leadbelly said:And you can bias the LM3886 ten times that 500mA figure if you want.
5A?!
Remember, DC-offset on the output will greatly increase.
And I don't think the chip will handle that heavy biasing.
I did try once to bias a LM1875-based amp with resistors on the output.
If I remember, I went to around 600ma.
As I raised the biasing, the sound progressively lost clarity, detail.
Too smooooth and sleep-inducing for me.
No biasing for me.
At least with resistors.
leadbelly said:And you can bias the LM3886 ten times that 500mA figure if you want.
Hehehe. Well at that point one might as well go with the discrete single-ended buffer.
As I stated in my original post, the goal was to get sufficient single-ended performance for high efficiency speakers, while keeping the overall efficiency a bit more reasonable.
se
carlosfm said:
5A?!
Remember, DC-offset on the output will greatly increase.
And I don't think the chip will handle that heavy biasing.
I did try once to bias a LM1875-based amp with resistors on the output.
If I remember, I went to around 600ma.
As I raised the biasing, the sound progressively lost clarity, detail.
Too smooooth and sleep-inducing for me.
No biasing for me.
At least with resistors.
What sort of speakers were you using? What was their voltage sensitivity?
se
Steve Eddy said:
I was using my bench speakers, with Visaton FR10/8 fullranges +(super)tweeters.
Then I confirmed my findings on my main system, with Epos ES11.
Not very sensitive, 86~87db.
It may be that with very sensitive speakers the results would be slightly different, but I have my doubts...
.
carlosfm said:
Ok. Reason I asked is that I tried it a few years ago (though not with this specific circuit) and didn't care at all for the result when I used it with lower sensitivity speakers. But it was a whole other story when I tried it with some 100+ dB speakers.
In any case, it's simple enough to try it and just yank the resistor if it doesn't work out.
se
Steve Eddy said:
Yes, of course.
For who has ultra-sensitive speakers, it's worth to try it out.
With moderate (normal) size heatsinks I wouldn't pass 500ma.
And a regulated PSU should be used.
Otherwise, besides injecting high PSU noise on the signal, voltage will sag on the negative rail.
Btw, not only the LM1875 chips and the heatsink burned my fingers, the small trafo I was using was also sweating.
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