Product: Monica 2 Zero-Oversampling DAC kit
Manufacturer: DIY-Paradise
Approx cost: variable depending on options (normally < 125$)
Reviewer: Nick Whetstone - TNT UK
Reviewed: November, 2005

Intro

I bought my first CD player in 1987, A Marantz CD65 with no remote control (remember those days?). I had auditioned a number of CDP's at a local hi-fi shop and thought that they sounded much the same. As I remember, the CD65 cost around 370 pounds, a not insubstantial investment for me, even when I was working! I consoled myself with the thought that it was a long term investment. After all, wasn't CD 'the perfect format'? So why would I need to spend any money on a source (or upgrade) for a long time to come!

A couple of years later and the hi-fi comics were full of talk of this DAC and that DAC and it seemed that you couldn't possibly enjoy CD's unless you had a stand-alone digital to analogue converter. And what was worse, most of them cost as much as a CDP and I was by then out of work and only able to dream of what one could do for my listening enjoyment. Fast forward to the last couple of years and the mysterious DAC has been exposed, simplified to little more than a couple of chips, and made available to just about everybody whether they want to build their own, or buy one of the kits or modules on offer from various suppliers. I took the plunge last year and ordered a DacKit from Scott Nixon. It was fairly easy to put together, and was a subtle but obvious upgrade to the sound of my modified Philip's CD723. I have been very happy with the DacKit but was pleased to get the chance to review the DiyParadise Monica2 DAC and compare the two.

Both the DacKit and Monica2 are NOS DACs. The NOS bit standing for non over-sampling. I'm nowhere near qualified enough to write about the technical aspects of this type of DAC but a quick 'Google' on the subject will provide plenty of reading! You can also have a look at our own DIY zero-oversampling designs here on TNT-Audio: TNT Convertus and TNT 1541. I believe that the original idea came from Ryohei Kusunoki of Sakura Systems (please read our exclusive interview with R. Kusunoki).

The Monica2 DAC differs from the Dackit by using a TDA1545A DAC chip (instead of the 1543). But the big difference is that it is re-clocked, or to quote DiyParadise, "it has asynchronous re clocking of the 3-wire eiaj signals". Goodness knows what this actually means but consulting one of my 'digital gurus', it seems that this should make for quite an improvement! But before we find out if it does, let's take a look at the what you get for your money.

DiyParadise obviously pride themselves on producing high quality items and as with their class-T amplifier module, the Monica2 comes with few corners cut. The PCB is silver plated (no tin for Monica!) By making the PCB double sided, the size is kept to a minimum and you could probably install this DAC inside your CDP if you wished. The component list is also impressive; with Black Gates and Oscon capacitors providing the 'reassuringly expensive' factor.

You can choose how you buy the Monica2. If you wish, you can buy just the PCB and pick your own favourite components. DiyParadise can supply you with the TDA1545 DAC chips. Or you can buy a whole kit with everything supplied except the 12 volt DC power source (eg a battery) and the case and connectors. Or you can buy an assembled and tested module. Even the last option will only cost 125 USD which makes this affordable for just about anybody.

DiyParadise are to be further commended for the clear way that they explain how to build and connect their DAC module. You can see on this page how everything is clearly illustrated.

Even if they are not confident enough to try building a module, anybody with some basic soldering skills should be able to put a pre-built one into a suitable enclosure and solder the connections to the input socket and two output sockets. Apart from that, the module only requires connecting to a suitable 12 volt DC power supply and it's ready to play!

So what does it sound like?

When I first put Monica2 into my main system, hooked up to my modified Philip's CD723, I noticed little difference between it and the Dackit. Thinking about this carefully, I remembered something that I had read on Scott Nixon's site about these DAC's preferring to work into a 20K load. My stepped attenuator was a 10K type so I ordered a 25K stepped attenuator kit from DiyFidelity in Australia. These are something of a bargain whether you order them as a kit, or ready-built. Amazingly, the attenuator arrived (here in the UK) just one week after I placed my order.

As soon as I had built the new attenuator, I installed it in my passive pre-amp in place of the 10K. I had gone back to using the DacKit because it has a higher output level than the Monica2 (I'll say more about that later). As soon as I played some music, I could hear a significant improvement. The sound was good with the 10K but now it was as though it was more freely escaping the loudspeakers and flowing into the room. I quickly knocked up another 25K attenuator, installed it in another passive pre-amp, and connected that to the Monica2 in my second system. A 12 volt battery was pressed into service and I sat back to listen.

The first thing that I noticed, was that the music sounded very 'analogue'. And this was with the DAC fed from an un-modified CD723! I did a few more listening sessions on this system and then one morning I went to listen and there was no sound. I had accidentally left Monica2 powered up and the battery had discharged. I put the battery on charge but keen to play some music, I picked up a spare SMPS module and connected it to Monica. I don't know quite what I was expecting but the result was dramatic!

When I reported this back to DiyParadise, they told me that they are actually developing a dedicated SMPS for both Monica2 and Charlize so I am not the only one to hear the benefits of this type of power supply.

Powered by the SMPS, the sound improved another couple of notches. Bass became deeper by what appeared to be another half octave, and was tightly controlled. And it was the same at the top end, the 'window' appeared to have been opened wider in both directions! Cymbals and other metallic sounds positively shimmered. I have never heard a top end so well portrayed. Detail was also improved and I would say that this DAC is a match made in heaven for one of the class-T amps (like the Charlize that is 'co-incidentally' made by DiyParadise). And still the sound was smooth, non-fatiguing and another step away from that 'digital sound' that we have all been trying to escape from since the birth of CD back in the early 1980's.

Playing some jazz, I noticed how well the acoustic double bass sounded. You could actually here the fingers contacting the strings. Imaging was superb with each performer and instrument clearly defined. Vocals were crystal clear and I could hear the female vocalist's breath, and even her lips parting after she had paused. As with the DacKit, the sound stage is also noticeably deep with Monica2, something that I noted on all the tracks I auditioned her with!

Turning to Nitin Sawnhey's 'Prophesy' I played the final track of that album and again found the control over all the different elements absolutely superb. This track gets quite 'busy' but with Monica2 in control, each element was easily distinguishable. Moving onto a Keb Mo CD (always good if you are looking for plenty of bass), I played a couple of tracks from the 'Keep it Simple' album. Again, the quality of the bass was commendable, as were the vocals, crisp guitar strings and timing. Putting on the Easy Stars All-Stars CD, 'Dub Side of the Moon', I was greeted with a wide sound stage with everything clearly spaced out between each side wall of my listening room. Bass lines 'danced' along so well, it was very hard not to listen to the whole album!

Trying something completely different, I listened to a few tracks from the Bryn Terfel CD, 'If Ever I Would Leave You'. Mr Terfel is better known for his opera singing but on this album he sings some favourites from the world of film and stage musicals. Listening to 'With a little bit of luck' (From 'My Fair Lady'), I noticed in the chorus that I could clearly hear individual voices rather than one mass of singers. Next I tried something classical, Hayden's piano concerto number 7. Here, the individual violins were clearly audible separately although they were playing together. The piano was realistic and placed in a realistic sound stage. I find that I need a good system to really enjoy classical music and I did enjoy it with Monica2!

Back with something a bit more modern, I played the Gwynneth Herbert CD 'Bitter Sweet and Blue'. Again vocals were particularly clear, as was each instrument. With the Monica and SMPS, I noticed that the bass went deeper than I had heard it before. In fact both bass and percussion (drums in this case) were very well portrayed. It was much the same with the Norah Jones album, 'Feels like Home'. The presentation being so clear as to make it seem as though Norah and her piano were actually in my room.

Moving up tempo a bit, I put the Shania Twain CD 'Up' into the CD723 and went to the track 'Ka-Ching'. Shania's producer (who also doubles as her husband - lucky chap) has gone for a big sound on this album. In fact some of it reminds me of the Phil Spectre sound from way back in the sixties. It would be easy to 'lose' the vocals in such a lavish production but with Monica, they are not lost and in fact it's quite easy to pick out the lyrics while enjoying the cacophony of sound and heavy, but well-defined bass lines. This is a dynamic CD and Monica2 does a very good job of following whatever is happening.

It was while listening to the 'Up' CD that I found the top end just a little - well I won't say tiring but a little 'too much'. I swapped the SMPS for the battery and listened again. Bass wasn't quite so deep but the top end was also tamed and the 'problem' solved. I also noticed that with the reduced bass and treble extremes, the overall effect was slightly more coherent. I think whether you prefer the SMPS or battery with a DAC like the Monica2 will probably depend on personal taste and the rest of your system (and even what you are listening to). But all-in-all, whatever I listened to, using Monica2 with either the SMPS or battery, was very enjoyable. It is a step up from the DacKit with slightly more detail, and possibly a more analogue presentation.

Moving Monica2 to my main system, I had an interesting experience with Roger Water's CD, 'Amused to Death'. Recorded with 'Q Sound', this album features an amazing assortment of sound effects that are placed all around the listening room. Comparing Monica2 to the DacKit, I noticed some details that I had not picked up with the Dackit. But the DacKit seemed to better place the effects around the room. That's to say, each effect was more definitely located. I also felt that the DacKit was slightly more 'punchy' and therefore more suited to this type of music. Consulting Yeo at DiyParadise, he confirmed that his preferences are for a musical sound rather than a 'hi-fi' sound, and therefore the choice of lower capacitor values on the output. Monica2 uses 4.7 uF Black Gate 'N' types, my DacKit has 47 uF 'NXQ's. I suspect the choice of output capacitor values will tailor the sonic signature of these DACs and fortunately, it is not difficult to change them! But as it comes, with the 4.7 uF capacitors, the Monica2 is optimised for a 'musical' rather than a 'hi-fi' sound. If you listen mainly to jazz, acoustic music or light classical you will find this DAC superb. If your preference is more for rock music, you may prefer the DacKit, or the Monica2 with higher value output capacitors.

I mentioned earlier that I had found the lower output level of Monica2 to not be enough in my system. However, while auditioning Monica2, I was also still playing around with the class-T amplifiers. I had come to the conclusion that they may sound better with an active stage, ie a buffer or active pre-amp. Originally, I had listened to the class-T's using a 10K attenuator as they have quite a low input impedance. Unfortunately, this didn't suit the Monica2 or the DacKit so I had moved to 25K attenuators. Anyway, not to get too side-tracked from the Monica2 review, let me just say that I built an active pre-amp incorporating one of the 25K attenuators and put it in the main system in front of the Charlize amplifier. The improvement was obvious straight away but what I hadn't expected was it gave quite an increase in volume! To be honest, I had been wondering how Yeo had found the combination of Monica2 and Charlize to give enough volume but with the active pre-amp, the system now goes plenty loud enough for my tastes!

Conclusion

So, to sum up, I am enjoying the improvement that Monica2 provides over the DacKit. It's only with more up-tempo electronic music that I feel the DacKit perhaps has an edge and I may try some different capacitor values with Monica2 to see if I can achieve a better compromise. If you are game enough to try one of these DAC's and can solder on the connectors etc, you will most probably be capable of trying different output capacitors for yourself so I have no hesitation in giving this DAC a very strong recommendation! At the price, it's also a bargain!