Nelson Pass said:
When my girlfriend says, "You're great," it sounds great.
But when she adds the feedback, "... but ...," it sounds worse.
Actually there is no clear answer. For example, Halcro makes an amazing amp that measures VERY LOW in distortion, DUE to lots and lots of negative feedback. I make an amp that measures pretty well, BUT not as well as the Halcro in harmonic distortion at just about any level. I use a moderate amount of negative feedback. We both have a Class A rating in 'Stereophile'.
What is the advantage of high negative feedback?
What is the advantage of high negative feedback?
It helps to have equipment evaluated by separate parties to the company. Magazines sometimes give this input, and we use it. It is like being given a quality rating in 'Road and Track'.
john curl said:
The Halcro dm58/68 measures that well not only "due to lots of negative feedbacks", but systematic effort to minimize distortion in every stage and application of feedback to locally linearized stages. This makes a great difference from common solution like "negative feedback as a cure for every disease". I do have some experience with linearization before application of GNFB. The effort to minimalize distortion in every stage results in minimalization of higher order harmonic distortion compounds, low overall distortion and - what is the most important - excellent sound quality.
We all try to reduce distortion 'at every stage' in an amp. Some people just reduce it further by adding internal feedback loops, like Halcro.
john curl said:
It could be that distortion per se (below a certain level) has little or no bearing on the sound of the amplifier. Distortion is one of those things that is easy to get your "hands around" and measure to the nth degree. I remain skeptical that when amplifier A measures -103 dB third (for instance) and B measures -105 dB and A sounds "much" better in a particular circuit, that the distortion has anything at all to do with it.
PMA said:
Why do you suppose it is that the stereo version of the amplifier
has fairly ordinary distortion specs?
mikeks said:
I can start off by giving you one fact. You will never see
a large group of people change their minds and come to a
collective agreement when it comes to a topic like this.
I think that you knew this up front so now im going
to ask a question. What was your motive for starting
this thread? Just what did you hope to accomplish with it?
Just being curious.
Glen
I do not know if there is the same circuit design for monoblock and stereo version. If it was the same, I would suspect the power supply unit.
blmn said:
Cheers mate! 🙂
scott wurcer said:
True...True....
I rather think the power supply has a great deal more to do with defining the character of an amp. than THD below a certain level of the later...of course...... 🙂
...and of course the ability of said amp. to deliver power from the supply into load without breaking wind....
I would recommend to some members less theoretize and more experiment with different modifications in a same amplifier (modify output stage, input stage etc.). Especially try difference between switching and non-switching output stage. Then speak about audibility of these modifications.
PMA said:
Yes.
To let insightfull ideas fend for themselves in the court is not only a sobering experience, it is educational too.
Rodolfo
- Status
- Not open for further replies.