Lead-free solder and audio quality.

[Sebba]

On page 627 of “High performance loudspeakers 7th ed.” by Martin Colloms there’s written something that seems almost unbelievable, and looks like audio voodoo. But the author is a very knowledgeable and scientific person who seems to be an expert in this field:​

….. Under double blind testing, leaded (cable) was clearly preferred as being more neutral and with more resolved detail……

……a complete amplifier design which was built in leaded and lead-free versions. Careful comparison showed the lead-free version to sound perceptibly bright with impaired spatial quality and transparency…..

..This loss in sound quality is now understood and accepted in the high quality audio…..(using lead-free solder)

Unfortunately, I do not undertand this claim. If it's true, what parameters are deteriorated by a led-free solder ? Amplifiers, dacs, speakers and cables are electrionic systems, and can be measured and compared. Most audio electronic devices measured on ASR with the AP which have almost perfect parameters are lead-free !

Can someone explain what the author claims in this book has some scientific/engineering background ? Are there any measurable differences between leaded and lead-free technology (eg. linearity, noise generation etc.) ?

 

[GXAlan]

Buckeye 3 Channel Purifi Amp Review

That's correct. For people who buy this amp, impeccable measured performance is key. For that reason, I think this is a more significant issue that it otherwise would be. ...thank you for posting this...I was thinking it shouldn't matter if inaudible... ...I remember making fun of youse...

www.audiosciencereview.com

The phenomenon we saw here might have been an issue in the early era of lead free solder where is less about the lead and potentially more about the other metals.

 

[fpitas]

I had that book! I threw it away.

 

[NTK]

Welcome to ASR!

Did he disclose his test protocol and method is detail and has a third-part audit, or better yet, was there a public demonstration?

If there is a measurable performance difference between lead-free solder and leaded solder, there would have been an uproar from the measurement/metrology world, where people routinely measure quantities at much higher sensitivity levels than those involved in audio.

 

[Chrispy]

Martin Colloms and science?

 

[fpitas]

Martin Colloms and science?

Oxymoron

 

[GXAlan]

Welcome to ASR!

Did he disclose his test protocol and method is detail and has a third-part audit, or better yet, was there a public demonstration?

If there is a measurable performance difference between lead-free solder and leaded solder, there would have been an uproar from the measurement/metrology world, where people routinely measure quantities at much higher sensitivity levels than those involved in audio.

https://www.msed.nist.gov/solder/NIST_LeadfreeSolder_v4.pdf

All of the data is here.

Leaded cable is not the same thing as leaded fuel or lead containing optical glass — it’s the solder/termination and it wouldn’t be incorrect to say that if two cables were terminated differently and one was terminated poorly that there could be some conditions where the difference is measurable.

If you still had the cables used for the test, we could easily analyze them.

 

[antcollinet]

On page 627 of “High performance loudspeakers 7th ed.” by Martin Colloms there’s written something that seems almost unbelievable, and looks like audio voodoo. But the author is a very knowledgeable and scientific person who seems to be an expert in this field:​

….. Under double blind testing, leaded (cable) was clearly preferred as being more neutral and with more resolved detail……

……a complete amplifier design which was built in leaded and lead-free versions. Careful comparison showed the lead-free version to sound perceptibly bright with impaired spatial quality and transparency…..

..This loss in sound quality is now understood and accepted in the high quality audio…..(using lead-free solder)

Unfortunately, I do not undertand this claim. If it's true, what parameters are deteriorated by a led-free solder ? Amplifiers, dacs, speakers and cables are electrionic systems, and can be measured and compared. Most audio electronic devices measured on ASR with the AP which have almost perfect parameters are lead-free !

Can someone explain what the author claims in this book has some scientific/engineering background ? Are there any measurable differences between leaded and lead-free technology (eg. linearity, noise generation etc.) ?

As has been pointed out - bobbins.

There is no electrical characteristic of lead free solder compared to leaded solder that could remotely impact audio signals.

Just as it doesn't impact the very much more critical signals in many other applications. (RF, PC Clocks and data lines etc etc)

 

[dfuller]

Lead free does have some issues (mostly with whiskering over time), but this makes no sense.

 

[Chrispy]

Lead free does have some issues (mostly with whiskering over time), but this makes no sense.

Martin Colloms often makes no sense, tho

 

[pseudoid]

Welcome aboard @Sebba,
You will get used to it but we sometimes like beating around-the-bush when direct questions are asked.

I heard there is a pixie-dust atomizer fundme page. It supposed to improve the sound of blueTooth in its vicinity, with transcendental bite in its transient musicality.

 

[valerianf]

Lead soldering is allowed for pace maker electronics because the end result is more reliable in time.
That is all about it.
By the way, if somebody sell consumer electronics which was lead soldered, it's illegal in most parts of the world!

 

[gene_stl]

I am sure the lead free solder is responsible for the decreased reliability of new electronics and electronics not old enough to deserve a failure.

 

[GXAlan]

I feel like no one has even clicked on the NIST.gov link I posted. (Shrug). It’s 77 pages but you just need to skim through to understand.

There are big differences between lead and lead free solder, along with good reasons to move away from lead solder. There are clearly mechanical property differences and that can cross over audible differences if there are cold solder/corroded connectors.

Pacemakers actually use 99.99% gold

Solder in Medical Devices: That Solder’s Going Where? | Jenny Gallery | Indium Corporation Blogs | Gold Solder | Hermetic Sealing | Lead Free Solder

INDIUM: Cardiac pacemakers generally use 99.99% Au preforms as the solder material in the assembly. Pure gold is highly pure, inert, biocompatible, has a high resistance to corrosion, and works excellently to provide a hermetic seal in the device. All of these properties provide the perfect...

www.indium.com

 

[pseudoid]

The EU's Restriction of Hazardous Substances (RoHS) directive took effect in 2006 (applies to Lead (Pb)),
Why was lead solder typically used?
Lead solder was technically an alloy of lead and tin and was sometimes referred to by its chemical formula, Pb-Sn. Lead solder was used heavily for PCB production because it:
• Cools slower than other metals, which reduces the chances of cracking of the joint
• Wets joints well, which provides a good electrical connection for leads and PCB pads
• Has a melting point rather than a melting range for the blend used in PCB production, 63% tin and 37% lead, which facilitates automation of PCB production with reflow ovens
• Has a lower melting point than lead-free alternatives, making it less likely to damage electronic component.
Benefits of lead-free solder
Lead-free solder can include a variety of chemical elements, such as tin, silver, gold, copper, zinc and manganese. One of the most common includes tin, silver and copper and is abbreviated SAC, after the chemical symbols for tin (Sn), silver (Ag) and copper (Cu).
The primary benefit of lead-free solder is that it is safer than lead versions. Lead is a powerful neurotoxin. Although most of the focus on lead poisoning has been on children exposed to lead paint, anyone can suffer from lead poisoning, including electronics assemblers.
Among other benefits, lead-free solder:
• Does not wet as well as lead solders. When connection pins are spaced very close to one another, the reduced wetting prevents solder bridges
• Creates joints that are harder than lead joints, giving them better mechanical properties
• Are compatible with existing manufacturing processes for a seamless transition from lead solders
Drawbacks of lead-free solders
Despite their benefits, lead-free solders are not flawless. In fact, the EU has granted a few exceptions to the lead-free directive to accommodate certain applications. For example, some ceramic capacitors can only be produced using lead solders and are therefore exempt from the EU directive.
Other drawbacks of lead-free solders include:
• Lead-free solders are prone to whiskering, a phenomenon where tin forms electro-conductive crystalline structures. Whiskers grow spontaneously in some soldered joints that are high in tin
• The melting temperature is not as stable, predictable or narrow as that of lead solders, sometimes leading to defects when solder fails to melt completely
• The melting temperature is higher than that of lead solder, and can damage PCBs and electronic components during manufacture.
From <

Comparing lead vs. lead-free solder for PCBs - Huntron News and Information

Learn the differences between lead and lead-free solder and the benefits of using lead-free solder for your PCB products.

huntron.com

>

 

[DWPress]

Nothing to do with audio (except I listen while I work) but I have been working with lead intensively for over 35 years. I make books the old fashioned way with lead type though we call it "type metal" nowadays because lead has such a bad rap. I work with it in its solid form and I also cast type from brass molds. Type is composed in lead 50‒86%, antimony 11‒30% and tin 3‒20% depending on the size and purpose of the type, my machines run a 84/12/4 mix for book size composition.

Lead must be consumed to generate toxic levels, it is are not passed by the body and gradually accumulates - once levels are attained, like other heavy metals, getting rid of it is a difficult painful process called Chelation Therapy. This is why there was a big push to eliminate it from paints. Lead is sweet, the romans used it to sweeten cheap wine and why chipping paint was something a kid would eat. Also use of lead in gasoline caused emissions that allowed lead to accumulate in organisms near industrial areas, roads and cities. Lead bullets left in the body won't kill you because of lead poisoning nor will lead splinters in skin.

Lead fumes are not toxic until boiling point which is 3180F, (pure) lead melts at 621F and is odorless. The fumes you get from soldering are from the flux which can be harmful.

Lead oxides are toxic. Freshly cast lead is mostly harmless, the white powdery "rust", the oxide that forms with time and exposure, is very toxic so don't just use a toothbrush to clean an old circuit board and take a deep breath and blow it away! And be sure to wash your hands!

There are no documented cases of a printer dying of lead poisoning - as far as being able to document a profession that's been around 584 years. A huge loss to artists as lead white was bright and opaque.

 

[Keith_W]

The EU's Restriction of Hazardous Substances (RoHS) directive took effect in 2006 (applies to Lead (Pb)),
Why was lead solder typically used?
Lead solder was technically an alloy of lead and tin and was sometimes referred to by its chemical formula, Pb-Sn. Lead solder was used heavily for PCB production because it:
• Cools slower than other metals, which reduces the chances of cracking of the joint
• Wets joints well, which provides a good electrical connection for leads and PCB pads
• Has a melting point rather than a melting range for the blend used in PCB production, 63% tin and 37% lead, which facilitates automation of PCB production with reflow ovens
• Has a lower melting point than lead-free alternatives, making it less likely to damage electronic component.
Benefits of lead-free solder
Lead-free solder can include a variety of chemical elements, such as tin, silver, gold, copper, zinc and manganese. One of the most common includes tin, silver and copper and is abbreviated SAC, after the chemical symbols for tin (Sn), silver (Ag) and copper (Cu).
The primary benefit of lead-free solder is that it is safer than lead versions. Lead is a powerful neurotoxin. Although most of the focus on lead poisoning has been on children exposed to lead paint, anyone can suffer from lead poisoning, including electronics assemblers.
Among other benefits, lead-free solder:
• Does not wet as well as lead solders. When connection pins are spaced very close to one another, the reduced wetting prevents solder bridges
• Creates joints that are harder than lead joints, giving them better mechanical properties
• Are compatible with existing manufacturing processes for a seamless transition from lead solders
Drawbacks of lead-free solders
Despite their benefits, lead-free solders are not flawless. In fact, the EU has granted a few exceptions to the lead-free directive to accommodate certain applications. For example, some ceramic capacitors can only be produced using lead solders and are therefore exempt from the EU directive.
Other drawbacks of lead-free solders include:
• Lead-free solders are prone to whiskering, a phenomenon where tin forms electro-conductive crystalline structures. Whiskers grow spontaneously in some soldered joints that are high in tin
• The melting temperature is not as stable, predictable or narrow as that of lead solders, sometimes leading to defects when solder fails to melt completely
• The melting temperature is higher than that of lead solder, and can damage PCBs and electronic components during manufacture.
From <

Comparing lead vs. lead-free solder for PCBs - Huntron News and Information

Learn the differences between lead and lead-free solder and the benefits of using lead-free solder for your PCB products.

huntron.com

>

I once had a chat with an engineer who helped design satellites. He told me that lead-free solder had some drawbacks when used in spacecraft, mostly brittle joints that are prone to failing. This is not an issue if it happens on Earth, but it would turn your spacecraft into floating space junk and cost millions of dollars.

I don't know whether the same is true for aircraft because you certainly don't want a solder joint failing and taking out vital electronics while you are in the air.

 

[solderdude]

Early lead-free solder had some issues, current lead-free solder is much improved and just as reliable. It just does not shine as much as leaded solder. One can even rework leaded joints using most lead-free solder these days. This gave problems with the early leadfree solders.
Whiskers can still be an issue but this could happen with leaded as well.
Has nothing to do with audio quality though.

One should ignore Martin Colloms.

 

[Sebba]

One should ignore Martin Colloms.

I agree. Maybe there were some other factors in his blind tests, not only lead/lead free solder. But such unsupported by measurements claims shouldn’t be included in engineering books.

 

[antcollinet]

audible differences if there are cold solder/corroded connectors.

Sure - but they are manufacturing failures. It may be that lead free solder results in more care being needed in soldering processes, but that is the job of a manufacturing organisation: to manage those processes to give adequate quality.

Lead free solder when correctly applied does not impact the conductivity of the joint in any way that will create audible differences.