From: jsc52962@uxa.cso.uiuc.edu (Jeffrey S. Curtis)
Subject: Installation Story
Organization: University of Illinois at Urbana
Date: Thu, 19 Nov 1992 07:39:11 GMT

Hi gang,

Just thought I'd let everyone know how my installation is going (for
the sake of getting back to the basics of this group for a minute).

My Proton CA-490 amp arrived today, along with 60 feet of StreetWires
14 ga., pure electrolytic grade copper speaker wire.

The Proton amp is a 2/3/4 channel amp.  It has 4 input channels, each
with individual input sensitivity adjustments, and four output
channels.  Channels 1 and 2 are 30W nominal/45W peak.  Channels 3 and
4 are 60W nominal/85W peak.  Each set is bridgeable to mono.  The amp
is stable to two ohms, and has a built-in fan.  There are both line
and speaker level inputs; buttons select between them.  I rate the
amp very high on aesthetics - it's very sleek, very cool.  It has
plates that go over all the connections, so you don't actually even
see any screws or terminals.  Everything's hidden.  Very nice.

I started with the amp behind the driver's seat and made the ground
and remote turn-on connections first.  The ground lead I decided to
mount to a screw attached to a very huge, unpainted chunk of metal
on the driver's seat's position guides.  The remote connection was
made with 12 ga. wire to the power antenna lead of my head unit
(massive overkill, I admit, but it was the only long piece of wire
I had handy).

I then made the +12v connection.  I ran the cable that came with
the amp (looks like 12 ga.; I didn't measure to find out for
sure - I plan on buying StreetWires Ultra-Flow 8 ga. soon) in between
the driver's and passenger's seats to a hot lead I already had for
my previous amp (well, booster/eq, actually) behind the center
console.  I wrapped the connection around the cable's ring clamp
(this is temporary, don't worry).

Then I took to the speakers.  I climbed in the trunk and made a
connection to one of my two Jensen JTX 3269 6x9"s on the rear
deck.  I managed to find a way to get them directly into the
passenger compartment (instead of going up through the corner of
the rear deck as I did previously - major kludge) through the edge
of the seat.  I made the connection to channel 3 (rear left) of
the amp and then attached the signal source (Sony D180-K Car
Discman) to the inputs.  Turned everything on.  The music was
barely audible.  I turned the Discman up to max power.  Still
barely audible.  I started playing with things - input sensitivities,
etc.  Nothing.  Then it occurred to me that I had the preamps
connected to channels 1 and 2 instead of 3 and 4, and, forgetting
that the Discman was on max, switched the inputs.  I got to listen
to my Jensen bottom out at about 111dB for about a quarter of a
second before admitting my stupidity and unplugging the input.
But this raises a question: why could I hear the music - albeit
faintly - if the inputs for channels 1 and 2 are (theoretically)
isolated from channels 3 and 4? I assume the answer to my question
is that they aren't.  But they *should* be.. anyway..

So to make a long story short, I made the rest of the speaker-level
connections, and then hit El Shak del Radeo` (Radio Shack) for
two 1 female:2 male RCA plug Y adapters for the inputs (to turn
two channels into four).  I should probably get better adapters
eventually - but these were only $2.79 each, and were available
immediately.  Speaking of which, does anyone know if anyone sells
1/8" to RCA cable that's of *good* quality (you know, the stuff
that comes with a Discman, but with decent connectors - gold if
possible)?

And I tried everything out.  And it sounded great.  :-)  Well,
all things relative - bear in mind that until then, I'd been
listening to a Realistic 4x20 booster/eq that was about 5 years
old.

Now here come the interesting bits (for anyone still reading):

Even though (for temporary purposes) my +12v line into the amp
was running right on top of the preamp cable, there was *almost
no noise* at all evident.  This held true even when the engine
was running - *zero* alternator noise and *zero* ignition noise.
Needless to say, I'm very pleased with that.  The only problems
I could find were that there was an extremely tiny amount of hiss
apparent (and I do mean tiny), and the CD player's electrical
motor noise could be heard for the first half second or so when
starting it up with the engine running (but never again after
that).

What remains to be done is to adjust all four channels' input
sensitivities, install two caps for the front woofers (-dB/octave
at 200Hz high pass), tuck the amp away under the seat, and run
the cables where I actually want them instead of all on top of
everything.

All in all, I'm *very* pleased with the results.  The only thing
I could possibly say bad is that the Proton's low end frequency
response ends at 50Hz (+/- 1dB), although they claim it would
make a great subwoofer amp.  For my purposes, though, this is
fine, since I already have a self-powered sub tube that draws
its signal from elsewhere.

In the specs section, the THD is rated at 0.08% for all four
channels from 50-20kHz at RMS power.  Below that, however, a
line reads "THD at rated power, 0.02%".  Is this a contradiction,
or am I not understanding the difference between the two
correctly?

Anyway, that's all for now.  Thanks to everyone who replied to
my questions about running power cable and everything else.  I
appreciate all the friendly responses and advice.  :-)

Catch ya all around,

Jeff
-- 
Jeffrey S. Curtis sidewinder@uiuc.edu | "Resplendent and full again, they revel
 The Power of 37  free2207 at uiucvmd | in their role as self-appointed critics
   Jensen - Polk - Sansui - Proton    | of the establishment..."
 Sony - StreetWires - Sanyo - Sennet  |   -- INXS _Welcome to Wherever You Are_
Newsgroups: rec.audio.car