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MDAC first listen (part II)

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Hi John can you put me down for an MDAC HQ PSU please. Thought I'd wait for the last one again :D

Eagerly waiting for PSU and mods to my newly ordered Touch as well.

Decided to take the plunge on the Touch. Current config is laptop win 7 asio4All foobar2K usb isolator combination and I'm occasionally getting dropouts late at night for some reason doesnt happen during the day. MDAC read as inactive so I have to unplug and reconnect. I've identified the fault to be with the Olminex isolator ( situated in between 2*1.8 mtrs of USB 2.0 spec cable) I don't think the USB port on my laptop is giving it enough juice. Doesn't happen a lot and as mentioned only late at night, but when it does its annoying and in fact so is the whole laptop as a source to be honest much prefer a source that doesn't take 5 minutes to boot up and thats after having to unpack the damn thing.
 
Plutox said:
That all sounds reasonable. It is often very difficult to tell which end of a USB link is to "blame" for a problem because the link is a two way street and an irregular or corrupted response can cause the link to hang, awaiting something that will never come. If the data become corrupt because of a power thump or whatever, the link could fail and neither end may necessarily be blameworthy.

If you had a driver issue too (driver for what?), multiple faults can easily compound the problem and confuse the results.
Click to expand...

Bare in mind the Laptop had the same USB playback/seize issue , which again points to the MDac/USB end of the chain rather than the PC itself
Not sure of what exactly the driver issue was tbh but the PC was saying 'driver issue' of some sort

About the USB seize/power issue im not overly bothered right now, with my right channel cutting out the unit will eventually be exchanged & if the USB problem persists then so be it, it's not a huge deal to have it seize playback once in a blue moon, it was more annoying when my old sub would trip it every 5 minutes! The latest culprit is the toilet flushing lol!

I'll be testing all my power points with that tester when it arrives...

PhilCTTE said:
. Current config is laptop win 7 asio4All foobar2K usb isolator combination and I'm occasionally getting dropouts late at night for some reason doesnt happen during the day. MDAC read as inactive so I have to unplug and reconnect.
Click to expand...

Have you tried just pushing stop & play to jog the connection? Or switching between sources on the MDac?
When my USB cuts out & shows 'inactive' i just push stop a few times then play & it resumes. If not i change to Optical, then back to USB & it shows as active.
 
I have an odd issue sometimes (prob once a week at most) with mine, its showing stuff on the level meter but no sound comes out... If I toggle the source up then down again (ie to coax 1 then back) then sound comes out. Has happened on all 3 types on input (laptop via usb, freesat via optical and SB Touch via coax).

Its always when I first switch on, never when I have been listening to something else and switch to that source.

Not a big issue, doesnt really bother me but thought I should raise it.

Any ideas?
 
Chronic, where do you live? I'm wondering if you are localish I could pop by and run through all the possibilities to get to the bottom of this for you.
 
Chronic said:
Bare in mind the Laptop had the same USB playback/seize issue , which again points to the MDac/USB end of the chain rather than the PC itself
Click to expand...
I think that's a unsafe conclusion...as I said, anything that causes a USB connection to become corrupt could legitimately cause the connection to 'hang'. The way each end handles this untenable position could easily give a false impression of 'blame'. In other words, what you are really testing is the gadget's ability to recover from an undefined state that ought not occur. Given that there still appears to be something of a mystery here...
Chronic said:
The latest culprit is the toilet flushing
Click to expand...
...it would be foolhardy to jump to too many conclusions. The above is suggestive of a weird earthing issue. The mains tester ought to reveal all.

Chronic said:
Have you tried just pushing stop & play to jog the connection?
Click to expand...
Pressing stop / play on music player software does not, in the normal course of events, reset the USB connection. In fact the only sure way of resetting a USB link is to disconnect it, wait for, say, 10 seconds, then reconnect.
 
PhilCTTE said:
... in fact so is the whole laptop as a source to be honest much prefer a source that doesn't take 5 minutes to boot up and that's after having to unpack the damn thing.
Click to expand...
With respect, a laptop that takes five minutes to boot up is either so slow as to be a liability or is so overburdened with crap in its various startup routines that it hasn't a hope of doing its real job properly.

While I'm not one of these obsessive folks who attempts to pare back every single process that isn't contributing to the hi-ness of the "fi", a low powered laptop shouldn't be carrying the burden of a whole host of spurious routines whose purpose is probably, directly or indirectly, to sell you something.

A small, dedicated netbook not otherwise used for surfing, writing or gaming (particularly the latter) should be almost the ideal source if your DAC has a decent USB input.
 
sq225917 said:
Chronic, where do you live? I'm wondering if you are localish I could pop by and run through all the possibilities to get to the bottom of this for you.
Click to expand...

Im in west london, if your local that would be much appreciated, if not i'll be testing all my mains soon with one of the testers Plutox suggested & will report back.

http://cpc.farnell.com/martindale-electric/ez150/non-trip-earth-loop-impedance-indicator/dp/IN04254

Plutox said:
I think that's a unsafe conclusion...as I said, anything that causes a USB connection to become corrupt could legitimately cause the connection to 'hang'. The way each end handles this untenable position could easily give a false impression of 'blame'. In other words, what you are really testing is the gadget's ability to recover from an undefined state that ought not occur. Given that there still appears to be something of a mystery here...

it would be foolhardy to jump to too many conclusions. The above is suggestive of a weird earthing issue. The mains tester ought to reveal all.
Click to expand...

Yeah im not jumping to many conclusions other than the USB connection being somehow affected by electrical signals when using certain appliances (hoover/CD player/old sub/toilet flush) i just don't think it's the PC's fault because the Laptop has the same issue.

The only reason i have an inkling its at the MDac's end is because the problem seems easier to trigger when using electrical equipment right next to the MDac, like switching on the CD player next to the MDac makes USB playback seize, but putting the CD player anywhere else & switching it on USB playback runs fine.

When i use this mains tester is there any tips?
Like does everything have to be unplugged from all the power points before i start testing them?
The tester itself looks easy enough to use...

Plutox said:
Pressing stop / play on music player software does not, in the normal course of events, reset the USB connection. In fact the only sure way of resetting a USB link is to disconnect it, wait for, say, 10 seconds, then reconnect.
Click to expand...

Yeah was just a suggestion really because when my USB seizes & says 'inactive', simply pressing stop/play or changing the source back/forth can kick it into action
 
Is the M-Dac plugged directly into a wall socket or into a splitter bar/power distribution unit?
Tried changing where its plugged in?
 
sam_cat said:
Is the M-Dac plugged directly into a wall socket or into a splitter bar/power distribution unit?
Tried changing where its plugged in?
Click to expand...

It's currently plugged directly into the wall & i also tried it on a surge protected/4 way extension (with PC/sub also plugged in to 4way) & USB playback can still seize

Some appliances like my 3000w heater if flicked on/off a LOT can cause the USB buffer to drop for a split second, but playback remains stable.
 
Chronic said:
When i use this mains tester is there any tips?
Like does everything have to be unplugged from all the power points before i start testing them?
Click to expand...
Yes, disconnect everything (i.e. remove the plugs) at first (if this is feasible) to ensure that any faulty appliances cannot corrupt the result.

These Martindale testers are very much 'go/no go' devices so anything other than 100% perfect results ought be investigated by a qualified pro. electrician.
 
Plutox said:
Yes, disconnect everything (i.e. remove the plugs) at first (if this is feasible) to ensure that any faulty appliances cannot corrupt the result.

These Martindale testers are very much 'go/no go' devices so anything other than 100% perfect results ought be investigated by a qualified pro. electrician.
Click to expand...

Ok, hopefully i get good results then, i don't think my friend really qualifies as a 'pro' so would have to pay for an electrician to come out

One of the mains/wall plugs will be very difficult to get to (cabinets built around it ) i'm currently running an extension lead off of it to have access to the power, do you think it will be ok to unplug everything from the extension lead & then test the extension itself considering all the other mains points in my room will be tested directly off the wall?
 
Plutox said:
With respect, a laptop that takes five minutes to boot up is either so slow as to be a liability or is so overburdened with crap in its various startup routines that it hasn't a hope of doing its real job properly.

While I'm not one of these obsessive folks who attempts to pare back every single process that isn't contributing to the hi-ness of the "fi", a low powered laptop shouldn't be carrying the burden of a whole host of spurious routines whose purpose is probably, directly or indirectly, to sell you something.

A small, dedicated netbook not otherwise used for surfing, writing or gaming (particularly the latter) should be almost the ideal source if your DAC has a decent USB input.
Click to expand...

I'll time it, as 5 minutes might be a tad of an exageration. Certainly wifi connection takes several minutes on top to obtain broadband connection.

I try to keep startup programs to a minimum. Mcafee is one. Will check later. Its just odd that this problem happens late night. Had it running several hours yesterday no problems at all.


Is there a utility to use which can provide diagnostics of usb activity.
Have no idea half the time of what processes are related to what app/os task when viewing via task manager.

I'll make an effort tonight to remove what I can. I noticed Sony Ericcson phone app is active all the time and also open office suite has some process milling around. So annoying when its not clear what process is related to which app. I've previously come unstuck when running a util called "crap cleaner" which removed processes and caused OS issues.:(
 
sam_cat said:
I have an odd issue sometimes (prob once a week at most) with mine, its showing stuff on the level meter but no sound comes out... If I toggle the source up then down again (ie to coax 1 then back) then sound comes out. Has happened on all 3 types on input (laptop via usb, freesat via optical and SB Touch via coax).

Its always when I first switch on, never when I have been listening to something else and switch to that source.

Not a big issue, doesnt really bother me but thought I should raise it.

Any ideas?
Click to expand...

Hi Sam,

The software with the "Lock update" improvements should help to resolve this,

John
 
Chronic said:
Ok, hopefully i get good results then, i don't think my friend really qualifies as a 'pro' so would have to pay for an electrician to come out

One of the mains/wall plugs will be very difficult to get to (cabinets built around it ) i'm currently running an extension lead off of it to have access to the power, do you think it will be ok to unplug everything from the extension lead & then test the extension itself considering all the other mains points in my room will be tested directly off the wall?
Click to expand...

I'm beginning to wonder if the Ground is somehow missing from your MDAC's USB connection - well at least DC Ground - the USB "Shell" is AC coupled which could explain why it still "functions".

To "diagnose" this fault condition (without proper equipment) you could get a second USB lead - plug it into a spare USB port on your PC, and with the other end of the USB cable touch the metal "shell" of this leads USB connector onto one of the MDAC'S RCA audio output's "Ground" connection (The Audio "Ground" is the "Metal" body of the RCA connector).

Somehow keeping the metal ends touching together - tightly taped together maybe? (Metal of USB connector shell to the MDAC's RCA Audio Ground connection) - then flush your toilet (I'm guess your Log Cabin has one of those electric "Waste disposal" type toilets)!!! see if the MDAC drops out...

50:50 it could be the problem...

Did I just recommend someone to tape a USB connector to their MDAC? Pls. nobody read this...

It reads like blue Peter.... and here's one we did earlier... and now go and flush your toilet to test... Oh dear...Oh dear...Oh dear... can there be any greater shame...

John
 
TimR said:
Hi, John,
Happy new year to yourself and all the PFM members!

Lots of developments here over christmas it seems! Very interested to read about the two analogue inputs on the MDAC PSU upgrade. Am I correct thatto connect both my turntable and HT bypass I would need just an RCA to XLR converter plus an in-line volume control ? If so, then the only benefit I can see for sticking with the CDQ over the upgraded MDAC would be remote volume control of the turntable. Did I understand correctly that (turntable-->phono amp-->pot-->mdac/psu-->power amp) offers a cleaner signal path than (turntable-->phono amp-->CDQ-->power amp) ?

If so, and if you still have room on your list, could you please add my name to your orders for a premium PSU upgrade in silver :)

Any suggestions for a suitable off-the-shelf volume pot + RCA/XLR converter?

Regarding the SBT clock lock upgrade, I for one would be more than happy to lose the analogue outputs, but it would be nice (not essentuial) to retain both digital outputs so I could dual connect it to the MDAC and also my surround processor.

All the best,
Tim
Click to expand...

Tim,

Happy new year - by the way I HATE YOU!!!

So I'm laying in bed thinking about your PFM post (sad indeed)... you know, what we SHOULD really do is have analogue gain control on the "AV Bypass"!! Its not going to add too much cost in the overall scheme of things - and it now really opens many doors... DAMN!

On the CDQ / DQ the "Electronic" switched attenuator we use limits the overall audio quality. As with Tim's system, I can see the real need for the "Highest quality" Analogue path for systems with Turntables etc - the only real HQ way to design a fully balanced attenuator is using "Stepped" relays... I hate relays because relays cause trouble.... But then we could use the much more expensive "Reed" relays (as we are direct selling - component pricing does not impact end retail price as much)....

So because of Tim - we now will offer the option of adding a "Step-attenuator" option to the "HQ PSU" allowing "Volume control" of the analogue input(s) - and while we are at it, we can also blame Tim for the SBT Clock Lock updates - BLAME Tim!!!

Its not going to be a cheap option (I need to look into the Reed relay pricing in China - and we will need many) - lets target a GBP100 option (hopefully cheaper)...

I'll design it so the "Stepped attenuator cards" it can be retrofitted by owners at any-time (Remove HQ PSU Lid, insert "Stepped attenuator cards", Close lid)....

Tim - your SBT is no longer in the best of shape - so I bought a new replacement unit for you...

John
 
JohnW said:
I'm beginning to wonder if the Ground is somehow missing from your MDAC's USB connection - well at least DC Ground - the USB "Shell" is AC coupled which could explain why it still "functions".

To "diagnose" this fault condition (without proper equipment) you could get a second USB lead - plug it into a spare USB port on your PC, and with the other end of the USB cable touch the metal "shell" of this leads USB connector onto one of the MDAC'S RCA audio output's "Ground" connection (The Audio "Ground" is the "Metal" body of the RCA connector).

Somehow keeping the metal ends touching together - tightly taped together maybe? (Metal of USB connector shell to the MDAC's RCA Audio Ground connection) - then flush your toilet (I'm guess your Log Cabin has one of those electric "Waste disposal" type toilets)!!! see if the MDAC drops out...

50:50 it could be the problem...

Did I just recommend someone to tape a USB connector to their MDAC? Pls. nobody read this...

It reads like blue Peter.... and here's one we did earlier... and now go and flush your toilet to test... Oh dear...Oh dear...Oh dear... can there be any greater shame...

John
Click to expand...

LOL

Yes it is one of those 'waste disposal' type toilets
I actually noticed it when i just used the tap in my bathroom (when i use the tap it kicks in the waste disposal unit) and it caused the USB playback to seize

I can see why people thought this was a windup!

I will give this a try tonight & see if it sorts it John, cheers ;)
 
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