The silver wire was a 6" jumper to set a baseline. The other two were 72" lengths. The shield if I recall correctly was a spiral served multiple fine wires.
Quite simply as most can identify the AC line intereference frequencies vs the IM distortion and the test setup was to show IM, the noise wasn't really my worry.
As to solders, I did one experiment about changing petformance of an amplifier circuit on a PCB. Turns out resoldering all the places does have a measurable result. However it was not from changing or renewing the solder it was from filling in the through vias! Not surprisingly the electroplated vias do not conduct as well as simply having more metal! I suspect actually using a copper wire through hole jumper would be even better.
Folks the test of 200 solder joints showed less distortion than a single bit of wire. Now what was not measured was the effects of solder whiskers or how the environment changes solder joints. It is well known that some soldering fluxes should not be used for electronics as they will degrade the connections with age.
How different is spiral wound shield vs braided shield vs foil shields and combos?
Ok what causes the IM finding do you think.
Makes sense, good reason to stitch vias.
As last stage of plenty of amplifier repair jobs was isop clean pcb>blanket resolder>isop clean pcb(>conformal coat maybe) jobs as standard process.
This was chargeable time that ensured renewed spec performance and long term reliability and zero returns.
Every last good or dodgy ops joint got renewed and this rebirthing altered amplifier sounds for the better as would be expected by optimising connections.
What I didn't expect was a new 'house sound' subtly different from the original and depending on the solder I used.
Any ideas why this 200 joints is less distortion than wire, what does this mean?
Yes ZC batt acid destroys solder joints and other corrosives too but I haven't seen whiskers to be a problem to speak of in old school audio gear.
I have to admit a tiny tinge of jealousy
Hi Bill,
Maybe you are imagining in your mind beautiful shiny new SP-10MKIIs...these had years of 24/7 use when there was only LPs, so they look pretty disreputable. Oh and did I mention how undisciplined college-age kids are at taking care of ...anything? How about writing and scratching names and swears into equipment?
You can't have anything nice at a college station without a harsh manager who fires people at will...if I was there full time things would be different.
I can keep the stuff working properly, but not looking new. I'll try to remember to take a pic when I'm back up there.
Cheers!
Howie
That should be obvious if you re-read the whole of his posts and what he wrote as opposed to what you think he wrote.
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Ed's data so NOT show a repeatable, substantive difference between solders, nor between solder and wire.
In the name of actually making progress understanding audio, please do not make unsubstantiated claims. Either provide factual evidence or just keep researching it yourself like Ed has until you understand the factor responsible, thank you. To do otherwise just lowers the S/N of the forum.
Any other policy will turn this (sometimes) productive forum into a suppositional fantasy land (great Jimi LP). We all have imaginations, but ideas they give us are just the first step in researching. We are creatures of relativity, it is our survival super-power. However this relativity of sensual perception has well-known limitations as far as repeatability and memory are concerned.
Listen to the same piece of music with bright red light and then again with dim blue light. If you are being honest you will feel differently about the music with each. Is the wavelength of the photons changing the air behavior? How does a slow acoustic piece sound to you after having an argument with your heart thumping in your chest and your eyes seeing red? If you are being honest it you will admit you perceive it differently than when you are happy and relaxed. Do anger brainwaves change the propagation of sound in a room?
What we perceive is not, without much repeating and controls on our other senses what is actually being reproduced. The trick is filtering data out of our perceptions using science.
Bring on the science Max!
Howie
A spiral shield is just that a bunch of uninsulated wires wrapped around the center conductor. Bend the cable and gaps in the shield can appear. Some use a double served shield where there are two wraps going in opposite twists. Most single spiral shielded cables I have looked at don't even use enough shield wires to be a truly effective shield.
A braided shield avoids the problem of bends opening gaps, but depending on the weave there are open areas.
A foil shield properly done covers the entire inner conductor but is thin enough that it often doesn't provide enough shielding.
For cable television use there are double shielded cables consisting of a woven and foil shield. The triple shielded use foil-woven braid-foil construction.
Then there is the quad shielded catv coax which is what I normally use for wiring large venues, foil-braid-foil-braid. It does require special connectors to allow for the thickness of the shields.
As to re-soldering PCBs to improve things, one should be cognizant that when wave soldering first started the common 60-40 solder didn't result in always perfect products. That is when the 63-37 formulas became popular. Not just lower soldering temperatures, but a much faster transition from liquid to solid resulting in reduced cold solder joints. It also required tighter control of the solder bath. That is something that isn't always as good as it should be. So there are PCBs produced that have less then optimum connections. Reheating or re-soldering joints on such products will have an effect.
(Guys I know the rumors are that Australians speak English, but can we look at some prior members here and their communication correlation coefficient?)
A braided shield avoids the problem of bends opening gaps, but depending on the weave there are open areas.
A foil shield properly done covers the entire inner conductor but is thin enough that it often doesn't provide enough shielding.
For cable television use there are double shielded cables consisting of a woven and foil shield. The triple shielded use foil-woven braid-foil construction.
Then there is the quad shielded catv coax which is what I normally use for wiring large venues, foil-braid-foil-braid. It does require special connectors to allow for the thickness of the shields.
As to re-soldering PCBs to improve things, one should be cognizant that when wave soldering first started the common 60-40 solder didn't result in always perfect products. That is when the 63-37 formulas became popular. Not just lower soldering temperatures, but a much faster transition from liquid to solid resulting in reduced cold solder joints. It also required tighter control of the solder bath. That is something that isn't always as good as it should be. So there are PCBs produced that have less then optimum connections. Reheating or re-soldering joints on such products will have an effect.
(Guys I know the rumors are that Australians speak English, but can we look at some prior members here and their communication correlation coefficient?)
In usage where low PIM and shield leakage is critical, semi-rigid coax is employed which has a copper tube as the outer conductor. For higher powers, Heliax is employed which has a corrugated outer tube conductor and is semi-flexible as well. I had thought about making audio cables using Commscope FSJ1-50A 1/4" Heliax which is pretty flexible, but the issue of properly mating RCAs rears its ugly head and I just don't have the time to futz with it. It was just easier to use quality balanced interconnects and be done with it.
I saw a meter of silver quad-shielded cable for $3800 the other day and almost choked on my tea..
Howie
Yes! That includes credible evidence that these <-120dB effects are audible even if they are measured.
For the record we send our precision A/D, DAC, A/D driver,etc demo cards out to ordinary assembly houses using ordinary SMT parts and have no recollection of any boards working but not doing the -120 or -130dB specs.
I wonder how many AP's or Stanford Research instruments need major rework rather than the built-in cals, it wouldn't be tolerated.
We both have put stations on the air. (Only three for me.) I noted rigid coax is standard copper tubing and the impedance is also nicely handled by selecting the proper standard copper tubing inside for that also.
The problem with using small diameter heliax for an audio cable of course is the tank of dry nitrogen gas and the regulator. An air compressor would just be too noisy!
I think I still have a reel or two of .75" semi-rigid MATV coax around. Some of it may even be plenum rated!
Of course TV camera Triax is used by some folks as the impedance of the cable between the two shields is about 8 ohms. Inventory says I have 1,540' of that in the back.
I do have the TDR to check the installed cable. The problem is most of the consultants spec'ing the installation are asking for frequency sweeps of the installed cable.
For those of you not familiar with frequency sweeps, most manufacturers do this on the finished spools of cable. A dip in the result indicates a defective cable. Very easy to do on a spool when the sweep generator and read out are in the same place and cross connected so the send and receive can be synchronized. The original test gear to do this from General Radio used a chain to sweep the oscillator and receiving filter in sync!
Minor problem trying to get that sync chain going from one end of a 1,500 foot cable run to the other end!
I, of course, unlike many here, think that solder type and quality can be important in some cases. However, not for most of you out there. For most everyone, I would recommend Sn63, because it is eutectic (less cold joints) much like Ed suggests. Personally I generally use SN62 (2%silver, and eutectic, and an even lower melting point than Sn60 or Sn63, and have done so for decades. I personally hate lead free solders, generally, but I realize that they are necessary for commercial products (by law) and that with extra effort, can be OK.
Lately, I have been given a serious sample of KAPPS Sn96.5, Ag3.5 that I have not yet tried, but I have hope for, for my really SERIOUS designs that I personally make. This is above any Parasound products (not practical), but it could be more (legal) for an extra quality new design.
I might remind some here that certain sophisticated designs, (like the Vendetta input phono stage), vacuum tubes (single ended), etc, can be very sensitive to power supplies and therefore any subsequent solder joints, so the addition of a 'better' solder might be suggested. The problem with Sn96 type solders is their cost and higher melting point. Thank goodness they are eutectic (look it up if you don't know what it means) as well.
Lately, I have been given a serious sample of KAPPS Sn96.5, Ag3.5 that I have not yet tried, but I have hope for, for my really SERIOUS designs that I personally make. This is above any Parasound products (not practical), but it could be more (legal) for an extra quality new design.
I might remind some here that certain sophisticated designs, (like the Vendetta input phono stage), vacuum tubes (single ended), etc, can be very sensitive to power supplies and therefore any subsequent solder joints, so the addition of a 'better' solder might be suggested. The problem with Sn96 type solders is their cost and higher melting point. Thank goodness they are eutectic (look it up if you don't know what it means) as well.
"I might remind some here that certain sophisticated designs, (like the Vendetta input phono stage)... can be very sensitive to power supplies"
Hence, local or onboard regulation. Not being all that familiar with your circuit I was wondering -- you had regulators in the PSU boxes. Were these pre-regulators? Is there "closer" regulation on the signal boards themselves?
Or would you move that IC regulation to the signal boards in a new project and avoid the long supply lines into the signal box? Thx.
Hence, local or onboard regulation. Not being all that familiar with your circuit I was wondering -- you had regulators in the PSU boxes. Were these pre-regulators? Is there "closer" regulation on the signal boards themselves?
Or would you move that IC regulation to the signal boards in a new project and avoid the long supply lines into the signal box? Thx.
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I have been playing with my arduino engineering educational kit. Minor problem is that some of the software is supposed to be downloaded from the folks at Microsoft. Of course it doesn't work. It lets me log in, but doesn't know I have a computer, so even when i get get to the right software download tab it won't load.
Directions to include my computer are a perfect circular loop! Select computer, select windows, go to settings, go back to MS, enter code, go to select computer...
Curious to see what happens to my documented complaint.
AHA found another site with the software. It works well.
Directions to include my computer are a perfect circular loop! Select computer, select windows, go to settings, go back to MS, enter code, go to select computer...
Curious to see what happens to my documented complaint.
AHA found another site with the software. It works well.
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I've not seen 1/4" helix that can be gassed. But I haven't looked hard. Most of the stuff we used was Andrews foam core as we didn't run anywhere near the power levels of the big boy TX towers.
Right, the 1/4" Heliax is only available foam core. 1/2" and above it is available in multiple dielectric configurations.
Howie