Has anyone ever used a a brand name "Crossfire" brand of Car Amp? I'm looking into a Crossfire VR 705D for my Century wagon, AL.
i have installed several crossfire amps in the past for local guys. they have all been excellent sounding and totally reliable i dont think you would regret buying it. they have honest power ratings and run pretty cool. shop around and you will find that you can really get some bang for the buck.
Crossfire Yuk, Thanks for the reply!! A installer turned me on to this brand and I've never heard of it till now. I feel better now about this. Thanks AL. :beer
I have installed 1 and heard several more. All were class d amps that sounded good. Great bang for the buck. Their subs perform well for the money too. Hard to find a good amp these days with all being made over seas. You will like them.
ppi, mtx, xtant, soundstream and others are made in the US. ... kicker has some that are made in OK i think. class d amps are used for subwoofer use. class d does not work well for higher frequencies. car audio GURU :Smarty: grizz archer wrote this ... about class d amps. "I have heard many, ridiculous definitions for class D topologies. I’ve heard people say, of course, that D stands for digital or even that the class is like a report card grade; A is the best type of amp, B is the second best, and so forth. These people must not know that topologies go far beyond the F grade... Actually, D just means 4. A was the first type of amp recognized by the IEEE, a group of professional electronic engineers. B was second, C was third, D was fourth, blah blah blah blah... Truth is, there is no such thing as a digital (audio) amplifier! If digital information is written in 1s and 0s, then what would a digital amp do? That’s right, make big ones and zeros ; ) Class D technology is growing in the 12 Volt industry. There are a few companies producing these amps and I suspect a few more companies will jump on the wagon for good reasons. The main reason is for dramatically increased efficiency. This is done by "Switching" and is therefore a "switching amplifier" as compared to a non-switching amplifier like a class A amplifier. A class D amp can be more than 80% efficient while a Class A/B (which most amps are) will fall into the 50-60% range. Let’s say we have two identical vehicles and we are going to put a class A/B sub amp into one of the vehicles and a class D into the other. Both amps, for comparison put out 1,000 watts RMS with 12 Volts. The vehicle with the class A/B amp will draw approximately 160 amperes of current and , being 50% efficient, will put out 1,000 watts of heat into the heat sink! Bummer, huh! The class D amp will only draw around 98 amperes to yield the same 1,000 watts RMS output. Not only will your vehicle like you better for not draining the power supply, but the amp will like you better as well because now you will only produce about 175 watts of heat into the class D heatsink! For you tweakers, that’s 40% less current draw and 82% less heat for the heatsink dissipate... Class D is great for bigger sub amps only as the benefits do not outweigh the cost for a smaller amp. So, why don't people make a class D amp to play 20Hz to 20kHz?! Not a simple answer, but here goes... The audio signal is used to modulate the shape of the square-looking waves of high frequencies. Then the high frequencies are eliminated, leaving audio output. The type of modulation used is called Pulse-width Modulation, or PWM. PWM, like the power supply in many car audio amps is used. Truth is, a PWM power supply as an amp that has DC output only. If you want to play 20kHz you would have to have the output devices switch at hundreds of kHz which almost reaches the AM radio frequencies. You see, the Pulse Width Modulated (PWM) wave frequency must be a lot higher than the desired playing frequency. To play 500Hz, we only need to switch at a frequency around 60kHz. In summation, class D amps put out more power and less heat with less current consumption. But as for now, they are only beneficial as larger subwoofer amplifiers."
About the classes of amps- it all has to do with how long the output devices conduct. Class A- output devices conduct 100% of the time. THis means about a 20% efficiency, but the best sound. If you research the best audio components for home use, you will find that many of them use class A output stages (and are able to heat the room quite well because of it). Check out passlabs equipment as an example. Class AB- output devices conduct somewhat more than 50% of the time, and less than 100% of the time. This means that pairs of devices alternate to produce the complete wave. One produces the + peaks, and one produces the - peaks of the music waveform. In AB, they conduct slightly more, so they overlap somewhat to reduce switching distortion. The more they are biased towards the class A side, generally the better it sounds, but the less efficient the amp will be. Class B- each device conducts approx. 50% of the time. More efficient, but careful attention has to be payed to the amp circuitry to make sure the switching is exact. Class G, H, etc.- usually means an AB amp with supply voltages that shift. Not very often used- more of a mid 70's early 80's japanese home stereo thing. Class D, as described above, is a switching amp. High frequency pulses approximate the sign wave. Using filtering gives you the sign wave with the pulses removed. Neat efficient technology, but not as musical as class A, AB. Good for subs. It has been improved quite a bit lately, and the high frequency response is much improved from older class D technology. ________ Marijuana Vaporizer
Crossfire WOW!!! :eek2: you guys are on the ball!!! :Smarty: !!! Has any one had any feedback on the V12 Alpine Amps like the MRV-F450 ? AL.
There's a company putting out a class "T" amp which is a class D with some sophisticated electronic wizardry to fix the musicality problems. Currently there is 1 in dash radio that uses this amp. It has 60 watts RMS (not peak!). If these amps live up to the hype external amps wouldn't be required for great sound.
i really like Alpines head units and changers and some of their processors but i never was a big fan of alpines amps..... their amps never were known for impressive power of better than average features ...BUT!!, when they started the V12 series, alot of that improved. i have a few friends with V12 amps and nobody seems to have any complaints. i like and have used Crutchfield(blue series), PPI, MTX, Soundstream, Alphasonik, and many others .... the only amps i have been dissatisfied with was the MTX and Alphasonik for realiability problems. the Soundstreams that i had never seemed to have much power even though they were rated to have it. i used Autotek (2 800Xi and 2 200Xi) amps early in my last car and they were pretty good. i ended up selling one of the 800s and using a single one bridged with 2 kicker S10A 10 inch 4ohm subs running off of it. although it was a 1 ohm load, the amp really pushed them well. i switched to JL amps before i sold the car. the JL 300/2 (class A/B) and 500/1 (class D) were my amps of choice. the 500/1 is a cool amp that has some great/useful features built right in. my next car(74 lesabre vert) has a Blaupunkt V7000 amp. 380 watts into 7 channels ...plus an Audio Control System 90 Model 11 powered (27@4X1 or 52@2X1 watts)center channel processor. i have not done any installation as of yet.
Thought I'd point out that the only true way to rate a power amp is in RMS wattage. Peak wattage is a marketing term and doesn't mean much of anything. RMS wattage into a load is the (peak output voltage times .707) squared divided by the load resistance (assuming it can deliver the required current, which isn't always the case). The only time peak wattage comes into play is how much headroom a class AB or B amp has. Sometimes the power supplies are designed so that they won't immediately lose voltage (sag) on a transient, and the amp can deliver more than it's rated wattage for a very brief instant (milli or micro seconds). Obviously, a loud sustained musical peak is going to exceed that time, so RMS wattage is the meaningful figure to watch. Music that has sustained levels will demand a lot from the amp. Metal and industrial come to mind. Interestingly, these type of musics seem to have as much content in the upper octaves as they do in the lower, which is not the case with acoustic recordings (where the break even point comes at around 350Hz- meaning that the amount of musical energy in the range of 20-350hz and 350hz to 20Khz is equal). Another thing to note is that to properly produce a 20Khz sine wave, you need the amp's bandwidth to extend out to 100Khz. If the high frequencies are rolled off before this point, there will be audible consequences in the upper treble. A lot more than you wanted to know, maybe. ________ Cleaning iolite vaporizer
Lots of good info.... Never used Crossfire myself, but have heard them & they sound good. Allways stuck to "Linear Power" amps myself, car I bought has an Eclipse amp & Sub that sound real nice for smaller units. Don't have that kind of cash to play with loud systems anymore (not to mention being deaf in my right ear because of one)... so I stick to nice.... respectable systems. Let us know how it works out for ya if you try it... allways looking for good, clean, cheap power...lol.
Good to see some stereo people on here at last. No mention of class X amps. As far as I know, a class X is a class D with a digital power supply. I have run 3 class X amps on subs and was pleased. Class D sounds like something is missing in the bass to me. I never liked the sound. Class X sounds a little more like the old AB sub amps. They are very efficient too. I went out on a limb a couple of years back and purchased 2 class X Visonik amps which turned out to be awesome for the money. They outperformed others I had played with like: Memphis, Rockford and the smaller Mmats. As mentioned above, X and D amps are currently for bass. They work well for competition amps because they don't draw much current compared to AB and especially A amps. Power wire for them is smaller, cheaper and easier to run. But, they will not win any SQ competitions. I competed in the late 80's and early 90's with class AB amps. I really miss the sound of them. They were huge, drew insane amounts of current and got hot, but they sounded awesome! I mainly used Hifonics VI and VII amps back then. They were built by Zed Audio which also made some Autotek, Lanzar, Rodek and ESX amps. If you can find any of those amps or any old Rockford amps, you will be pleased. Someone above mentioned Linear Power amps. They were very good sound quality amps, and still sound good today. Other good sound quality amps are: Mcintosh, Zapco, Brax and Audison. You can used these good amps on the small speakers (high freq.) and then use a big amp for the subs. Long gone are those days when I craved the huge thump. A little bass is good, but I want a balanced sound now. I have a small collection of some old amps. May post a couple of pics of the huge ones for some of you to get a laugh at.
Never heard of class X. I'll have to check that out! Any car amp that has more than about 18 watts of power will have a switching supply. What is the difference between a switching supply and a digital supply? ________ Medigap forum
Alpine CDA-D855 I need to find someone that is knowledgable on the Alpine CDA-D855 DIN in a half head units. My whole system is Alpine and want to hook up my XM tuner to the Ai-Net connection.
Alpine XM OK, here is what I got, CDA-D855 head unit, TUA-T020XM tuner, and a CRA-1667RF changer/XM Radio Controller. I've been told that my head unit is not XM ready but does have a Ai-Net port in the rear of the set. Has any one did a install like this? AL.
i'm here ... just been gettin ready for 40+ christmas guests... i have no experience with the alpine sat radio systems ... i helped my cousin put his pioneer sat system in and it would have been almost impossible to mess up any of the connections. im sure the alpine is thought out just as well. have you looked at the plugs close enough to see if there is only one way it can all be hooked up? surley you have some stereo buds around with some experience...
Alpine XM Yuk, thanks for your reply!!! :TU: As far as connections that is not a issue because of my electrical back ground. The issue is the switching part of the amp interfacing the XM part as a "aux" post as Alpine calls it Ai-Net. Alpine started the receiver line with the Ai-Net port for there CD changer first them came XM the the later Alpine units came XM ready and didn't require a separate interface adaptor to use a XM tuner. I'm very fussy on apperance and will not install a single Din in the place of a Din in a half. I love my Alpine CDA-D855 head unit but is not XM ready but does have a Ai-Net port. I posted a pix of the rear of the receiver to show the connections, the Ai-Net is a no brainer but there is another port that is related to the CD changer option and I'm woundering if this is needed to trigger the "aux" at the A-Net port on is this for something else. This unit over 4 years old and plan to keep it because of it versitillity, performance and its great factory install apperance. I guess I need to do more reading but I've been told this will work on XM not using FM modulation. AL.
