| Author |
Message |
    
Moonraker
Intermediate Member
Username: Moonraker
Post Number: 255
Registered: 3-2005
| | Posted on Sunday, July 11, 2010 - 11:44 pm: | 
|
Hey everybody I took a break from the radio so it's been a while. I'm looking into getting an 8 transistor competition amp for the mobile and can't decide what to do.
My first thought was to get a straight 8 transistor (2879's) and drive it with my galaxy 95t. I would really like keep using the s9 and am thinking about a 2x8 comp amp. I'm just not sure if the s9 will be too much for the 2 driving transistors.If I do go with the 2x8 would I be better off with 2290's or 2879's for driving transistors?
My truck has a 136 amp alternator and 2 750cca batteries. Would I need to upgrade the alternator before I even think about an 8 pill? |
Dale
Senior Member
Username: Dale
Post Number: 1615
Registered: 12-2002
| | Posted on Monday, July 12, 2010 - 7:10 pm: |
|
imho you,d be better with the 95t and straight 8
the s9 would be pushing the 2x8to the limit id think. id perfer a straight 8 any day over
one with a driver
dale/a.k.a.hotrod
cef426
cvc#64
|
Moonraker
Intermediate Member
Username: Moonraker
Post Number: 256
Registered: 3-2005
| | Posted on Tuesday, July 13, 2010 - 12:31 am: |
|
Thanks Dale. I don't have a lot personal experience with amplifiers and wanted to get some opinions before I open a potential can of worms. |
Moonraker
Intermediate Member
Username: Moonraker
Post Number: 257
Registered: 3-2005
| | Posted on Sunday, July 18, 2010 - 5:40 pm: |
|
No one else has any input? If I were to use a single final radio would there any benefits to an amp with a built in driver or is a straight 8 with a separate driver the better way to go? |
Charliebrown
Member
Username: Charliebrown
Post Number: 78
Registered: 10-2002
| | Posted on Tuesday, July 20, 2010 - 6:00 pm: |
|
The amps needed for the truck + all the amps needed for the cb amp and the radio you always need to go at least 25% bigger on the alternator amps. If the cb amp pulls 125 amps and the radio pulls 30 amps then you have already maxed you truck amp. This is still not counting on the lights , fan, air condition, or the other accessories on your vehicle. If I were in your place I would go no less than 175 amp altrenator. The bigger it is the easer it will be on the alternator. It will also help all your cb accessories as well. You might even consider a 200 amp alternator in case you ever go with a bigger cb amp. ASK ONE OF THE TECHS AND YOU WILL MOST LIKELY BE TOLD THE SAME. You might also add another battery with the bigger alternator. Some might say this is over kill but, would you run low power into your home with the risk of damage to your electronics? I hope this will you help with your question about your alternator. |
Dale
Senior Member
Username: Dale
Post Number: 1618
Registered: 12-2002
| | Posted on Tuesday, July 20, 2010 - 9:47 pm: |
|
moonraker here hope this helps
single final radio 148,grant=texas star 667v
dual final under 50 watts 2950=ts 350v
dual final 50 watts plus= ts 500v
radio w/ built in amp= straight 6-8 pill
basically if ya have a low power radio im talking 4-12 watts you,ll need a amp with a driver like 2x4. a low power radio wont drive
a stright 4 much less a straight 8.you can also use a 1pill or 2 pill with a low power radio.then use that to drive a straight 4 pill.
for the magum s9 you CAN use the texas star 500v
just dont key more than 2 watts into it.
i was asleep on first post..lol. give me more
info on exactly what your looking to run and mode i can help ya out more
dale/a.k.a.hotrod
cef426
cvc#64
|
Moonraker
Intermediate Member
Username: Moonraker
Post Number: 258
Registered: 3-2005
| | Posted on Tuesday, July 20, 2010 - 11:56 pm: |
|
I have the s9 and an xforce 400hd (4 2879's) and it is an awesome combination but I want more power. I only run AM so a class C amp will work for me. I want to upgrade to an 8 transistor competition amp (either davemade or xforce).
I have never owned an amp with a built in driver and really didn't know if they were prone to more problems than a setup with a separate driver. I wouldn't want to use my s9 on a 2-pill "commercial grade" amp like a texas star but wasn't sure if a class c amp with 2-2290 or 2-2879 drivers would handle it. I should have been more specific in my first post but didn't want to ramble on. |
Charliebrown
Member
Username: Charliebrown
Post Number: 79
Registered: 10-2002
| | Posted on Wednesday, July 21, 2010 - 11:37 am: |
|
MOONRAKER, Always make sure you have a more than enough power to supply you cb amp needs. No matter if it is a home or truck or if the cb amp has it own driver or a straight 8 pill. Too lower amps or volts will result in the power supply or alternator and the products you are running to over heat and fail. I also suggest to put a fan on any cb amp to keep them cool because with todays electronics the heat will shorten the life of the cb amp. I have not seen any problems with my straight 8 pill nor the 350 that has its own driver. I use to do wireing for electric motors and alternators and homes. I know the damage low power can do to anything that uses power no matter if it is AC or DC it is still a factor in all electronics. If you use only a low watt cb a amp with a driver it will work fine. I use the straight 8 pill amp on my high power radios and it will work fine for you as well. I did not mean to ramble on but, I would like to offer what I know so money would not be wasted in lost cbs or amps and you will get more joy and watts for your effort. |
Dale
Senior Member
Username: Dale
Post Number: 1621
Registered: 12-2002
| | Posted on Wednesday, July 21, 2010 - 7:04 pm: |
|
i agree with charilebrown. my only question is
your a am only guy?but using a magnum s9??????
i dont know if a 2 pill class c amp will handle
the magnum or not.but you could add a straight 8
pill to your current set up,using the 4 pill xforce as the driver.or buy a connex 4600 turbo
and hookup a striaght 8 pill up to it.[what id probaly do.]basically any amp with a built in driver isnt going to work long.could use a cobra 29 or uniden 78 and buy a amp with a driver 2x8. this would be the simplest way..imho
dale/a.k.a.hotrod
cef426
cvc#64
|
Moonraker
Intermediate Member
Username: Moonraker
Post Number: 259
Registered: 3-2005
| | Posted on Wednesday, July 21, 2010 - 10:27 pm: |
|
I used to use sideband and the upper and lower channels back when I bought the s9 but most of the locals seem to have given up the hobby, got their ham ticket, died or moved away and the ones that are left are on am.
I am worried about excessive amp draw. This is another reason I would rather have a class C than an AB biased amp. Xforce says their 2x8 draws 80 amps continuous and 180 amps max. This is the spec they give for their straight 8 and 2x8 so I'm not sure how accurate that is.
It will definitely have a couple of fans on it and I'll keep an eye on the voltage. I was hoping the dual batteries might compensate for the peaks. My truck is diesel so I won't have an ignition system drawing current and the intake heater won't be draining the batteries once I'm rolling down the road...maybe that's just wishful thinking. Thanks again guys. |
Dale
Senior Member
Username: Dale
Post Number: 1655
Registered: 12-2002
| | Posted on Wednesday, November 17, 2010 - 8:22 pm: |
|
hey moonranker its been a while now have you
gotten something going?if so what u get?
i am too thinking about going with either
a 2x4 or 2x8.
dale/a.k.a.hotrod
cef426
cvc#64
|
Moonraker
Intermediate Member
Username: Moonraker
Post Number: 263
Registered: 3-2005
| | Posted on Thursday, November 18, 2010 - 8:23 pm: |
|
I went with a straight 8 fatboy. I've been using the 95t and getting a 400dk and about 1200pep on AM and 1500pep on ssb. I found an old grant XL last week and just bought a Texas star 250 from copper for a driver so I'll get to see how that works this weekend.
It doesn't use as many amps as I thought it would...maybe the 180 amps only applies to running it at 15 volts and driving to the limit. I tested it with a clamp on amp meter and got a max amp draw of 103 amps from the radio and the amp on ssb. I can't remember the amp draw on am but want to say around 80 max. I'm just not sure how accurate a clamp on amp meter is when RF is involved.
I'm sure the amp draw will go up with the grant and the 250 since the grant actually has forward rms swing and the galaxy does not. Right now my rms power swings backward with modulation.  |
Audiophile73
Intermediate Member
Username: Audiophile73
Post Number: 161
Registered: 5-2004
| | Posted on Monday, January 17, 2011 - 12:21 am: |
|
If your RMS wattage swings backwards you have a problem. Have you checked your SWR before you fired that amp up? Those clamp amp meters are pretty rock solid. Huge amp man, crazy, but good crazy. Ground the heck out of everything. I would run at least two 4 gauge ground wires from your - battery terminal to the frame of your truck. Have fun. |
Moonraker
Intermediate Member
Username: Moonraker
Post Number: 268
Registered: 3-2005
| | Posted on Tuesday, January 18, 2011 - 11:22 pm: |
|
A different radio with an external driver has it all working like it should. The swr is well under 1.5 with the amp on or off. I have everything grounded...I learned about rf burns back when I was a younger mud duck. The galaxy sounded great with the amp behind it but was just not up to par.
I put the 95t back on the base. It works great on its own. |
