$keywords = "tech tips,tech tip,Vox,Cambridge 30,V9310/9320,Tremolo,Robert M. Braught,Robert Braught";
$title = "Vox Cambridge 30 V9310/9320 Tremolo";
$tech_tip = '
As some of you techs know by now, the tremolo \'assembly\' (opto-coupler
p/n LT9914) has a reputation for failure... causing distortion in clean
channel operation, poor/no tremolo... one on the frizz can make the amp
sound like the output IC\'s blown...

<P>
Word from Korg USA last week, no \'recall\' in the near future, no
substitute part recommended, etc. From my field experience it appears
the LDR portion fails, possibly linked to voltage/current (? customers
have reported after \'blasting\' signal through their amp, it \'quit\'.)
List price on the \'original\' Vox(Korg USA) part $24   :(

<P>
I\'ve successfully tested a \'regular\' Vactrol, ala Fender p/n 16282, OEM
#&nbsp;VTL5C3/2 as a suitable replacement. Use both LDR elements in series
(leave the center wire unconnected / clipped.) The circuit will require
\'recalibration\', twiddle ref VR11 and VR12 (on the main board) \'til
tremolo sounds right (\'normal\' full depth) and signal pass is good with
tremolo \'off\'. No harm will come from the adjustments being dimed or
turned back full CCW. This sub is less than half the part cost of the
orig Vox part, and my experience with the Vactrol units (as in Fenders,
etc) is that they are a very high reliability part, with long life
expectancy. FWIW <EM>this will not change your tone</EM>.   :)
';

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