Hello,
After reading hrough many threads on here about DIY copper foil speaker cables I am going to build a pair of 3.5 metre long from Mundorf copper foil.
I haven't quite got my head around what materials I am going to use to insulate the copper wire or how I will do this but I would like to ask if anyone would be so kind to answer my question on this.
One of the options I was looking at was plumbers PTFE thread tape which I would wrap around the copper foil, but as these PTFE tapes are very thin at around a tenth of 1 mm thick, I was concerned that this may not be thick enough to safely insulate the + and - runs from each other which I intend to lay on top of each other in the construction. Would voltage spikes be a concern with a thin insulation material like this? My amplifier is a 18watt SET valve amplifier so it is not a high powered beast if this is a consideration.
Perhaps a second layer of PTFE tape or a layer of packing tape made of Polyurethane or Polyester. If anyone who has made these could chime in I would be very grateful.
I saw in one of the threads someone mentioned polyurethane spray, has anyone used this in ths construction? From what I read this would help prevent oxidisation. Would a second layer of material still be needed here?
Many thanks in advance.
After reading hrough many threads on here about DIY copper foil speaker cables I am going to build a pair of 3.5 metre long from Mundorf copper foil.
I haven't quite got my head around what materials I am going to use to insulate the copper wire or how I will do this but I would like to ask if anyone would be so kind to answer my question on this.
One of the options I was looking at was plumbers PTFE thread tape which I would wrap around the copper foil, but as these PTFE tapes are very thin at around a tenth of 1 mm thick, I was concerned that this may not be thick enough to safely insulate the + and - runs from each other which I intend to lay on top of each other in the construction. Would voltage spikes be a concern with a thin insulation material like this? My amplifier is a 18watt SET valve amplifier so it is not a high powered beast if this is a consideration.
Perhaps a second layer of PTFE tape or a layer of packing tape made of Polyurethane or Polyester. If anyone who has made these could chime in I would be very grateful.
I saw in one of the threads someone mentioned polyurethane spray, has anyone used this in ths construction? From what I read this would help prevent oxidisation. Would a second layer of material still be needed here?
Many thanks in advance.
Sounds like you are trying to make capacitors 🙂.
Packing tape will give plenty of insulation, but the whole mess will not be very flexible, if kinked it could easily short your 18watt SET valve amplifier.
I hate it when that happens 🙄
What qualities are you trying to add (that work within the audio range of hearing) compared to a speaker wire of normal construction and similar AWG?
Packing tape will give plenty of insulation, but the whole mess will not be very flexible, if kinked it could easily short your 18watt SET valve amplifier.
I hate it when that happens 🙄
What qualities are you trying to add (that work within the audio range of hearing) compared to a speaker wire of normal construction and similar AWG?
Hello,
Many thanks for replying. Yes it is rather like a large capacitor. I understand that this is the way that the Goertz ones are constructed and also the ones from Allen Wrights cable cookbook.
I have read alot of positive comments about these here on the forum enough to make me interested in trying this for myself. I currently have a 3.5 metre pair of TNT Ubyte DIY speaker cables that were great for the cost and would like to try something different now.
Yes cables kinking could be a problem so extra layers of insulation and something to allow strain relief would be in order.
I do not know how important the dielectric constant is or how much this would influence the performance but if I am going to take the time to build these I would like to use something with the lowest possible dielectric constant if possible.
Unfortunately the polyurethane spray looks to have a dielectric constant of around 3 vs teflon at 1.2 but I need to ensure that the cables don't oxidise. I understand that polypropylene packing tape could be used but the adhesive itself can cause a reaction and oxidisation.
Many thanks for replying. Yes it is rather like a large capacitor. I understand that this is the way that the Goertz ones are constructed and also the ones from Allen Wrights cable cookbook.
I have read alot of positive comments about these here on the forum enough to make me interested in trying this for myself. I currently have a 3.5 metre pair of TNT Ubyte DIY speaker cables that were great for the cost and would like to try something different now.
Yes cables kinking could be a problem so extra layers of insulation and something to allow strain relief would be in order.
I do not know how important the dielectric constant is or how much this would influence the performance but if I am going to take the time to build these I would like to use something with the lowest possible dielectric constant if possible.
Unfortunately the polyurethane spray looks to have a dielectric constant of around 3 vs teflon at 1.2 but I need to ensure that the cables don't oxidise. I understand that polypropylene packing tape could be used but the adhesive itself can cause a reaction and oxidisation.
The only thing that would happen if the foil were to oxidize would be that resistance would go up only a tiny amount.
Hi,
It will be around £50 for the copper foil depending on which width I go for (28mm or 44mm) plus whatever I buy for insulation.
I can't find any copper foil inductors in the UK which I know some have used.
It will be around £50 for the copper foil depending on which width I go for (28mm or 44mm) plus whatever I buy for insulation.
I can't find any copper foil inductors in the UK which I know some have used.
spray paint them black so that light reflecting off of them won't be a hindrance to your experience. You could use flexible undercoating spray for automotive applications, or maybe truck bed liner.
or you might wish to suspend them on wooden dowels so that the floor bounce effect won't create a reflection back to the amplifier... :-;
or you might wish to suspend them on wooden dowels so that the floor bounce effect won't create a reflection back to the amplifier... :-;
Hi moley. Boy that seems rather dear for cabling. Are you wanting to use the flat wire so you can place them under the carpet?
Not that you asked:
Back in the day a number of amps were known to go up in flames when presented with capacitive speaker cables. Might be worth investigation before you go too far.
Cyclotronguy
Back in the day a number of amps were known to go up in flames when presented with capacitive speaker cables. Might be worth investigation before you go too far.
Cyclotronguy
You can buy flatwire and solid, not stranded, speaker cable at Fry's for pretty much the same cost as normal speaker wire. Might not be a bad idea to try that first. Its jacket is paintable. If I remember correctly, you'd have to fold them in half lengthwise to really make a capacitoresque wire out of them, but it could easily be done. I think they even come with a sticky side to make it easy.
Dan
Dan
If an amp oscillates because you connected a very large distributed capacitor, there was an issue with the design to begin with.
I did this 10 or 15 years ago and worked nicely with my single ended tube amps. I tried the foil cables with a LM 3886 chip amp which didn't work at all. This type of design can be problematic with solid state. Forget the teflon since it is a major pain to install and it does very little to prevent tarnishing. After thinking about the situation for a bit I decided that plain old brown grocery bag paper would do the trick. It was relatively simple to accomplish. First you just cut the bottom out and down one crease of a large bag. This gives you a starting point. Just cut up enough bags to cover the length of the foils. Then measure the width of the foil you are using and mark the width on the cut open bag. Besure to add about a eighth of an inch. You do not want the tape to contact the foil. Mark off 3 lines and cut away from the rest of the bag. Now fold the the paper along the lines into a Z and put the foils into folds of the Z and tape the paper to secure the foils in the folds. Do not get the tape on the foils since it will increase the capacitance. Do this for the length you need. You just tape the new section, overlapped a bit, to the previous. Terminations can be what ever you like, you can us the foil itself by folding and soldering or you can use whatever you like for connectors.
This works well for interconnects also but is a bit more work intensive and more care is needed. I just took a 1 inch foil and marked quarter inch widths on the foils and then just cut along the lines. I used the grocery brown bag as in the speaker wire. Here again with tube pre to tube amp sounded wonderful, not so much with solid state. As stated else this type of cable can be a problematic for solid state.
This works well for interconnects also but is a bit more work intensive and more care is needed. I just took a 1 inch foil and marked quarter inch widths on the foils and then just cut along the lines. I used the grocery brown bag as in the speaker wire. Here again with tube pre to tube amp sounded wonderful, not so much with solid state. As stated else this type of cable can be a problematic for solid state.
Hello,
Thank you to everyone for your replies, alot to consider here.
Auplater - Thanks for the suggestions, I hadn't yet considered light reflecting off the foil. Black tape perhaps would be good keep the cable visually neutral. As for the wooden dowel cable risers, I will have to try this as I did not realise that this could alter performance.
Cal Weldon - Yes it is a bit expensive, its the price of the copper foil and the lengths that I need (3.5 metre stereo pair). I haven't purchased it yet due to weighing up how I am going to build the thing and the cost versus the fact that it may degrade and oxidise / fall apart if I don't construct it well. There are no other options for copper foil in the UK that I have found. I don't need it to be flat to route it under carpet or anything like that I was mainly interested in hearing the sonic performance of the foil and seeing how such a very low inductance and resistance cable would perform in my system.
Perhaps the 44mm wide foil (equivalent 3.30mm sq) that I am looking at is overkill.
Maybe the 28mm wide (equivalent 2.08mm sq) or even the 17mm wide (equivalent 1.30mm sq) would be totally adequate and more importantly are also alot cheaper.
Regarding the high capacitance issue which can cause damage to some amplifiers, I have done some reading on this and from what I have understood this is more of a problem for solid state amplifiers. My current cable (ubyte) is a high capacitance design and I have not experienced any issues with this connected to my amp.
Dantheman - thanks for the suggestion I will have a look.
Andy Bartha - Many thanks for your comprehensive reply. You mentioned ensuring that tape does not get on the foils as it will add capacitance, thats interesting but I don't understand how this would add capacitance, am I missing something? Is it to do with the adhesive? With the tape sealing the cable over the brown paper in your construction did this stop the copper from oxidising? Sounds like a good way to save some money on the materials.
I did comne across some polypropylene strapping that looked like it could be good as a strong durable insulation material with a low dielectric constant and not too pricey at less than 80p per metre.
Thanks.
Thank you to everyone for your replies, alot to consider here.
Auplater - Thanks for the suggestions, I hadn't yet considered light reflecting off the foil. Black tape perhaps would be good keep the cable visually neutral. As for the wooden dowel cable risers, I will have to try this as I did not realise that this could alter performance.
Cal Weldon - Yes it is a bit expensive, its the price of the copper foil and the lengths that I need (3.5 metre stereo pair). I haven't purchased it yet due to weighing up how I am going to build the thing and the cost versus the fact that it may degrade and oxidise / fall apart if I don't construct it well. There are no other options for copper foil in the UK that I have found. I don't need it to be flat to route it under carpet or anything like that I was mainly interested in hearing the sonic performance of the foil and seeing how such a very low inductance and resistance cable would perform in my system.
Perhaps the 44mm wide foil (equivalent 3.30mm sq) that I am looking at is overkill.
Maybe the 28mm wide (equivalent 2.08mm sq) or even the 17mm wide (equivalent 1.30mm sq) would be totally adequate and more importantly are also alot cheaper.
Regarding the high capacitance issue which can cause damage to some amplifiers, I have done some reading on this and from what I have understood this is more of a problem for solid state amplifiers. My current cable (ubyte) is a high capacitance design and I have not experienced any issues with this connected to my amp.
Dantheman - thanks for the suggestion I will have a look.
Andy Bartha - Many thanks for your comprehensive reply. You mentioned ensuring that tape does not get on the foils as it will add capacitance, thats interesting but I don't understand how this would add capacitance, am I missing something? Is it to do with the adhesive? With the tape sealing the cable over the brown paper in your construction did this stop the copper from oxidising? Sounds like a good way to save some money on the materials.
I did comne across some polypropylene strapping that looked like it could be good as a strong durable insulation material with a low dielectric constant and not too pricey at less than 80p per metre.
Thanks.
how about rc airplane skin.
they make a thin film that has a heat actavated sticky back, plain silk, thin paper realy thin fiberglass.....just a thought.
they make a thin film that has a heat actavated sticky back, plain silk, thin paper realy thin fiberglass.....just a thought.
Many thanks for the link, they look really like they are worth a go at the price. I think I might go for those. The width of the copper foil is alot smaller though (17mm equivalent to 1mm) than the Mundorf foil I have been looking at.
For a relatively low powered tube amp (18 Watts per channel) driving 87db speakers, is it likely that the higher resistance of the 17mm foil would be sonically noticeable versus the 28mm or 40mm over a 5 metre length of cable?
For a relatively low powered tube amp (18 Watts per channel) driving 87db speakers, is it likely that the higher resistance of the 17mm foil would be sonically noticeable versus the 28mm or 40mm over a 5 metre length of cable?
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