I can't find a diagram with the configuration similar to that of the datasheet, but in inverting mode.
Or if there are similar inverting and non-inverting equivalent schemes, so I can compare them as they sound differently.
can someone show me some links?
Or if there are similar inverting and non-inverting equivalent schemes, so I can compare them as they sound differently.
can someone show me some links?
Inverting and noninverting circuit are the same thing, just with the input node and the feedback ground node swapped. You can thus always convert one into the other, with the obvious caveats re: input impedance and gain.
Hmmm, you state its the same thing. But its not. Not only inverted needs buffer on the input instead of volume pot, but it sounds totally different.
Tubes & The Gainclones
Tubes & The Gainclones
Sound is subjective.
What is better for one may not be better for someone else.
Definitely not the same.
I preffer current feedback (transconductance) config.
What is better for one may not be better for someone else.
Definitely not the same.
I preffer current feedback (transconductance) config.
It helps to have flat impedance.
But its not an absolute requirement.
When you drive fullrange with normal voltage amp, it will roll of in low frequencies due to increasing resistance. But when you drive it with current source, feedback will provide more voltage and compensate for increased resistance. Thus extending low frequency.
Turning disadvantage into benefit.
I built 3way active system with three stereo transconductane amps based on lm3886 chips. Powering normal speakers. Great sound. Even have my own way of wireing them. There is thread out there.
I do have about 10 stereo lm1875 amps, each different configuration. Standard based on application note, inverting with various buffers (mostly jfets), and many current source. Each type has its unique sound, even on the same speakers.
Saying that inverting and noninverting is the same is just wrong.
But its not an absolute requirement.
When you drive fullrange with normal voltage amp, it will roll of in low frequencies due to increasing resistance. But when you drive it with current source, feedback will provide more voltage and compensate for increased resistance. Thus extending low frequency.
Turning disadvantage into benefit.
I built 3way active system with three stereo transconductane amps based on lm3886 chips. Powering normal speakers. Great sound. Even have my own way of wireing them. There is thread out there.
I do have about 10 stereo lm1875 amps, each different configuration. Standard based on application note, inverting with various buffers (mostly jfets), and many current source. Each type has its unique sound, even on the same speakers.
Saying that inverting and noninverting is the same is just wrong.
in fact that was what I wanted to verify. what changes in sound between in and non-inverting non-buffered and buffered. if you can explain your feelings, thank you
that would be pretty much impossible, but I can try
standard non-inverting is sterile, dry, but accurate
inverting with good buffer is better, more musical
current source is best, musical and engaging, seems even more dynamic
here is my theory, but I do not have data to prove it...
normal voltage amp is configured to amplify the signal, signal comes in, gets amplified, and negative feedback from the amps output is compared to the input to correct all the non-linearities, to have lowest distortion and flat response
voltage amp does this no matter what is connected to it, it does not even care if something is connected or not (just like sgrossklass)
in current amplifier, there is feedback reading what is actually on the speaker
this amplifier actually corrects signal to adopt to the speaker and its non-linearities
not only amps non-linearities
so in a sense it cares about what is connected to the amplifier
and that's how it should be
i believe it sounds better because transients are better, but as i said I do not have data to prove it
there is one italian web page which has some data on it, showing much better transients in current drive
long time ago, when I had my own work office, i had little fullrange bookshelf speakers hooked up to my computer
powered with classD amp they sounded thin, dry and boring, i did not used them much
when i used lm1875 in transconductance circuit, sound was way better, more bass, better highs, as the amp compensated for impedance increase, music was juicy, and when I added little sub under the desk, it was so good, that my colleagues at work were
not believing it
that was while ago, now I share the office, so I use headphones
standard non-inverting is sterile, dry, but accurate
inverting with good buffer is better, more musical
current source is best, musical and engaging, seems even more dynamic
here is my theory, but I do not have data to prove it...
normal voltage amp is configured to amplify the signal, signal comes in, gets amplified, and negative feedback from the amps output is compared to the input to correct all the non-linearities, to have lowest distortion and flat response
voltage amp does this no matter what is connected to it, it does not even care if something is connected or not (just like sgrossklass)
in current amplifier, there is feedback reading what is actually on the speaker
this amplifier actually corrects signal to adopt to the speaker and its non-linearities
not only amps non-linearities
so in a sense it cares about what is connected to the amplifier
and that's how it should be
i believe it sounds better because transients are better, but as i said I do not have data to prove it
there is one italian web page which has some data on it, showing much better transients in current drive
long time ago, when I had my own work office, i had little fullrange bookshelf speakers hooked up to my computer
powered with classD amp they sounded thin, dry and boring, i did not used them much
when i used lm1875 in transconductance circuit, sound was way better, more bass, better highs, as the amp compensated for impedance increase, music was juicy, and when I added little sub under the desk, it was so good, that my colleagues at work were
not believing it
that was while ago, now I share the office, so I use headphones
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We like to hear good music & that's the most important thing. You said it sounds better, subjectivly? we don't know & to know more about it we have to build one. But yes i understand your point. Although according to you it colours music through signal correction. The only current feedback amp i've ever built was tda2003 chipamp & as far as i can recall i liked that chip 🙂
that's why Mr. NP designed quite a number of amps without negative feedback
if you care about music and how its sounds, build those
but that is of topic
if you care about music and how its sounds, build those
but that is of topic
The VFET amps I am using from time to time, excellent amp, has ~2% distortion at 10 watts
The speakers I am using, four dayton 4" reference al cone midbasses as short array (like nola) with dayton amt tweeter have ~0.1% distortion at 1 watt (I rarely use more)
what are you trying to say?
we should forget the distortion in the amplifiers?
good one, ha ha
The speakers I am using, four dayton 4" reference al cone midbasses as short array (like nola) with dayton amt tweeter have ~0.1% distortion at 1 watt (I rarely use more)
what are you trying to say?
we should forget the distortion in the amplifiers?
good one, ha ha
I'm sorry that now you have to listen to music with that headphones, which I personally never liked.
If you can give me the link of the page in Italian, thank you
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No i didn't say that & kindly mention THD+N of your VFET amp at the level of 1watt. I was just trying to say that we shouldn't think too much about distortion & bla bla bla...... different isn't always better(subjectively). What we need is a good amplifier+ speaker combo which approximates signal level at a respectable level. Anyway voltage feedback is more popular & thats for a reason.
Its down right now
Perhaps you can use wayback engine
Ultrasound-hifi.com
Ultrasound used to make current drive amps like Otello and Parsec