Premier Class-A Amps

[Dr. Dan 10+ year member]

Anyone have any experience with the Premier class A models?

such as the:

Premier GM-X1024

ODR RS-A2

Some of the specs look great...very low thd, and high S/N ratio.

I know Premier amps are highly underrated, but are these true class A SQ for cheapo prices?

Click to read more...

 

[flakko 5,000+ posts]

how much power do they put out? you can ususally tell if they are true class a through the wattage.

 

[3.5Max6spd 10+ year member]

very few TRUE class A amps out there, and those are not them...

The likely are the the classA-class A/b bias designs alot of companies put out..

 

[Dr. Dan 10+ year member]

Various wattages Flakko, I've seen 50-100 rms.

I believe in purest defintion of class-a, it would have to be an all tube amp. I do own a tube guitar amp that's true class A. Sounds like heaven.

But from what I know, the old soundstream class-a amps are basically what you mentioned 3.5Max6spd.

This is my rudimentry understanding of it:

The amp is actually divided in 2 halves, each side taking turns in putting out the juice. In a class-a amp, each side "ramps" up before it's active, yeilding a smooth transition when switched and therefore better sound quality.

Non class-a amps instead, just switch fully on and off, almost in a square wave type pattern. When the amp switches internally, this sudden transition results in a colder or harsher tone.

Don't hold me to this though, I use this stuff a whole lot more than I engineer it : )

 

[thch 10+ year member]

Various wattages Flakko, I've seen 50-100 rms.I believe in purest defintion of class-a, it would have to be an all tube amp. I do own a tube guitar amp that's true class A. Sounds like heaven.

But from what I know, the old soundstream class-a amps are basically what you mentioned 3.5Max6spd.

This is my rudimentry understanding of it:

The amp is actually divided in 2 halves, each side taking turns in putting out the juice. In a class-a amp, each side "ramps" up before it's active, yeilding a smooth transition when switched and therefore better sound quality.

Non class-a amps instead, just switch fully on and off, almost in a square wave type pattern. When the amp switches internally, this sudden transition results in a colder or harsher tone.

Don't hold me to this though, I use this stuff a whole lot more than I engineer it : )

no need for tubes. you could use any technology applicable, even down to mag-amps (rare devices).

discription is a bit off. in class A, devices never switch. basically one device always fights the other, stronger, device. one transistor might always pull 1A. the other will push 0 to 2A. if it pushes 1, then the other pulls that 1, meaning 0A output. if the device pushes 2A, the other only pulls off 1, meaning 1A out. device pushes 0A, other pulls 1A, thus -1A.

in class B or AB you allows the devices to switch. in class AB you change the abrupt "switch" seen in class B to a gradual handoff by letting the transistors operate in class A near this crossing region.

"Class A Circuitry"

note that in any amplifier design, the vast majority of the amplifier is class A biased, at low currents. you're input stage, voltage amplification stage, and driver stage can all be class A biased. further, you could class A bias the opamps in the crossover section. this statement is a bit ambigous becasue it doesn't say if all or just some class A circuitry is used.

given the amp is listed as 1ohm stable, and is fairly small, i'd assume the output stages are all class AB.

 

[JimJ 5,000+ posts]

The amp is actually divided in 2 halves, each side taking turns in putting out the juice. In a class-a amp, each side "ramps" up before it's active, yeilding a smooth transition when switched and therefore better sound quality.

Not all Class A amps use two active devices per channel. Single ended amps use one device per channel.

Nelson Pass (http://www.passdiy.com) built several excellent single-ended MOSFET amps, single transistor per channel, always-on. Nice little amps.

 

[squeak9798 5,000+ posts]

Best way to tell if it's a true Class A output amp is by it's idle current draw. They'll draw full current at idle....

Though I'm not really sure of the appeal for true class A amps in car audio. Low efficiency (

 

[Dr. Dan 10+ year member]

Wow, great responses.

It's very tempting to always try to get top shelf gear, but in this case I'm starting to think that some of the trade-offs might not be worth it.

The noise floor in car audio, particularly in my ride at the moment, is just too high to probably truely enjoy a class-a amp. I'll come back to this idea when every last rattle and squeak is dead and my power situation is nice and stout.

Although, In an active setup, I'd love to compare a class-a and a/b amp for tweeter duty. You'd be able to get away with a lower watt/draw setup just running those.

And glassy, shimmery treble is what I've been most impressed with in the class-a amps I've heard so far.

 

[squeak9798 5,000+ posts]

Although, In an active setup, I'd love to compare a class-a and a/b amp for tweeter duty.

In all honesty, chances are highly likely you wouldn't hear a difference between them (assuming they are of the same power)....unless either amp was designed to intentionally alter the signal, in which case, I wouldn't want that amp in my system anyways.......who wants an amp that intentionally alters the sound reproduction? That's counterproductive to what we are trying to do.....

 

[thch 10+ year member]

note that you can force an amp into class A operation. adding a resistor or current source (transistor based) to the output stage (to the -Vee supply) is a simple mode to move the amp into class A operation. a 2ohm stable HC amp probably would work as a 8ohm or maybe 4ohm stable class A amp with this type of mod. you need to have a lot of heatsinking and current capabilities, which the 2ohm HC amps would have.

The CCS is always on, and prevents one of the output stage devices from conducting. this class A.

 

[flakko 5,000+ posts]

mmmmmm 2kw class A hehe

 

[squeak9798 5,000+ posts]

mmmmmm 2kw class A hehe

Yeah...and you would want to connect it directly to your city's power station for power //content.invisioncic.com/y282845/emoticons/crazy.gif.c13912c32de98515d3142759a824dae7.gif