given to implementation, it gets really very special.

Addendum:

About the same time, three and a half years or so ago, just before I became aware of the Nixon DAC, I was auditioning the Zanden "Uber" DAC at home, also a non oversampling DAC, pointed out to me by Doug Schneider of Soundstage.com. A fabulously musical machine, and a shrine to industrial art, (and conspicuous consumerism) I might add. I might also add that it is a $12,000 piece. I LOVED the sound of the Zanden. Then the $250 Nixon came along. I didn't love the Zanden $11,750 more than the Nixon. Sonically, the Zanden is NOT in another league. I am beginning to prefer the sound of the $120 Monica II to the $250 Nixon. For the sake of my own musical enjoyment, frankly, I can afford the Zanden, because life is short, delicate, and there are no guarantees. After the Nixon, I couldn't JUSTIFY the Zanden. Again, I am beginning to prefer the Monica to the Nixon, and I really like my Nixon DAC. So, if you want to get it "right," and you don't DIY, get the Zanden. It's twelve grand, and you will be assured, you Got It Right. Enjoy.

[Horizons]

Dmason, your hearing is very similar to mine.

Never heard the Zanden but I sure fantasied about owning one.  I would never say anything negative about the Nixon DACs. Superb value and sound for the money and they also happen to sound as good or better than many kilo$ DACs out there.

The Monica to my ears sounds more extended at both freqencies than the Nixon. It also sounds a little more analog in the mids. I also believe that the 12V battery has a lot to do with how well this DAC sounds. If you are powering your Nixon or Monica with a wall wart, all bets are off IMHO.

The combo of Monica, tube stage, and the digital wonder JVC F10 is music to my ears. Relaxing as music can be.

[Dmason]

Horizons,

The JVC F-10 and especially the ES-1 are even better examples of this object lesson in diminishing returns. People thought I was nuts advocating such dreck. The JVC was just plain "wrong."  ...The rest is history.

The Monica II presentation has a sort of "airy" quality, it floats along, almost as if there is a very subtle phase shift, but of course there isn't, just a ham-handed analogy. The FR on both ends has extended noticeably from the time I left the house and came back. Onward and upward.

[Wayne1]

I have changed a few things around in my office system today. I have been doing some minrt mods to a DeHavilland Ultra Verve preamp. I put that in place of the Clarinet. WOW  What a great preamp. BIG FAT sound. It maches up really well with the JJAZ 500 watt stereo amp I am breaking in for a customer..

With all these changes the Monica 2 works just fine. No problems with gain. I still can't turn the volume past 12:00.

I did hear a SN Tube DAC in my system and didn't care for it. At the time I did prefer the modded DI/O. I have been listening to the Mensa and the Monica 2 on and off throughout the day. Right now I am listening to the Reprise Collection of Frank Sinatra. For this music the Monica 2 wins out over the Mensa.

As Dmason mentioned it is VERY analog sounding. In comparison the Mensa is analytical. For some systems and some music, the Mensa would be preferred. Right now, in this set-up i just want to have a cocktail and listen to some more Frank on the Monica 2  

[KT]

Wow! Yet another exciting affordable-but-incredible-sounding component to try.  

So I went to diyparadise.com and couldn't find it anywhere. Also, did Yeo solve the payment issue yet? I really want to get one. What's the status on this?

I'm really interested in the Peter Daniel kit, too. What to do... what to do? How long before a shootout of all these great dacs is done?

Right now I'm running a Scott Nixon DacKit on SLA and I really like it a lot. I've also got a SN built TubeKit board that's configured like the new generation TubeDac+ which I still have to put together.

I have all the dacs I need but I still want to try the Monica 2. Dang!

Dmason, you've done me right before by steering me towards the JVC ES1sl and I thank you greatly for it. You may be steering me in the right direction again, but I must know one thing first: does your SN DacKit use the Blackgate N output caps, as featured in the Monica 2? If not, do you think the changing these to BG Ns would bring the sound of the DacKit closer to the Monica 2? I ask because I don't want to buy an extra dac (even though it is a great bargain) if I can upgrade my current DacKit and achieve similar results. Please let us know!

And let the fun continue!

Best,
KT

[Dmason]

KT,

I have no idea and I wish not to speculate. All I know as of now is that the design is wrong and that it sounds increasingly right, with each passing hour.

Listening right now to the Yellowjackets, it is liquid and funky and kinda sleazy just like the tune is trying to present. It works a treat. So I am not going to opine. I only trust my ears, and every tune can easily be identified in its key signature. That tells me more than what type of capacitors. Screw capacitors. Get the Monica II and try it. Like I said, I prefer so far, the Monica, and I love the Nixon DACkit.

[KT]

Dmason,

Wow, sounds like you are in the throes of audio nirvana. When you don't care about what a premium capacitor can do for you anymore, you must have truly found the music!

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.

I'm very interested in seeing how the Monica II finally settles in as well as how the Peter Daniel dac turns out. Hope Yeo doesn't raise the price by then!

Oh, and I did find the diyParadise link to the Monica II. It was right there in Wayne's initial post. Duh.

Best,
KT

[doggie]

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.

Hi KT,

I am assembling a SN DacKit as we speak to go with my modded SI amp. I will be running it from an SLA battery. Would you mind elaborating on any upgrades you performed on the DAC.

Thanks a lot,

Paul

[ooheadsoo]

Funny, this is only the second time that I've heard that the timbre of instruments can affect the ability of people with perfect pitch.  Since I don't have perfect pitch and relative pitch doesn't work ANYTHING like that, I sometimes pity those with perfect pitch.  but only on these few rare occasions...  Makes me wonder what happens when you come across an old crappy piano bar!  So this Monica will do it, eh?  Could be a fun trip for only about $150.  I hope my coming dac will do it as well.

[Ulas]

In reply to Yeo of DiyParadise:

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.

Good. In the picture that was posted here I saw only one regulator and assumed the PCB was designed for only one supply.

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 AC/ACT logic family is well known for its noise; that’s why it is rarely specified in new designs. As I recall, AC/ACT was one of the first CMOS logic families to equal the speed and drive of TTL logic. In those days, if you wanted TTL speed and drive but the low power consumption of CMOS, you didn’t have very many choices. Today there are many more choices and matching the performance of, or interfacing with TTL is seldom a requirement. Unless you evaluated every 5-volt logic family and determined ACT sounded the best, I see no good reason to use it. In this case, the consensus at diyAudio is correct.

 

the overall jitter does indeed increase but more interestingly, look at
the spectrum. it's "spread out" further away from the clock freq.

Ideally, you want the spectrum to be as narrow as possible. If the spectrum is “spread out” it means more clocks are farther away, in time, from where they should be. That means the each sample is more likely to be in the wrong place. The result is distortion.

but enlighten me on this. with the asynch reclocked dac, how come i
hear better overall definition/image?

Do you really expect me to comment on what you hear? In audio, human perception rarely correlates with scientific measurements.

the question is, hv you listened to one?

Listened to one what? A reclocked DAC? No. But what difference does that make? I have not commented on the audio performance of your DAC. I only gave a brief technical critique of your design from what I saw in the picture posted here and from what I read from you web site. If you must know, I prefer non-oversampled, filterless DACs that are clocked from FSYNC (when appropriate) or, preferably, from a local oscillator, but never SCLK.

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.

I didn’t say your DAC wouldn’t work or that it sounded bad or that no one should buy it. I am very sorry if you got that impression.

So, at the end of the day, except for the provisions for two power supplies, you haven’t refuted anything I wrote.

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.

I find non-technical diyers outnumber technical diyers. Perhaps it’s because the techies can find gainful employment pursuing their heart’s desire and don’t have to diy, whereas the non-techies, because they lack the technical knowledge, are left to stab-and-try. Both camps are capable of producing work that is good, bad, or indifferent. Why do non-techie, design-by-ear diyers always compare their work to the high-price stuff? “Just as good as blah-blah but cost much less.” Why don’t they compare their work to the absolute reference, live music? That’s what most of the high-end (high-priced) builders use as a reference.

enough said.

Agreed.