Please excuse a very basic question. I'm getting ready to buy an assortment of wire for a couple of solid state amp projects, probably no more than 25 watt output. I'm thinking 22 gauge, in stranded and solid, and 18 gauge in stranded would be a good start. What are your thoughts?
I'll also be working a power supply for these amps. Will 18 be sufficient or would it be best to have 16 or 14 on hand?
Thank you for your help. I've been out of the electronics field for 30 years and my 60 year old brain just isn't clear!
Joe
I'll also be working a power supply for these amps. Will 18 be sufficient or would it be best to have 16 or 14 on hand?
Thank you for your help. I've been out of the electronics field for 30 years and my 60 year old brain just isn't clear!
Joe
Make sure the current handling is sufficient for the intended use (more than the fuse for a start!), and that the resistance isn't an issue either. You don't guess the wire size and discover later it makes a better fuse than the actual fuse! If your amp and its power supply are protected by 10A fuses, pick wire that handles at least 15A continuous for instance (fuses don't blow at their rated value, that's the current that doesn't blow them!). Fuses are there to prevent wires catching fire, so make sure the wiring is adequate.
There are lots of tables for wire sizes for amperage (both for confined trunking and open point-to-point use) - use one, be conservative, and all should be well.
Most signal wiring is already limited to very low currents, 10's of mA, and you are free to use whatever is convenient. You might want thicker signal grounding wires sometimes to limit the resistance in the grounding - nothing to do with safety this time.
Solid core is great for breadboards, but I don't recommend it for general wiring as its too stiff.
There are lots of tables for wire sizes for amperage (both for confined trunking and open point-to-point use) - use one, be conservative, and all should be well.
Most signal wiring is already limited to very low currents, 10's of mA, and you are free to use whatever is convenient. You might want thicker signal grounding wires sometimes to limit the resistance in the grounding - nothing to do with safety this time.
Solid core is great for breadboards, but I don't recommend it for general wiring as its too stiff.
Check out ApexJr on eBay for Teflon jacket silver plated wire of all gauges and colors. He has both stranded and solid core. Prices are good and quality is mil spec. I get all my wire from him. He also has ApexJr.com for more stuff. He’s very helpful and ships quickly. Teflon jacketed wire is resistant to rubbing and heat. It’s mil spec for a reason. It’s harder to strip for some people but with a good stripper it’s easy. He also sell assortments of colors to make it easy. Plus Steve is a nice guy!
I use 24 ga stranded for the front end of SS amps, the current is milliamps. I use 20 ga stranded for the 2-4 amps of the power sections. Dynakit used 22 ga for front end and power, so I feel a bit luxurious on the power end. You can't solder 14 or 16 ga directly to power transistor legs, it would burn the die. 18 would be dicey. You can use 16 or 14 ga running from the chassis terminals out to the 8 ohm speaker, where long runs make the resistance penalty greater. I've found 25' run of 16 ga to my speaker gave the top piano notes vibrato, which is obvious distortion. Wood pianos don't have vibrato. I terminate 16 14 and 12 ga with TE connectivity crimp terminals; more reliable than solder in that size.
Teflon is nice but hard to strip with a miller tool. Teflon prevents me having to replace burned wire when I wave the soldering iron around. i'm not in my twenties anymore. Kynar is about has hard to burn with the soldering iron and easier to strip.
Solid wire from NTE has been extremely likely to break if bent. Waste of money. I had some quality old solid belden wire from the seventies but it was carted off to the scrapyard during covid by my local housepainter/burglar.
If doing vacuum tube projects, be sure insulation is rated 600 v.
Besides apexjr, surplussales of nebraska has been handy for 100' of pvc insulated wire. No silver plate on this old milspec surplus.
Teflon is nice but hard to strip with a miller tool. Teflon prevents me having to replace burned wire when I wave the soldering iron around. i'm not in my twenties anymore. Kynar is about has hard to burn with the soldering iron and easier to strip.
Solid wire from NTE has been extremely likely to break if bent. Waste of money. I had some quality old solid belden wire from the seventies but it was carted off to the scrapyard during covid by my local housepainter/burglar.
If doing vacuum tube projects, be sure insulation is rated 600 v.
Besides apexjr, surplussales of nebraska has been handy for 100' of pvc insulated wire. No silver plate on this old milspec surplus.
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Make sure any wire you buy is tinned, and not just bare copper.
Some cheap wire is actually mostly aluminum. You can check that by weight.
Get a high quality, precision wire stripper, not the basic kind that is continuously adjustable.
You won't be sorry. Nicking wires as you strip them will cause eventual breaking at the nick.
Some cheap wire is actually mostly aluminum. You can check that by weight.
Get a high quality, precision wire stripper, not the basic kind that is continuously adjustable.
You won't be sorry. Nicking wires as you strip them will cause eventual breaking at the nick.
I use ul1332 Teflon insulated tin plated copper stranded wire available from an eBay supplier. Ordered a few times without any problems. Yes get some good wire strippers as well. 18 and 24 awg are good choices for amplifier builds.
"Good wire stripper" is certainly a shopping link. Not. The miller is now sold by Dorman at auto supplies.
I had a great pair of wire strippers at work in the 1970's, but have been unable to duplicate it. The best I can find is the Klein, which only goes down to 28 ga.
I use this guy for pretty much any type of small gauge wire... Teflon coat, PET, rubber PET...
https://www.kleintools.com/catalog/combination-cutting-tools/klein-kurve-wire-stripper-and-cutter
https://www.kleintools.com/catalog/combination-cutting-tools/klein-kurve-wire-stripper-and-cutter
Thanks for all the help! I have very good wire strippers that I got 30 years ago in electronics school. They have been treated extremely well and still do a great job. I do admit I've never tried them on teflon.
I did work, for 3 years, as an industrial electronics tech in a factory but that was more electrical than electronics. After that I got pulled into the IT field and never really used what I'd learned in school. Most of that was work with a breadboard anyway. I'm trying to relearn a lot of this stuff and have been working through my old text books. I'm now 60 years old an my brain just isn't as quick as it used to be.
Thanks again!
Joe
I did work, for 3 years, as an industrial electronics tech in a factory but that was more electrical than electronics. After that I got pulled into the IT field and never really used what I'd learned in school. Most of that was work with a breadboard anyway. I'm trying to relearn a lot of this stuff and have been working through my old text books. I'm now 60 years old an my brain just isn't as quick as it used to be.
Thanks again!
Joe
I've always used Ideal T-Strippers (https://www.amazon.com/IDEAL-Electrical-45-120-T-5-T-Stripper) since my days as an engineering tech in the semicon industry in the early '80s. I only use teflon coated wire anymore, and these strip them quite well.
For wire, I've used NavShips on ebay for silver plated teflon coated wire.
For wire, I've used NavShips on ebay for silver plated teflon coated wire.
The Ideal tools are very good, and also have versions for smaller gauges.
https://www.idealind.com/us/en/shop/product-type/hand-tools/wire-strippers.html
https://www.idealind.com/us/en/shop/product-type/hand-tools/wire-strippers.html
I have some 20 AWG in various colours that I use for control signals and other low-current connections. I also often use 16 AWG for the higher current paths in an amp. I generally use red, black, and blue for V+, GND, and V-, respectively. Green for chassis ground. Maybe a few other colours for control signals. Its UL1007 wire with PVC insulation rated for 300 V. UL1015 600 V rated wire for tube amps.
If you're in the US, Remington Industries has good deals on wire in bulk. I bought some 100' (30 m) and 200' (60 m) spools from them many years ago and still pull from those spools: https://www.remingtonindustries.com/hook-up-wire/
Teflon insulation is nice in that it doesn't pull back or melt with heat, but that's also the only advantage that I can see. If you don't have a good wire stripper it's a royal pain to work with. You have to score the insulation all the way around, then pull it off. Once you get the wire strippers dialled in it can be easy to work with but getting to that point requires significant pain in my experience.
I prefer stranded wire as I find it easier to work with than solid. Definitely get tinned copper wire. There's no need for silver wire or anything like that. The silver coating will dissolve in the solder anyway unless you also use silver solder ($$).
I use a Knipex 11-01-160 end-type wire stripper. I've had it for over three decades now and it performs as well today as it did when it was new.
The Knipex 13-72-8 shown below is truly amazing too. I use one for electrical work around the house. Those strippers are sharp! For electronics work I prefer the adjustable strippers above, though.
I've had varying luck with the cheap 'automatic' wire strippers. The cheapies either don't strip the wire or pull wire strands off with the insulation. Some don't even hold the wire in place as it's stripped. No good!
Buy good tools. Cry once. Buy cheap tools. Cry every time you use them.
Tom
If you're in the US, Remington Industries has good deals on wire in bulk. I bought some 100' (30 m) and 200' (60 m) spools from them many years ago and still pull from those spools: https://www.remingtonindustries.com/hook-up-wire/
Teflon insulation is nice in that it doesn't pull back or melt with heat, but that's also the only advantage that I can see. If you don't have a good wire stripper it's a royal pain to work with. You have to score the insulation all the way around, then pull it off. Once you get the wire strippers dialled in it can be easy to work with but getting to that point requires significant pain in my experience.
I prefer stranded wire as I find it easier to work with than solid. Definitely get tinned copper wire. There's no need for silver wire or anything like that. The silver coating will dissolve in the solder anyway unless you also use silver solder ($$).
I use a Knipex 11-01-160 end-type wire stripper. I've had it for over three decades now and it performs as well today as it did when it was new.
The Knipex 13-72-8 shown below is truly amazing too. I use one for electrical work around the house. Those strippers are sharp! For electronics work I prefer the adjustable strippers above, though.
I've had varying luck with the cheap 'automatic' wire strippers. The cheapies either don't strip the wire or pull wire strands off with the insulation. Some don't even hold the wire in place as it's stripped. No good!
Buy good tools. Cry once. Buy cheap tools. Cry every time you use them.
Tom
Hello @tomchr ,
When would you think that 14g wire was necessary over 16g wire?
Thinking of using 16g to feed from power inlet to Meanwell UHP-500r-48,
When would you think that 14g wire was necessary over 16g wire?
Thinking of using 16g to feed from power inlet to Meanwell UHP-500r-48,
- which would be about 20" of wire from inlet to switch and back to PSU at max 4.85 amps at 110v
- about 8" of 16g at 48v max of 10.45 amps (theoretical max, normal listening I expect <~1-2 amp draw)
- about 8" of 16g from amp output to speaker out terminals.
If you know the cross-sectional area of copper of a cable you can calculate its resistance-per-unit-length directly and don't need a chart - that's why the rest of the world uses square-mm as wire size measurement.
At room temperature the resistivity of copper is 1.7x10^-8, ohm-m, so for a 1mm^2 wire the resistance-per-unit-length is a million times this or 17 milliohm/m. So a simple formula is
resistance = 0.017 * length (in m) / area (in mm^2).
What you do need a chart for is the maximum safe current limit, as that depends on more than the resistance, for instance the thermal environment (free wires v. multi-wire cables, whether in trunking or not, whether the insulation is PVC of PTFE, etc etc).
Again I recommend learning to use these tools, guesswork isn't reliable until you have a lot of experience.
For instance with 500W 48V supply (thus 10A, probably more like 20A at limiting) over 20 inches (0.5m each way), you might consider a loss of 0.5V acceptable, so maximum resistance = 0.5/20 = 25 milliohms, suggesting 1mm^2 copper is well capable of providing a low enough voltage drop. However the safe current handling is likely to dominate here and require thicker wire. With long wires and low voltages it can be the resistance that is the limiting factor, not safe current handling.
So always check both...
At room temperature the resistivity of copper is 1.7x10^-8, ohm-m, so for a 1mm^2 wire the resistance-per-unit-length is a million times this or 17 milliohm/m. So a simple formula is
resistance = 0.017 * length (in m) / area (in mm^2).
What you do need a chart for is the maximum safe current limit, as that depends on more than the resistance, for instance the thermal environment (free wires v. multi-wire cables, whether in trunking or not, whether the insulation is PVC of PTFE, etc etc).
Again I recommend learning to use these tools, guesswork isn't reliable until you have a lot of experience.
For instance with 500W 48V supply (thus 10A, probably more like 20A at limiting) over 20 inches (0.5m each way), you might consider a loss of 0.5V acceptable, so maximum resistance = 0.5/20 = 25 milliohms, suggesting 1mm^2 copper is well capable of providing a low enough voltage drop. However the safe current handling is likely to dominate here and require thicker wire. With long wires and low voltages it can be the resistance that is the limiting factor, not safe current handling.
So always check both...