# Soundstream Class A experts ?



## azvrt (Nov 11, 2010)

Hi, I am building a system around old Soundstream Class A amplifiers.
The first Class A amplifier I had (and still have) was a DLS Genesis SA-50. I was surprised that such a small amplifier sounded better than my 10 million dollar Becker Energy 600 Limited. I am aware of the high bias thing and I am okay with that. To me they sound great and that's the most important.

I have never had a Soundstream amplifier until I read good things about them and purchased an old Class A 50 II amplifier several weeks ago. I will soon have two Reference Picasso's in my car and I just purchased a malfunctioning Reference 405, which we repaired and I am now selling, because it doesn't produce such emotional sound as the Class A's (it does sound very good though). I just purchased a Ref 300 for bass speakers.

I am wondering, does anyone have experience with some of these older class A models ?

How does the A100 II compare to the A50 II ? Does it just have more power or is there a sound quality difference ?
Same question for the A 6.0 and A 3.0.
Same question for the 10.0 and 6.0.
And how do the 6.0/3.0 compare to the A100 II/A50 II ?

Keep in mind I'll have so many amps in my small car that power is not much of a factor as each amp will work at a fraction of its potential and should perform within the bias thing most of the time.

The reason I ask is I am still looking around for more class A amps to finish my system, I have my eyes on a A100 II and a 3.0 in my country. Up till now I have only heard the DLS Genesis SA-50 and the SS A-50 II and while the SS sounds very good, the SA-50 sounds way better. The voices almost bring tears to my eyes with this amp. A person from Genesis confirmed that these amps were loosely based/inspired on the SS A-50, for the first series they even used SS heat sinks. My SA-50 is a series 2 ('94 - '97).


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## ace956 (Aug 28, 2009)

azvrt said:


> Hi, I am building a system around old Soundstream Class A amplifiers.
> The first Class A amplifier I had (and still have) was a DLS Genesis SA-50. I was surprised that such a small amplifier sounded better than my 10 million dollar Becker Energy 600 Limited. I am aware of the high bias thing and I am okay with that. To me they sound great and that's the most important.
> 
> I have never had a Soundstream amplifier until I read good things about them and purchased an old Class A 50 II amplifier several weeks ago. I will soon have two Reference Picasso's in my car and I just purchased a malfunctioning Reference 405, which we repaired and I am now selling, because it doesn't produce such emotional sound as the Class A's (it does sound very good though). I just purchased a Ref 300 for bass speakers.
> ...


azvrt,
Hello, Iam Wade Stewart the engineer that designed and manufactured all of the Soundstream amps from 1982 thru 1997. All of the early class A's that you mentioned and others were designed by me and manufactured in my factory. As far as sound quality they all use identical circuitry just more output devices as the power increases. I have a paragraph that explains how they work.

, I have a brief explanation of Class A. A real Class A design dissipates the maximum output all the time, a 200 watt Class A dissipates 200 watts at idle, very inefficient, That's why most amps are Class A/B. At Soundstream we had a special bias scheme designed into our Class A amps. Our Class A amps run in Class A for a percentage of the output signals, eliminating any possibility of crossover distortion, which all Class A/B amps have. Even Class G and H still have crossover distortion. Anyway, our Class A runs in Class A mode at low power where crossover occurs, average output power at listening level is only about 12%, this means that at normal listening levels the amp is always running Class A. At higher power levels it runs in Class A/B. The amplifiers runs a little warmer at idle but there maximum heat and output power is identical to the Class A/B design. The end result of all this is an amplifier that sounds much warmer and sweeter.
If you would like any other information feel free to contact me.
ace956, email: [email protected]


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## turbo5upra (Oct 3, 2008)

I have used ref. picasso, 5.0, 10.0 and rubicon Sleeping beauty, 10.0 and a maybe a few others.....I haven't noted a difference in tone on them,... although I will say they do sound very distinct compared to the normal blue's.


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## azvrt (Nov 11, 2010)

Thank you for your answers.
Mr. Stewart, I am sending you an email.


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