John Curl's Blowtorch preamplifier part III

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#31,461
mountainman bob said:
Just got done reading a mile long thread about MQA over at ASR (I thought the back and forth was bad here!)
It reinforced a lot that I’d already heard in that although lossy, the parts lost are of no consequence.
There is an argument between all being 13/44.1 and folding the rest, and (where I thought was 24/48 flac) is really 16/48. (It is labeled as 24/48 flac and comes up on the receivers display as such?). Edit.....after a little more research it does seem to indeed resort to whatever the parent file was up to a max of 24/48.

Doesn’t seem like anyone really knows for sure and that’s the problem.

One thing that really surprised me (if it’s true) is that Qobuz is supposedly using MQA tracks in its library and not labeling as such. When called out on it, they stated it sounded better?

Dunno......I’d still like to pick up a a good/cheap MQA dac (maybe Pro-Ject pre box) to see for myself. I’d go to a audio showroom but there are none here on the redneck riviera!
Click to expand...

It's still just a way of extracting cash for no benefit....
 
#31,462
I’m not sure I follow that thought.....seems to me the only extra cash involved would be the layout for a MQA compatible dac, and if your in the market for one anyway what’s the difference? Tidal hifi gives the MQA files at no extra charge and it’s not like the dac only does MQA.

I should wait for marks new 4499 equipped dac/pre to hit the shelves.....maybe he will hop on the MQA bandwagon! 😀
 
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#31,466
RNMarsh said:
Hahahaha. I am supposed to remember something in 2013?
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It was right there right after the link you just posted.

For instance this statement, comparing mode of gain and type of feedback, makes no sense. You keep showing schematics of what everyone else calls cfa and call them something else. All the schematics Damir has shown are cfa's even he calls them that.

Current-mode amplification has unique characteristic not like vfb.
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#31,468
gpauk said:
Unless something has changed, MQA dacs are more expensive.
And add to that the pointless messing with the data...
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But relative to the dac itself it really doesn’t seem significant.....what does the certification cost, and does the manufacturer just eat the cost in hopes of selling more dacs? Anyway you look at it it’s not much more total cost involved.

I’d rather touch the hot stove to see for myself 😀
 
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#31,469
scott wurcer said:
It was right there right after the link you just posted.

For instance this statement, comparing mode of gain and type of feedback, makes no sense. You keep showing schematics of what everyone else calls cfa and call them something else. All the schematics Damir has shown are cfa's even he calls them that.
Click to expand...
When, in a CFA like, the feedback impedance is high in such a way that it limits both the "current on demand" and the feedback bandwidth with the parasitic emitter capacitance of the input stage, should we still consider such an amp as a CFA?

It seems to me still a semantic controversy between you. One speaks of the mode of operation and the other of topology.
 
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#31,470
mountainman bob said:
...does the manufacturer just eat the cost in hopes of selling more dacs?
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Bob, MQA is just a new angle on DRM so the record companies have more control over their content and have more ways to monetize it. DAC manufacturers like it because they can sell everybody a new dac. Streaming companies like it because it reduces their internet bandwidth costs. The only group that gets screwed on the deal is consumers.

Look, they give you a low res option or a higher res paid option that still isn't all that good. Much better to take plain old 16/44 and convert it to DSD256 or DSD512, but you can't do that if using MQA, you are stuck with middling PCM.
 
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#31,472
scott wurcer said:
It was right there right after the link you just posted.

For instance this statement, comparing mode of gain and type of feedback, makes no sense. You keep showing schematics of what everyone else calls cfa and call them something else. All the schematics Damir has shown are cfa's even he calls them that.
Click to expand...

I dont care what "everyone" in DIY-land calls it... I said before and I'll say it again. I am using IEEE definition --- they call it current-mode amplifier.

Modern designs use current convyers and there is a great book published by Linear Audio on the CMA as inherently linear amplifer topologies which I consider the SOTA for audio.

If the amp has the characteristics of a CMA, then it IS a CMA. A amp with 'cfb' may or may not be in CMA mode. [that will probably confuse some]




Some interesting reading:

Current-mode amplifiers - IEEE Conference Publication
A CMOS current-mode operational amplifier - IEEE Journals & Magazine
Design of current mode operational amplifier with differential-input and differential-output - IEEE Conference Publication
An enhanced current-mode instrumentation amplifier - IEEE Journals & Magazine
CMOS Current-mode Operational Amplifier - IEEE Conference Publication
https://ieeexplore.ieee.org/document/6704632



THx-RNMarsh
 
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#31,474
Markw4 said:
Bob, MQA is just a new angle on DRM so the record companies have more control over their content and have more ways to monetize it. DAC manufacturers like it because they can sell everybody a new dac. Streaming companies like it because it reduces their internet bandwidth costs. The only group that gets screwed on the deal is consumers.

Look, they give you a low res option or a higher res paid option that still isn't all that good. Much better to take plain old 16/44 and convert it to DSD256 or DSD512, but you can't do that if using MQA, you are stuck with middling PCM.
Click to expand...

Hi Mark,

Are there any down load services left which are true 24/96+ files..... not messed with?


-Richard
 
#31,476
RNMarsh said:
Modern designs use current convyers and there is a great book published by Linear Audio on the CMA as inherently linear amplifer topologies which I consider the SOTA for audio.

If the amp has the characteristics of a CMA, then it IS a CMA. A amp with 'cfb' may or may not be in CMA mode. [that will probably confuse some]







THx-RNMarsh
Click to expand...

I used current conveyors in my preamps first and built it Current conveyor as a voltage amplifier
No NFB line amp (GainWire mk2) and simulated several power amps with and without global NFB but never built any.
Damir
 
#31,478
Markw4 said:
Bob, MQA is just a new angle on DRM so the record companies have more control over their content and have more ways to monetize it. DAC manufacturers like it because they can sell everybody a new dac. Streaming companies like it because it reduces their internet bandwidth costs. The only group that gets screwed on the deal is consumers.

Look, they give you a low res option or a higher res paid option that still isn't all that good. Much better to take plain old 16/44 and convert it to DSD256 or DSD512, but you can't do that if using MQA, you are stuck with middling PCM.
Click to expand...

As it stands my tidal hifi subscription has relegated my CD player to near 8 track status....not only due to ease of use but sound quality also.

MQA is more a curiosity for me than a must have.....if it’s better than what I’m getting now on tidal i’d be impressed......if it’s snake oil I’ll be the first to admit it.

It’s like there’s a circus sideshow going on and I just wanna see schlitzie!
 
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