MDAC First Listen (part 00100011)

[JohnW]

I'm sure that if John wished to start a global empire, maximising profit and efficiency then the 1st thing he would do would be to employ a project manager.

Then MDAC2 would probably end up being an overpriced (to pay for the project manager for one) compromised box of mediocrity like so much that already exists in life.

Patience is a virtue.

Paul,

A very big thank you from Renata and myself (and our little gang of 4) for the Christmas card - you got all bases covered, A blond lady wearing boots + the small dog Brilliant, I'll be keeping this card !

 

[JohnW]

How much does the modification cost? Does it take a lot of time? I might be interested.

We will recommend a machine for upgrade (such as the Oppo as this is a fairly common design and well featured) - its important that the player has internal access to the direct DSD stream not all players are compatible - in fact most are not as they process the DSD stream in some way.

The board with installation will be about GBP400 its quite a involved and fiddly process... (which also involves machining the rear panel).

 

[Joke721]

We will recommend a machine for upgrade (such as the Oppo as this is a fairly common design and well featured) - its important that the player has internal access to the direct DSD stream not all players are compatible - in fact most are not as they process the DSD stream in some way.

The board with installation will be about GBP400 its quite a involved and fiddly process... (which also involves machining the rear panel).

Thank you for information. This seems to be quite challenging!

 

[Vinz]

Vinz - you may wish to amend this post.

I don't mean it in a bad way. At my work I struggle with many technical issues all the time (atm I/O, microfluidic, ...) but I like it anyway. I'm sure many people share that (sadistic) feeling.

 

[ilmostro749]

LarsS,

I appreciate your offer - but if I where 'managed' then I'd loose the very 'ethos' of my designs.

I'm with you, I'm a total nightmare and why I've never been fully employed by a company, rather always worked as s consultant which gives me that extra flexibility I require.

As we approach production then I really need to consider employing someone to take on this burden (I've put this off until the Lab is completed due to space issues) - production needs organisation, planning and follow through - this are not my skill set!... but its a good start to see ones weakness

I counting on the PCB subcontractor to arrange general component sourcing - I'll source (collect) the more critical components during by visit to China.

I have to agree with Lars.

John if you were a bus driver, we would be on a journey to some unknown destination, but rumours of it being DisneyLand, every other junction you'd take a tangent because it seems like a good idea or it is a nicer route. None of your passengers would know when they are going to get there, or where 'there' even actually is.

When I got my M-DAC over 2 years ago, I mostly used it on headphones, and wanted to occasionally use it with some small desktop speakers (the amp is in my 'office'). I joined this forum and saw the talk of the M-AMP, M-IMP or whatever, and looked at the pictures:









So I assumed that the work was well underway - but that's not the case, and it gets less and less likely every week because a small project to upgrade a few M-DAC's to Fusion Spec turned into an epic 2 year design project. This tangent is now tangenting into a V-FET amp project and then circling back into an old T-DAC project. We'll be stopping off at the clock locking CD player - thankfully Audiolab made the M-CDT so you don't need to make the M-TRN. Will the M-DAC matched power amps ever see the light of day? Who knows!

For this reason I got the M-PWR. Because you know, even a mediocre Audiolab amp sounds infinitely better that a pipedream!

I'm sure that the many JW sycophants will be outraged by this post, but please understand that this is not in any way meant to offend. I do hope that your many projects come to fruition, but I fear that you will run out of time before you run out of talent.

In all honestly, if I were you I'd take up Lars's offer, even if he only gives a few hours a week, maybe reading the PM from PFM forum or doing a ruff project plan / timeline or whatever. Anything to help you stay on track!

 

[JohanH]

Anything to help you stay on track!

Please reread Johns answer.
He is on track; on the road to perfection.
While I agree I'd like to be there sooner rather than later, adding a PM would probably do more harm than good.

Anyone is free to join or not and to leave or not.
Me, I'm staying and patiently waiting and following the progress.
Keep up the good work John

Cheers,
Johan

 

[BrianC]

For the VFET amps, is it to say that the only first 10 watts is pure class A sound ?
More than 10 watts, the current dumpers start to kick-in to supply the remaining demands of the speakers ? So my question is for above 10watts, is it still class A or a blend of Class A, AB ?

As John has said the temp is about 50deg on heat sink, it's considered warm to the touch. So the bias of the output stage (current dumping circuit) should be moderately low, right ?

 

[Ale79]

Personally I love the ride! It's great fun to read through these posts everyday: my wife has "Beautiful" (a never ending us soap opera) and I've got John!
I think I'll be mildly disoriented when the time comes to install my MDAC 2 in my system, what then?..
This is also a great way to keep in check my spending, if it wasn't for John I'd probably be continually buying new components in search of that ever so elusive perfection.., but with John's projects I've transferred the burden on him and I just sit back waiting for the end result!

 

[therixonator]

John, I think I've got the same problem as busb. Sometimes it refuses to come on altogether, I.e. blank screen. Then a few hours later it's fine again. Is this the crystal? Does it get replaced with the M-DAC2 board or is it a trip back to CZ. Btw my unit is a Toy upgrade.

 

[jansen]

Personally I love the ride! It's great fun to read through these posts everyday: my wife has "Beautiful" (a never ending us soap opera) and I've got John!
I think I'll be mildly disoriented when the time comes to install my MDAC 2 in my system, what then?..
This is also a great way to keep in check my spending, if it wasn't for John I'd probably be continually buying new components in search of that ever so elusive perfection.., but with John's projects I've transferred the burden on him and I just sit back waiting for the end result!

+1 !!!!!!! yeah

 

[JohnW]

John, I think I've got the same problem as busb. Sometimes it refuses to come on altogether, I.e. blank screen. Then a few hours later it's fine again. Is this the crystal? Does it get replaced with the M-DAC2 board or is it a trip back to CZ. Btw my unit is a Toy upgrade.

Yes, this is typical of a crystal fault - the whole PCB is swapped during the upgrade so will no longer be an issue.

You have a lifetime "return to base" warranty on your MDAC toy - so I'll repair your unit for free at anytime...

 

[JohnW]

For the VFET amps, is it to say that the only first 10 watts is pure class A sound ?
More than 10 watts, the current dumpers start to kick-in to supply the remaining demands of the speakers ? So my question is for above 10watts, is it still class A or a blend of Class A, AB ?

As John has said the temp is about 50deg on heat sink, it's considered warm to the touch. So the bias of the output stage (current dumping circuit) should be moderately low, right ?

Brian,

With the current dumping topology the ClassA VFET amplifier stage is ALWAYS controlling the load - with the current dumpers "boot strapping" the ClassA amp so that it only ever gets to 'see' a 10W load...

Its not the same as a ClassA/AB design where the design might be ClassA for a few watts then an abrupt change into ClassB operation.

Whats important is that there is no abrupt change in output stage impedance as the dumpers start to contribute to the signal.

The design as rather complex, as the Dumpers are Non Switching (always on) and error corrected so that the ClassA amp does not see nasty abrupt transitions unlike the Quad designs...

The Dumper stage itself is HIGHLY linear (not the ClassC design of the Quad), and part of the development stage will be to test the Dumper stage openloop... I'm expecting 0.001% type THD figures... then you have the "Beautiful" ClassA VFET stage determining the 'sound' of the design

Its not Pure classA, but where it matters that the Amplifier output source impedance does not significantly vary across the audio cycle and without abrupt discontinuities of loop Gain the VFET design behaves like a ClassA design.

ClassA sounds good for a reason, and I believe its due to these two reasons.

BTW, 60 deg is considered "hot" too touch, you can leave your hand on 50DegC all day long...

 

[iansr]

Limostro
Calling most of the followers of this thread sycophants simply demonstrates your naivety and lack of perspicacity. We have worked out that John is a rare animal in the hi fi world. Firstly, he is an exceptionally knowledgeable and creative designer. Second, bullshit is as alien to John as a silicon based life form is to planet Earth. Third, he is remarkably fair and generous; do you know any other manufacturer or designer in hi fi who supports, often FOC, products that they no longer have any legal or commercial responsibility for?

The journey may take unexpected twists and turns and even involve going down some blind alleys, but most of us understand that is just part and parcel of John's modus operandi and without it John's creations would be diminished.

And if you think this is just sycophancy then I'm afraid you are again just not getting it.

 

[dtd]

@Limostro

As you've said, if you want something on time, better look elsewhere! Those of us already on waiting lists etc all know only too well that JohnW will do his best at his own pace. That's fine by us. He's semi-retired after all.

 

[misterdog]

Paul,

A very big thank you from Renata and myself (and our little gang of 4) for the Christmas card - you got all bases covered, A blond lady wearing boots + the small dog Brilliant, I'll be keeping this card !

John,

glad you enjoyed the subtle nuances, it was as if the card had been designed especially for you !

Did the Penguins turn up via e#mail a week or so ago ? if they have taken a detour on their journey from the south pole I shall have to chase them up.

 

[therixonator]

Yes, this is typical of a crystal fault - the whole PCB is swapped during the upgrade so will no longer be an issue.

You have a lifetime "return to base" warranty on your MDAC toy - so I'll repair your unit for free at anytime...

Hi John,

Cool thanks. Ok well let's hope it holds out until the M-DAC2 board is ready. If not, I guess I could just send the toy board over to you rather than the whole box?

With the M-DAC2 board, I wonder if they'll be any market for the hand made boards you made for us? I don't want it going to waste, but I've only got a need for one dac here. I guess everyone on here will want the latest and best stuff you've designed. At the very least is there anything salvageable on them you can use? I'll happily post it to you for nothing if it has a use for you.

Btw, I'm going to be after a level 3 as I'd like to go vinyl soon. Will need a phono stage too if you do design one. And if one exists could you add me to the interest list for the vfet amps if you do get hold of enough extra parts. It sounds too good could miss out on.

I'm also on the tdac list I think and I'd still like one. As always, no rush, just keep designing awesome sounding gear and I'll enjoy it when it's ready.

 

[ilmostro749]

Limostro
Calling most of the followers of this thread sycophants

I never said most - there are some who practice Idol worship (IMO), but that's always the case in all walks of life, and not John's fault.

The problem is that not everyone follows this thread that well, so unrealistic expectations have been built up. I know other people with M-DACs and they absolutely won't read this thread now because of this.

 

[ilmostro749]

Please reread Johns answer.
He is on track; on the road to perfection.

Johan - I read it well. This is not the first time you have criticised me. You know sweet FA about me, so please mind your own business, thank you very much!

 

[JohanH]

I don't remember criticising you before.
Nor was this meant as such.
So thanks

 

[jadidih101]

Since we are discussing creation, perhaps we could consider how God did it. God had every resource available to create the universe but God took six days to do it (rested on the seventh). I think God needed six day because God had to think it all through.

I recon if there was a PM or customers involved, God would have been forced to stop on the third day and we all would have missed out on what God created on the last three days.

I am probably going to hell for using God's name in vain but as I told John I had to sell my soul to the devil to afford the VFET amps.

John, I certainly do not believe you are God or a God but based on your long track record in hi fi world and my sense of your attitude towards your work I am willing to trust your judgement regardless of the extra time it will take.

I am not after just a hi fi product. I am after THE product.

Wishing everybody a happy Holiday.