Best type of solder for audio quality
Jan 12, 2011 at 4:41 PM Thread Starter Post #1 of 48

mojo

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I have been experimenting with different kinds of solder for use in audio. My experiments have all been on cables but presumably it affects PCBs as well.
 
I mostly use 60/40 leaded solder. IMHO all the lead-free stuff is crap, takes too much heat to flow properly and make a really good join plus the fumes are worse than the leaded stuff. There is still some variation between types of leaded solder though.
 
The main type I use is Goot SE-06008 as it flows well but is also malleable enough to make bridges when doing matrix board or cable joins. It is 60/40 183-190C 0.8mm multicore I believe with flux built in. I also tried some Goot SD-60 which has much more flux and consequently is more "wet" and hard to make bridges with. It flows very easily and is good for making very "close" and minimal joints. The SD-60 is designed for SMD work so is not ideal for making cable joins from an ease-of-use point of view, and I am still in two minds about the sound quality. I think a good metal-on-metal joint with SE-06008 is superior most of the time which I think could be down to the SD-60 working in between everything and thus forming a layer between the two surfaces. On the other hand in situations where it is hard to make that type of connection with normal solder such as wires direct to SMD ICs it might be better.
 
I suppose it really depends on the application then. I also have some Almit KR-19 which is 0.65mm and less wet than the SD-60 but still quite clingy. It is easier to work than the SE-06008 but seems not to make as good joints, but I have not done any ABX testing so it may just be the result of inhaling whatever they put in it... Seriously, it smells floral!
 
Anyone else noticed any differences between types of solder?
 
Jan 12, 2011 at 7:06 PM Post #4 of 48
when Merlin Music Systems was forced to go to lead free solder to comply with EU regulations, they unexpectedly found that it took their speakers to a higher level of performance. i'll bet that this type of talk will make some roll their eyes.  some folks hear no differences amongst cables while others hear differences ranging from subtle to significant. i think you'll find the same with solder.
 
Jan 12, 2011 at 7:21 PM Post #5 of 48
Well I am quite sceptical about cables generally speaking. There is a difference between the cheap ones and reasonable quality ones, but not between good £10 cables and £500 cables. My suspicion is that a combination of poor soldering and low grade plugs is what ruins the cheap ones. The quality of hand-soldered parts from Chinese factories in particular nose-dived when ROHS came in. I'm all for removing dangerous substances but it's frustrating that no-one has managed to make a good lead-free solder yet.
 
The claims by Merlin don't match my own findings. I suppose there were unlikely to say that it made the sound worse since that would mean all their products received a downgrade. The biggest problem seems to be the amount of heat required to melt it. With leaded solder you can easily heat the parts being soldered to the 180-190C required to melt solder so it flows well around them completely. With lead-free the parts need to be in the 300C+ range which is difficult when you are using a normal iron. Really hot air or flow soldering is required. You end up with poor, dry joints and the loss of sound quality is audible IMHO.
 
A note on upgrading existing soldering. Remove the old stuff first and don't mix solder types. Also use an old iron/bit for removal because it will get trashed pretty quick with cheap PCBs.
 
Jan 12, 2011 at 7:44 PM Post #6 of 48
The best sounding solder will invariably be the one that you find easiest to flow into solid, perfect joints.  No amount of silver/palladium/voodoo will make a cold joint work better than a shiny, well-flowed connection. 
 
Jan 12, 2011 at 9:31 PM Post #7 of 48


Quote:
Use eutectic solder like 63/37.  Personally, I'm a huge fan of Cardas Quad solder, melts at low temperatures, stays liquid as long as you need and has enough flux to make good joints every time easily.


X^n for Cardas Quad. Cheap but works like charm. I tried some WBT and Mundorf Silver/Gold solder, they are both great but don't do anything better than the Cardas.
 
Jan 12, 2011 at 10:24 PM Post #8 of 48
Maybe some folks eyes would roll, not mine. One of the pleasures of the Merlin's is Bobby provides upgrades throughout the life of the speaker. I purchased TSM-MX and over the course of a their seven year life had them updated twice at minimal cost. They continue to be very highly regarded. When I move back to a big rig, the VSM's will be contenders up front. 
 
Back to the solder thingy, the difference with the MXe update (RoHS compliant) was significant in my system. I've used Kestor (in the late 60's and early 70's for my Dynaco and HK kits), Cardas, WBT, Mundorf (more recently), RS. The Cardas flows the best, I think.
 
Quote:
when Merlin Music Systems was forced to go to lead free solder to comply with EU regulations, they unexpectedly found that it took their speakers to a higher level of performance. i'll bet that this type of talk will make some roll their eyes.  some folks hear no differences amongst cables while others hear differences ranging from subtle to significant. i think you'll find the same with solder.



 
Jan 12, 2011 at 11:13 PM Post #9 of 48
I agree that the point of solder is to make a permanent, physical connection. I've experimented with the boutique stuff, but nothing flows as well as 60/40. I don't like the higher temperatures, either. It's too easy to damage components unless you do a lot of heatsinking, which is a pain. 60/40 lets you get in and knock off a clean joint faster, with less heating.

An excellent joint will perform better than a boutique cold solder.
 
Jan 12, 2011 at 11:24 PM Post #10 of 48
The only reason for ever using anything special is if you have an all silver setup (wire and connectors), silver solder will help keep the uniformity of it all (forget what I read exactly, but silver will oxidize if not treated or done properly unlike gold, so it may be a concern to some applications, other than that, anything works as long as it's not resulting in a weak cold-joint. 
 
I've always used Radio Shack 60/40, but then again, I don't have that great of a selection without special ordering everything. I may try something different with my next setup as the spool of it I got this last time has terrible flux.
 
If you live somewhere that demands everything be RoHS though, you're kinda stuck with the harder to work with stuff.
 
Jan 13, 2011 at 12:42 AM Post #12 of 48


Quote:
Quote:
The only reason for ever using anything special is if you have an all silver setup (wire and connectors), silver solder will help keep the uniformity of it all

That would make more sense if you could find a PCB maker that can offer silver traces :~)
 


Well yeah... I guess that only applies to cables. But if you can get a silver clad board, you could do a PCB in silver 
biggrin.gif
 
(You'd waste a ton of silver through the etching process. But... you would have a silver PCB)
 
Jan 13, 2011 at 12:43 PM Post #14 of 48


Quote:
Originally Posted by Rdr. Seraphim /img/forum/go_quote.gif
 
Back to the solder thingy, the difference with the MXe update (RoHS compliant) was significant in my system.


The problem I have with that sort of thing is that there is no way to compare before and after directly since you have to send the speakers off to be modified. With cables although I have not got around to double blind testing I have used one type for left and another for right stereo and can hear the difference. I'm not saying that solder in speakers doesn't make a difference, just that the amount and nature of it is hard to determine without direct comparison.
 
As an experiment if I can find some lead-free solder I will try to compare directly. It is entirely possible I am prejudiced against it because of the difficulty I have have working with it (I used to do electronics repairs and they got a lot harder when RoHS came in).
 
For PCBs one trick people used to use before PCBs were coated was to put a thin layer of solder all along the traces. Apparently it made a measurable difference in radio equipment (reception rather than audio quality presumably).
 

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