I hate imperialism, but I love those Imperial wire strippers! I've been using them exclusively with Apex's teflon since I began building amps. They haven't worn out yet, but if using solid core, I always examine the wire closely to make sure I didn't nick it. If there's a nick, I throw it out!
For folks who don't know, I also wanted to mention that teflon wire does not have the same current handling capability as PVC coated wire - it's actually much higher! With teflon coated wire you can use 22AWG for the entire amp.
I am not commenting on the current handling capability of teflon vs. PVC, but I just finished an amp using PVC and found it to be much less robust than teflon. There just didn't seem to be as much physical wire mass in the PVC as Teflon for the same gauge. The PVC tends to unravel much easier and "fluffed" very easily when flowing solder. Of course you have to be quick and decisive with PVC so you don't melt the sleeve, but the teflon I have use(d) has a denser weave (which is what I mean about more mass). It also stays put very nicely. If there is more mass in the teflon weave, then it makes sense that it very well could have more current handling capacity.
Hired Hand, the PTFE insulation can handle the heat of the conductor, which is why it's rated for higher currents - there's a relationship between the conductor size and insulation. PVC can't handle the heat, so the conductor needs to be bigger. Hope that makes sense.
I thought insulation was rated for Voltage.
Do the wires in guitar amps get so hat that you have to worry about what type of insulation is used?
I never even thought about it. So how hot are the wires in a guitar amp?
If the wires in an amp got so hot that it affected the insulation, I'd quit using that amp immediately!
Itis not the wire temp in a tube amp that's teh problem, - it's the fact that several componens in a tube amp, can get so hot that it'll affect wires in close proximity to hot components.
Wire gauge must be chosen to match the current requested for that wire.
For most normal tube amps, using appx 18 ga for heater wires ( 2-3A) is quite sufficient, 20-22 ga for signal wires carrying up to 200 mA is also enough. If 2 ft of 18 or 20 ga have maybe 100 milliohms resistance, pulling 3 amps through it gives 30mW of effect loss over it's ful length- no problem! It is the combined effect of wire loss AND a warm environment that may cause problems, if wires are routed without concern.
Sloppy soldering techniques and PVC insulation is no good match - teflon is a lot more foregiving in this combination.......
I used to use teflon stranded for most of my builds.
I worked for over 20 years at Hughes Space & Communications building comm. and military satellites and teflon wire was used for the most part on the flight hardware assemblies. I use the Teledyne thermal strippers discussed earlier and would strongly recommend those for teflon stripping.
Improper technique using the Teledyne can actually weaken the wire if too much heat is allowed to hit the wire conductor.
I now use a combo of different wires types for my builds to reduce the amount of mechanical coupling you can encounter using teflon in certain parts of the circuit. I recall reading years ago that Gerald Weber used to advertise that he liked to use teflon wire in his amps that he would install fender style cloth insulation over to help reduce problems with microphonics.
badtweed wrote:I now use a combo of different wires types for my builds to reduce the amount of mechanical coupling you can encounter using teflon in certain parts of the circuit. I recall reading years ago that Gerald Weber used to advertise that he liked to use teflon wire in his amps that he would install fender style cloth insulation over to help reduce problems with microphonics.
This is from the web somewhere, cheers to the original poster. Clever easy clean solution to keep the teflon from rattling. I already bought me a roll of felt weatherstrip for my next build.
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badtweed wrote:I now use a combo of different wires types for my builds to reduce the amount of mechanical coupling you can encounter using teflon in certain parts of the circuit. I recall reading years ago that Gerald Weber used to advertise that he liked to use teflon wire in his amps that he would install fender style cloth insulation over to help reduce problems with microphonics.
This is from the web somewhere, cheers to the original poster. Clever easy clean solution to keep the teflon from rattling. I already bought me a roll of felt weatherstrip for my next build.
hmm... not sure I'd want that material in any electronic assembly as it might be a moisture trap or worse depending on where your amp travels.
Pardon my ignorance, but what is the carpet pad for? Rattling, and only with Teflon wire? Is that something that happens with a combo amp, or with a head on top of a speaker cab?
This is the first time I have ever heard of this. I have only had my hands inside of amps for a few, short years. I am sure there must be lots of stuff like this that flys under my radar........
Thank You
You can also use small dabs of clear silicone sealant or calking to anchor the wires down.
Also the use of nylon cable ties help to bundle wires and keep them from vibrating too badly.
I have noticed on most amps that just about everything around V1 is microphonic if you tap on them.
It just shows the sensitivity of the normal 12ax7 that is most commonly used for the first stages.
Having a thicker gauge chassis is also helpful as it is less resonant than a thin, tinny chassis.
I have seen just about everything there is to dampen things used in tube amps.
The one question you have to ask is, is it flammable?
Or lets say it gets 150F degrees in side the chassis, is that weather stripping or other damping material going to degrade due to the heat?
I'm not too worried about microphonics, lucky so far, but the teflon, unlike cloth or pvc, is hard like a plastic or metal rod and can rattle against the chassis like a loose component. Different every time and you just have to built it and see, it may not be a problem for you. I tried tape and silicon but it looks like the kluge it is. Maybe nice equal length strips of yellow kapton tape like in a computer or perfect domes of hot glue would look more pro. I can never seen to avoid the hershey kiss look. The felt looks very purposeful and not like a kluge, I thought it was clever.
The use of silicone goop, tie down devices and chassis thickness does not effectively reduce the mechanical coupling that the use of certain types of teflon wire exhibits.
Stops the wires from flopping around but that is different from the mechanical coupling.
badtweed wrote:hmm... not sure I'd want that material in any electronic assembly as it might be a moisture trap or worse depending on where your amp travels.
Good point, maybe not UL either could burn. I know where I can find some thin silicon sheets, maybe I'll experiment w/ that if I can get it to stick.
I've been using them exclusively with Apex's teflon since I began building amps. They haven't worn out yet, but if using solid core, I always examine the wire closely to make sure I didn't nick it. If there's a nick, I throw it out!
