Any good TDA1541A DAC kit?

[abraxalito]

Dunno about the double insulated rated safety standards gear, but if you have 240 volt and just the usual 2 wire mains supply wire into a metal cased cd player of 15 - 20 years ago, the metal case will rarely have a chassis earth connection at all, but relies on the signal's sheild wire of the interrconnect for safety earth - with the insulated plastic cases like some of the Marantz, etc, players, this won't apply provided the lid is kept on and so on ...

No, it can't rely on an external connection for safety because that might not be provided. It relies on having more layers of insulation internally to protect against a single point failure resulting in exposure of a person to hazardous voltages.

However, if you are into DIY and maybe using older metal chassis players (without lid, bare mains fuse holders, bare wires at the switch, etc, etc) and it doesn't have a chassis earth connected via a 3 wire cable, I would stongly suggest you add one (or an IEC socket) and tie the metal chassis to the earth pin for safety and then isolate the phono plugs from the metal case - and maybe seperate/float the original central 0 volt point on the pcb from the new chassis earth via a resistor, thermistor, etc

Use of a component - like resistor - for ground lifting is dangerous unless that component can handle any potential fault current for long enough to blow the line fuse. So you're in danger of making your equipment more unsafe, whereas it was relatively safe before you started modding it...

 

[Extreme_Boky]

I'm still looking for a DAC that will produce the recorded music as it is, without any additions and omissions…

I have achieved nice results with dual differential 1704 and AD811 as I/V - however, flat input impedance of < 1 ohm was crucial factor….. also, a lot of measurements & very low noise environment.

I almost completely wasted 3 years on 1541.

Sigma/delta DAC's in very low noise implementations served me as reference for achieving high frequency spectrum resolution with difficult to implement, but superior sounding 1704's.

Good CD transport is of equal importance as DAC, and with CD transports -> I learned that heavy plastics of an appropriate density make or break the end-result. I still have to find a single useful thread on internet that discusses this topic with due relevance to the digital reproduction (sensible ones decided to forgo CD mechanism altogether and accept flash as digital source!)


Boky

 

[ThorstenL]

Hi,

Mains earth should not be connected to metal case -> this applies to all HiFi components in a system.

This is EXTREMELY dangerous and in many cases also very "un-sound" advise.

Unless a given piece of equipment can be shown to reliably pass all the requirements for Class II Double Insulated equipment it must be considered Class I and requires a mains earth connection to all metal parts that can be touched or reached through louvres etc. (that includes for example exposed metal binding posts on Amplifiers and RCA connector shells).

Appliance classes - Wikipedia, the free encyclopedia

Those are very serious requirements mandated by law in almost any country and strongly enforced in first world countries and even many 2nd world countries..

In the case anything happens (e.g. someone receives an electrical shock and requires medical treatment and is perhaps disabled or your house burns down) and you used equipment that did not comply with safety regulations you may find yourself without any insurance and liable for all costs incurred.

Mains electricity can kill. Often it does not kill or maim you, but others.

So PLEASE take electrical safety VERY serious.

If you have DIY Gear, build it according to applicable standards and perform a PAT (Portable Appliance Test) on it after building and regularly afterwards.

Past that, removing the Earth from any unit designed to operate with earth can cause unpredictable behaviour and poor sonics.

AMR's gear is all designed as Class I and had measures taken to avoid the common problems while passing all mandated tests. Moreover it requires the normal mains earth to "dump" any mains born noise intercepted by the transformers screens and core into this earth.

In an extreme case at a show in old hotel in the US where the mains power had no earth we had major issues with CD-Players skipping, until an earth cable was run from the metal water pipes in the Bathroom!

In other cases the inability to get rid of noise caused poor sound quality.

Further, the concept that "mains earth is noisy" is in many ways meaningless.

It must be "noisy" in reference to something. This could be the local "true earth", however HiFi Gear on a stand and on (electrically) isolating feet will have extremely low capacitance to this earth, so bonding the chassis to mains earth for safety is unlikely to introduce any appreciable problems.

If neccesary a mains earth connected metal plate could be placed under especially sensitive equipment to screen this out, but normally the metal case already performs this function very well.

Problems arise when multiple earthed appliances are interconnected and the earth/ground interface is not managed correctly and possibly circulating chassis currents are introduced.

There are many ways in which the situation may be improved without violating electrical safety codes though and they should be tried first.

If it is ABSOLUTELY essential to lift the earth, the safe way to do this is to convert your equipment to 115V Power Supply and use a Building Site Balanced Safety Isolation transformer. These contain a centre tapped secondary with a total of 110V but the centre-tap earthed and usually additional screens to minimise leakage.

They are big portable yellow boxes normally designed to supply power tools. This way should a worker drill through a power cable, drive a nail through a power cable or otherwise connect himself to one of the power lines (preferably while working wet cloth, in the rain and standing in a puddle) will not be permanently hurt (beware of pacemakers though)

This way the maximum voltage available referenced to earth is 55V which qualifies as SELV (Safety Extra Low Voltage) and anything on the "safe" side essentially becomes Class III equipment. This may be a good choice for DIY gear anyway.

Ciao T

 

[Extreme_Boky]

Hi,



This is EXTREMELY dangerous and in many cases also very "un-sound" advise.

Those are very serious requirements mandated by law in almost any country and strongly enforced in first world countries and even many 2nd world countries..

you've obviously no clue whatsoever.... the only appliances that must be mains earthed are those that contain motors / solenoids where windings shorting to metal frame can bring the same to mains potential.

all hifi / video components are double insulated at mains transformer-end, they are not required to be earthed – and are better left un-earthed.

.... good laugh though, just before the bed time....

Are your "high-end" designs mains earthed? Ha ha ha….

Boky

 

[ThorstenL]

Hi,

I have achieved nice results with dual differential 1704 and AD811 as I/V - however, flat input impedance of < 1 ohm was crucial factor….. also, a lot of measurements & very low noise environment.

I almost completely wasted 3 years on 1541.

Good you found something you like. It seems however you never got anywhere close to the potential of the TDA1541, OR you like a very different sound to many in this thread.

When dealing with CD signals I have yet to hear anything beat a fully optimised TDA1541 design.

Good CD transport is of equal importance as DAC, and with CD transports -> I learned that heavy plastics of an appropriate density make or break the end-result. I still have to find a single useful thread on internet that discusses this topic with due relevance to the digital reproduction

If the CD-Drive has been competently implemented and integrated there no issue.

It is important that the CD cannot resonate by itself and that the system can read without errors that cannot be corrected (note - CD-Error correction does 100% correct errors), so concealment is not required.

Error concealment happens when error correction is impossible due to too much missing data and one or more samples are interpolated to avoid extremely audible pops or clicks.

If the drive can reliably read good data AND we can make sure the clock driving the DAC remains unaffected by any transport activity or other issues (varying RFI due different processor activity during error correction) then one will find that all transport differences magically disappear.

Unfortunately very little if any CD-transports/players consequently implement the necessary power supply separations, ground separation, shielding etc., in fact looking at most they seem to be designed to maximise these problems instead, certainly in many cases I could not do worse then what we see implemented.

Ciao T

 

[abraxalito]

Further, the concept that "mains earth is noisy" is in many ways meaningless.

It must be "noisy" in reference to something.

All earth wires terminate at the planet at some point. So its noisy relative to itself - the near end is noisier than the end buried in the ground. Nothing magical about that.

Or we could just say that the earth is noisy relative to the aether. It radiates when noisy, it doesn't when its not.

 

[ThorstenL]

Hi,

you've obviously no clue whatsoever.... the only appliances that must be mains earthed are those that contain motors / solenoids where windings shorting to metal frame can bring the same to mains potential.

First, before providing such "advise", you may wish to review the relevant standards applicable, I believe for you this would be:

AS/NZS 3820:2009 Essential safety requirements for low voltage electrical equipment

all hifi / video components are double insulated at mains transformer-end, they are not required to be earthed – and are better left un-earthed.

Double insulation is not conferred by the presence of a mains transformer, but requires the observance of specific clearances, insulation requirements etc.

AMR Equipment conforms to the most stringent (German) electrical safety regulations though we generally cross-check against other legislation to make sure we are compliant with all relevant electrical and other safety requirements. Most countries are now trying to harmonise electrical safety in like the with IEC Standards, though over time expect convergence on these.

I am hardly an expert on Australian regulations, however they do have provisions for multiple equipment classes and require the attachment of a safety earth for some classes.

Ciao T

 

[ThorstenL]

Hi,

All earth wires terminate at the planet at some point. So its noisy relative to itself - the near end is noisier than the end buried in the ground. Nothing magical about that.

Yes, or as I pointed out, if you drove a suitable local earth stake (or several) into the local PHYSICAL earth you could measure that there is noise on the mains safety earth.

However, as long as you do not complete any circuits between this physical earth and the mains earth this noise does not matter. The circuit completed through parasitic capacitances is very minimal and should (competent design given) complete only through the actual earth wires and not through the signal circuit.

Or we could just say that the earth is noisy relative to the aether. It radiates when noisy, it doesn't when its not.

I have not heard the term æther used in a long time. I though the concept was discredited over a 100 years ago? You still adhere to the view that this alchymical element is actually real? Or have I missed the article in nature where æther was re-instated as real?

Ciao T

 

[abraxalito]

However, as long as you do not complete any circuits between this physical earth and the mains earth this noise does not matter. The circuit completed through parasitic capacitances is very minimal and should (competent design given) complete only through the actual earth wires and not through the signal circuit.

You seem to have omitted something vital here - all noisy earths are noisy in their own individual ways. Thus a noisy earth at the CD player will differ in potential from the noisy earth presented to the preamp. Ditto preamp to poweramp.

I have not heard the term æther used in a long time. I though the concept was discredited over a 100 years ago? You still adhere to the view that this alchymical element is actually real? Or have I missed the article in nature where æther was re-instated as real?

I take the view that the vacuum is in fact a plenum yes - after all it has properties. Quantum physicists nowadays talk of 'quantum foam' or some such rather than aether.

 

[mekr]

hello,

Thanks everyone for their kind suggestions.

Regarding power safety, here in india ,we are dependent on electrician for safety,as there is no govt manual or instructions for the safety of power supply lines
I am on the 6th floor of the building and have direct dedicated power line for my audio system.the dedicated power line is cryoed and runs from utility company,s meter on the ground floor to the output recepctacle of Maestro used in tripoint power conditioners,with a circuit breaker in between for safety.
the background of the music i hear is very black.
Now i will start hunting for TDA1541 based Cd player and it has to be with 220 or 240V electric input.

 

[ThorstenL]

Hi,

You seem to have omitted something vital here - all noisy earths are noisy in their own individual ways. Thus a noisy earth at the CD player will differ in potential from the noisy earth presented to the preamp. Ditto preamp to poweramp.

Well, that is not an absolute given. At the initial point at the wall there is just one mains earth line with one amount of noise to local physical earth. Of course, there may be local noise injected into a non-zero impedance, but that's usually smallfry, but VERY IMPORTANT small-fry, as it may create loops and circulating currents.

But it has nothing as such to do with "the mains earth is noisy"...

I take the view that the vacuum is in fact a plenum yes - after all it has properties. Quantum physicists nowadays talk of 'quantum foam' or some such rather than aether.

Lovely. Got any citation that links this with the originally alchymical concept of æther...

 

[abraxalito]

Lovely. Got any citation that links this with the originally alchymical concept of æther...

I don't know if any of these papers reference the 'alchymical concept' of aether but they do begin by deriving both space and matter from a more fundamental reality. As such its monistic science rather than dualistic as is the fashion in the mainstream nowadays.

Index of Papers for Process Physics

 

[Joshua_G]

Hi Thorsten,

If it is ABSOLUTELY essential to lift the earth, the safe way to do this is to convert your equipment to 115V Power Supply and use a Building Site Balanced Safety Isolation transformer. These contain a centre tapped secondary with a total of 110V but the centre-tap earthed and usually additional screens to minimise leakage.

They are big portable yellow boxes normally designed to supply power tools. This way should a worker drill through a power cable, drive a nail through a power cable or otherwise connect himself to one of the power lines (preferably while working wet cloth, in the rain and standing in a puddle) will not be permanently hurt (beware of pacemakers though)

This way the maximum voltage available referenced to earth is 55V which qualifies as SELV (Safety Extra Low Voltage) and anything on the "safe" side essentially becomes Class III equipment. This may be a good choice for DIY gear anyway.

In my country the mains is 230V.
On my audio setup I use few isolation transformers, all are 230V -> 230V, while on the secondary of most transformers there is a center tap connected to the mains safety ground. On 1 transformer, feeding the power amp, the secondary is floating.

I don't know if it's the best solution, however those isolation transformers had a big positive impact on the sound quality of my setup.

 

[ThorstenL]

Hi,

I don't know if any of these papers reference the 'alchymical concept' of aether but they do begin by deriving both space and matter from a more fundamental reality. As such its monistic science rather than dualistic as is the fashion in the mainstream nowadays.

Index of Papers for Process Physics

Lovely stuff, I shall immerse myself...

Things change so fast in physics. Hard to keep up.

I still remember Λεύκιππος'ς and Δημόκριτος'ς άτομα (atoms) and now we are swimming in a sea of leptons, neutrinos and boson's and Demokritos knows what.

Do people still believe in electrons? I lost count...

Ciao T

 

[ThorstenL]

Hi,

On my audio setup I use few isolation transformers, all are 230V -> 230V, while on the secondary of most transformers there is a center tap connected to the mains safety ground. On 1 transformer, feeding the power amp, the secondary is floating.

I don't know if it's the best solution, however those isolation transformers had a big positive impact on the sound quality of my setup.

Well, if safety is any concern, as long as you have a connection to mains earth that is low impedance at 50...100Hz you can break the connection at higher frequencies.

If not, if you break the earth connection, you sure like to live Simba in "The Lion King" (Danger? Hah! I walk on the wild side. I laugh in the face of danger. Ha ha ha ha!)...

I have had my share of direct connection to voltage/current bearing wires as occupational hazard (Electronic Engineer and Dissident in a Communist Police State). I already notice that E_B seems to be applying for a Darwin Award, guys, please be safe.

A big and bad iron cored low DCR choke, combined with frequency range extenders may be used. You can easily gets a few 100mH that way, especially as you only need to design the choke for a few mA operational current, who cares if it saturates when there is a fault?

There are some Manganese/Nickel/Iron torroid cores that have incredibly high AL. I recently had a bunch of 2.2mH/10A DC chokes made that come in at around 10 Turns of very thick wire (for a solid state Amp Psu) and have basically FA DCR for the Inductance.

I am sure you could do something with these for that kind of job.

Ciao T

 

[ThorstenL]

Hi,

AS/NZS 3820:2009 Essential safety requirements for low voltage electrical equipment

Alas, while this is correct, in fact the applicable standard for AV Gear in Oz/Nz (I said I was no expert) is:

AS/NZS 60065:2003

This is the same as IEC 60065 which suggests that in fact the requirements for AV Gear are now harmonised with the EU and North America.

IEC 60065 has clear definitions of classes of safety of AV gear and includes Class I, Class II and Class III equipment. Any equipment that cannot be certified under Class III and Class II is considered Class I and must have the Mains attached to all accessible metal parts.

As said before, non-compliance leaves you uninsured if anything bad happens and there are reasons for the existence of such standards.

Under no circumstances should the earth connection be removed from any equipment that has this installed by the manufacturer and is marked as Class I appliance.

And unless an appliance is marked as Class II and reliably independently certified (especially if it comes from China, Vietnam and other low cost producers) one should consider it better to be covered under Class I.

And if the device is not wired to Class I requirements and not formally and independently certified as Class II or Class III it needs to be re-wired and tested to Class I standards (insulation and earth bond) or should be considered dangerous and be disposed of.

For more details please see IEC 60065 Standard.

Ciao T

 

[ThorstenL]

Hi,

AS/NZS 60065:2003

This is the same as IEC 60065 which suggests that in fact the requirements for AV Gear are now harmonised with the EU and North America.

A nice "executive summary" on safety testing especially for double insulation etc. ccan be found in this presentation:

http://hkelectronicsfairse.hktdc.com/pdf/Presentation-K-F-Siu.pdf

Note, this should not replace the reference to international standards, it merely specifies testing and a simple overview of requirements for safety.

Ciao T

 

[Joshua_G]

Hi Thorsten,
Thanks.
All the power outlets after the isolation transformers have uninterrupted connection to the house safety ground by thick electric wires. The in-wall power installation has separate line to the audio setup, with a dedicated ("audiophile") fuse, from a power phase that isn't in use while I listen to music.

 

[Ceglar]

you've obviously no clue whatsoever.... the only appliances that must be mains earthed are those that contain motors / solenoids where windings shorting to metal frame can bring the same to mains potential.

all hifi / video components are double insulated at mains transformer-end, they are not required to be earthed – and are better left un-earthed.

.... good laugh though, just before the bed time....

Are your "high-end" designs mains earthed? Ha ha ha….

Boky

Mate I'm an electrician by trade, take it from me and the Australian Standards (AS3000), you want your metal chassis earthed if it has mains power coming into it.

I think I know what you're meaning, and I agree about mains earth. Another safer method is to float your signal common, connect it to the chassis (mains earth) with like 2M2 in parallel with an MOV. I still personally think that you want a mass of conductive material connected to the signal common, but for different reasons.

 

[AudioLapDance]

Wasn't this about 1541 DAC kits?!?

Joshua_G, it's too bad you didn't ask this question a few months earlier:

Raindrop was selling a WM8805 to NOS TDA1541 with no I/V. Although a train-wreck like T says, there's less to go off the track and for $90 it will be a fun thing for me to play with. I emailed him/her and they aren't offered anymore.

Anyway, let's try to get this thread back on track:

T's first hints:
http://www.diyaudio.com/forums/digital-line-level/203511-any-good-tda1541a-dac-kit-4.html
Post 35

T's veroboard:
http://www.diyaudio.com/forums/digital-line-level/203511-any-good-tda1541a-dac-kit-13.html
Post 123

Pics of T's 1541 DAC
http://www.diyaudio.com/forums/digital-line-level/203511-any-good-tda1541a-dac-kit-5.html
Post 44

Decoupling on T's DAC
http://www.diyaudio.com/forums/digital-line-level/203511-any-good-tda1541a-dac-kit-6.html
Post 51

Popping 74HC175 into digikey and selecting "in stock" and "through hole" I get two options

568-7801-5-ND
NXP Semiconductors
part#: 74HC175N,652
Frequency - Clock: 89MHz
Delay Time - Propagation: 16ns

and

296-8257-5-ND
Texas Instruments
part#: SN74HC175N
Frequency - Clock: 60MHz
Delay Time - Propagation: 13ns

Popping 74HC4040 into digikey and selecting "in stock" and "through hole" I get three options

296-8324-5-ND
Texas Instruments
part#: SN74HC4040N
Count Rate: 33MHz

and

MC74HC4040ANGOS-ND
ON Semiconductor
part#: MC74HC4040ANG
Count Rate: 50MHz

and

568-1451-5-ND
NXP Semiconductors
part#: 74HC4040N,652
Count Rate: 98MHz

Are this chips really different speeds or is it just an artifact of coming from different companies?
If they are truly different, which ones should I select?

Cheers,
Jeff