[andyr]

Darren, Mal, Ginger and others who have contributed posts in previous "Nirvana" threads ... I am interested in your comments on the following:

What effect does a very thick teflon insulation have on the signal travelling down the conductor??

For instance XLO make a solid-core Cu wire which is 24awg (0.5mm diam.) with 0.25mm thickness of teflon insulation, to give an overall diam. of 1mm.  I use this for signal wire inside my amps & crossovers, and for ICs (it's more expensive than Cat5, so it must be better, right??   ).

How would you compare the above XLO wire with another wire which was also solid-core 24awg Cu but which had 1mm thick teflon insulation, to give an overall diam. of 2.5mm??

I can see two opposing points of view here:

1. More of ANY dielectric (except none - ie. air) degrades the sound ... so the XLO/Cat5 wire with its thinner teflon layer would sound better;

2. The thicker layer of teflon would space the conductors of a twisted pair apart more, compared to the XLO wire ... and this would reduce capacitance, which must be good??

Whaddya reckon??

Andy

[ginger]

Andy,
You like to ask the bloody difficult questions.

Any reduction in capacitance between the twisted pair wires is of benefit. This capacitance is in parallel with the input impedance of the driven section of the circuit and will produce a high frequency roll off. Of course in most cases we are talking about a frequency roll off so high that it doesn't make a rats hind quarters difference.

My personal opinion is that you won't notice any difference between the thick and thin walled teflon insulated wires. (Unless you want the amp to run at 100 MHz). I get involved in this sort of arguement for GPS Antenna wiring and the like but not usually for Audio Amplifiers.

Make your decision on cost for this one. For my Valve Amps I generally use ordinary tinned copper wire fed down the centre of PTFE Tubing for all the signal hookups.

Cheers,
Ginger

[Malcolm Fear]

Very interesting question. Where is this stuff available in Oz?
I have no idea how they should sound. Suck it and see.
I have played around with geometries (leave the CAT 5 as twisted pair, untwist it an loosely re braid it), I have played with number of strands. I have not tried other types of teflon coated wires.

[DSK]

Hi Andy,
Cable design is something I've never studied. At the risk of being flamed alive here, I guess I've always viewed the better DIY cables as outperforming much more expensive mid-level cables, but not being up to true high end cables. However, I must confess that this is largely based on what I have read as opposed to what I have heard with my own ears.

All I can suggest is that you use foamed Teflon if possible, but you probably already know that. I do remember reading a thread somewhere that pondered the benefits of enamelled copper vs teflon copper. Some suggested that the enamel is an inferior dialectric but is far thinner than the typical teflon coating and thus has less effect on the signal. From what I recall, nobody had done direct tests though, it was all theoretical.

As Mal said, if both thick and thin teflon coated wires are readily available, how about trying them and reporting back?

Cheers,
Darren.

[andyr]

Andy,
...... For my Valve Amps I generally use ordinary tinned copper wire fed down the centre of PTFE Tubing for all the signal hookups.
...

Thanks, Ginger, I simply ask questions about things I muse upon (generally while under the influence of a bottle of red, listening to my music!!)!

I am curious about your use of:
a) tinned copper wire, and
b) putting it thru PTFE tubing (to stop shorting, presumably?).

I understood any plated wire does not sound as good as clean, bare Cu ... because tin-plating and silver-plating can be considered as introducing contaminents into the vital (outer) area of the wire that the signal is going through - such contaminents being baaad!!

The tinning, of course, stops the Cu from tarnishing - which also introduces contaminents into the signal path.

Also, PTFE tube is not quite as tight to the metal as teflon is, thus you have a measure of "air dielectric" around the metal.

It thus seems that one is between "Scylla and Charybdis" as far as signal cabling is concerned ... either you have teflon dielectric and bare Cu or some air dielectric and tin-plate.  I choose the former but did you choose the latter bcoz you think it's the better choice or is there some other thinking at work here?

Regards,

Andy

[Malcolm Fear]

I thought that the best dielectric (least intrusive sound wise) is air, followed by teflon. Isn't the insulation of the mega expensive Nordost Valhalla (there's that word again) cable made up of air and teflon?

[andyr]

Very interesting question. Where is this stuff available in Oz?

Malcolm,

The thick-teflon wire I was talking about is the "OTA Hookup Wire" mentioned on this page:  http://www.nearsota.com/

I found it on the Cable Asylum.  It seems to be US$2 per foot, so it's not exackerly dirt cheap!!

I was thinking about using it as I need some shielded signal cables for the MC and MM phono inputs of the GK-1 that I am constructing.  I'm going to buy some shield to put around the twisted signal/return wires in these instances and, as the thick teflon would keep the shield and the signal wire separated by 1mm, I thought it might be a good thing to do.

Whereas if I put the shield over XLO/Cat5 wire, the distance between the shield and the signal wire would depend on whether the shield was right next to the teflon or spaced away a mm or so (by the curve of the wire).

However, as Ginger says the resulting capacitance difference wouldn't make any difference at audio frequencies and Darren points out that "more must be bad" in terms of dielectric ... I'll save me money!

Thanks, guys, for your input.

Andy

[Malcolm Fear]

I didn't shield the wire inside my GK-1, for the phono stage. Works fine.
In fact, the cables from my head amp were the usual 4 strand CAT5, no shield.