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MDAC first listen (part V)

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You can always try and see what works/sounds better. In my case, it was a no-brainer: MDAC straight into my power amp was so much better than having the pre-amp in the chain. I have since sold my pre-amp and I do not miss it one bit.

Bluedroog said:
Does anyone have any experience or thoughts on using the volume on the M-DAC in conjunction with a separate pre-amp? Would it defeat the object of having a separate pre-amp? My pre-amp does not have a remote control and having remote use of volume control is something quite important to me. I want the pre in the system.

I will be running a SB Touch in to a DAC, then Croft pre / Quad 900 power. I did in the past use the volume on the SB but found it really didn’t work well, I had a hiss issue which disappeared when I disabled it. So will setting the pre volume at a fixed point and then using the volume on the M-DAC work without any limitations?

Cheers.
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I guess all I can do is try and listen for myself in the context of my system. Having a pre-amp for analogue inputs is a large consideration as I want to incorporate the pre-outs from my AV amp. I understand the M-DAC may be able to take analogue inputs with an add-on in the future?

Out of interest what pre-amps have you guys been using that you preferred to take out of the chain? I like the solid sound a tube pre can bring and also have not enjoyed success using a DAC as a pre in the past, I understand the M-DAC is more geared up for acting as a pre mind.
 
Bluedroog said:
Does anyone have any experience or thoughts on using the volume on the M-DAC in conjunction with a separate pre-amp? Would it defeat the object of having a separate pre-amp? My pre-amp does not have a remote control and having remote use of volume control is something quite important to me. I want the pre in the system.

I will be running a SB Touch in to a DAC, then Croft pre / Quad 900 power. I did in the past use the volume on the SB but found it really didn’t work well, I had a hiss issue which disappeared when I disabled it. So will setting the pre volume at a fixed point and then using the volume on the M-DAC work without any limitations?

Cheers.
Click to expand...

I borrowed Primare's new class D A34.2 power amp for a week with my M-DAC feeding it directly via an XLR lead. The sound was just startlingly good to my ears driving my bi-wired Totem Arros. The most apparent trait was the level of detail I've never heard before.

The volume control works very well on the M-DAC - far better than on my Primare i21, despite having the same volume increments. Because the i21 has a remote, I'm swapping it for a now old Restek Challenger with its volume up full & M-DAC feeding directly into the power amp section. Works fine with the Restek as it did with the A34.2.

The volume is normally set from about -20dB downwards. The A34.2 in particular sounded very good at low volumes so I didn't worry too much about external fixed attenuators between the M-DAC & amp. At -80dB I can barely hear anything - unlike the i21 where the difference between 0 & 1dB was quite a jump (it worked the other way round to the DAC).

Driving a power amp directly makes the M-DAC an even better bargain, IMO.
 
Bluedroog said:
Does anyone have any experience or thoughts on using the volume on the M-DAC in conjunction with a separate pre-amp? Would it defeat the object of having a separate pre-amp? My pre-amp does not have a remote control and having remote use of volume control is something quite important to me. I want the pre in the system.
Cheers.
Click to expand...

It will work, but in this configuration you are adding more electronics between the source and the poweramp, for no obvious purpose. Unless the preamp is doing some form of impedance matching there really isn't any way it will improve the sound quality. However it may act like a sort of tome control / filter which may give you a sound you prefer, but maybe not as accurate. Using the MDAC to get rid of my preamp was possibly one of the biggest single upgrades I've done.
 
Hello,
I would like to know if, as well as adding the MPax PSU, there are other upgrade options for the MDac. I understand some owners are sending their units to JohnW but I wasn't able to clarify whether it was for tweaking or repair. I was particularly interested to know if an asynchronous USB 2.0 solution is in the works and, in case it is, whether it will be a separate box solution or an internal aftermarket mod.
I'm sorry if these questions have alredy been answered, I tried to read through the whole thread but might have missed some posts...
Thanks,
Ale
 
Ale79 said:
Hello,
I would like to know if, as well as adding the MPax PSU, there are other upgrade options for the MDac. I understand some owners are sending their units to JohnW but I wasn't able to clarify whether it was for tweaking or repair. I was particularly interested to know if an asynchronous USB 2.0 solution is in the works and, in case it is, whether it will be a separate box solution or an internal aftermarket mod.
I'm sorry if these questions have alredy been answered, I tried to read through the whole thread but might have missed some posts...
Thanks,
Ale
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Hi Ale,

I offered to tweak a unit for a customer who's unit failed - as a way of compensation as I feel bad every time I hear one of my designs failing...

The MTRN (CD Transport) will include a Async 192 USB input and will be optically isolated and clock locked with the MDAC.

We might release the Async USB as a standalone unit...

At the moment I'm fighting this "Budget DAC" design.

John
 
Sebbyp said:
Keep fighting this Budget DAC design John.. It sounds so good I may have to just buy it to hear it!
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I'm wondering how good it will be.

To meet the price point I'm really pulling my hair out - almost everything is discrete...

Its got ClassA MOSFET CROSSII output stage :)

Class A PSU (read Shunt regulators)

Dual Diff DAC's (Separate DAC IC's per Channel)

On cost grounds we could not use the JFET's in the discrete opamps (as we did on MDAC) - but we have used MOSFET's in the output stage - and I've re-design the circuit to be better suited to Transistors in the input stages.

The PSU is a major update - in fact based upon the MPAX circuit... simulations seem promising (although simulations say nothing about sound quality).

I believe its going to be a real killer of a DAC :)

I guess I'm really excited about this DAC as I've really pushed my design skills :) and developed many new circuits - Dom's also got a few tricks up his sleeve for the DSP & Software :)

John
 
JohnW said:
Hi Ale,

I offered to tweak a unit for a customer who's unit failed - as a way of compensation as I feel bad every time I hear one of my designs failing...

The MTRN (CD Transport) will include a Async 192 USB input and will be optically isolated and clock locked with the MDAC.

We might release the Async USB as a standalone unit...

At the moment I'm fighting this "Budget DAC" design.

John
Click to expand...

Hello John,
Thank you for your reply. I sincerily hope you'll release the Async USB standalone unit, I think many music lovers are veering towards computer audio. I, for one, would promptly buy it!
I bought your Mdac today and can't wait for it to be delivered!!!:D I don't know if you are alredy taking orders for the MPax, if so I would be very grateful if you could sign me up for a silver unit, please let me know how to proceed to place a formal pre-order.
Thank you very much,
Ale
 
ADL said:
Hi John,
This new dac will spund better then the mdac?
Click to expand...

To be very honest I don't know ATM.

1. The ESS DAC's are MUCH cheaper then the 9018 used in MDAC - but then we using a pair in Dual Diff. mode (one DAC per Channel) - from my experance in the past this has made a big difference.

2. MDAC has pairs of matched JFET's on the input stage of the CROSS circuit which are too expensive to use on the budget dac - but then the budget DAC has an updated and much improve "CROSSII" circuit that uses MOSFET's in ClassA in the output stage. Also I optimized the input stage which (now) uses transistors to reduce its sensitivity to RF IMD. Again from past experience MOSFET's OPS sound VERY good - "CROSS" version 2 should sound VERY good (hopefully).

3. We cannot fully bypass the Budget DAC's internal digital filter (which is akin to MDAC's "fast" filter which is universally disliked) - but we are externally pre-processing the data to hopefully bypass its effects - how effective this will be remains to be seen (heard).

4. The budget DAC has the best PSU I've ever designed (based upon simulation results) - I've spent a couple of months developing the circuit - its a derivative of the pending M-PAX PSU circuit - but again I've not listened to it, but working on my gut instincts its should sound very good (With Hi-Fi there are no certainties)...

5. It does support Async 192 USB... and will be half the price of MDAC...

I'd hope it will sound better then MDAC - it will sound different that's for sure, weak points are the use of Transistors in the CROSS input stage, and "un bypassed" internal Digital filter - but I'm hoping (believe) these will be more then compensated for by other the circuit refinements...

I am really looking forward to the design - for sure it will offer unbelievable performance for the money :)

John
 
I kind of hope it desn't sound as good as mdac after spending £600 on one only last month :rolleyes:

Hopefully there'll be some upgrades/tweaks for MDac users along the way that keep it up the top of the sound quality hierarchy. Wonder how much better Mpax will make it sound?

If your new budget DAC does sound as good there'll be an awful lot of Mdacs appearing on the classifieds over the coming months.....

Any idea on an eta for the new dac?

John
 
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