🚀 go-pugleaf

[This followup was posted to hk.rec.audio-visual and a copy was sent to the cited 
author.]

In article <33CE8A4B.800@nortel.ca>, heath@nortel.ca says...
> Jimmy CHAN wrote:
> > 
> > We have just purchased one CROWN Macrotech MA-600 and one MA-1200 for
> > our JBL 4982 speakers in our church.  We got an annoying "POP" sound
> > when we turned on or off the AC power of MA600 which is used for driving
> > the high frequency of the speakers and the MA1200 is used for driving
> > the woofer of the speakers.  We have pulled down all the fader for the
> > mixer already and power of mixer kept on when we turned off the power
> > amplifier.
> > 
> > The pop sound comes from the MA600 only.
> > 
> > Is it normal?  Will it hurt the speakers? Any method to kill the POP
> > sound.
> 
> It's not 'normal' and if there's a DC component it may damage the voice
> coils in the speakers. You can wire a DC-blocking cap in series with the
> high frequency driver to reduce the possibility of damage. I'm sure 
> someone with more recent circuit experience will post appropriate
> values,
> but you want a non-polarized capacitor with a 200V or so rating, and
> the capacitance needs to be selected with regard to your crossover
> frequency.
> 
> > Both amplifiers are brand new.
> > 
> > The technical staff of CROWN replied that it it normal and there is no
> > relay for the output of the power amplifier.
> 
> I don't think it's acceptable, but I've had similar experiences with
> several Crown amps, and no real technical answers from Crown. I make it
> a practice not to connect speakers until the amp's had time to
> stabilize.
> I realize that's not a realistic option for you in a fixed installation.
> 
Do you think that connecting an external relay box is a good idea to solve the 
problem ? 
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