Hey guys, I would like to get your recommendations for, of all things, hookup wire! 
The audio signal will be passing through this wire so it needs to be low resistance. The conductor can be either solid or stranded but it needs to be 20 AWG. The points I am hooking up in the circuit are 10 inches apart. Do I need exotic silver-plated wire or is that overkill?
BTW, I saw a table saying that 20 AWG copper wire has a resistance of 10.4 Ohms per 1000 ft. Is that a standard for any copper wire or are there higher quality copper wire with lower resistance than that?
Thanks in advance for any help!
The audio signal will be passing through this wire so it needs to be low resistance. The conductor can be either solid or stranded but it needs to be 20 AWG. The points I am hooking up in the circuit are 10 inches apart. Do I need exotic silver-plated wire or is that overkill?BTW, I saw a table saying that 20 AWG copper wire has a resistance of 10.4 Ohms per 1000 ft. Is that a standard for any copper wire or are there higher quality copper wire with lower resistance than that?
Thanks in advance for any help!
Resistance is a function of the gauge and it is a constant for copper of common purity levels, silver plated wire will not affect that significantly.
Better to spend your money on irradiated pvc or teflon insulated wire. I prefer stranded, but many prefer solid.
If you really need lower resistance (and I am betting you don't -do the math) then you need to use a larger gauge wire. I could make some crack about superconducting wire, but won't..
What sort of signal is it that a short conductor's resistance is a big concern?
Better to spend your money on irradiated pvc or teflon insulated wire. I prefer stranded, but many prefer solid.
If you really need lower resistance (and I am betting you don't -do the math) then you need to use a larger gauge wire. I could make some crack about superconducting wire, but won't..
What sort of signal is it that a short conductor's resistance is a big concern?
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Resistance is a function of the gauge and it is a constant for copper of common purity levels, silver plated wire will not affect that significantly.
Better to spend your money on irradiated pvc or teflon insulated wire. I prefer stranded, but many prefer solid.
If you really need lower resistance (and I am betting you don't -do the math) then you need to use a larger gauge wire. I could make some crack about superconducting wire, but won't..
What sort of signal is it that a short conductor's resistance is a big concern?
I have an AD converter unit that allows me to select three different input gain settings (either input pot mode, trim pot mode, or fixed -15 dBFS reference mode) by means of jumpers. The jumpers are simply selecting the L/R channel pair of audio signals that will get to the PCM4202 ADC chip. The thing is, the jumpers are inside the unit and I often need to make changes in the settings depending on the kind of input I am feeding to the converter (e.g., input pot mode for unbalanced consumer -10 dBV sources or trim pot mode for balanced professional +4 dBm sources). So I would like to install an external DIP switch with the wires running from the jumpers to the switch. This would allow me to change settings conveniently without having to remove the ADC from the rack, unscrew the cover, etc. I know this is less than ideal, as the jumpers with their short signal path would be better as far as sonic integrity is concerned. Heck, if I didn't need to change settings at all, I could just solder a thick wire permanently in place of the jumpers for the particular setting that I would always use and never change. But such is not the case, and I think I can sacrifice a little signal degradation for convenience. I would not like to sacrifice too much signal for convenience though
so I want very low resistance wire. I understand that the wire needs to be thick to have lower resistance, but I have determined that I can only use up to 20 AWG wire due to the connectors on the DIP switch being so small and close to each other. I would not be able to solder any larger wires on them.In summary, I need the wire to be very low resistance as far as 20 AWG could be, in order to minimize the signal degradation when using the switch compared to using the jumpers directly. Of course, the quality of the switch is another issue, but let's take things one at a time.
I'm interested in this solution, thanks!
I don't know much about relays. Could you please give details describing the exact part I need to buy based on the following info:There are six jumpers, JP1 to JP6. They are all on one row. The input pot mode is set by turning on JP1 and JP4. The trim pot mode is set by turning on JP2 and JP5. The fixed -15 dBFS reference mode is set by turning on JP3 and JP6. Thus, each of the three modes is set by turning on a pair of jumpers. I have already bought a 3-position DPST switch. Will I be using this in conjunction with the relay?
On the other hand, I haven't totally given up on the "wires" solution, so other posters please keep your recommendations coming on that.
Thanks again!
I'm interested in this solution, thanks!
There are six jumpers, JP1 to JP6. They are all on one row. The input pot mode is set by turning on JP1 and JP4. The trim pot mode is set by turning on JP2 and JP5. The fixed -15 dBFS reference mode is set by turning on JP3 and JP6. Thus, each of the three modes is set by turning on a pair of jumpers. I have already bought a 3-position DPST switch. Will I be using this in conjunction with the relay?
On the other hand, I haven't totally given up on the "wires" solution, so other posters please keep your recommendations coming on that.
Thanks again!
I have seen relay switching used for source selectors on amplifiers so the signal pathway is kept as short as possible. Essentially the same thing you want to do, but I do not have the expertise to design one. Maybe someone else can help you with that?
A simple google search for "relay switching for amplifier source selector" led me to this without looking past the first few sites. A finer tuned search or deeper look into this one may yield better results.
Simple yet versatile relay-controlled A/B switch box
Good luck!
I don't know, I am sort of with him on this. What he is trying to do is tap off the internal jumpers and wire to an external switch. Maybe there will be noise pick up or something. I wouldn't worry much about the resistance, more that the signal wires may become little antennas and so a relay switch would keep the signal path short and inside the cabinet.
I looked in DigiKey and couldn't find a relay with enough pins for 6 jumpers. That means I will have to buy several relays but they are too bulky and won't fit.
I also read that relays have issues with causing possible damage to nearby IC's when the power is turned off (unless you put a current-limiting diode, but then that would add to their already bulky footprint). So, unfortunately, I'm back to my original quest for low resistance wire.Relays are cool for switching , I built a guitar amp with Relays for channel switching and it worked out well ......
Relays are basicly switches that are switched by applying voltage to a coil inside the relay ... the problem with them is they need a voltage source so you would have to take a tap off the existing voltage inside the unit ....
Cheers
Relays are basicly switches that are switched by applying voltage to a coil inside the relay ... the problem with them is they need a voltage source so you would have to take a tap off the existing voltage inside the unit ....
Cheers
Well the OP mentioned resistance and I was responding to that. Yes, long leads on any signal circuits can lead to interference of one sort or another. Resistance is seldom a factor, however.
A relay system has risks also. A possible solution is to mount a rotary switch close to the circuit, with a shaft that can be reached without difficulty.
A relay system has risks also. A possible solution is to mount a rotary switch close to the circuit, with a shaft that can be reached without difficulty.
multipole relays
Tbar relays have as many poles as you want. They are not cheap. here's a google link to a surplus house-T-Bar Relays else alliedelec.com is a usa stocking distributor. If you want new 20 ga wire, check farnell.com uk or newark.com usa. It also is not cheap, is usually multistrand, and after the european lead rules, from them it is usually silver coated. If you want cheap 20 ga, go to an electrical supply (lighting and power), they can get it but it will only have 7 strands and not be flexible and come in 500' rolls. If you think noise might mess up your signal, using RG8 (closed circuit TV coax wire) and grounding the shield at one end would help. Every yard sale around here has an end of roll (30' or less) TV coax item. Sorry about the bold print, it came from Google and I didn't know how to turn it off.
Tbar relays have as many poles as you want. They are not cheap. here's a google link to a surplus house-T-Bar Relays else alliedelec.com is a usa stocking distributor. If you want new 20 ga wire, check farnell.com uk or newark.com usa. It also is not cheap, is usually multistrand, and after the european lead rules, from them it is usually silver coated. If you want cheap 20 ga, go to an electrical supply (lighting and power), they can get it but it will only have 7 strands and not be flexible and come in 500' rolls. If you think noise might mess up your signal, using RG8 (closed circuit TV coax wire) and grounding the shield at one end would help. Every yard sale around here has an end of roll (30' or less) TV coax item. Sorry about the bold print, it came from Google and I didn't know how to turn it off.
Holy s**t, those T-Bar relays are expensive! I have just about given up on relays and decided to use simple wires. I can buy nice cable per foot from the nearby Pacific Radio store. What do you think of Canare DA206 digital audio cable? Or what about Canare 4S6 star quad speaker cable? I will just be using the conductors with their insulation, not the whole cable. I can even probably use CAT6 cable but that's 23 AWG.
Can we get back to ground level?
I'm afraid you have some serious misconceptions about wire resistance and its importance.
"The audio signal will be passing through this wire so it needs to be low resistance." That is nonsense as a general case.
All copper wire is effectively the same for a given gauge. As you say, 20AWG copper is 10R/1000ft. Thus 1ft = .01 ohm, which is totally negligible except perhaps in high power / high current applications, which this one isn't!
The effect of this resistance depends on the EXISTING IN-CIRCUIT RESISTANCES. For example, if your jumpers are selecting 1K resistor, the error using your 1 foot of 20awg will be .01R in 1000R, which is 1/100,000 !
Totally negligible.
You want to extend some jumpers to "out of the box". The problem may be one of screening or hum pickup, in which case you need to use screened cable with the shield connected to ground at on end only. It is unlikely that this will be necessary, but dead easy to check: just extend a sample jumper using simple thin wire and see if the noise/hum increases.
The only practical solution is, I feel, using relays. All you need is a single TINY miniature form-A (look it up!) relay for each jumper. NOT one big relay with lots of contacts!
These relays need to be "programmed" open or closed by some external switch (rotary?) or even moving the jumpers to the box case - the jumpers then switching the relays.
In any case, this involves some quite delicate work and would benefit from a pcb.
With respect, your comments do not indicate that you have enough electronics understanding or experience to tackle this.
As always, it would be a great help if you included a schematic so that we could make more useful suggestions rather than just speculating.
It may be that the circuit impedances are low enough not to suffer from simple wire extensions to the jumpers, in which case the solution is easy.
Hey guys, I would like to get your recommendations for, of all things, hookup wire!
BTW, I saw a table saying that 20 AWG copper wire has a resistance of 10.4 Ohms per 1000 ft. Is that a standard for any copper wire or are there higher quality copper wire with lower resistance than that?
Thanks in advance for any help!
I'm afraid you have some serious misconceptions about wire resistance and its importance.
"The audio signal will be passing through this wire so it needs to be low resistance." That is nonsense as a general case.
All copper wire is effectively the same for a given gauge. As you say, 20AWG copper is 10R/1000ft. Thus 1ft = .01 ohm, which is totally negligible except perhaps in high power / high current applications, which this one isn't!
The effect of this resistance depends on the EXISTING IN-CIRCUIT RESISTANCES. For example, if your jumpers are selecting 1K resistor, the error using your 1 foot of 20awg will be .01R in 1000R, which is 1/100,000 !
Totally negligible.
You want to extend some jumpers to "out of the box". The problem may be one of screening or hum pickup, in which case you need to use screened cable with the shield connected to ground at on end only. It is unlikely that this will be necessary, but dead easy to check: just extend a sample jumper using simple thin wire and see if the noise/hum increases.
The only practical solution is, I feel, using relays. All you need is a single TINY miniature form-A (look it up!) relay for each jumper. NOT one big relay with lots of contacts!
These relays need to be "programmed" open or closed by some external switch (rotary?) or even moving the jumpers to the box case - the jumpers then switching the relays.
In any case, this involves some quite delicate work and would benefit from a pcb.
With respect, your comments do not indicate that you have enough electronics understanding or experience to tackle this.
As always, it would be a great help if you included a schematic so that we could make more useful suggestions rather than just speculating.
It may be that the circuit impedances are low enough not to suffer from simple wire extensions to the jumpers, in which case the solution is easy.
Thanks for the education!
I'm really just good at soldering and know only a little about electronics, but I can manage with some research and asking questions on this forum.I know the resistances are negligible but I'm very anal especially with this high-end AD converter that I use for recording in my studio. I would like to use the best quality copper that I could find within my budgetary limits because my philosophy is to use the best materials for this project. It may not matter technically but I have a thing with quality. Also, in my research I have found that not all 20 AWG copper wire have the same resistance. For example, Mogami 3231 (solid) has 8.5 Ohms/1000 ft, Canare DA206 (solid) has 10.1 Ohms/1000 ft, and Canare 4S6 (stranded) has 11.4 Ohms/1000 ft. By the way - and this should be a question for another thread but I want to ask anyway - which wire is better for audio interconnect cable such as RCA or patch cable: stranded or solid?
I have actually made some initial tests already, using ordinary CAT5 cable to connect the jumpers to the DIP switch. I did not find any hum issues but I did find that the stereo crosstalk measurement in RMAA degraded by 10 dB. Do you have any ideas on a remedy for this degradation? I did not untwist the pairs of the CAT5. Could this be the reason? I cut out six pairs from the CAT5. Each pair went into a jumper on the board and a pair of pins on the DIP switch. I did not untwist the pairs because I didn't think it mattered since each pair was going into only one jumper, not separate jumpers. But now that I think of it, I guess I should have untwisted them to avoid any inductance effects, right? Also the benefits of a twisted pair are nonexistent in this manner of using those wires since there is no longer a balancing/noise-cancellation circuit involved, right?
My last question is this: Is there a non-negligible difference between using a jumper to engage two header pins vs soldering a thick wire across those pins? And is there a non-negligible difference between using a jumper to engage the pins vs using a short wire connected from the pins to a switch? (For this question let us consider resistances only and not any hum or screening issues with the wire.)
Thanks again!
Honestly, you'd be so much further ahead if you'd simply use those resistance figures and calculate how much the total conductor resistance of the length used in your circuit is compared to the circuit impedance there. Convert the ratio to dB and realize what you're actually dealing with, keeping in mind the "sound" of less than .01 ohms in a 3000 ohm circuit. Chances are you'll suddenly get interested in 36 AWG. Try some jumpers. See if you can hear them.
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Thanks for the education!
I know the resistances are negligible but I'm very anal especially with this high-end AD converter that I use for recording in my studio. I would like to use the best quality copper that I could find within my budgetary limits because my philosophy is to use the best materials for this project. It may not matter technically but I have a thing with quality. Also, in my research I have found that not all 20 AWG copper wire have the same resistance. For example, Mogami 3231 (solid) has 8.5 Ohms/1000 ft, Canare DA206 (solid) has 10.1 Ohms/1000 ft, and Canare 4S6 (stranded) has 11.4 Ohms/1000 ft. By the way - and this should be a question for another thread but I want to ask anyway - which wire is better for audio interconnect cable such as RCA or patch cable: stranded or solid?
I have actually made some initial tests already, using ordinary CAT5 cable to connect the jumpers to the DIP switch. I did not find any hum issues but I did find that the stereo crosstalk measurement in RMAA degraded by 10 dB. Do you have any ideas on a remedy for this degradation? I did not untwist the pairs of the CAT5. Could this be the reason? I cut out six pairs from the CAT5. Each pair went into a jumper on the board and a pair of pins on the DIP switch. I did not untwist the pairs because I didn't think it mattered since each pair was going into only one jumper, not separate jumpers. But now that I think of it, I guess I should have untwisted them to avoid any inductance effects, right? Also the benefits of a twisted pair are nonexistent in this manner of using those wires since there is no longer a balancing/noise-cancellation circuit involved, right?
My last question is this: Is there a non-negligible difference between using a jumper to engage two header pins vs soldering a thick wire across those pins? And is there a non-negligible difference between using a jumper to engage the pins vs using a short wire connected from the pins to a switch? (For this question let us consider resistances only and not any hum or screening issues with the wire.)
Thanks again!
Sorry. I am an engineer and not qualified to deal with snake-oil questions like this.
10 Ohms/1000 and 11 Ohms/1000 ARE the same as far as the losses in a typical audio circuit.
"I know the resistances are negligible but I'm very anal especially with this high-end AD converter that I use for recording in my studio".
OK, but don't expect rational answers involving numbers - you are condemning yourself to endless shuffling of components until it "sounds good", or accepting someone else's opinion that cable "A" is "better" than cable "B".
I hope you enjoy searching for rainbow's end!
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Sorry. I am an engineer and not qualified to deal with snake-oil questions like this.
10 Ohms/1000 and 11 Ohms/1000 ARE the same as far as the losses in a typical audio circuit.
"I know the resistances are negligible but I'm very anal especially with this high-end AD converter that I use for recording in my studio".
OK, but don't expect rational answers involving numbers - you are condemning yourself to endless shuffling of components until it "sounds good", or accepting someone else's opinion that cable "A" is "better" than cable "B".
I hope you enjoy searching for rainbow's end!
Nope, no snake oil.
I am requesting your help in giving me an objective, quantified analysis. Please estimate the differences in resistance (or whatever relevant measure) between those connection options that I mentioned in my last question...I would like to get an idea based on numbers whether the differences are negligible or not. Thanks!
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