This amplifier is distorting high frequency, some audio compression too. Know why?

[MikeB]

Hi thanh !
Yes, more feedback decreases DC-offset, but the amount of feedback
possible is limited by the fact that olbw needs to be "flat" for low tim.
As i use tripledarlingtonout the sound is already very powerful.
But the mainpoint is, matching devices is not only for low dc-offset,
it is mandatory for low distortions. So, if i have dc-offset, i know matching
is far from perfect. With "simple" matching i get dc-offset easily below
20mv, but lower is difficult due to thermal variations.

And, input-dc-offset can only be eliminated by matching devices, if
you have inputoffset, higher gain can even increase dc-offset !

Mike

[MikeB]

Hi carlos !

Have found some time for trying/evaluate my design ?
I did some more listeningtests, i still think it sounds excellent.
Now i will make some PCB for a nice stereoversion, only listening
mono does not reveal all weaknesses/strengths...

Mike

[thanh]

HI mikeb! I think offset voltage should be below 1mV
mikeb! I suppose "powerful sound" is not similar to "poweful bass "
and "soft sound " is not synonym with "smooth sound" .You can get "smooth sound" by decreasing noise but it can be annoying because distortion (or some magic reason)

[Workhorse]

CARLOS i am Waiting for ur list of mosfets?

ampman

[thanh]

cát-lót! Is "audio commpressing" means its sound is not plump?

[MikeB]

Originally posted by thanh
HI mikeb! I think offset voltage should be below 1mV
mikeb! I suppose "powerful sound" is not similar to "poweful bass "
and "soft sound " is not synonym with "smooth sound" .You can get "smooth sound" by decreasing noise but it can be annoying because distortion (or some magic reason)

Below 1mv ? Even commercial amps are above 1mv...
I'm satisfied with < 50mv. Then adding a dc-cap to the feedback
would give ~1mv

The "powerful sound" also makes strong deep sound, but the whole
sound get's more "intense", giving the feeling that the plays effortless.
Also you can hear the amp saying "gimme more !"
With "soft sound" i mean that the sound is not bright/harsh. I hate
"smooth sound", i want clear trebles. If i want smooth sound i can
still drop bandwidth below 16khz.
A good example are hihats and triangles, with "smooth sound" they
get lifeless, with bright/harsh sound they get annoying/distorted.
With good amp you can hear these absoulutely detailed, making
fun to hear them.

Mike

[thanh]

oh! mikeb! fun perhaps I will try to making a triple darlington O

[destroyer X]

I will stay with one of them..... you have the preference in the choice... and our friend "chucrute" will take care of the third one..... we will change her transistor.

hehe

Carlos