[78-L] NULLING VERTICAL COMPONENT

[Steve Williams]

We're into AC and inductance theory concerning bridging the two cartridge
coils together, but in effect each coil is a high impedance load to the
other when both are generating signals in phase, (lateral) and low impedance
or a partial short when signals are out of phase, so there is a physical
damping effect to vertical components both by presenting a low target
impedance to the driving coils for vertical signals, and actual attempted
physical movement of the stylus to opposite phase of the vertical signal.
Another thing is that the usual differing frequency and impedance curves of
the two coils/armature sets are actually equalized to each other (Where one
coil is more resonant, that is damped more by the other coil), so there is
better out of phase cancellation at all points of the frequency bandwidth
than by bridging the preamp to mono. It's ok, it works well.  There is some
difference in sound between paralleling the coils and bridging at the
preamp, but it's hard to quantify.  What must NOT be done is to short ANY
preamp output, this presents a dead short to the power output for out of
phase signals and can cause saturation and bias distortion.  Outputs may be
taken to each end of a linear taper potentiometer, with the wiper being used
to balance the signals to the next amplification stage.  Incidentally
putting the two phono coils in series doesn't work well because that
exacerbates difference in response, and there is resonance rather than
damping for vertical signals.

..  Steve Williams  ..

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Date: Tue, 8 Nov 2011 13:05:20 +1000
From: David London <jusmee123 at gmail.com>
Subject: Re: [78-L] NULLING VERTICAL COMPONENT - was: stereo/mono and
	noise	reduction
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>Curious as to why you see it as a problem?  It is done quite a lot.

On Tue, Nov 8, 2011 at 12:18 PM, Mark Durenberger
<Mark4 at durenberger.com>wrote:

>> Uhhmm...I'm not sure it's good to jumper most cartridge outputs together.
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