True Class A amplifiers

[AAAAAAA 10+ year member]

I remember there being some compagnies that made true class A amplifiers for cars, any one know the name or have a link to the web site(s).

Tanks.

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[Rich B 5,000+ posts]

Soundstream is the only one I can think of right now.

Theres several on ebay at decent prices.

 

[AAAAAAA 10+ year member]

^ Sound stream built amps that said class A, but they waren't true class A. None of them were as far as I am concerned.

 

[squeak9798 5,000+ posts]

http://www.hssfidelity.it/english/Main_page.html

Only pure class A I'm aware of.

Rest of the typical "class A" amps are all high biased A/B's (or in some cases simply labeled "class A" by the marketing department).

 

[2critical 10+ year member]

Check out the Critical Mass websitehttp://criticalmassaudio.com

 

[Zpeedy McLovin]

the only class a that are worth the price are helix and tru tech i think audison has one

http://www.audiotec-fischer.com/102.html?&L=1

 

[CrazedCat 10+ year member]

I believe Sinfoni makes Class A

 

[shiipseki 10+ year member]

I believe genesis has class A amps

 

[AAAAAAA 10+ year member]

the only class a that are worth the price are helix and tru tech i think audison has one

http://www.audiotec-fischer.com/102.html?&L=1

I dout any of those are true class A, not with there rated power. Seems impossible to me. no?

 

[squeak9798 5,000+ posts]

I dout any of those are true class A, not with there rated power. Seems impossible to me. no?

Indeed.

I don't believe any of the amplifier's mentioned other than the HSS are true, pure class A on the outputs for their entire power range.

There are NO solid state, pure 100% class A amplifiers on the 12V market.

The Tru is just a high biased class A/B. The Genesis DMA is a high biased class A/B also. Sinfoni's are class A/B, as are Audisons.

Helix doesn't even offer a high biased A/B's that I can think of off hand. Nor Critical Mass.

I do believe the ONLY 100% pure class A, that never switches out of class A operation, is the HSS HT230

 

[req 5,000+ posts]

squeak 10, noobx 0.

 

[GlasSman#1 10+ year member]

They're all Class A up to 15 watts or so then switch to Class A/B.

If it's pure Class A it doesn't put out more than 20 or 30 watts.

Pure Class A is too ineffiecient for a 12 volt system.

 

[squeak9798 5,000+ posts]

They're all Class A up to 15 watts or so then switch to Class A/B.

Not all are class A up to 15w. Most cut out of class A operation well before that.

The previously mentioned high-baised class A/B amps may give you 15-25w in class A operation......but those aren't "most" class A/B's.

Though this spec has sort of went by the wayside (and could be overstated by wise manufacturers even if it is given)....the easy way to tell class A operation is to look at the idle current spec.

http://www.carsound.com/artman2/publish/spkrsandsubs/JL_Audio_E6450_268.shtml

(first one I could find with an idle current measurement listed)

Idle current draw of 1.9A

Under IDEAL conditions, 14.4V supply voltage and 25% efficiency (maximum for class A operation), it would generate 6.84w in class A operation. Being a 6 channel amplifier, that equates to about 1w per channel before switching out of class A operation........

That type of idle current draw/power output is more representative of the masses of class A/B's than the high biased 15w+ variety.......

 

[thch 10+ year member]

A classically designed class A amplifier will draw at least as much power as is required by full loading of the amplifier. eg, for a 100W amplifier, the class A amp draws 200W at idle (200W is the peak power of a 100W avg amplifier).

Keep in mind that a class H amplifier refers to a PSU modification to an amplifier. So a class A amp might have a tracking PSU (class H design) and might still be called a class A design.