What's good about teflon board and 2 oz copper board?

[Sunsun22]

I have a phono kit that uses teflon board? Besides it is flexible and as alleged, it can absorb vibration, what's good about teflon board?

The kit supplier recently debut a new teflon board with 2 oz copper (and a little bit rearrangement of traces) and I bought one. After moving all the parts to the new board and the usual tuning, I must say the performance is extraordinary good. The highs and lows are extended while the highs are silky smooth. I must say the new teflon board with 2 oz copper brings the performance to another high.

What is 2 oz copper board? What does the usual circuit board use?

[jean-paul]

Hi, AFAIK "2 oz" means that the copper tracks are double the thickness of normal material. Since I don't even bother to understand non-metrical stuff : in Europe we call it 35 micrometer versus 70 micrometer for the extra thick material. I never noticed much difference with small signal applications but I would prefer thicker pads and tracks with power supplies and power amps. When tinned the tracks will be around 100 micrometer which will be able to carry pretty much current.

I would rather prefer it if the manufacturers would focus more on the quality of the material. Nowadays only touching the tracks/pads with a soldering tool is enough for peeling off the tracks/pads, be it normal or extra thick material.

Teflon has better electrical properties and is superior to epoxy. It is very good material for RF circuits but it is expensive and more difficult to machine/cut. I don't have experience with a direct A-B comparison with the same circuits but since it is better electrically I suppose it will measure/sound better too. Teflon is much more heat resistant but when overheated it will give a hazardous gas. You can google yourself for the properties of Teflon.

[Sunsun22]

Thank you for your input. I just don't know why changing to a 2 oz circuit board could make such a difference bearing in mind this is a very low signal phono preamp.

Talking about quality of copper on circuit board, how do I know what kind of quality is being used by manufacturer? If I want to make circuit board, is there any grade (other than 2 oz copper) of material that I can specify?

[johansen]

the thickness of the traces don't matter provided the resistive voltage drop is negligible. I'm confident the re-arrangement of the traces is the only reason it sounded different.

they make half ounce board as well as 1, 2,4,6,8, and 10 ounce board.
as far as the quality, you aren't going to find low oxygen copper circuit board, its just generic 99% IACS copper.

[bear]

There are two things to consider in the trace - the width and the thickness.
Using "2oz." traces that are super thin buys you not much compared to a double width trace of 1oz. Although there may be some difference at UHF and up due to the shape factor...

I prefer fatter traces for audio, and don't understand why some folks design audio boards with the same super narrow width traces common to data designs.

The heavier copper also is better for soldering since it sinks more heat and doesn't pull off the PCB quite as much when heated a bit too much...

So I vote for wide and fat traces for audio.

The "teflon" board is best at very high freqs. The board is a dielectric, just as it is in a capacitor. Especially if there is a ground plane. But regardless. Teflon caps are on top of the list for capacitor performance.

It's difficult to say why or if an identical layout would sound better made from one material or the other. One would have to try and test it. Needless to say it is unlikely to hurt.

Oh, the flexibility may very well effect any microphonic effects... audible? Dunno.

_-_-bear

[Sunsun22]

When one buys copper cable, one can look for OFC, 5N copper, 6N copper etc. Does this mean when I order circuit board, I cannot specify such grading? Does this mean all circuit board are using the same kind of copper plating?

[johansen]

the quality of the copper makes no difference, but that's a debate for another day.
I don't know of anyone selling 5n or 6n copper pcb boards. unless you want that copper on a 99.99% alumina substrate, shipped to you in a container purged with argon..... which would come out to triple digit $/square foot.

[macboy]

On boards that have plated through-holes, the boards are etched, then drilled, then copper is deposited via electroplating. I think that the copper will not be especially high purity, and you won't be able to specify what purity you want; it will be limited by the process. The resulting trace thickness (initial copper thickness + plating) is described either by thickness in micrometers or in "oz" which is the weight of copper (in ounces) per square foot of area. Someone already mentioned that "1 oz" is equal to "35 um" (micrometer).

[johansen]

but once you solder it there is no current flowing though the "unclean" copper.

Electroplated copper is going to be no different than "electrolytic tough pitch copper" anyway, but that's also going to vary with who made the board.

[wakibaki]

Since most equipment is built down to a price FR4 is much more common than Teflon (PTFE) as a substrate, Teflon being considerably more expensive. Depending on the application, FR4 starts to get problematic above ~2.4 GHz, this is because the permeability is less well controlled than that of Teflon. This makes no difference at baseband (audio) frequencies, but has increasing significance with frequency in designs using distributed components.

Of more interest are the commonly available finishes which are applied to the copper. These are I.S, (Immersion Silver), HASL (Hot Air Solder Levelling) (lead free now) and Au/Ni (gold over nickel) or Au/Pd/Ni which has an intermediate palladium layer, the Ni and Pd are normally electroless deposition, with the gold being immersion.

None of these, however, make any real difference in audio applications, unless you were thinking of using an edge connector. If you're interested in this stuff, you'll learn more from google than asking here.

w