From Civic8017@aol.com Mon May 5 21:10:59 1997
Date: Mon, 5 May 1997 17:10:59 -0400 (EDT)
From: Civic8017@aol.com
To: zmax@world.std.com
Subject: Re: MTX Thunder/Blue Thunder Amps
David,
Amps are rated at different voltages. Many rate their amps at 14.4
volts, which is not really fair. Just about every car delivers a little over
12.5 volts when running. This is one of the great things about MTX amps...
they are rated at 12.5 volts. The only way to get more voltage is to replace
your alternator with a more powerfull one.
About the watt ratings. Yes 4-ohm is the standard when rating an amp.
A MTX Thunder 280, for example, is rated at 40w x 2 @4-ohms. When you drop
the resistance to 2-ohms (stereo), you can get 80w x 2. When you bridge the
amp to a 4-ohm load (which is like combining the 2-ohm stereo to one
channel), you can get 160w x1 (rated) power. (Actually you'll get around 300
watts) Now, when you compete in a sound-off, the 4-ohm stereo rated power is
what determines what power class you compete in. So, you are competing with
20w x 2 or "40 watts" but you actually have over 300 watts! Now lets say
this amp was stable to 1-ohm stereo (which is 2-ohm bridged). Then you could
bridge the amp to a 2-ohm load and get around 400 watts and STILL compete
with "40 watts"! That's why many people look for amps that can drive a low
impedance load. The thing with the MTX amps, is that they are NOT stable to
1-ohm, but they deliver almost double their rated power, so it's like the
same thing. That's the story behind the underrated amp thing.
By the way, paralleling two 4-ohm speakers will give you a 2-ohm load.
So instead of getting a four channel amp, you could get a two channel amp
and parallel the front/rear right speakers to one channel, and do the same
thing with the left speakers. This would give you a 2-ohm load to each
channnel, thus doubling the output.
Anyhow, you've done a great job in choosing an amp... MTX amps are just
about the best amps out there for the price. There is no comparison other
than SS, PPI, and other more expensive amps.
What do you want to amplify? How many speakers? What kind of speakers?
-Hope I've been of some help.
-Be sure to write back...
-Civic
From Civic8017@aol.com Tue May 6 16:04:39 1997
Date: Tue, 6 May 1997 12:04:39 -0400 (EDT)
To: zmax@world.std.com
Subject: Re: MTX Thunder/Blue Thunder Amps
David,
> Ok. So its not like youre running 20x2 at 4ohms and when you hook it
> up youll get 40x2. The only way to get 40 is to bridge it or run
> parallel and get 40x2 that way thru 2 ohms. ?
I don't understand exactly what your saying/asking here... but, lets say
that the ratings on the amps were exactly correct and that the amp was rated
at 20 watts x2.
That is 20 watts x2 at 4-ohms stereo. If you use parallel wiring, and get a
2-ohm load, you will bring the power up to 40 watts x2. Bridging the amp is
totally different... you will only get one output. You would get 80 watts
bridged from this amp at 4-ohms (which is the same at 2-ohm stereo).
Well, this amp does exist and it's called the MTX Thunder 240. It
delivers around 30 watts x2 at 4-ohms. Around 60 watts x2 at 2-ohms. And
over 120 watts bridged
into 4-ohms.
> Yes but how does this affect the sound? Will it sound the same or
> does sound quality decrease?
There is no way in hell that anyone could hear the difference between an
amp driving a 4-ohm load and the same amp driving a 2-ohm load. Sound
quality is not even a question here. The only thing is that if you only use
4-ohm loads on the amp, it won't ever get a chance to even warm up. The amp
will run a lot cooler. Dropping the load to 2-ohms will let the amp deliver
the kind of power it was designed for. (I even know a guy who run a MTX amp
at 2-ohms bridged... which is 1-ohm stereo. The amp is not rated to operate
well at such a low resistance, but it works fine anyway.) However, I don't
recommend this.
> What is series wiring then?
Series wiring will double the resitance of the speakers. If you wire
two 4-ohm speakers in series. They will combine to provide an 8-ohm load.
Series wiring is not usually recommended because it "lightens" the load, not
letting the amp deliver the power it could.
With the speakers you described in your car, I would reccomend getting a
four channel amp and wiring the two front speakers to the amp as 4-ohms and
paralleling the four rear speakers for a 2-ohm load to the rear channels of
the amp.
A better idea (my opinion) would be to scrap the 4-inch speakers in the
rear. If there are 4-inch speakers back there, I would assume that the 6
1/2" speakers are only reproducing the lower freq. That is perfect! You
could fade the system to the rear, to get a little more mid-bass from the 6
1/2s, but still have a strong front image, thanks to the only high freq.
comming from the front! Then you could get a two channel amp and wire the
four speakers to it in parallel. Or even better, get a 4-channel amp and
bridge the rear channels to the subwoofer.
About the subs... you hit it on the head with the Kicker Comps! I have
two Kicker C-12 running from a MTX Thunder 2300 and the bass is outstanding!
Great choice! About the JLs... these are the most loved speakers around.
You've been reading the newsgroups so I guess you know this. To tell you
the truth (just my oppinion), I don't see what all the hype is with these
subs. Have you ever actually heard them? The w0 series is a joke... and the
w1s aren't much better. Neither one can handle much power and they don't
provide the "kick" that you expect from a subwoofer. Now, the w4 and w6 are
very good subs... they deliver quit some "kick" and they handle much more
power than the w0s and w1s, but for the price, they aren't worth it... not
even close. If you want to spend that kind of money... get a good Oz
subwoofer. They are just as "musical" as the w6 and are built a lot heavier.
They can handle much more power and give more of a "kick".
If you go with Kicker, I assure you... you won't be dissapointed!
You metioned a x-over... If your front speakers are 4-inchers and you
will be driving them with an amp... they will need to be x-over or the bass
will fry them in a second. If you are going to parallel the front/rear
speakers, you will need to use a passive x-over. If the speakers are going
to be run off of their own channel, you can use a pair of in-line RCA filters
that just connect between the RCA wire comming from your head unit and the
amp channel that will be powering the 4-inchers. You should cross them over
at about 200 Hz and let the rear speakers handle the mid-bass. (I would
REALLY recommend upgrading the factory speakers... there are no good stock
systems... just the better of the bad.)
You cannot afford SS amps but you can afford Phoenix Gold and Orion?
These amps cost about the same, for comparable models. The outstanding HCCA
series from Orion (stable to 1-ohm stereo) costs much more than the SA series
from SS. It all depends on what models you compare. But, why would you pay
the $$$ for an expensive Phoenix Gold amp to run your factory speakers??
Even if you think these things are pretty good, they will not be able to
handle the power of a serious amp. Well, I won't really get into it with the
amps... no matter what anyone says, all the brands you mentioned, plus a/d/s,
MTX, Rockford Fosgate, PPI, and any other well known brand sound the same.
It's all about features, power, and price. And this is where I think MTX
takes the cake... clean, powerfull, no turn on/off noise... they're just
outstanding!
One last note... the gain knob is NOT a volume knob... it is only used
to match the amp to the head unit. Since your exellent Sony deck has a high
output voltage, you can turn down the gains quite a bit and still get plenty
of clean power.
Hope I've been of some help... be sure to write back...
-Civic
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