# Tube amp power cord



## jtienhaara (Dec 4, 2013)

I'm gathering the things I'll need to replace the 2 pronger in a new (to me of course) Traynor YBA-2B combo amp.

I will be installing an IEC receptacle. So I will just need to wire up components on the inside of the amp, not run a cord all the way to the 3 prong plug.

Is there any reason I should not use 14 AWG solid core house wire inside the amp?


Side rant: I went to the Home Depot near work on Friday and waited 1/2 hour for the electrical salesman to come cut me some 14 gauge SJT wire; after 1/2 hour of waiting I gave up and left. Today I went to the Home Depot near home. Of course they had none left. I felt like I was in the Cheese Shop... The electrical salesman suggested cutting up an extension cord, which I might do if the house wire is a bad idea for any reason. Or I might just give up and chop up an 18 AWG cord to use for the internals.


Any advice / cautionary tales / "Home Depot sucks" / etc would be welcome. Thanks!

Johann


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## greco (Jul 15, 2007)

jtienhaara said:


> Is there any reason I should not use 14 AWG solid core house wire inside the amp? Johann


I'm not an expert, but I would choose *stranded* 14 AWG.
It might be considered overkill.

Possibly stranded 16 AWG would also be a reasonable choice.

Wait to see what the experts here suggest.

Cheers

Dave


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## jb welder (Sep 14, 2010)

Yes, you need stranded wire, not solid core.
Do you have a thrift shop or similar nearby? I'm not averse to buying a $1 toaster to get a piece of cord when in a pinch.


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## loudtubeamps (Feb 2, 2012)

I use leftover bits of 14/ 2 in builds for ground buss and short runs between high voltage points all the time. 
10 guage bits for inexpensive replacement tips in my (ancient) Weller dual heat gun. :sSc_eeksign:


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## knight_yyz (Mar 14, 2015)

to the best of my knowledge, the only difference between stranded wire and solid core wire is the ability to flex. One does not flow electricity better than the other. So, if the wires inside the amp are sitting there doing absolutely nothing, then solid core wire is fine. But if it needs to be flexible, and i'm sure in your case it does not, then you use stranded.


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## greco (Jul 15, 2007)

knight_yyz said:


> to the best of my knowledge, the only difference between stranded wire and solid core wire is the ability to flex. One does not flow electricity better than the other. So, if the wires inside the amp are sitting there doing absolutely nothing, then solid core wire is fine. But if it needs to be flexible, and i'm sure in your case it does not, then you use stranded.


@ Johann ...Try the 14AWG solid core and let us know what you think of working with it for your application. I can understand it for ground busses and short runs, as loudtubeamps states. However, beyond that and I suspect that you will find limited pleasure in working with it (i.e., in comparison to 14 AWG stranded).

Cheers

Dave


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## jtienhaara (Dec 4, 2013)

Yeah I guess that's true, Dave. I find it painful enough just wrapping the ground wire around the big nut in an electrical outlet, let alone trying to squeeze and bend solid core 14 gauge around tiny nuts and into tiny holes etc. I think I'll abandon the house wire approach.

I do have an extension cord that I was planning on giving away to clear up some space; I could chop it up instead. Unfortunately it has no markings at all -- not on the cable, not on the connectors. Is there such a thing as an orange extension cord that is less than 14 AWG? I can't imagine anyone doing that, but I guess if you don't even put your company logo on the cable, you can get away with murder! Not that 16 or 18 would be bad, but I tend to prefer overkill with any kind of wire or cables.

(My guitar patch cord is actually a balanced TRS cable -- so that I can use it to connect recording equipment that actually *is* balanced, in a pinch; though I guess that's more of a cost-saving thing than overkill, but still).

Incidentally there are differences in the way current flows / electrons move in stranded vs. solid core wires. I won't pretend to be knowledgeable, but I have seen discussions online, by people who did claim to be knowledgeable, of the Skin Effect. It also seems to me I've seen discussions of differences in capacitance and/or inductance (can't remember which, maybe both) between stranded and solid core. What effect will all of this have in wire used to carry a small amount of current maybe 18 inches (at most) inside a guitar amp? Zero. But for long runs I'm sure it's pretty important -- in case anyone here is thinking about laying down electrical lines to the city a few hundred kilometres down the highway.

Anyway thanks very much for your input everyone! I'll likely be back some weekend in the future, asking for more advice about how to wire up this baby, and/or better hardware shops in the Halifax area. 'Til then... Thanks & cheers,

Johann


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## High/Deaf (Aug 19, 2009)

Skin effect is quite controversial among hi-fi enthusiasts, and they are dealing with highs of 20kHz (and above). Guitarists don't have to worry about much more than 5kHz. Skin effect is non-existant at these frequencies. Well, non-existant to everyone but those that are selling snake oil and scarily monstrous cables.

If you are building stuff for VHF, UHF and up, skin effect may be critical. Audio frequencies, I don't believe it is.

And the length of cables you're talking about (inside an amp chassis), capacitance isn't much of an issue either. Inductance can be, but that more a factor of how you run the wires (perpendicular or in parallel) that the wires themselves.

Sorry, trying to be objective, but I know my bias is showing.

Stranded wire is so much easier to work. I would only use solid for busses. Also, if anything moves (like a flexing front panel when you jack in), solid wire can fatigue and break over time, whereas stranded will not.


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## jb welder (Sep 14, 2010)

Even though it seems solid enough, the IEC receptacle (or the panel it's mounted on) will be flexing a bit when the cord is connected/disconnected, stressing the solder joints. 
Agree with using solid core only for buss wire. 
Another thing to consider is that house electrical wire is not designed for soldering, so I don't know if the insulation can take the heat as well before it starts melting.
As far as the gauge, it's kind of pointless having anything thicker than the gauge of the detachable cord you will use.


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## greco (Jul 15, 2007)

jb welder said:


> Even though it seems solid enough, the IEC receptacle (or the panel it's mounted on) will be flexing a bit when the cord is connected/disconnected, stressing the solder joints.
> 
> Another thing to consider is that house electrical wire is not designed for soldering, so I don't know if the insulation can take the heat as well before it starts melting.
> 
> As far as the gauge, it's kind of pointless having anything thicker than the gauge of the detachable cord you will use.


Three excellent, practical and applicable points.

Hats off to jb welder!










Cheers

Dave


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## knight_yyz (Mar 14, 2015)

Romex is good for 90*C, which is about the norm for most wiring at 14 gauge. I just checked an 18 gauge extension cord and it is good for 90*C as well.


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## greco (Jul 15, 2007)

knight_yyz said:


> Romex is good for 90*C, which is about the norm for most wiring at 14 gauge. I just checked an 18 gauge extension cord and it is good for 90*C as well.


I think those temperature specs are indications of the maximum temperature the wire can be "exposed to"/operate in (or something of that nature) and be safe. 

Soldering irons heat the wire to well over 300 degrees Celsius.

The melting temperature of the "plastic" insulation is the key factor to know here, as to avoid a gooey mess and a resultant poor solder connection.

Cheers

Dave


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## jb welder (Sep 14, 2010)

greco said:


> Hats off to jb welder!


Dave, where do you want me to send the payola?


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## greco (Jul 15, 2007)

jb welder said:


> Dave, where do you want me to send the payola?


Rather than payola, just respond to whether I'm correct/reasonably accurate in post #12 above.

Cheers

Dave


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## knight_yyz (Mar 14, 2015)

The temperature rating on the insulation is how hot it can get and still function properly as an insulator. It can readily be softened and re-softened byrepeated heating, but remains in a safely usable solidform when operated within its rated temperature limits


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## jb welder (Sep 14, 2010)

Right, they only guarantee it to insulate and not melt up to 90 degree Celcius. When using it as buss wire, you strip off the insulation anyways so no problem. But if you are trying to connect it to chassis or something, that takes a lot of heat, and I think it would be fairly easy to melt the insulation. (so Dave I agree with your post #12)
Here are some temps for various insulation types:
http://www.openelectrical.org/wiki/index.php?title=Cable_Insulation_Materials


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## knight_yyz (Mar 14, 2015)

There is no doubt though, that if you are soldering, I wouldn't even dream of using solid core.


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