[Wayne1]

DIYParadise.com is offering a fully assembled NOS DAC circuit board for $115.00 plus shipping.

This uses the 1545 DAC and reclocks the digital input at 80 Mhz.

I have just received a couple of them to play around with.

The assembled version comes with leads soldered to the board with RCA jacks. All you have to do is hook it up to 12 VDC and you are ready to go.



I have listened to the assembled version for a few hours now. It is very nice sounding. In comparison to a Mensa Plus DI/O, it does seem to lack dynamics and high end and low end extension. I am sure things will improve in time. It does use BlackGate "N" series coupling caps.

I thought I would mention this for folks who may be looking for a NOS DAC that could run off a 12 VDC battery. It does invert phase so you will have to switch your speaker cable polarity around.

[Figo]

I have been waiting to order one, apparently yeo of diyparadise is having problems with his online payment system because of the country he is in (Malaysia).

When he gets it worked out I will post impressions after I receive mine... it does seem like a great deal.

[JoshK]

Yeo is a great guy to deal with too!  My tube preamp that some have seen is based on his Simple 5687 preamp and sounds too darn good for the little money it costs to build it.

[Vinnie R.]

DIYParadise.com is offering a fully assembled NOS DAC circuit board for $115.00 plus shipping.

This uses the 1545 DAC and reclocks the digital input at 80 Mhz.

I have just received a couple of them to play around with.

The assembled version comes with leads soldered to the board with RCA jacks. All you have to do is hook it up to 12 VDC and you are ready to go.



I hav ...

Yes, this is the dac that I installed in Dmasons custom Reali-T and it is a great value!  

I've been playing with one for the past few weeks and am really enjoying it.  Yeo at diyparadise is getting very, very busy these days  

Regards,

[Vinnie R.]

In comparison to a Mensa Plus DI/O, it does seem to lack dynamics and high end and low end extension. ...

Hi Wayne,

Out of curiousity, what are you using as a preamp (active or passive)?  I've been using it with just a 10k passive attenuator and the dynamics seem to be there in my sysytem, but this dac has a lowish output voltage of around 0.6V - 0.7V (as opposed to the conventional 2V dvd/cd player output voltage).  Therefore, with a passive attenuator, the volume needs to be turned up higher than usual.
Yeo mentions that the 1545A chips can be paralleled (piggy backed) to get more output voltage, but he says doing so doesn't sound as good to him.  Have you tried doing this yet?  I haven't...just curious.

Regards,

[Wayne1]

Vinnie,

I just hooked it up last night in my office system.

I am running it into my modified Hagerman Clarinet tube preamp.

The output is a bit lower, but there is plenty of gain in this system.

Running it all day so far, the dynamics do seem to be getting better.

I am a bit concerned about the phase and impedance issues. I may experiment with a transformer on the output of the DAC so phase can be switched as desired. This could also increase ouput levels if needed.

[BRN]

I have been wanting to purchase the DAC from Yeo and ran into the same problem as Figo. I went to order the kit and was not able to because of the online payment system. Go figure when I want to get something there is always some problem.

I did not know that the DAC inverted phase and I was concerned about the low output as well. I was thinking of thinking of using step-up transformers for the voltage problem. I guess the concern is the reduced current when doing this. When I brought the topic up to Yeo he said that if you run long IC's this can cause a problems. I have 1M IC's, but can shorten them to accomidate the transformers. Not sure if I would be able to kill to birds with one stone using step-up trans for both phase and voltage. Since I'm not an expert on these try of things I was hoping to get some imput on what the people on the forum think.  

Let us know what the final outcome is with the DAC.

Brad

[Wayne1]

If you are using a passive preamp, the lower output level might cause a little bit of a problem. With my active tube preamp, I do have to turn it up a bit more than the DI/O, but it still is far too loud at 12:00 to 1:00 on my volume control.

If you are just using one input, the DAC, there should be no trouble with phase. You can just reverse your speaker cables polarity. If you are using multiple sources, then you might run into some problems.

http://www.jensen-transformers.com/as/as042.pdf

Here is a diagram from Jensen showing how to hook up one of their transformers so you can switch phase.

Edcor makes some less expensive transformers that will also work in this application.

BTW, my credit card transaction went through very smoothly with DIYParadise.

[Vinnie R.]

Vinnie,

I just hooked it up last night in my office system.

I am running it into my modified Hagerman Clarinet tube preamp.

The output is a bit lower, but there is plenty of gain in this system.

Running it all day so far, the dynamics do seem to be getting better.

I am a bit concerned about the phase and impedance issues. I may experiment with a transformer on the output of the DAC so phase can be switched as desired. This could also increase ouput levels if needed.

Hi Wayne,

>>Running it all day so far, the dynamics do seem to be getting better.

I ran mine for about 24 hours straight, but in my experience, those Black Gate caps (especially the signal caps) take time to break in and sound their best.  To me, the midrange purity is quite good.  The treble is on the relaxed side...smooth with good detail, not too analytical.  

I recommend you also try it with one of the Tripath boards you are working on, and using a 10k passive volume control.  I thought that a higher impedance volume control would be best (in order not to load down the passive I/V stage of the dac), but 10k sounded better to me than a 25k and 50k volume control (more bass AND dynamics).  

The Monica 2 seems to have nice synergy with the Tripath amps, which are very fast and dynamic to begin with    
Pretty nice little dac board, and Yeo has been a pleasure to deal with too!

Regards,

[Wayne1]

Thanks for the suggestions, Vinnie.

I will give it a try.

[Figo]

This thread just makes me want the DAC more

Hurry yeo, hurry!

[Vinnie R.]

This thread just makes me want the DAC more

Hurry yeo, hurry!

Poor Yeo!  He is in the process of moving and we're all ganging up on him      

Looks like his Monica 2 board are a big hit!

[Jay S]

Great - keep us in the loop!  I think that there is some tweaking to be done with these non-OS dacs to improve frequency extension and dynamics.  My Tube Dac improved after Scott updated the specs (mine was an early version), but it still can't match the Mensa DI/O in these aspects.  

Anyone have a good source with 2 coaxial digital outputs?  

By the way, this may be a dumb question, but why does a non-OS dac (redbook is 44.1 kHz) have an 80 mHz clock?  Wouldn't the clock need to be some multiple of the sampling frequency?

[Ulas]

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. Furthermore, the reclock jitter has a linear distribution where all possible values have equal probabilities. In other words, the likelihood that any particular clock edge occurs 8ns later than it should is the same as any particular clock edge occurring 1ns late or any other deviation from the correct time. The jitter from the CS8414 receiver is spec’d at less than 200ps rms. The natural jitter of the PLL in the receiver has a Gaussian distribution where the closer a value is to the correct time, the higher its probability. In other words, most of the clock edges will be at or very close to the mean frequency of the PLL.

Again, discussing non-oversampling DACs from a strictly technical viewpoint, the period of the DAC sample clock should be identical to the period defined by the sample rate of the digital audio data. Any deviation in the period during the D-to-A conversion results in distortion in the analog signal. A 1KHz sine wave at 0dBFS reclocked at 80MHz has a calculated S/N about 5.5dB lower than the same signal without reclocking.

If you thought reclocking somehow reduced or eliminated jitter, think again. If you prefer the sound of a reclocked DAC, enjoy.

[konut]

Ulas------ you dont get invited to alot of parties do you.  

[bubba966]

Anyone have a good source with 2 coaxial digital outputs?  

Yes. My Pioneer DV-AX10 has dual coax outs. The Pioneer DVD/LD players also have dual outs, but aren't up to the quality level of the AX10.

[Panelhead]

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. Furthermore, the reclock jitter has a linear distribution where all possible values have equal probabilities. In other words, the likelihood that any particular clock edge occurs 8ns later than it should is the same as any particular clock edge occurring 1ns late or any oth ...

Ulas,
  I goimg to try one anyway. My first try with NOS. From a technical point of view does a higher frequency ocillator help. Yeo told me that the flip flop can only handle 125 Mhz. Would going from the 80 Mhz to say  a 100 Mhz ocillator reduce the 8 nsec jitter to 6?
  I am not convinced on the NOS dacs. The ones I have heard were not any better than a modified one box player. But I have not heard many, and none were in a system that I knew the sound of to begin with.
 
                          George

[doggie]

Yes, this is the dac that I installed in Dmasons custom Reali-T and it is a great value!  

I've been playing with one for the past few weeks and am really enjoying it.  Yeo at diyparadise is getting very, very busy these days  

Regards,

Hi Vinnie,

I had assumed that you would put the Scott Nixon NOS DAC into Dmason's Reali-T. Does this represent a shift in your direction? Will you be moving toward the diyParidise DAC?

Thanks,

Paul

[BobM]

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.

Anyone know the output of the DAC chip? I like the idea of a transformer output (helps filter out the high frequency grunge that NOS DAC's are known to produce). What ratio would be best to achieve a standard 2V output?

Thanks,
Bob

[Vinnie R.]

Hi Vinnie,

I had assumed that you would put the Scott Nixon NOS DAC into Dmason's Reali-T. Does this represent a shift in your direction? Will you be moving toward the diyParidise DAC?

Thanks,

Paul

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.  

Therefore, I can offer either board in this custom installation.  This gives my customers another flavor to choose from.  

Regards,