🚀 go-pugleaf

Howard Ferstler wrote:
> > Well, you're just plain wrong.
>
> I'm certainly willing to learn. Now, with this near short
> pulling just about all of the juice out of the amp, where
> does this speaker load, with a resistance way, way higher
> than the near short in parallel with it, get the juice to
> make any noise?

Howard, you know your way around libraries, yeah? At least
that's the rumor.

See if you can find your way clear to looking up something
called "Ohm's Law." When you've mastered that, check out
"Kirchoff's Current Law."

Once you've done that, try the following:

   Imagine a circuit consisting of three resistors hooked
   to a voltage source. On one side of the voltage source
   one end of one resistor, call it R1, is connected.
   On the other side of that resistor, both ends of the other
   two resistors, called R2 and R3 are connected, and the
   other sides of those resistors are connected to the
   other side of the voltage source.

   If you actually knew something about the topic on which
   you choose to hold forth, you might recognize the following
   as a SPICE netlist for the circuit I just described:

      Vsrc   1   0   AC SIN 10.0 0.0
      R1     1   2   0.5
      R2     2   0   4.0
      R3     2   0   0.2

   Now, if you did indeed know something, you would notice that
   R1, which we'll pretend is the resistance of the very thin
   wire the OP is using is 0.5 Ohm. And the "speaker" has a
   resistance of 4 ohms, and the "near short" whisker has a
   resistance of 0.2 ohms.

   Real quick, Howard, since you are a "widely published" author
   in the field, can you determine from the above description
   whether or not ANY signal flows through R2, the "speaker"
   in this case. If the value is NOT 0, the speaker WILL make
   sound.

   All of this can be calculated with freshman high-school level
   algebra.

   Dum de dum de dum .....

   Give up?

   Well, in fact, we can first say that the series combination
   of R1 and the R2 and R3 in parallel form a voltage divider
   whose gain is determined by essentially the parallel result
   of R2+R3, which is:

      R2 R3 /(R2 + R3)

      4 * 0.2 /(4 + 0.2)

      0.8 / 4.2

   or 0.19 ohms, call it Rp for convenience. The gain of the
   circuit is:

      Rp / (R1 + Rp)

      0.19 / (0.5 + 0.19)

      0.19 / 0.69

   or a gain of 0.275. That means if that the amplifier can
   produce a voltage of 1 volt into that load, then 0.275
   volts of that will appear across BOTH the "speaker" and
   the "short."  And since the total load is simply:

      R1 + Rp

   or 0.69 ohms, (wait for it) .... according to Ohm's Law:

      I  =  E/R

      I  =  1/0.69

   or 1.45 amps.

   And, by the same reckoning, we can calculate the current
   through the "speaker" and the "near short:"

      I2  =  0.275/4
      I2  =  0.0688 A

      I3  =  0.275/0.2
      I3  =  1.375 A

   And, just to satisfy the conservation-of-energy accountants
   and Mr. Kirchoff:

      It  =  I2 + I3

      It  =  0.0688 + 1.375

   which is satisfyingly close to 1.45 amps.

   So, it seems that even with a "near short," some current does
   flow through the speaker. Enough, in fact, to produce

     I2 * 0.275V

   about 20 milliwatts worth of power in the "speaker". Assume
   the speaker has a reference efficiency of about 1%, for
   argument's sake, that means 0.2 milliwatts of acoustic power
   output, equivalent to a sound pressure level at one meter of
   about 72 dB at 1 meter (1 acoustic watt at 1 meter produces
   an SPL of 109 dB, 0.2 milliwatts is 37 dB below 1 watt).

   72 dB SPL.

   72 dB SPL.

   Got it?

   72 dB SPL

   That's quite audible, don't you think?

   It's more audible that you're insistance on 0 output, don't
   you think?

   Now, what might you think happens if you hook this to an
   amplifier that is capable of playing into a 1 ohm load only
   at low levels, but say when the current drawn exceeds something
   like, oh, 2 amps, the over current protection circuitry turns
   on? And what do you think might happen if that overcurrent
   protection is built into the large hybrid integrated circuit
   that's the power output module for THAT channel, and operates
   independently from the other channel?

   Yup, one channel would have weak sound until the volume got
   turned past a certain level, and then it would shut down.

   Now, where did I get all this stuff from?

   Well, Howard, I took a Sony amplifier, which happens to be
   built pretty much as I described above and hooked it up pretty
   much like what the OP described AND I GOT EXACTLY THE SAME
   RESULTS AS THE ORIGINAL POSTER.

   Well, Howard?

   Howard?

   Howard?

   Are you still with us?

   Do you now understand why, when people know a LOT more than
   you, it's because they know a LOT more than you?

   Do you NOW see why, Howard, you're such a dumb, arrogant
   moron and why it's a good idea either to make at least a
   token attempt to understand that which you choose to hold
   forth as an expert on, or simply drop the silly pretense,
   admit you're clueless, and go take up shuffleboard to fill
   out the rest of your retirement in the obscurity you have so
   richly earned?

   Haven't you done enough damage with your "books" and
   "articles?"