JohnW
pfm member
430mm ! It's too wide John!
Just messin' with ya
I'm sure for a handful it will be
430mm ! It's too wide John!
Just messin' with ya
Sorry for interrupting the regularly scheduled program but as a relatively late backer, can I ask a few small questions?
1) What is this USB Detox Development option? Is it part of the MDAC2 or something totally different?
2) Is the MDAC2 mainboard still going to be shipped by itself and the case and HQ PSU developed at a later stage?
3) Where exactly is John at the moment? Is he developed globehopping powers so he can be in multiple places?
4) Has the company still got my details so I can be informed when it's payment time?
Thanks for this. I'm tempted to write to HFN and ask PM to show his workings. Chances of that letter being published?From here:
"Rise and fall time measurements for USB compliance
Mandate: Required
Effective Date: August, 2007
There has always been a problem accurately measuring rise and fall times, especially on high speed devices. The measurement of interest is the edge rate, or slew rate, during the state change time. To help improve accuracy of the measurement, the USB-IF is standardizing on one test fixture for high-speed signal quality.
Aside from the fixturing and probes used to take the measurements, major contributors to the inaccuracies in these measurements are the shape of the edge, noise on the signal and the method of calculating the 10% and 90% points as defined in Sections 7.1.2.1 and 7.1.2.2 of the USB 2.0 Specification.
A waveform with slow corners (see sample eye diagram below) will result in a measured rise time that is slower than the actual edge rate would indicate. Also a small change in the position of the 10% and 90% points due to noise on the signal, etc., can cause a relatively large change in the measured rise time."
USB 2.0 HS defines the fastest edge rate crossing speed as 100ps with a warning given for 300ps so any edge rates faster than 100ps will fail but it doesn't mention the slowest edge rate but the maximum interpacket delay times give an idea of this "So the maximum interpacket delay of a host's response to a device is <= 264 bit times + 60ns, which equates to 610ns or 292 bit times."
The FDAC is 430mm wide, 70mm High and 300mm to 320mm Deep.
+1.
If JohnW says an increase in SQ for the MDAC is/maybe possible with this proposed USB-Hub device with its own Linear PSU...I'll take such a unit....worth a punt I guess, if it's below the £100 mark?
A single box if possible please.....I don't like too many gubbins!
Also since this is expected to help iron out quality control issues for the FDAC......And it gives me something to play with while I wait for the FDAC...I'm in....
Oh yes it could well be. I get that. Have you seen the HFN article though Simon? the frankly the two eye diagrams look so similar that I still can't see it.Adam, isn't he just describing it away with that slower/ faster corners bollocks. Reducing noise gives faster corners, faster corners give a faster edge rise time that is cloiser to expectations based on the slope alone.
Seems to me like he's admitting its just a measurement frig.
Oh yes it could well be. I get that. Have you seen the HFN article though Simon? the frankly the two eye diagrams look so similar that I still can't see it.
And use anyone one of these Detox at the beginning and end of a USB cable?
F.s.
I am currently using a Jitterbug on one end and a Regen on the other. The fact that both have a positive effect suggests that John's 3-stage solution will be better still - and that one will be sufficient.
Mine was almost certainly an extreme case - in hindsight a windows laptop plus MDAC/Meridian amp/Focal Utopia speakers was a seriously bad idea and it's taken a while to overcome the noise problem. Now that I have, it's great, and I appreciate how much detail was hidden in the noise floor.
We know computers are inherently noisy and that USB wasn't designed with music in mind: what's harder to grasp is that noise that you can't actually identify as such (it's not obvious, like tape hiss, for example) can nevertheless affect the sound. The effect of cutting it right down is akin to seeing HDTV for the first time.
I am currently using a Jitterbug on one end and a Regen on the other. The fact that both have a positive effect suggests that John's 3-stage solution will be better still - and that one will be sufficient.
Mine was almost certainly an extreme case - in hindsight a windows laptop plus MDAC/Meridian amp/Focal Utopia speakers was a seriously bad idea and it's taken a while to overcome the noise problem. Now that I have, it's great, and I appreciate how much detail was hidden in the noise floor.
We know computers are inherently noisy and that USB wasn't designed with music in mind: what's harder to grasp is that noise that you can't actually identify as such (it's not obvious, like tape hiss, for example) can nevertheless affect the sound. The effect of cutting it right down is akin to seeing HDTV for the first time.