Lead-free solder and audio quality.

[GXAlan]

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.

Which is exactly what I have been conveying in this thread…

 

[Galliardist]

So, for the benefit of this non-expert, I'm reading this as potentially a test between a poorly made amplifier and a well made one. And if I understood some of the attached information correctly, that could be as simple as the soldering iron not being at the correct temperature for the lead free solder. Have I got that right?

 

[antcollinet]

So, for the benefit of this non-expert, I'm reading this as potentially a test between a poorly made amplifier and a well made one. And if I understood some of the attached information correctly, that could be as simple as the soldering iron not being at the correct temperature for the lead free solder. Have I got that right?

Possibly - or it might just be bad science.


But in any case - hopefully not a soldering iron temperature. But a poorly managed reflow or solder wave process - since I'd not want to buy a hand soldered amp.

 

[Sebba]

Thank you all for the answers. I've never measured the parameters of the lead free joints but I suppose they are inferior to leaded ones at least mechanically. For example medical, metrical, controlling and many other professional devices are excluded from RoHS directive and still use leaded solder.

Of course the quality of metal joints matter. Some years ago I measured my DIY amplifier and the 19/20KHz test showed me a lot of IMD spikes. At first I suspected the output relays but in fact a small (~5mm) metal “soldering eyes” in the speaker connectors were the culprit ! They were made of gold-clad steel, which saturated even with moderatr currents.. I soldered the output wires directly to the connectors, and the IMD disappeared.

 

[TheBatsEar]

Welcome to ASR

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

I doubt the validity of these double blind tests.

 

[restorer-john]

It would be interesting to ask an avionics engineer about reliability of Pb-free solder. My last interaction with someone back in the day seemed to suggest the military was sticking to 60:40 lead/tin as lead free was a reliability nightmare in aero stuff. Things may have changed, I have no idea.

I personally hate lead free solder. It's nasty, unreliable and horrible to rework. It lacks all the attributes that make a reliable, long term connection, especially in the presence of heat, vibration and high humidity.

 

[JSmith]

avionics

To date, no other material provides the proven safety and reliability of tin lead alloy solder. Thankfully, all soldering operations performed on avionics are performed by highly trained and certified personnel who follow strict risk management processes. They are further protected by a framework of existing legislation and industry best practice. Although the removal of lead from solder would reduce the very small, potential exposure risk to personnel, it would in fact increase the risk of aircraft and other critical systems failures, with far greater safety implications.

https://leadmatters.org/wp-content/uploads/2020/09/Lead-Matters-Casestudy-Aviation.pdf

JSmith

 

[Thomas_A]

Just to note - I repaired a Macbook PCB where joints had cracked around one IC (lead-free tin), and there were several reports of the same issue by others. Probably the PCB goes through heat and cold-cycles, causing small mechanical movements of the solder joints, which in the end may cause cracks. So question is whether leaded solder is softer and manage such variations better? Any "hard evidence" that modern electronics have shorter life span?

 

[Sokel]

The biggest curse in audio is our age.
When people reach 40 yo anything new that introduces things that intuitionally doesn't keep them in their comfort zone and the nice and settled little reality feels like an enemy.

And lets face it,the vast majority of audio enthusiasts are of a certain age (myself included in my 50's) so everything new is difficult.
On a not so innocent note,new stuff make old ones of less value (same with the cheap disposable ones) so it's something to consider too.

Doesn't matter if it's led free solder,new grounding practices,better PSU's,etc.
Old one that still works is a comfort.

 

[TheBatsEar]

When people reach 40 yo anything new that introduces ....

Stopped reading right there and then. Leaded vs unleaded solder is about physical properties and environmental protection, not age.

 

[Philbo King]

It would be interesting to ask an avionics engineer about reliability of Pb-free solder. My last interaction with someone back in the day seemed to suggest the military was sticking to 60:40 lead/tin as lead free was a reliability nightmare in aero stuff. Things may have changed, I have no idea.

I personally hate lead free solder. It's nasty, unreliable and horrible to rework. It lacks all the attributes that make a reliable, long term connection, especially in the presence of heat, vibration and high humidity.

The biggest reliability headache with lead-free is called tin whisker growth. This is where tin ions grow into microscopic rods that short together adjacent circuit points that are at different voltage levels. It really limits the lifetime of a product.

Lead-free solder: A train wreck in the making

A slow-motion train wreck in military and aerospace electronics design is taking place right in front of us.

www.militaryaerospace.com

 

[Sokel]

Stopped reading right there and then. Leaded vs unleaded solder is about physical properties and environmental protection, not age.

That's not what the thread title says.If it was about mechanical and other properties I would agree.
As for me I'll continue with my Mouser's Chip Quik SMDSW as it's a joy to work with and never failed me once,despite my strong environmental feelings .

 

[raindance]

I'd say for home hobbyists the biggest issue is the higher temperature requirement for lead free solder. Some people don't realize it and some have equipment that just doesn't cut it, but both would cause frustration.

Also the higher temperature required makes it possible that certain components could sustain damage if the heat is applied for too long a duration.

But in the interest of the thread intent, I highly doubt one type of solder vs another type vs a crimp connection vs a friction connection vs twisted wires would make any difference to sound unless the connection is bad or there is substantial oxidization.

 

[Ricardus]

I just can't...

 

[fpitas]

But in the interest of the thread intent, I highly doubt one type of solder vs another type vs a crimp connection vs a friction connection vs twisted wires would make any difference to sound unless the connection is bad or there is substantial oxidization.

But the leaded solder will sound old-timey and smooth.

 

[egellings]

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.) ?

Sounds a bit slithery to me. If there are any differences, they would be nanoscopic, vastly below any ability to hear them.

 

[pseudoid]

Things may have changed, I have no idea.

Last I recall, the management provided fan hoods at the workstations... turned into "solder" stations... where work was done... but those were the good old PTH board stuffing days. ROHS was just making a cameo, back then.

 

[pseudoid]

Have I got that right?

No! Just don't send your preciou$ audio equipment to space!

 

[DVDdoug]

I work in electronics (I only solder rarely) and I'm not sure if we use ANY lead solder.

At home I use regular-old tin/lead solder and water soluble flux. I haven't tried every lead-free alloy but what I have tried just isn't as-easy to work with. Since I only handle it infrequently as a hobby I'm not worried about lead poisoning. (I also don't have kids.)

As far as the original topic, I don't believe the results-conclusions either. If the blind listening tests are valid and repeatable, etc., there could be many other differences between two amplifiers that you think were built identically.

The cable... I just don't believe it and I'd like to see measurements of the "neutral" and "resolved detail". ...Is it 3dB more neutral?

 

[fpitas]

One should ignore Martin Colloms.

That is the beginning of audio wisdom.