So what in solder "sounds" bad, and what can be done about it?

[guitician]

I would say that the best way to leave the solder out of the signal path is to use tight mechanical connections first, then solder the joint. The electrons will take the path of least resistance, which would be the copper, or tin plating. The RohS solder leave out the lead and add copper, which should make them better conductors, but melt at a higher temp. adding to the working difficulty.
Electrical resistivity and conductivity - Wikipedia, the free encyclopedia
Solder - Wikipedia, the free encyclopedia

[Jim Shine]

There is a lot of truth about people in audio field don't know much about electronics. This is also true about guitar amp. Look at the top quality amps, they are all tubes and you look at the schematics, they pretty much remain the same as 40 years ago. People just copy each other, change a few values and call it their own design. Most circuits are just old Fenders and Marshalls.

And Leo Fender just tweaked existing amplification designs. Much of what he was doing was taken from schematics in books and the jukeboxes he was servicing. The designs were old even then!

I took electronics courses for 4 years. Everything I needed to know to service guitars and amps fell within the first year-year and a half. This stuff is super simple. I think some people like to make it seem deeper and more complex than it really is. Maybe to add mojo or sophistication?

[RedHouse]

Maybe to add mojo or sophistication?

Yep.

[guitician]

And that's why they got it PERFECT from the start. And why it is so hard for the industry to do any better today. But now, the recording/playback part of it, well that's another thing entirely. Although the need to keep increasing profit, and make more with less is fighting progress all the way, the audio industry has made some nice sonic advancements.

[Alan0354]

(Alan's link has a nice plot about halfway down that verifies that the skin depth for copper is a bit less than 1 mm for those who do not want to check his calculation.)

It is amazing that actual effects get ignored or laughed at by the same people who swear by things that not only seem ridiculous when computed, but certainly do not stand up to real AB tests (like the difference between a ceramic and a polypropylene capacitor, especially with the full .5 Meg tone pot in series).

Few people realize that it is the mu term in the equation for skin effect that allows a steel core pickup to work. The loss in the cores is still very important, but without the mu term you would have a much greater loss in the midrange and lows. (The highs probably would still be OK because the inductance resulting from flux leakage is in series with the resistance.)

I always look at all the claims with skeptical eye. I was once that don't believe in speaker cable and I was actually surprised. I am not a pup maker and I cannot say anything about metal or magnet. But I also have issue with kind of cap. ceramic cap is good for multi GHz, it should not have any loss problem at audio frequency. It is a standard practice to parallel caps each of a decade apart. eg. you want 10uF, ideally you parallel 0.1 with 1 and 9uF as an example. So when the lead and structure inductance of the larger cap start kicking in, you have the next lower value to pick up the slag and so on. People spend a lot of money for those poly or myler cap just don't make sense. Like you said, using in high impedance circuit like 500K tone pot just don't make sense. ESR is not important at 500K environment.

Also the metal film vs vintage carbon resistors, both work from DC to microwave frequency. There should be absolutely no difference..............of cause if you use wire wound resistor, then you are asking for it. It is funny you see 100K carbon resistor for a few dollars each!!!! Also the CTS pots, I just don't see how a resistor can make a difference. I have them and I surely don't hear any difference.

I am open to be wrong, but people have to proof to me in scientific theory, not just tall tales.

[FunkyKikuchiyo]

And that's why they got it PERFECT from the start. And why it is so hard for the industry to do any better today. But now, the recording/playback part of it, well that's another thing entirely. Although the need to keep increasing profit, and make more with less is fighting progress all the way, the audio industry has made some nice sonic advancements.

The way I see it, the longer the signal chain, the more degradation on the sound. Designers tend to only think in terms of EQ... making things warmer, brighter, or whatever instead of keeping it sounding musical. You can't "EQ" a trumpet to sound like a flute! So, new amps have over-engineered themselves into a corner. I've played some older solid state amps that sound so nice, so vivid, that you can't believe they are solid state... and that is when it strikes me that it isn't just about the components. Modern SS amps are waaaaay over designed. What is the secret to the sound of little old tweed amps? That you can fit all the components into your pocket, that's what! YMMV.

Sorry. Got a little emotional there...

[Possum]

I think there might be some substance to the "bad sounding solder" deal because if you're dealing with printed circuit boards the electrical path from component to component is super thin and the total of all the solder joints adds up to maybe being a substantial part of the electrical path. Lead/tin solder is old school connection methodology meant for hand wired point to point connections using more solder than a tiny PC circuit board connection. So probably for PC boards something like the silver solder would be "better"and maybe you COULD hear it, so I wouldn't totally laugh at this until you solder identical boards both ways and take a listen to see if its true. As RH said, what you hear IS the sum of EVERYTHING you use, solder, wire, PC board or not, different brands and types of components. It all adds up and the smallest things can often be heard very well....

[Mike Sulzer]

I think there might be some substance to the "bad sounding solder" deal because if you're dealing with printed circuit boards the electrical path from component to component is super thin and the total of all the solder joints adds up to maybe being a substantial part of the electrical path. Lead/tin solder is old school connection methodology meant for hand wired point to point connections using more solder than a tiny PC circuit board connection. So probably for PC boards something like the silver solder would be "better"and maybe you COULD hear it, so I wouldn't totally laugh at this until you solder identical boards both ways and take a listen to see if its true. As RH said, what you hear IS the sum of EVERYTHING you use, solder, wire, PC board or not, different brands and types of components. It all adds up and the smallest things can often be heard very well....

The resistance of the solder connections is still very small.

Silver solder a pc card? I think the temperature might be a bit high!

[Steve Conner]

Mike, I've seen audiophiles silver solder anything. I hope they mean just regular solder with a hint of silver, not the silver brazing process that needs red heat from an oxyacetylene torch. Although that would be a fitting end for some of the overpriced crap sold on the hi-fi market.

Funky, I've also had that experience, indeed I've built simple transistor circuits that sound the way you describe. I don't think modern amp designers are stupid, they just think the market wants that compressed "modern" sound that you and I happen to be tired of. And they're quite possibly right.

Alan: Here's a story about ceramic caps. I had a Presonus parametric EQ that I never liked the sound of. So one day I put it on my distortion measuring rig. When you applied boost or cut on the bass band, you got 0.25% THD! The manual spec'd 0.007%. I opened it up to find that they had used tiny SMT ceramic capacitors everywhere. The distortion came from the voltage coefficient of the ones used in the filter networks. Moral: Ceramic capacitors come in two kinds. The high value ones are the bad ones, they vary their capacitance greatly with voltage and temperature, and are microphonic too.

[Plucky]

Here's a chart provided by Indium:

http://www.indium.com/products/alloy...loy_number.pdf

There is no debating whether or not there is a measurable difference, but when dealing with the limited number of connections in most guitar circuitry, the quality of the application of solder is paramount to its composition. Keep in mind that measurable does not necessarily mean audible.

If anyone here can hear the difference between various solder compositions in guitar circuit applications, you may need medication. Or possibly less medication.

[km6xz]

The skin effect claim for more hi-fidelity reproduction is really a stretch as has many double blind tests and lab tests indicated. What a reviewer had for dinner has more of a impact in subjective tests than could be repeatably detected in these uncontrolled "tests" that hi-fi types pride themselves in excelling at.
Just what impact would that .09db difference at 20khz make, when the dye on the carpet or material the painting on the wall would impact 20khz an order of magnitude more? Shifting listening position 1 inch would swamp and equipment differences in frequency response.

Regarding components, ceramic caps are measurably detrimental to audio. Read the article the famous analog engineer Bob Pease wrote when he out to prove that it was all non-sense. He apologized, that was one, the only one of the golden eye claims that turns out to be true. Simple IMD or impulse tests clearly slow microphonics and piezo effect where the amplitude of the signal mechanically modulated the capacitor's parameters, they become voltage controlled capacitors and all the non-linearity that entails when mixing complex waveforms.
Wire...not so much.

Solder does have some problems in signal, or more specifically current flow...HIGH current that is, not what is found in hi-fi systems. The best connections are no connections but if a system needs them, direct metal to metal compression such as in lugs that are to handle high current, are not supposed to be soldered at all. They are terminated with high compression so the connector and wire are crushed together so tightly that there is maximum surface contact and no air gap. Solder is primarily intended to be a joint stabilizing element, not a conductor which is it a pretty good one. A successful joint is one that is mechanically solid and low resistance before the solder is added to seal it. PC boards do have a weakness there, there is no good mechanical or electrical connection before solder is added to complete the connection. Fortunately, most pc through hole or surface mount connections are very low current. Power supply or power amp sections of the circuit are another story and bad engineering is practiced routinely. Leads need to be long enough to be able to be bent over and soldered over a longer portion of their length to increase contact area but machine board stuffing does not do that.

[Plucky]

Robert Allen Pease (August 22, 1940*– June 18, 2011)

Brilliant man. May he rest in Pease.

/Sorry, I couldn't help myself.

//seriously, the guy was an electronics guru.

///random guy: "are you a wizard?"
Robert Pease: "yes".

[Steve Conner]

Yes, the late Bob Pease was one of my favourite electronics writers. His book on troubleshooting is packed full of information that has helped me no end, both at work and in hobby projects.

The irony is that he died by crashing his car after publishing a book on how to drive safely.

The other sad thing was that this happened on the way home from the funeral service of Jim Williams, my other favourite electronics writer, who died of a stroke the week before.

[Mike Sulzer]

Mike,
Alan: Here's a story about ceramic caps. I had a Presonus parametric EQ that I never liked the sound of. So one day I put it on my distortion measuring rig. When you applied boost or cut on the bass band, you got 0.25% THD! The manual spec'd 0.007%. I opened it up to find that they had used tiny SMT ceramic capacitors everywhere. The distortion came from the voltage coefficient of the ones used in the filter networks. Moral: Ceramic capacitors come in two kinds. The high value ones are the bad ones, they vary their capacitance greatly with voltage and temperature, and are microphonic too.

It is very easy to demonstrate non-linear behavior in the "bad" kind of ceramic caps; just run them near their voltage rating and look on a scope! But the distortion is very low at low levels. The .022 and .047 caps used in a guitar are run at levels well below their rating. This kind of distortion is by its nature voltage sensitive: low voltage, very low distortion. (Kind of like amp clipping) When the full 500K tone pot is set on 10, then the voltage across the C is really very small. Yet we do hear claims that the cap matters, even on 10. Even though the tiny tiny non-linear components generated by the tiny voltage across the C have to come back through the 500K resistor and develop a signal across the pickup impedance. Also, I have not heard a significant microphonic effect from such Cs in a guitar. I guess that there are a lot of other things more sensitive to vibration in a guitar, or maybe you need to play at levels beyond my threshold of pain.

(For those who want the details about cap distortion, see Bateman's excellent work. Search for capsound3.pdf. 1 and 2 have the background.)

An equalizer is exactly where you need the best caps. The actual transfer function depends directly on the IV characteristic of some cap when you are boosting or cutting. Use of a low voltage rated ceramic in that application is ignorance at its worst.

[Possum]

There is a solder called silver solder I got from Radio Shack thats supposedly better and it is an electronic solder, don't really know anything about it. Well, if you use enough distortion it pretty much masks everything anyway. Making a beautiful clean sounding amp is the hard part ;-)