[Baldr]

Gosh, right now I'm enjoying the mimby, best DAC I've heard yet. A good night of listening, needed it!

Thanks so much for returning us to topic!!

 

[Keirapc]

Can Anyone here review about Modi Multibit sound sign instead of technical issue?

 

[svetlyo]

[repost] 
@Baldr - About the recommendation to keep Modi MB running - 'warming up' means that the SHARC processor is constantly running a numerical analysis method which is improving over time (in the case of Modi - it needs around 2 hours to 'stabilize') , i.e. it doesn't have something to do with actual temperature, right? Or I'm getting this all wrong?

 

[Lohb]

Oh, I can see why there is no portable battery-powered option then, if it needs to be on all the time.
Would love me some transportable Schiit multibit  ;-(

 

[scottbrown5271]

[repost] 


@Baldr - About the recommendation to keep Modi MB running - 'warming up' means that the SHARC processor is constantly running a numerical analysis method which is improving over time (in the case of Modi - it needs around 2 hours to 'stabilize') , i.e. it doesn't have something to do with actual temperature, right? Or I'm getting this all wrong?

 


Hopefully the software running on the DSP isn't improving itself towards an AI singularity that will destroy all life on the planet!! Seriously though, the warm up time has to do with stabilizing the R2R DAC chips. There are a lot of critical-dimension elements in those chips that only come to their linearity specs when the chips are at their proper operating temperature. I would guess that medical and military devices using these chips require a certain operating temperature before they perform as designed. The DSP software is running from read-only memory that never changes in normal operation.

There has been a bit of discussion from Schiit about temperature controlled ovens for the DAC chips (not a practical solution given the target price of the devices), which is probably the way that these DAC chips are implemented in critical (life threatening, literally) applications. Schiit's simple answer for audio: Leave It Running.

 

[svetlyo]

 

  [repost] 
  @Baldr - About the recommendation to keep Modi MB running - 'warming up' means that the SHARC processor is constantly running a numerical analysis method which is improving over time (in the case of Modi - it needs around 2 hours to 'stabilize') , i.e. it doesn't have something to do with actual temperature, right? Or I'm getting this all wrong?

 


Hopefully the software running on the DSP isn't improving itself towards an AI singularity that will destroy all life on the planet!! Seriously though, the warm up time has to do with stabilizing the R2R DAC chips. There are a lot of critical-dimension elements in those chips that only come to their linearity specs when the chips are at their proper operating temperature. I would guess that medical and military devices using these chips require a certain operating temperature before they perform as designed. The DSP software is running from read-only memory that never changes in normal operation.

 
 
Thanks for the explanation. The only thing that made me believe that we're not talking about simple warmup of the electronics was some
post of @Baldr where he said that Yggie needs around 72 hours to enter "the zone", but because Modibit (and Bimby) are only 16 bit
they'll need only a little more than 2 hours  - why this dependency on the bit depth? Sure 8 more bit means a lot more resistors in the ladder 
(also Yggie has more R2-R chips, i.e. more IC surface area to warm up), but still - sound strange.

 

[Baldr]

  [repost] 
@Baldr - About the recommendation to keep Modi MB running - 'warming up' means that the SHARC processor is constantly running a numerical analysis method which is improving over time (in the case of Modi - it needs around 2 hours to 'stabilize') , i.e. it doesn't have something to do with actual temperature, right? Or I'm getting this all wrong?

It is not the DSP which needs to thermally stabilize.  It is the DAC chip which needs to settle into its INL spec.  Regret the slow comment; I have been distracted by the Schiit Show.

 

[svetlyo]

 
It is not the DSP which needs to thermally stabilize.  It is the DAC chip which needs to settle into its INL spec.  Regret the slow comment; I have been distracted by the Schiit Show.

 
Thanks. And no worries - just after posting my question I watched the Jotunheim introduction and after that - people's impressions of the Schiit Show 2 - I was quite distracted myself by that
I've just received my Modibit this Friday - one of the first ones in Europe! Enjoying it since then via the Vali 2. Now I just hope that you've made enough Jotunheims and they soon be available
by Sonority audio (schiit-europe.com). 
Just one more question - if I feed Jotunheim with my Modi MB via the SE input will I be able to use the balanced output?

 

[AviP]

 
It is not the DSP which needs to thermally stabilize.  It is the DAC chip which needs to settle into its INL spec.  Regret the slow comment; I have been distracted by the Schiit Show.

Sorry for the ignorance, but what do you mean by "settle into it's INL spec"?
According to the AD5547 datasheet, the operating temperature is -40C  to +125C

 

[scottbrown5271]

   
 
Thanks for the explanation. The only thing that made me believe that we're not talking about simple warmup of the electronics was some
post of @Baldr where he said that Yggie needs around 72 hours to enter "the zone", but because Modibit (and Bimby) are only 16 bit
they'll need only a little more than 2 hours  - why this dependency on the bit depth? Sure 8 more bit means a lot more resistors in the ladder 
(also Yggie has more R2-R chips, i.e. more IC surface area to warm up), but still - sound strange.

 
I started to write this in the last post:  16 bits is 65,536 discrete voltage levels coming out of the decoder.  22 bits is 4,194,304 voltage levels.  More bits means more resolution.  That means that in order to operate in a linear manner, the temperature of the chip itself is more critical for more bits.  These chips aren't really simple resistor ladders, they do some sort of hocus-pocus internally with cascading sets of resistor ladders that I don't really (have to) understand. If you push that least significant bit out another six bits, as between Yggy and Mimby, that last bit has a much smaller value relative to the most significant bit and the components in the DAC chip are that much more sensitive to temperature.  I'm sure the guys at Analog Devices (or Baldr) could give you a much more detailed, scientific explanation of what is going on, but the above is my simple take on the subject.

 

[pkcpga]

[repost] 


@Baldr - About the recommendation to keep Modi MB running - 'warming up' means that the SHARC processor is constantly running a numerical analysis method which is improving over time (in the case of Modi - it needs around 2 hours to 'stabilize') , i.e. it doesn't have something to do with actual temperature, right? Or I'm getting this all wrong?

 


Hopefully the software running on the DSP isn't improving itself towards an AI singularity that will destroy all life on the planet!! Seriously though, the warm up time has to do with stabilizing the R2R DAC chips. There are a lot of critical-dimension elements in those chips that only come to their linearity specs when the chips are at their proper operating temperature. I would guess that medical and military devices using these chips require a certain operating temperature before they perform as designed. The DSP software is running from read-only memory that never changes in normal operation.

There has been a bit of discussion from Schiit about temperature controlled ovens for the DAC chips (not a practical solution given the target price of the devices), which is probably the way that these DAC chips are implemented in critical (life threatening, literally) applications. Schiit's simple answer for audio: Leave It Running.

I can tell you in the medical field their are no chips used that require more than a couple seconds to be fully functional. My wife works as a physician in the surgical field with robotic surgery and she stated if an emergency happens all equipment needs to be able to be transported set up and turned on in a very short time so a chip that requires 2 hours to work properly would not be used. And it sounds more like the programming needs to run its course more than the chip and the complex programming verse equipment capability of running it, forces the DAC to get bogged down and requires time to be fully functional.

 

[scottbrown5271]

I can tell you in the medical field their are no chips used that require more than a couple seconds to be fully functional. My wife works as a physician in the surgical field with robotic surgery and she stated if an emergency happens all equipment needs to be able to be transported set up and turned on in a very short time so a chip that requires 2 hours to work properly would not be used. And it sounds more like the programming needs to run its course more than the chip and the complex programming verse equipment capability of running it, forces the DAC to get bogged down and requires time to be fully functional.

There are different classes of equipment.  A robot will operate correctly at startup just the same as a computer will (aside: DS DACS operate as accurately as they ever will at startup, no warm up required).  A piece of high precision, high accuracy diagnostic equipment depends on digital data processing, as well as precision digital to analog and analog to digital conversions.  There are a lot of diagnostic applications for precision conversions, and those probably take some time to come up to operating temperature.  Stuff that medical professionals rely on for triage and emergency work has to function correctly the instant it is turned on, and it does.  High precision diagnostic tools are used in a different environment.  Ask your wife to find out if the lab rats leave their equipment on all the time so it works correctly.
 
The DSP software that comprises the megaburrito filter takes an input data word, compares it to the next word and interpolates between those to create intermediate values (upsampling).  The filter is made up of about 18,000 transforms, all of which are hard-coded and can't change.  The DSP chip takes input, runs the transforms, then give the result to the DAC chip(s).  It does it the same way every time.  When there is no input to the DSP it still sits there and interpolates zeros and passes them to the DAC chip(s). The analogy here is that the DSP is like the computer that runs the surgical robot:  It does its thing exactly the same from startup to shutdown.
 
I tend to think about digital electronics as simple on-off devices, and they either work or they don't.  The only thermal effect that I think about in digital electronics is overheating, and that results in a non-functional, possibly ruined, device.  The actual transistors, resistors, capacitors, etc. in a digital processing chip are designed to function within a relatively large thermal envelope.  Non-linearities don't matter because on is on, and off is off.  Analog electronics are all about linearity, and temperature effects do matter.  When it comes time to set the bias on some output transistors they have to be at operating temperature to get it right, for example.  Analog audio stuff sounds different depending on the thermal state of the device.
 
Tha DAC chips themselves will give a different output depending on the thermal state of the chips.  When I turned on my Mimby for the first time, sound came out as soon as it got done booting up.  The sound got better after it warmed up.  The difference in sound was because the DAC chip in Mimby was cold and did not put out accurate results.  When it got to operating temperature, it sounded better.

 

[pkcpga]

There are different classes of equipment.  A robot will operate correctly at startup just the same as a computer will (aside: DS DACS operate as accurately as they ever will at startup, no warm up required).  A piece of high precision, high accuracy diagnostic equipment depends on digital data processing, as well as precision digital to analog and analog to digital conversions.  There are a lot of diagnostic applications for precision conversions, and those probably take some time to come up to operating temperature.  Stuff that medical professionals rely on for triage and emergency work has to function correctly the instant it is turned on, and it does.  High precision diagnostic tools are used in a different environment.  Ask your wife to find out if the lab rats leave their equipment on all the time so it works correctly.

She states blood analysis machines are regularly rebooted to ensure proper functioning, older MRI machines they left running since they used to take time until they functioned properly but with newer technology they can be up and running in less than 3 minutes. Most equipment in hospitals are required to be turned off when not in use to conserve energy to follow new energy conservation laws. Only equipment left running are blood bank monitoring fridges and machines but they are technically in use since they constantly monitor or the hospitals main server but that's always in use as well. She has not heard of any equipment requiring long start ups or be constantly running for at least 7 years now, equipment like that has been replaced with newer more efficient technology. Robotic systems for surgery used to have some very long start up times since they are very complex and require very precise movement with lasers, vacuums, arms but technology today allows for the systems to start up the programs and run them fully in less than two minutes. My chord Dave runs the same from a minute after I turn it on or wether it has been running for hours so the technology is available in DACs as well.

 

[scottbrown5271]

She states blood analysis machines are regularly rebooted to ensure proper functioning, older MRI machines they left running since they used to take time until they functioned properly but with newer technology they can be up and running in less than 3 minutes. Most equipment in hospitals are required to be turned off when not in use to conserve energy to follow new energy conservation laws. Only equipment left running are blood bank monitoring fridges and machines but they are technically in use since they constantly monitor or the hospitals main server but that's always in use as well. She has not heard of any equipment requiring long start ups or be constantly running for at least 7 years now, equipment like that has been replaced with newer more efficient technology. Robotic systems for surgery used to have some very long start up times since they are very complex and require very precise movement with lasers, vacuums, arms but technology today allows for the systems to start up the programs and run them fully in less than two minutes. My chord Dave runs the same from a minute after I turn it on or wether it has been running for hours so the technology is available in DACs as well.

Very cool!!  I love these forums, I always get to learn something.  Thank you for that!!
 
I'm not sure how they managed to engineer their way around thermal dependencies, but I would be willing to bet that it would not be cost effective to do so with audio equipment.  Of course there are people out there who cheerfully spend a half million or more on their audio equipment, and there really could be a market for that sort of optimization, albeit miniscule in comparison to the medical market.
 
Dave is a delta/sigma device, and yes, it should run and sound exactly the same from startup to shutdown.  My Modi 2 Uber doesn't sound any different now than it did the first time I turned it on.   My Modi Multibit, on the other hand, requires a warm up period to sound best.  Its the nature of the beast.  I've seen comparisons of old Dave there with multibit DACs, and there really is no consensus from what I've read about which one sounds "better."  I happen to like the sound of multibit, your mileage may vary, these things are completely subjective.  I haven't heard Dave, so I don't have a personal frame of reference.  It is not out of the realm of possibility that I would like it better than Mimby.  Or not.  Don't know, can't afford to find out...

 

[mentt]

She states blood analysis machines are regularly rebooted to ensure proper functioning, older MRI machines they left running since they used to take time until they functioned properly but with newer technology they can be up and running in less than 3 minutes. Most equipment in hospitals are required to be turned off when not in use to conserve energy to follow new energy conservation laws. Only equipment left running are blood bank monitoring fridges and machines but they are technically in use since they constantly monitor or the hospitals main server but that's always in use as well. She has not heard of any equipment requiring long start ups or be constantly running for at least 7 years now, equipment like that has been replaced with newer more efficient technology. Robotic systems for surgery used to have some very long start up times since they are very complex and require very precise movement with lasers, vacuums, arms but technology today allows for the systems to start up the programs and run them fully in less than two minutes. My chord Dave runs the same from a minute after I turn it on or wether it has been running for hours so the technology is available in DACs as well.

There is no point for this discussion. Medical equipment will work right after it is turned on. Shiit DACs are working too right after they are turned on = generating sound. Only difference is that audio gear is sensitive to chip temperature(DAC sounds good or not as good  )  and Medical equipment is not.