[tcb] Re: I need instructions or a diagram
- From: "Gerald V. Livingston II" <gerald.tcb@xxxxxxxxxxxxx>
- To: tcb@xxxxxxxxxxxxx
- Date: Wed, 16 Jan 2008 18:47:20 -0600 (Central Standard Time)
I think Denis is running a single amp for the sub using RCA outputs already
on the head units he has been buying and has been running the mids/highs
from the head unit built in amp. No splitting allowed doing that. You can't
split before the line-level converters because they appear as a regulat 8
ohm speaker load (10 ohms actually) to the head unit. If you also run a set
of speakers then it becomes about a 4.5 ohm load.
Total resistance = (R1*R2)/(R1+R2)
Total resistance = (10*8)/(10+8)
Total resistance = 80/18
Total resistance = 4.44~ ohms
If the amp in the head unit is rated for 8 ohm loads then cutting that in
half will eat the amp in short order.
Denis, you need a new amp to run the mids separate from the sub amp *OR*
run only two mids directly from the head unit with no line-level convertor
(using only the front channel for those) and use the line-level convertor
and the rear channel to run the amp for the sub. If the amp running the sub
has inputs labeled *HIGH* then you don't even need the line level
convertor. Now, the old head unit running speakers directly probably only
puts about 10 (matbe 20) watts per channel out. Newer head units commonly
do 40 or 50 watts per channel.
If you want to run more than two mids then you'll need an amp for them. A
little 200 watt amp (50 watts per channel) should be fine. And then Brian's
crossover comes into play. If it's a 4 channel crossover then you run from
the head unit to the line0level converters then to the crossover --- *OR*
staright from head unit to crossover if it a unit that has high inputs and
line-level outputs. If your amps have built-in high/low filters you don't
need the crossover. The line-level signal can be split out to as many amps
as you want to run ON THE LINE LEVEL SIDE. Just no splitting on the other
side to run speakers and the converter.
Got a headache yet?
On Wed, 16 Jan 2008 15:42:29 -0600 Brian Denning
<i_am_cool_fred@xxxxxxxxxxx> wrote:
> they make splits to where you can run rca's to an amp...if you have a
> dedicated amp for your subs it will, hopefully, be a sub amp with a
> low-pass switch, bass boost, etc. then all you have to do is switch to low
> pass crank up the boost adjust your gain and you are set.
> if it doesn't have a low pass switch i can sell you an infinity
> electronic crossover that allows you to fine tune the bass including bass
> boost, you have a decible range you can choose etc. it's a nice little
> tool. i used it when i was running 400 watts to my subs in my truck cause
> the amp didn't have that type of capabilities.
> infinity makes the good ones and honestly, i've seen them in jc
> whitney before (don't know about quality but i have seen them)
> Denis, if you are interested in my electric crossover to fine tune the bass
> going to the dedicated sub amp then let me know. i'll let you have it for a
> spot with a view at psychoblooie
> > Date: Wed, 16 Jan 2008 09:54:48 -0600
> > From: gerald.tcb@xxxxxxxxxxxxx
> > Subject: [tcb] Re: I need instructions or a diagram
> > To: tcb@xxxxxxxxxxxxx
> >
> > http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=360014245308
> >
> > 2 required (one each for front/rear).
> >
> > Hooking up a separate sub without a dedicated sub output on the head unit
> > will be ... interesting ... unless your amp has a passthrough feature to
> > feed another amp for the sub. If you have been feeding ONLY the sub from an
> > amp you may now have to go to feeding the mids/highs with an amp (with a
> > passthrough port) to keep the sub.
> >
> > Brian is right, no cap needed where you're at in power requirements. When
> > the amplifier needs constant voltage at high amperage (more than the
> > alternator can provide --- 70+ amps with the alternator already feeding
> > everything else) the capacitor provides the juice. When there is no cap for
> > a big amp you get things like flickering lights, stuutering ignition, and
> > batteries that die quickly because the stereo hits them for the extra power
> > and they are not designed to have high amperage drwan from them in short
> > bursts. Adding more betteries can help the "dying battery" syndrome because
> > they each get only part of the extra amperage drawn from them when they
> > take a hit. But it still causes flickering lights etc. because it grabs
> > from the alternator output before the batteries when the alternator is
> > operational.
> >
> > If you go the route I did then you might want to add a cap to save the
> > battery from taking extra hits (stereo separate from main wiring on a
> > dedicated aux battery). With one of those orange batteries my stereo would
> > last for 8 - 12 hours at reasonable volume (Family reunion '06). With the 4
> > I have in there it was still going strong after over 24 hours at
> > "unreasonable volume" (T4P). I have a 1600 watt amp on the subs and a 200
> > watt amp on the mids. I want to add a 50 watt amp to run separate tweets
> > and take the highs out of my mids. Of course, you can always buy one more
> > battery from me to get extra run time <grin>.
> >
> >
> > Gerald
> >
> > On Mon, 14 Jan 2008 10:57:05 -0600 Brian Denning
> > <i_am_cool_fred@xxxxxxxxxxx> wrote:
> >
> > > a farad won't help you hook your amp to your radio that simply just
> > > gives your amp a constant power source. what you need to hook the amp to
> > > the radio is a little box they sell at radioshack that you hook yoru
> > > speaker wires into and it has the rca jacks on it. as far as farads...it's
> > > up in the air... do you have an altenator or generator? if you have an
> > > altenator with a decent sized battery you shouldn need need one for a
> > > little 500 watt amp. i am running a 1000watt on mine with no problems and
> > > i
> > > don't have a farad installed. my truck however is pushing 2500watts and i
> > > am in dire need of a 1/2 farad to help wiht the power...i go through
> > > batteries every other year in the truck because of the 2500 watt amp
> > > pushing the subs and the 250 pushing the highs.
> >
> > > don't know if that helps or not but there ya go.
> > >
> > > i'm all about sound systems so i can probalby help ya out.
> > >
> > > > From: coocoo@xxxxxxx
> > > >
> > > > I have a new shaft style stereo for my bus. It is
> > > > special because it will fit in the hole in the dash. They don't make
> > > > many
> > > > anymore, so it's pretty cool to find a new one in the box. Anyway, I
> > > > have a 4
> > > > channel 500 watt amplifier and I am looking for a simple drawing or
> > > > clear simple
> > > > instructions on how to install it using all four channels. I guess that
> > > > I am
> > > > also supposed to put in a capacitor of, at least, 1/2 Farad, although,
> > > > from what
> > > > I read a 1 or 2 Farad will do. The radio I bought does not have RCA
> > > > outputs, just wires. Help?
> > > >
> > > > I have asked for Gerald's help, he knows all this
> > > > stuff. He also showed me the gear to make Murray a plug and play
> > > > electrical
> > > > wonder, and I even offered to bring Murray to Galveston to do this,
> > > > since having
> > > > all the parts and hooking it all up so that Murray doesn't burn to the
> > > > ground in
> > > > front of my eyes is two different things.
> > > >
> > > > If anyone can draw and scan and send me a drawing
> > > > for all this stuff, I can install it. Nobody, it seems makes sensable
> > > > schematics
> > > > to hook it all together.
> >
> >
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