Linear installation; Grounding & all that other good stu

[gohusan]

I have several questions that maybe acouple of you gentleman can answer for me.

1stQ. I've recentlly aquired a Linear amp(Galaxy 250) :mrgreen: An am having my local tech guy matching it to my cobra 148 GTL. Now my question is I was speaking to my tech guy about a quick disconnect setup to my Linear. Had bought a 8 guage wires for a hook up to my battery but ran into a puzzle. The power cord coming out of the Linear read (12 AWG) now I'm assuming that means the cord is a 12 Guage. :? He told me if I connected the two through that method I'd litterlly melt the connection & god knows what else. So this probably mean I'll have to get some 12 guage wiring to hook up to my battery instead, right? The innards of the amp are (2X457). My tech said they are rated @ 80watts each so that means 160watts Max if everything runs smoothly which most likely will not.

2ndQ. I am trying to install this in a 2006 colombian FREIGHTLINER(work truck) an was planning on running the powercord to a connection in the fuse panel that connects directly to the batteries, good Idea? :? The other end; the neg/ground cord is still unknown yet and was wondering what would be a good suggestion. Take note the next question will determine the lenght I will probably need. :arrow:


And 3rd would be; There really is not alot of places if any to put my amp @ so I was planning to place the Linear amp right above my radio in the overhead CB hole. :shock: Now I know the 2 should not touch one another so I was thinking of putting something like a wood board or a piece of cardboard in between. :| The only thing I want to make sure of is if that will cause a problem with the amp being so close to the radio.

 

[lords]

first your matching(adjusting) the radio to the amp,if a diode is pulled(for modulation) or a swing kit put in ,take it back out or you will be fighting with the amp
that small of an amp shouldn't matter with the wires..8-12 guage
i think you meant 2X455(mrf455's) don't know about no 457's
about 160-170 ..I DK at 3/4-1 watt and swing to 10 watts with one and get about 175 PEP....at 13.8 volts into the linear..
ground it in sections..Example: radio to door, to frame..
as for being by the radio right above it or below it wouldn't really matter..course if that galaxy 250 wasn't tampered with and redone
to get more out of it..it should be filtered pretty good ..AM/SSB

 

[W5LZ]

gohusan,
1. Use the #8 wire that you already have. It won't 'hurt' anything. If the joint between the #8 and the #12 is done correctly (even sort of close to correctly) it will be one of the last things you will ever have to worry about.

2. The power connection going to the fuse panel may work just fine, it just depends on the fuse panel. Your amplifier will probably pull more current than anything else in your truck. If that, along with whatever else is used 'in' the truck doesn't over-load the fuse panel's current handling ability, it should work just fine. If not, run the power line to the battery. Running the power line from the battery isn't a bad idea, just remember to turn the amp off when you're through with the truck - lol.

3. Where to put the thing? As long as you remember that the amplifier will need adequate air circulation to keep it cool, you can put it almost anywhere you can or have to. I don't know why the amp and radio can't touch each other, they are "touching" electrically, so other than for some mounting reasons, don't see why they couldn't "touch" physically. Remember the cooling requirement though. A heat build up isn't good for the amplifier or the radio.

A 'quick disconnect' has two requirements. It has to provide a fairly fast way to disconnect things, and it has to provide an adequate contact for whatever you use the thing on. If your quick-connector can do those things it ought'a work fine. It may not be all that easy to hook up, which would depend on how the thing is made and for what purpose it was made for to start with. (It also sort of depends on what your 'tech' is familiar with, you know?) That may be where the question of the size of the power line comes in, the #12 and #8.
Have fun and good luck.
- 'Doc

 

[lords]

idea, like doc said about the quick disconnect..
mount the linear to the top of the radio
and have it on the same quick disconnect...this way you just have to pull the cord..and walk away..well besides the coax
and like doc said to about heat..remember the longer the keyup the hotter it will run...
BTW those MRF455's can take a beating ,I have 2 installed
in a moded texas star 350HDV..not using the variable pod
keying 3/4 of a watt swinging 9 gives the amp a 20watt key up
swinging 180..

 

[gohusan]

2. The power connection going to the fuse panel may work just fine, it just depends on the fuse panel. Your amplifier will probably pull more current than anything else in your truck. If that, along with whatever else is used 'in' the truck doesn't over-load the fuse panel's current handling ability, it should work just fine. If not, run the power line to the battery. Running the power line from the battery isn't a bad idea, just remember to turn the amp off when you're through with the truck - lol.

3. Where to put the thing? As long as you remember that the amplifier will need adequate air circulation to keep it cool, you can put it almost anywhere you can or have to. I don't know why the amp and radio can't touch each other, they are "touching" electrically, so other than for some mounting reasons, don't see why they couldn't "touch" physically. Remember the cooling requirement though. A heat build up isn't good for the amplifier or the radio.

A 'quick disconnect' has two requirements. It has to provide a fairly fast way to disconnect things, and it has to provide an adequate contact for whatever you use the thing on. If your quick-connector can do those things it ought'a work fine. It may not be all that easy to hook up, which would depend on how the thing is made and for what purpose it was made for to start with. (It also sort of depends on what your 'tech' is familiar with, you know?) That may be where the question of the size of the power line comes in, the #12 and #8.
Have fun and good luck.
- 'Doc

Thank U both for this informative data. Do appreiciate it alot. as for question 2 You see there is a connection FROM the battery terminal That connects to the fuse box By a Vinyl Ring Terminal(connection with a circle in it) & is held in place by a hex nut. By tapping in @ these spot in a sence I'm bypassing the fuse box and going directly to the battery; I think? :?

The 3rd Q. well the space is triangled shape with an openning only as big as I would saay 2 radios stacked on top of one another. If need be the adjacent side can be left open while the linear is in use. The alternative would be to set the Linear on the dashboard; Making the Quick disconnect a must. As for them not touching one another, I was told that if they are touching metal casing to metal casing Any stray voltage/watts/current can possiblly fry any & all circuits.

That being said that is why I'm also wonderign what would be a good ground for the NEG- In both that on top of the radio & the dashboard setup.

 

[W5LZ]

gohusan,
The power thingy. By-passing the fuse panel means that you are still using the same line that the panel is using. If that line is large enough to handle the current used both by the things in the panel and your radio set up, fine. If it isn't large enough, then you'll need a another line to the battery. (You see where I'm going with this? It really isn't the fuse panel, as such, it's the line supplying the fuse panel.)

The reason you were given to not let the two touch each other sounds like the advice giver isn't exactly an electronics genius (neither am I for that matter!), or has little experience with radios/amplifiers/etc. With out upsetting him too much, I think I'd see about getting other advice. (And that's what you're doing here, isn't it? Forget I said that.)

The places you have to put things is limited, I know. All I can say is that you have to make do with what you have available in the best way you can. The 'on the dash' isn't exactly the best place in the world for a couple of reasons. Whatever it is can be seen, and the dash does get hot from sun light. Of the two, the first is probably the most 'dangerous' cuz it might "disappear" some day (nicest way I can think of to say some @#$ will steal it - lol). I guess the 'where you put it' is up to you, since I have no idea what to tell you.

Best grounding for power is a close place that provides a good return to the battery. That should be at least be the equivalent of that #8 wire as far as conductivity goes. Where are other things grounded? Body of the truck cab? That ought to work for the radio/amplifier too. The truck's frame is usually one of the options. Mainly because the cab might be fibreglass, or whatever, which makes for a very lousy ground of any kind - lol. Having to run a separate ground wire to the battery for the radio/amplifier is honestly the exception, not the rule.
- 'Doc

 

[lords]

very well stated Doc

ya don't do the dash(if your going to do that just give it away) :shock:

idea to keep it cool :twisted:
12 foot jumper run it in the front of the truck inbetween the rad and the frame ...never have to pull it wont be seen and it will keep cool at nice speeds...also needs a bug screen to cover it
LoL ...I really don't hope he tries that...just stating a bad fact
like putting it on the dash...then going to eat at a truck stop
and bingo ,its a goner :idea:

 

[gohusan]

OH NO WAY I'm leaving that puppy on the dash while I'm out (hence the quick disconnect) AS for it getting hot; I work night's between the times of 5:30 pm to 5-7am & I would not turn it on till after sunset. As for the power connection I will have to see what kind of wiring is in the truck. However How would I be able to determine what is acceptable. What would classify as having to run wiring to the battery
I guess if I have to run wiring to the battery I would do the same to the neg-. Thanx again fellas.

P.S. The advice about not letting the 2 touch each other was from a friend who knows very little or limited knowledge of radios so no worries. See that IS why I come here, very good advice. You know what they say; "If not satisfied with prognosis seek advice from a second DOC".


P.s.s. you were right my bad they were not 2x457; but were 2x454's. MRF454 rated @ 80watts