11 replies to this topic

[SCorpion]

i am setting up an SQ car and have some old skool Class A amps.

now im only new to understanding how these sort of amps work. BUT. it has occured to me that they have similar distortion levels to a class AB for lower frequency but at frequency's above 6kHz they have the potential to be significantly better than the class AB.

my question is that if i run my tweeters off the class A amps and say use a class AB amp for the mid bass drivers (ill be running the 3-ways bi-amped at least) will their be phase issues? and if there is will i be able to rectify this using TA?

i think i may have answered my own question but ill still put it to u.

thx.

if this doesnt make sense just yell and ill see if i can write the post up a bit better

[s_tim_ulate]

You wont have any 'phase' issues... You could use class D amps and not have any phase issues.

You will have phase issues if you mess up your polarity but this can occur on any amp. (eg +'ve and -'ve swapped around)

The class of the amp wont affect this though.

Is this what you were after? Or did you want to know whether the additional distortion through half of your setup will affect the SQ noticeably?

[Immo_G]

This is actually less of an issue because i'm yet to see a Class A car amplifier, best I've seen was Tru Techs A class, which is class AB with a class A region to about 18 wrms.

[mick66]

wow class A amps for car use, there's a nice oxymoron. The heatsinks would be 3 times the size of the actual amp! Just kidding. Just out of curiosity what brand are they SCorpion?

[SCorpion]

im not totally sure how 'true' Class A they are. i haven't got the manuals for them. i HOPE my uncle still has them so i can figure it out. i opened one of em up the other day and there is bugger all circuitry in them. the heat sinks are pretty big for wat they are. normal daily listening my uncle said he couldnt touch them. the heat sink even singed the carpet on his sub box.

these amps were purchased for 4 grand back in 1991 and had to be imported. as far as we can figure it out only 4 ever hit australian shores. they are JVC digifine amps. my uncle used to win SQ comps bak in the early 90's with em.

i cant think of any possible issues except for power supply. i think i can overcome this with the dual battery, bigger alternator setup. can neone else think of any possible issues?

[Kev]

Dammit, I'm waiting for someone to either go meh digifine or OMGZ digifine.... um there crap sell them to me

[SCorpion]

i just wanna hook em up to my rainbows and morels. LOL.

[supa-roo]

virtualy all Class AB amps will run class A for a few watts, and alot of places just bais there amps higher so they stay in class-a region for longer, then try flog them off as class A
but for a car, it aint worth it, that whole at most 25% efficiency aint all that worth it. in a car

[Pulse-R]

class A amp can be good or bad

good - cleaner sound
bad - more power at low volume

as for phase issues, you might find that the phase linearity of the class A and AB amps are different, but this will make only a small difference in the car environment.

much harder is to stop the inside of the car from resonating at 30 or more different frequencies, and resonance is much more noticable than phase distortion or phase linearity.

[supa-roo]

more power at low volume?
there constant current, so they drain the same power no matter the volume.

[SCorpion]

yer. im only integrating them into my system coz my uncle gave em to me and he was really excited about my system. so i thought. why the hell not use em. he'll get a kick and ill get some great amps for nothing!!

Thanks Pulse-R. its a pretty tough topic to discuss as it really goes into the circuitry of amps. i was unsure as to whether the linearity was going to cause a problem.

besides. the total draw of the amp isnt going to be significant wen compared to the whole system. my front stage alone comes in at 1000wrms.

but anyway I was thinking of either:

A) run all my tweeters off the amp if i go fully active setup

or

B) just run the center channel and rears off em wen using 5.1.