Dissection of Audio/Video Gears Components

[denom]

Starting a new thread that should be of interest to the DIY'ers & gyaani's of the forum who can then explain the good/bad/ugly of the components/design implementation of some expensive gears, so that lay persons can also learn from it.

Should be an interesting thread - I hope
Request all the senior's/guru's of our forum to generously contribute with their views :clapping:

Starting off with a rather fancy looking 'object' called the ChordQBD76 hdsdal

Products: QBD76 HDSD DAC

Pics courtesy Chord QBD76 HDSD si Primare DAC30 tehnica la vedere | Noutati despre echipamente audio video profesionale, review-uri, tutoriale si sfaturi - Blog AVstore.ro

 

[kanwar]

So at 8500USD,


All you get is 5 pieces of cheap LM317 linear regulators[Diy fancy] which someone said "crystal regulators", Xilinx Spartan FPGA which is under 50USD, An outsourced Clock Module, Metal shell connectors, A high EMI switching supply which needs its separate compartment otherwise inferno will break hell loose and yes a rock solid aluminum shell for attractive looks.

I fail to see any conforming Tropical climate chemical treatment given to such PCBs + components which are suppose to carry such high speed circuitry. Only black Loctite/filler masking is present on PCB.


Eye catching piece of equipment for the Rich "Audiophiles" :yahoo:

 

[kapvin]

Kanwar, I love these threads. In a voyeuristic, vicarious kind of way. But that's probably because I cannot afford the high end.

But you've likely to catch hell from those who do. Something about sum greater than parts etc. Etc.

 

[kanwar]

Kanwar, I love these threads. In a voyeuristic, vicarious kind of way. But that's probably because I cannot afford the high end.

But you've likely to catch hell from those who do. Something about sum greater than parts etc. Etc.

Kapvin,

I did not know that there are people like you who get a kick out of seeing undressed electronics , rather than watching the female form in all its glory!:lol: Jokes aside, what you must realize is that such 'exhibitions' truly reveal the level of a company on many counts, what they are, is open for interpretation, but the wise will realize what am saying. To me, seeing a buyer being severely shortchanged is a big disappointment. But then people buying such gears are happy to see a flashy product than a one that actually is worth is price technically at least.

 

[denom]

Hi Kanwar,

Many thanks for your frank & forthright views. Appreciate it :clapping:
Calling a spade a spade is not in every ones blood, but you not only have that trait but also that of being brutally honest with a technical background to support it, which is sone pe suhanga! :thumbsup:

Next in the firing line:

My Beloved Antelope Audio Zodiac Gold DAC :licklips:

Pics Source: High Fidelity

Oh gyaani, pls tell me that my heart has fallen for the right piece of gear 'technically'

 

[Thad E Ginathom]

Good grief! Taking the lid off is one thing, taking the whole thing apart is quite another ... please tell me that isn't actually your DAC!

So at 8500USD, All you get is...

And the name "Chord" on that aluminium shell. Sadly, to someone like me who can't identify the circuits (or even many of the components these days), and who is unlikely to accompanied to the shop by an electronics engineer, it could just be enough to sell it.

Advice on this forum is, often, the next best thing to being able to take one of you guys shopping.

I did not know that there are people like you who get a kick out of seeing undressed electronics...

I came across an entire blog of such hifi porn only the other day. If I can retrace my browsing steps I'll post the link. But... it is really really NSFW.

(Not Suitable For Wife)

(Unless she happens to be an engineer!)

 

[square_wave]

I support the good intentions of the technically inclined.

But a particular model from chord Dac family is a favorite with someone I know. He can afford Dacs which costs many times over but after trying out many he settled down with the lesser priced chord dac only for the results. I guess there are many ways one can look at this.

I of course accept that electronics porn as a tool is used extensively in the media to sell.

 

[kapvin]

Kapvin,

I did not know that there are people like you who get a kick out of seeing undressed electronics , rather than watching the female form in all its glory!:lol: Jokes aside, what you must realize is that such 'exhibitions' truly reveal the level of a company on many counts, what they are, is open for interpretation, but the wise will realize what am saying. To me, seeing a buyer being severely shortchanged is a big disappointment. But then people buying such gears are happy to see a flashy product than a one that actually is worth is price technically at least.

Oh, Kanwar, I think you misunderstood. Not the photos. but the (your) analysis. And the qualitative response I knew that it would bring.

OT: when are you bringing out the lower power versions of the amplifiers you promised. (100w / 200w)

More off topic, have you ever thought about doing a class D amp that accepts an i2s input? (and consequently SRC in front off it that accepts other inputs / Spdif /AES/usb?) that might actually make DACs irrelevant going forward.

 

[kanwar]

Oh, Kanwar, I think you misunderstood. Not the photos. but the (your) analysis. And the qualitative response I knew that it would bring.

Kapvin

OT: when are you bringing out the lower power versions of the amplifiers you promised. (100w / 200w)

As someone said fingers crossed....!!!:licklips:

More off topic, have you ever thought about doing a class D amp that accepts an i2s input? (and consequently SRC in front off it that accepts other inputs / Spdif /AES/usb?) that might actually make DACs irrelevant going forward.

Technically there are 2 ways to do it.

1. Make a stand alone Digital input section to take every known digital input and then convert it into analogue and then feed into the analogue class-D amplifier.

2. Implement DSD/USB/SPDIF/I2S/COX/TOS/AES-BU using a chip and directly get PWM as output [no PCM to analog conversion, direct PCM to PWM]and then use class-D power stage section only to drive speakers, just like Zetex chip is doing in Naim. Zetex claims to use digital feedback in order to mitigate the effects of zero PSRR in direct digital PWM power stage, which needs regulated supply and further investigation.


My take would be USB2.0 mated with class-D amp + PFC..........:yahoo:

keep it sweet and simple

 

[square_wave]

So at 8500USD,


All you get is 5 pieces of cheap LM317 linear regulators[Diy fancy] which someone said "crystal regulators", Xilinx Spartan FPGA which is under 50USD, An outsourced Clock Module, Metal shell connectors, A high EMI switching supply which needs its separate compartment otherwise inferno will break hell loose and yes a rock solid aluminum shell for attractive looks.

I fail to see any conforming Tropical climate chemical treatment given to such PCBs + components which are suppose to carry such high speed circuitry. Only black Loctite/filler masking is present on PCB.


Eye catching piece of equipment for the Rich "Audiophiles" :yahoo:

Hey Kanwar,

I have always wondered about chord harping about their one-piece aluminum chassis. There is hardly any space in there

 

[kapvin]

Technically there are 2 ways to do it.

1. Make a stand alone Digital input section to take every known digital input and then convert it into analogue and then feed into the analogue class-D amplifier.

2. Implement DSD/USB/SPDIF/I2S/COX/TOS/AES-BU using a chip and directly get PWM as output [no PCM to analog conversion, direct PCM to PWM]and then use class-D power stage section only to drive speakers, just like Zetex chip is doing in Naim. Zetex claims to use digital feedback in order to mitigate the effects of zero PSRR in direct digital PWM power stage, which needs regulated supply and further investigation.


My take would be USB2.0 mated with class-D amp + PFC..........:yahoo:

keep it sweet and simple

I was talking about option 2. direct conversion to PWM.

here is one which really got me thinking.

http://www.minidsp.com/products/minidspkits/miniamp

 

[kanwar]

Hi Kanwar,

Many thanks for your frank & forthright views. Appreciate it :clapping:
Calling a spade a spade is not in every ones blood, but you not only have that trait but also that of being brutally honest with a technical background to support it, which is sone pe suhanga! :thumbsup:

Next in the firing line:

My Beloved Antelope Audio Zodiac Gold DAC :licklips:

Oh gyaani, pls tell me that my heart has fallen for the right piece of gear 'technically'

Denom

Even a noob can see how well implemented the DAC is. Let me put it into simple terms:

1. National semi's Dual buck converters with shielded inductors which are part of main power supply are clearly visible.

2. Dedicated outputs using state of the art LME49600 amplifier already known for its good transparent sound.

3. Well implemented Burr-Brown PCM1792 DAC + AD9851 DDS. This combination is used in high-end pro mixers as well.

4. Uncluttered placement of key components and separate sections are clearly visible.

5. Ample use of Groundplane with stitching Vias

Though the connectors and pots are not fancy high -end stuff like in Chord.


Just some normal insights

Kanwar

 

[kanwar]

Hey Kanwar,

I have always wondered about chord harping about their one-piece aluminum chassis. There is hardly any space in there

Reminds me of a JEff Rowland amplifier with ICE power module borrowed from Bang & Olufsen and installed in single billet aluminum shell just to shield from EMI getting out as band-aid

 

[kanwar]

I was talking about option 2. direct conversion to PWM.

here is one which really got me thinking.

http://www.minidsp.com/products/minidspkits/miniamp

Oh Man, its a cheap Texas Instrument chip based amplifier TAS5760 types . They have integrated I2S frontend with normal analog class-D Pre filter feedback amp into one chip.

A great product for consumer market.

 

[denom]

Denom

Even a noob can see how well implemented the DAC is. Let me put it into simple terms:

1. National semi's Dual buck converters with shielded inductors which are part of main power supply are clearly visible.

2. Dedicated outputs using state of the art LME49600 amplifier already known for its good transparent sound.

3. Well implemented Burr-Brown PCM1792 DAC + AD9851 DDS. This combination is used in high-end pro mixers as well.

4. Uncluttered placement of key components and separate sections are clearly visible.

5. Ample use of Groundplane with stitching Vias

Though the connectors and pots are not fancy high -end stuff like in Chord.


Just some normal insights

Kanwar

What a relief! It ticks the boxes then :yahoo: Thanks for the 'post mortem' report :clapping:

Reminds me of a JEff Rowland amplifier with ICE power module borrowed from Bang & Olufsen and installed in single billet aluminum shell just to shield from EMI getting out as band-aid

hyeah:

May I request the other FM's who have participated so far in this thread & others who are just reading it, to post some 'nudies' too :lol: so that we learn some more. Am glad that Kanwar is devoting his precious time to give us insights :clapping:

 

[kapvin]

Oh Man, its a cheap Texas Instrument chip based amplifier. They have integrated I2S frontend with normal analog class-D Pre filter feedback amp into one chip.

A great product for consumer market.

yes. My point was more on the concept than the product.

 

[denom]

One more big bucks DAC, called the CAD 1543

Computer Audio Design

Pics Source: 6moons audio reviews: CAD 1543 DAC

 

[kanwar]

yes. My point was more on the concept than the product.

But this concept is what i already told as option 1.

Its not the option 2, because in the miniamp, the chip has an internal I2S to analog conversion before interfacing it with inbuilt class-D.

Don't you think that USB2.0 is more attractive, i don't know about how much I2S is popular in home audio.

 

[kapvin]

But this concept is what i already told as option 1.

Its not the option 2, because in the miniamp, the chip has an internal I2S to analog conversion before interfacing it with inbuilt class-D.

Don't you think that USB2.0 is more attractive, i don't know about how much I2S is popular in home audio.

this is becoming a separate thread.

i'll reply by pm.

 

[kanwar]

this is becoming a separate thread.

i'll reply by pm.

Don't worry ,
if you wish you can keep it here only