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From: pmr@drutx.UUCP (Rastocny)
Newsgroups: net.audio
Subject: Re: Speaker Fusing - While we're on the subject ...
Message-ID: <1758@drutx.UUCP>
Date: Sat, 12-Jan-85 23:36:23 EST
Article-I.D.: drutx.1758
Posted: Sat Jan 12 23:36:23 1985
Date-Received: Mon, 14-Jan-85 01:23:36 EST
References: <271@olivej.UUCP>, <10834@watmath.UUCP> <826@hound.UUCP>
Organization: AT&T Information Systems Laboratories, Denver
Lines: 53

<>

I agree with Dick on the subject of fuses.  There are two camps: those that
fuse and those that do not.  I belong to the latter camp.  My power amp,
except for the line, has no fuse.  Fuses are nonlinear resistors when they
become warm, like when your music is played loud.  And since most people I
know buy a stereo to play their music loud, they listen to this nonlinear fuse
in combination with their music.

So what does a fuse sound like?  That's a good question.  I have never set up a
deliberate listening session to observe a fuses effects.  I removed my fuses in
the process of beefing up the supply and output device wiring.  I am a firm
believer in the KISS principle and believe that fuses are NOT as simple as they
appear to be on the surface.  I also believe that the average person with a
receiver and speaker selector switch in series with the speakers will never
notice the effects of removing the fuse without first removing the selector
switch.

Fuses can hide in all sorts of places: Hafler puts them on the wiring between
the main supply filters and the PC boards for each channel AND on the line
(5 fuses total on the supply).  Then they fuse each of the speaker leads
(2 more, for a total of 7).  Is all this fusing necessary? Yes and no.  Some
engineers believe in making an amplifier user-mistake proof (people may short
leads out and try to plug is interconnect cables with the amplifier on and
speakers connected, etc.).  All of this degrades the sound in some way.

So what happens when you defeat the most of the fuses and speaker protection
circuitry (leaving only the line fuse) and something goes wrong with the
amplifier?  The worst thing that could happen if you don't make the above
mistakes is that an output device or bridge may die and take the main fuse out.
Before the fuse goes, it may send a large enough DC pulse to the woofer to take
out its voice coil and possibly those of the other drivers.  The line fuse may
not react fast enough to the surge and the surge may take some of the traces on
the pc board.

So why do I risk it?  I feel that it's a small risk.  Life is made up of many
risks and compromises.  Without taking some risks, you never get anywhere.  In
the case of fidelity, you never know what you're missing until you take the
fuses out and see if it makes a difference.  I know that when I finished the
wiring and fuse mod I made on my amp, the system sounded TOTALLY different.
How much of this difference the removal of the fuses contributed is not known.

One other thing to remember is that a fuse cannot degrade the sound any more
than the other pieces of equipment in the reproductive chain already have.  My
chain is highly already refined (esoteric wires, cables, internal speaker
wiring, etc.).  Those of you with receivers will probably never hear the
benefits of removing fuses.  Those of you with higher end equipment probably
will.  I'd go for it.  After all, I enjoy listening to music, not fuses.

		Yours for higher fidelity,
		Phil Rastocny
		AT&T-ISL
		ihnp4!drutx!pmr