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MDAC First Listen (Part 00101001)

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Any M-DAC owners have experience of the Regen USB in conjunction with a SBT? Or JW perhaps you could answers based on the theory? I want to know if the M-DAC remote would still be able to control the SBT is used in via the Regen?

Anybody use SBT (edo) – Regen – M-DAC and have any experiences to share sound wise?

Thanks.
 
JohnW said:
Ian,

I understand your proposed system - but cost is an issue :)

Ideally you should have one master FDAC plus 2 slaves, and really 3 pairs of VFETS - but that's just not financially viable!!! - so I suggest just stay with your current FDAC Master + single slave and we will work with your existing MDAC for LF output (via the Master DSP / SPDIF connection).
Click to expand...

Sounds like a good idea :)

So just to confirm my understanding, all the DSP settings for all three "ways" would be set in the master FDAC, and all that the slaves do is do the digital to analogue conversion? But wouldn't that require a separate spdif output from the master FDAC to each of the slaves (one of the slaves being my MDAC) ?

I think VFETs on the bass would be wasted don't you ;-)
Having them on the treble would be nice, but I'll be happy with my Ncores there, despite the total overkill power-wise.
 
ti33er said:
...however might a single VFET powering some MartinLogan not be a more sensible solution!? 8-/
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And might even sound better, but that is spoiling the fun ;)

I am going to use 2 pairs of VFET into these (passive)
Epicon8-ruby-ugrill_600_mirror.png

So slightly less overkill :D
 
iansr said:
Sounds like a good idea :)

So just to confirm my understanding, all the DSP settings for all three "ways" would be set in the master FDAC, and all that the slaves do is do the digital to analogue conversion? But wouldn't that require a separate spdif output from the master FDAC to each of the slaves (one of the slaves being my MDAC) ?
Click to expand...

Yes, the Master FDAC DSP's will process all channels and output the DSP'ed processed data via the Slave interface / SPDIF outputs - with the other Slave / DAC's just being "Flat response".

iansr said:
I think VFETs on the bass would be wasted don't you ;-)
Having them on the treble would be nice, but I'll be happy with my Ncores there, despite the total overkill power-wise.
Click to expand...

I think the VFET's will make Excellent "Bass" channels as they will be able to effortlessly swing high peak currents, don't underestimate how much "resolution" is required to reproduce clean accurate Bass.
 
fusion5 said:
I've used my dark side drawing skills to make this picture:

DSC_0359_vfet.JPG


Your amps might be a bit overpowered just to drive an AMT Tweeter or two small midrange chassis. But on the other hand.... :D
Click to expand...

I was thinking about it while out to diner - the solution is to use fewer Mosfet output devices for the Mid's and drop the current dumping (only having the low power VFET Class A section for the tweeter)... this would reduce the cost - but the reality is the chassis cost around GBP500 EACH so are the largest single cost of the project.
 
JohnW said:
I was thinking about it while out to diner - the solution is to use fewer Mosfet output devices for the Mid's and drop the current dumping (only having the low power VFET Class A section for the tweeter)... this would reduce the cost - but the reality is the chassis cost around GBP500 EACH so are the largest single cost of the project.
Click to expand...

Argh.. the dark side is strong..

Could you send me a price estimate via PM?
 
JohnW said:
I think it was a crazy idea to go through the whole effort to "ReGen" the USB Data and then to power via a switching PSU which would inject extra RF leakage currents into the system!

To me it just suggests that the designers missed the point of the whole exercise...

I look forward to measuring a unit - I'll test with both a SMPS and Linear supply.
Click to expand...
I wouldn't be so dismissive about SMPSs today - you can now get resonant "soft-switching" SMPSs in very small packages and many of them apparently pass the EMI/RFI safety regulations because I've seen a few new ones in a local hospital few months ago.
Maybe it'd be an alley worth investigating a little.
 
jirij said:
I wouldn't be so dismissive about SMPSs today - you can now get resonant "soft-switching" SMPSs in very small packages and many of them apparently pass the EMI/RFI safety regulations because I've seen a few new ones in a local hospital few months ago.
Maybe it'd be an alley worth investigating a little.
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Have you seen the design difference between medical equipment and consumer Grade Equipment? There are VERY strict guidelines for Earth leakage current in medical equipment for the very reason that the Consumer grade SMPS are so very poor.

I find I receive an unpleasant "Tingle" when gently running my fingers along the edge of Apple Laptops (and all Apple Metal body products). This Tingle is due to the Earth Leakage currents of there SMPS designs.

There is a huge difference between the Dynamic range of a HiFi system and the allowable level of RF that will still pass the CE limits.

I've designed Low RF SMPS (the FDAC uses a very high performance local Switching regulator to improve efficiency) and they are vastly different and more complex then any plug-in the wall AC adaptors.

Yes, SMPS can perform very well - but I never seen a consumer grade unit that does.
 
JohnW said:
I was thinking about it while out to diner - the solution is to use fewer Mosfet output devices for the Mid's and drop the current dumping (only having the low power VFET Class A section for the tweeter)... this would reduce the cost - but the reality is the chassis cost around GBP500 EACH so are the largest single cost of the project.
Click to expand...

Get thee behind me Satan ! John that is a truly wicked temptation re just the VFETs for the tweeter. Given that I'd have the really nice enclosure s for the full VFET amps I'd be very happy with just a generic case for the tweeter amps - you could get something with heatsinks for about £200 I reckon.
My Ncores could then be used for the bass and they are the perfect amps for that; loads of power, extremely neutral and transparent.
 
iansr said:
Get thee behind me Satan ! John that is a truly wicked temptation re just the VFETs for the tweeter. Given that I'd have the really nice enclosure s for the full VFET amps I'd be very happy with just a generic case for the tweeter amps - you could get something with heatsinks for about £200 I reckon.
My Ncores could then be used for the bass and they are the perfect amps for that; loads of power, extremely neutral and transparent.
Click to expand...

The only one of its kind in the world: that's surely almost irresistible! :)
 
jirij said:
I wouldn't be so dismissive about SMPSs today - you can now get resonant "soft-switching" SMPSs in very small packages and many of them apparently pass the EMI/RFI safety regulations because I've seen a few new ones in a local hospital few months ago.
Maybe it'd be an alley worth investigating a little.
Click to expand...

The Ncores come with SMPSs and nobody has any complaints about them.
Edit. Just seen your post John. I think the NCore smps is an example of a very high quality one.
 
iansr said:
The Ncores come with SMPSs and nobody has any complaints about them.
Edit. Just seen your post John. I think the NCore smps is an example of a very high quality one.
Click to expand...

Maybe we will start complaining about the nCore SMPS when we have heard the VFET in our systems.
 
Ian,

Yep, I visited the vendor in China and I don trust the quality - they are still a fall back plan if my preferred option does not come through - but my experience says this vendor would be a whole bag of hurt.

My crazy idea for the lower power Class A was to modify a "full" VFET unit by simply modifying the PCB to remove the current dumping stage - otherwise its not practical from a time perspective - the chassis is an integrated part of the design (the PCB is designed around the Chassis).

Sadly, the chassis being CNC milled from solid ingots are expensive - the current quotes are around GBP500 each, but then they do represents the quality of the design :)

This are a once in a litfetime design - my personal units will serve as my reference amplifiers :)
 
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