a simple lesson learnt

[mveitch]

Dont really expect many replies to this (if any) but I thought I just share something I learnt today: the wire you use really does make a difference!

Sounds obvious but its true.  I've built a tremolo (my first proper build) and was deeply concerned about how much of the high end just seemed to be missing from the output - it sounded kind of cool actually, but not really that acceptable if you switch between the effect and the normal signal in the middle of a song.  It was also very surprising also, as there is no place in my circuit where that much of the high end could be attenuated.

Anyway, I was using Maplins' (UK) bell wire I think they call it.  The stuff you can push into breadboards easy. I had also bought some screened cable (from Rapid) just for posterity if nothing else, just to make the thing watertight.  I decided to give it a go in the final circuit (in the signal paths), and what a difference! The high end, though not entirely, magically appeared!  Boy was I happy that I didnt have to redesign the whole circuit.  I think its fair to say that it isnt the fact that it is screened that made the improvement, its the 'audioness' of the cable, ie it was manufactured specifically for audio and passes higher frequencies than your bog standard. I just hadnt realised that the audio quality of that bell wire was that bad.  This isnt Maplin bashing by the way, more wire bashing.

I guess im saying that I will no longer assume that just because the circuit does what its meant to, doesnt mean it cant be improved by the use of the proper construction methods and materials.

Anyway, ill not go on, hope this helps someone else, just like other random posts have helped me.

matt

[StephenGiles]

Every time I've been into the Maplin shop in Croydon, I've looked at that wire and thought about buying some, but never have.
Stephen

[mveitch]

the bell wire is excellent for prototyping cause its solid core and easy to put into the breadboard (though there is the loss highs). i would still use it for that. but when building the real thing the audio freindly cable is the way to go just to get the best out of the pedal.

matt

[mikeb]

I think its fair to say that it isnt the fact that it is screened that made the improvement, its the 'audioness' of the cable, ie it was manufactured specifically for audio and passes higher frequencies than your bog standard. I just hadnt realised that the audio quality of that bell wire was that bad.

What is bell wire, BTW?

Mike

[mveitch]

I'm not sure why they call it bell wire. Its just thin solid core wire that can be used with breadboards.

[Albert Kreuzer]

It's called bell wire because its main use is (was?) for electric doorbells    (no kidding)

Cheers,
Albert

[jmusser]

I went through the process of setting up an account with them the other day, because I wanted the transformer John Hollis uses in his Titan Boost an Octave. After I got through the process, I found that they didn't ship to the US :cry: I have looked through several electronics catalogs on line, and can't find one with the same primary and secondary ratio.  :x  So, I guess I'm sunk. By the ratio of the thing, it looked like it would be a screaming up octave. Oh Well.

[Karmasound]

So what was the difference of the new wire? Stranded? Different material?


What is considered to be the standard for wiring stompers?

[mikeb]

I asked because I find it hard to believe that changing - what? - 4 inches of wire from one type to another could make such a big difference. In my experience, for such short lengths you can use just about any wire/cable at all.

Mike

[onboard]

I'm guessing the hookup wire was thicker than the bell wire? Here's a chart that shows AWG (American Wire Gauge) and the metric equivalent, with the SWG number (Imperial Standard Wire Gauge). I think the norm for audio circuits in stompboxes is AWG 22 or 24, stranded or solid core. The wire diameter gets smaller as the number gets bigger   :?

[niftydog]

doesnt mean it cant be improved by the use of the proper construction methods and materials.

Like high reliability soldering techniques?!?!

Was the wire soldered? I'd hazard a guess that may have had more to do with it than the wire... but I'm willing to hear arguments the other way. I just somehow doubt that the frequency cut off of a piece of wire would be in the audible region.

[mikeb]

I'm guessing the hookup wire was thicker than the bell wire?

It won't make a difference for audio signals - consider how narrow the 'wire' is inside opamps etc.

Mike

[mveitch]

Ok, im in danger of talking from a different part of my anatomy here but...

The bell wire looks to be something like aluminium. Its silver coloured and is solid.

The screened 'audio' wire is copper strands, surrounded by a sheath of plastic, surrounded by copper starnds (to provide screening), and then a final insulating sheath around that. This is what I used. Again, the use of this type of wire did seem to bring back a lot of the highs, but not all of them.

I *think* the key issue in all this is the conductivity of the material. Aluminium has a significantly lower conductivity than copper. I cant remember the relationship  between conductivity and frequency response, but it definitely makes a difference. I can't vouch for the accuracy of this link, but is a uni-affiliated page: http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/audio/skineffect/page4.html

Figure 7 shows the roll off caused by the material choice. I believe that this is definitely in the audible range.

As a further point, Hi Fi dealers say that your choice of interconnect is paramount to the sound of your Hi Fi. That is why people are willing to pay through the nose for gold connectors/cables, rather than stick with the packaged cheap wire.

Can anyone back me up on this, or am i talking nonesense?

Cheers
Matt

[mveitch]

Ok, yes, I am in danger of talking out of my backside.

I read that link that I posted and they suggest that there is only a small difference in frequency response between the aluminium and the copper. However, I also read another article that suggest that the fact that a wire is solid core can make a difference to AC conductitivity. See, apparently in AC you get something called the skin effect, which is that as the frequency of the AC gets higher, the electrons flowing through the wire flow closer to the outer edge of the conductor. Essentially at high frequencies nothing flows through the middle of the wire. As the frequency increases the more the electrons try to flow closer to the edge of the wire and therefore the space for them to flow through decreases. Therefore the resistance of the wire appears to increase.

So. *Deep breath*. If the wire is stranded the surface area available for the electrons to pass through is much larger (as it is effectively lots of little wires) and therefore the impedance of the whole wire appears a lot lower. Whereas if you have a solid core you only have one effective wire and therefore less surface area available for the electrons to move down. Making the wire thicker, in both the stranded and solid core cases, provides more surface area for the electrons and hence a lower impedance.

There does seem to be a lot of conflict out there as to whether all these differences make a difference in the audible range. Im beginning to think im listening too hard and imagening things.

Sorry to go on. Not such a simple lesson after all.

Matt

[Dai H.]

(Sorry!), but the change sounded far-fetched. Maybe there was something wrong like it wasn't touching where it wasn't supposed to and the signal was being bled off, etc. And wouldn't it make more sense the other way around (shielding high impedance run giving less apparent highs)? Don't worry, I've done things like turning a knob and "hearing" more volume or something like that--then realizing it wasn't even in the signal path(!).  :oops: Not to say that subtle, mojoistic things don't exist at all, however.

[niftydog]

The bell wire looks to be something like aluminium. Its silver coloured and is solid.

highly unlikely, aluminium is expensive, bell wire is cheap. Chances are it's tinned or nickel plated copper.

That is why people are willing to pay through the nose for gold connectors/cables

gold connectors I understand - no corrosion. But, it's only good if the sockets are gold plated as well.

Ludicrously expensive copper wire I DO NOT understand. Law of diminishing returns springs to mind. Once you get to a certain point it's hardly worth making any further improvements because you are gaining very little advantage.

Figure 7 shows the roll off caused by the material choice. I believe that this is definitely in the audible range.

Um, yes.. but 0.025dB @ 25khz is virtually nothing... in fact, I'd even be so bold to say that it IS nothing, especially when in relation to guitar signals which top out at 10khz max.

The difference between the conductor materials is even more negligible.

apparently in AC you get something called the skin effect

I would doubt that audio frequency signals would cause any skin effect that was significant. However, your thought train is right on the money.

the change sounded far-fetched. Maybe there was something wrong like it wasn't touching where it wasn't supposed to and the signal was being bled off, etc.

...like bad soldering joints perhaps?!?!

[JIG]

Ok, yes, I am in danger of talking out of my backside.

I read that link that I posted and they suggest that there is only a small difference in frequency response between the aluminium and the copper. However, I also read another article that suggest that the fact that a wire is solid core can make a difference to AC conductitivity. See, apparently in AC you get something called the skin effect, which is that as the frequency of the AC gets higher, the electrons flowing through the wire flow closer to the outer edge of the conductor. Essentially at high frequencies nothing flows through the middle of the wire. As the frequency increases the more the electrons try to flow closer to the edge of the wire and therefore the space for them to flow through decreases. Therefore the resistance of the wire appears to increase.

So. *Deep breath*. If the wire is stranded the surface area available for the electrons to pass through is much larger (as it is effectively lots of little wires) and therefore the impedance of the whole wire appears a lot lower. Whereas if you have a solid core you only have one effective wire and therefore less surface area available for the electrons to move down. Making the wire thicker, in both the stranded and solid core cases, provides more surface area for the electrons and hence a lower impedance.

There does seem to be a lot of conflict out there as to whether all these differences make a difference in the audible range. Im beginning to think im listening too hard and imagening things.

Sorry to go on. Not such a simple lesson after all.

Matt

You may be on to something here, especially the bit about solid vs. stranded wire. IT is true that there is more surface area in the cumulative area of many "smaller" stands in a particular gauge of stranded wire vs. the same gauge wire in solid. If what you are saying about the characteristic of the electron travel is true, and I have no reason to argue that it isn't, then that could account for what you are hearing. This coupled with the fact that aluminum is a poorer cunductor of electricity than copper could have an affect on your pedal.

Aluminum wire was used extensively in new home construction extensively in the '70s as a cheaper alternative to copper. BUT, becuase aluminum can't handle the same load as copper can, houses started to burn down because the wire was getting hot. Basically there is much more resistance in aluminum than copper. To get the same current handling capabilities of copper out of aluminum would require a larger gauge wire. Needless to say, home builders went back to copper and if you have a house with aluminum wiring... seriously think about having it rewired!!!

I am not sure how this relates to very small currents encountered in stompboxes. I know that added resistance in a circuit will cut the highs. Just gut instinct talking here :roll:  but it makes sense.

Someone please feel free to correct me if I am off base.

JIG

[ErikMiller]

If you used one kind of wire in a breadboard, and another in the final, soldered-together build, my guess is that it ain't the wire that's making the difference.

Breadboards have lots of stray capacitance and inductance. I always figure when I'm prototyping something on the breadboard that how it sounds soldered together will be a pleasant surprise.