linear constant beta upto icmax bjt for audio output stages

[mastertech]

Do you guys know any good linear power bjt complementary pairs above conventional types
that have constant beta up to Ic max for use in hifi low distortion
audio power amps output stages and dont cost much

 

[Nigel Goodwin]

Re: linear constant beta upto icmax bjt for audio output sta

Do you guys know any good linear power bjt complementary pairs above conventional types
that have constant beta up to Ic max for use in hifi low distortion
audio power amps output stages and dont cost much

No transistors have 'constant beta', they all change under different voltage and current conditions. The low distortion of an audio amplifier is more down to good design, rather than the individual transistors used.

What power amplifier are you looking to build?.

 

[SteveM]

I used MJ15022 and MJ15025's for my HiFi amp which work fine. Most transistors will depending you select them for maximum collector current and collector-emitter volts and power dissipation ofcourse. The rest is down to careful circuit design. I'm in the process of writing up my experiences of building a simple HiFi amp at www.circuithut.com

Cheers

Steve M

 

[mastertech]

Nigel Goodwin:
No transistors have 'constant beta', they all change under different voltage and current conditions. The low distortion of an audio amplifier is more down to good design, rather than the individual transistors used.
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first i thank you for your input
yes youre right,not exactly constant,but close, ive used the term there
loosely,there are a few types by toshiba that their beta on 100% scale
falls down to to about 88% and this roll off
is near the Icmax region and the graph looks constant for the most part
this kind of linearity in devices yields very low distortion in the output
stage where distortion becomes critical, good design is about conventional
design that performs satisfactorily, i am concern with design that performs
above conventional design even though most improvements may be
inaudible to the ear this class of design is all about true hifi

 

[mastertech]

stevem thanks
many motorola types have made into amplifiers claiming low distortion
you dont make any mention of this pair specification
i thank you again for letting me know of them

 

[Russlk]

Linearity is obtained by using negative feedback. The minor improvement by using more linear output transistors would not be perceived by the most discerning listener. Moreover, some hi-fi enthusiasts like tube amps because of the distortion!

 

[mastertech]

my amps i call precision instruments, even though many improvements may not be perceptive by the human ear as they are by test instruments and that doesnt mean
you shouldnt aim for even more precision and cleaner operation, to give you
an analogy, a ferrary has the potential for speed but is rarely used
at that potential,yes conventional design is all about negative feedback and the linearity and stability and many other benefits a circuit gets
from it, moreover negative feedback alone doesnt make precision instruments like my amps, to give you an example
linear loads, 0 phase shifts,0 thd,ps ripple rejection, circuit topology,ground loops,
advanced small signal techniques,symmetry,device charactiristics,circuit charactiristics,load stability,hf stability,thermal protection,etc
these issues and plus many others i use in my precision instruments are
rarely used in consumer electronics even by companies claiming
hifi operation instead they use money making philosophies like
conventional design,low power,gold connectors,oxygen free cables,pleasing casing,and the amps come with 10% thd at maximum output and subjective listening, to the ear all this adds up to another perception of what a hifi amp should be but actually isnt