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Wire gauges

basstard

Member
2008-01-19 12:33 pm
Sorry if this has been discussed before, did more than a search and couldn't find anything [mods can check my activity logs],,,

I'm building another guitar preamp and I'd like to know what wire gauge/type it's best to use for both ease of soldering on tube socket pins [which are quite small in this case] and current ratings.

I can only access normal wire suppliers so, nothing exotic,,,

The voltages I'm working with are around 280-300v max. Power consumption is very small, just 3x12ax7 [bar the filaments]. It's based on a Bogner XTC amplifier.

I'm thinking of using VERY small single strand wire for wiring the low voltage areas like volume/eq pots and multistrand speaker wire for the higher voltage areas [tube anodes and higher voltage signal paths]. I'll also use normal powercord wire for the power section and filaments which will be fed by a SMPS.

Do you think this is correct? Speaker wire should be quite low impedance so it should be ok right?

Ideal would be the thinnest possible wire [i.e. easier to solder] without compromising reliability,,, thanx
 

basstard

Member
2008-01-19 12:33 pm
thanx,,,
thing is I'm sh*t when it comes to imperial measures,,, what's that? 0.022 inches or what?

I used some 'normal' [if that makes sense] shielded wire for my previous ~500V mesa boogie preamp and nothing has melted down until now,,, but on this new one the tube socket pins are kinda small so I'd prefer to do a tidy job and use smaller wire,,,
 

luvdunhill

Member
2006-07-09 6:59 pm
mashaffer said:
Where do you get the 600V wire? The only 600V I have been able to find is at the local Ace Hardware but it is 14ga which is a little extreme I think. All of the tube parts houses seem to be selling 300V.

mike

"Teflon coated silver plated copper multistrand conductor with teflon coating. 600v rating. 200°C. Can be used in audio signal lines, B+ or heater circuits."

http://www.hndme.com/productcart/pc/viewCategories.asp?idCategory=19
 
This question is not directly related to the original post by Basstard but I think it is the thread where I might get a helpful answer.
This the problem. How do you accurately measure the diameter of a wire of unknown gauge?

I have several large quantities of single strand, enammelled copper wire which I am guessing range from about 14 to 22 gauge. (or around 1mm +or- half a mm. I can't think in metric although any "metric" solution would be fine for the purpose of subsequent calculations!)
I don't know their size and I don't feel a micrometer would be accurate enough. Given that the weight/volume of any coil made from them is an "R-squared" relationship to the wire size I am conscious that errors in diameter will have large consequences.

Any ideas please?
 
Wire gauge tool.
This is one in the picture.


Nick
 

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OzMikeH

Member
2007-03-18 9:22 am
Jonathan Bright said:
......
I don't know their size and I don't feel a micrometer would be accurate enough. Given that the weight/volume of any coil made from them is an "R-squared" relationship to the wire size I am conscious that errors in diameter will have large consequences.

Any ideas please?

If your requirement is too critical for a micrometer then insulation compression is going to be a bigger issue. Of course this will vary with how tight you wind them as well. You might be confusing a micrometer with a vernier caliper.

If you need accurate numbers out of a micrometer let everything stabilise at 20 degrees, only handle it by the plastic grip so your fingers don't warm the metal up. Clean the anvils by closing it on a sheet of copy paper and drawing it out. Then check your zero. Only ever close it by the torque limiting handle on the end.

accuracy within half a thou, easy.
 
Thanks Elwood. Bought a very cheap secondhand iron laminated inductor and transformer both weighing substantially more than your average housebrick and intend to canabalise them for speaker x-over coils. With the price of copper now they were a bargin. But as my father used to say "It's only a bargin if you need it!" and so I just wanted to make sure I could utilise them effectively.
Why do you ask about the function? Jonathan
 
For a guitar preamp, you don't need silver wire, or wire with Teflon insulation. Teflon is nice, but not necessary. (Especially when you accidentally bump your soldering iron against it). For small signal apps., you can use 24-26 gauge wire w/ insulation rated 105C @ 600V. I use Alpha MIL spec wire from http://www.mouser.com It's about $20 a roll (100ft).

~John~
 

basstard

Member
2008-01-19 12:33 pm
Thx everybody for the replies,,,

dave_gerecke said:
To help you with conversion between AWG and metric, try this webpage:

http://www.hardwarebook.info/AWG

pace,

Dave


Thx for the table link, VERY useful!


ray_moth said:
Single core wire is easier to use and lay out tidily than stranded wire, in my experience.

How true mate! but it doesn't seem so common 'round here,,, my mechanic goes to a wholeseller round here that has 'tons of different wires' he says so will have to pop there and what's the story,,,

at the mo I settled for a 21 and a 24 roll which, as far as the table kindly linked by Dave goes, are good for 0.6 and 1.2 Amps so they'll be more than adequate for sure,,,

TubeHead Johnny said:

For a guitar preamp, you don't need silver wire, or wire with Teflon insulation. Teflon is nice, but not necessary. (Especially when you accidentally bump your soldering iron against it). For small signal apps., you can use 24-26 gauge wire w/ insulation rated 105C @ 600V. I use Alpha MIL spec wire from http://www.mouser.com It's about $20 a roll (100ft).

~John~

My last Mesa Boogie Rectifier replica was indeed realized with that sort of wire but I really wanted to be sure nothing goes bang in this new one,,,