Post by JohnH on May 9, 2005 6:20:28 GMT -5
I’ve been thinking further about the factors that affect the sound of a humbucker, when cut to a single coil. So I have made some tests, aimed at finding out the following:
Does bypassing the non-active coil, by shorting out its leads, sound any different from fully disconnecting it? It would be good to know, because many designs for coil-cut switching work by bypassing, rather than disconnecting. Heres and example of each:
The reason to do this is based on some discussions here and elsewhere, which suggested it could be significant. Hence some simple ‘Myth-busters’-style testing was required (but without actually exploding my guitar).
In theory, although a bypassed coil can’t directly contribute to the electrical output, but could, by forming a closed loop, induce emf’s within itself that affect the magnetic field which it shares with the other (active) coil, therefore changing the sound. It could also provide damping to the strings. This would be analogous to the braking affect which you get if you short the leads to an electric motor while turning the spindle.
In earlier tests, I listened to different coils of a pickup, but to properly isolate these effects, one coil only should be monitored in an A/B comparison.
My test setup was to connect to one consistent coil with all other coils disconnected, and then to short circuit other coils to check the affect on the sound. I monitored carefully with headphones on a ‘clean’ amp setting. I would expect any effects due to magnetic interference to results in a slight but immediate drop in high harmonics, while changes to string damping would affect the decay of the high frequencies with time.
Test 1: This was to listen to Coil 1 of the neck pickup, while shorting or disconnecting the adjacent Coil 2. Any difference could be due to either change in string damping or change in magnetic interference between the coils.
Test2: Involved listening to a single coil on the bridge pickup, while shorting or disconnected one or both parallel connected coils of the neck pickup. Any difference in sound would not be likely to be caused by direct magnetic interference (pickups too far apart), but could be caused by damping of the strings, which would affect all coils.
Results: With this test set-up, I found no audible differences at all in either test.
Conclusion: Although these effects may occur in theory, they were not significant in the case tested, and I expect that they are probably not significant with other pickups either. If so, it makes no significant difference to the sound whether a coil-cut setting is made by bypassing one coil, or by disconnecting it. That’s good news for circuit designs, since coil bypassing is a handy technique and it would be a shame to be losing some tone because of it.
Myth Busted!…Any comments?
(Please note that I am not commenting on whether such a coil-cut HB sounds exactly like a real SC!, just investigating the ways by which to get a reasonable approximation.)
Does bypassing the non-active coil, by shorting out its leads, sound any different from fully disconnecting it? It would be good to know, because many designs for coil-cut switching work by bypassing, rather than disconnecting. Heres and example of each:
The reason to do this is based on some discussions here and elsewhere, which suggested it could be significant. Hence some simple ‘Myth-busters’-style testing was required (but without actually exploding my guitar).
In theory, although a bypassed coil can’t directly contribute to the electrical output, but could, by forming a closed loop, induce emf’s within itself that affect the magnetic field which it shares with the other (active) coil, therefore changing the sound. It could also provide damping to the strings. This would be analogous to the braking affect which you get if you short the leads to an electric motor while turning the spindle.
In earlier tests, I listened to different coils of a pickup, but to properly isolate these effects, one coil only should be monitored in an A/B comparison.
My test setup was to connect to one consistent coil with all other coils disconnected, and then to short circuit other coils to check the affect on the sound. I monitored carefully with headphones on a ‘clean’ amp setting. I would expect any effects due to magnetic interference to results in a slight but immediate drop in high harmonics, while changes to string damping would affect the decay of the high frequencies with time.
Test 1: This was to listen to Coil 1 of the neck pickup, while shorting or disconnecting the adjacent Coil 2. Any difference could be due to either change in string damping or change in magnetic interference between the coils.
Test2: Involved listening to a single coil on the bridge pickup, while shorting or disconnected one or both parallel connected coils of the neck pickup. Any difference in sound would not be likely to be caused by direct magnetic interference (pickups too far apart), but could be caused by damping of the strings, which would affect all coils.
Results: With this test set-up, I found no audible differences at all in either test.
Conclusion: Although these effects may occur in theory, they were not significant in the case tested, and I expect that they are probably not significant with other pickups either. If so, it makes no significant difference to the sound whether a coil-cut setting is made by bypassing one coil, or by disconnecting it. That’s good news for circuit designs, since coil bypassing is a handy technique and it would be a shame to be losing some tone because of it.
Myth Busted!…Any comments?
(Please note that I am not commenting on whether such a coil-cut HB sounds exactly like a real SC!, just investigating the ways by which to get a reasonable approximation.)
