Boards should arrive May 26. I have some LM3886, so I'll test that also. See you in a month or two...
Yes. This is one of the things I will actually test.
Yeah, maybe.
This dumpster fire of a topic has lots of talking and very little measuring
(except what anatech posted)
At some point I'll need some amps that are known to sound terrible, to measure them and see what I find. I don't know what I'll find, that's the point of experimentation, but I do have suspicions.
So, I'll ask for a recommendation list of the shittiest amps you've ever heard.
Because I have this hunch that if something is audible, then it's not happening at -120dB down or whatever. Ears aren't that good. If there is an audible difference, there should be a measurement where it sticks out.
For sighted listening with no measurements to show that the latest glom hasn't caused a significant change I would personally consider it to be that simple.
Not an answer to the question, a quick sketch of the test bed in post #19068 might help. I have no idea what you mean exactly but if you think that no one has tested amplifiers for THD/IMD while injecting +-DC current into the output or conversely applying a DC offset and doing the same you are sorely mistaken.
Ah ah ah
One one the worst and repeated ramblings on the topic, as usual.
It pairs with Johnego.
I call it negationism
I think a lot of us are just listening to the technology & respecting the technology as the aesthetic expression.
In other words not trying to achieve a duplicate of the studio recording / live recording.
It's like... I like the sound of this high-end DAC, this high-end amp... this Titanium speaker... I am listening to the technology.
If I listen to music I am ok with $5 earbuds.
Lab equipment changes it mind when it starts measuring a new parameter. Or the human adjusts something.
This dumpster fire of a topic has lots of talking and very little measuring
This is another good point.
I suspect most of the people who are claiming the absolute truth are not able to handle a soldering tool (they are in the famous 9%).
Although I usually disagree with him I respect syn08 because I'm sure he owns the necessary skills, he owns a nice lab, he is doing something useful for the audio community.
Of course, I like to defend myself from his personal attacks, sorry.
Then there is the noise floor (unfortunately several dB), those who criticize my measurement tools (which aren't that bad) and don't even own a 3 1/2 digit DMM.
Because they wouldn't know how to use it.
But they are the custodians of the truth.
I really look forward to your investigation.
An amp that sounds terrible is the Audiogram MB1 (or MB2), early versions from '90s (there is a very simple reason)
Audiogram MB1 review – Ters Audio.
Thanks, but that's gonna be hard to find... It would be faster to build one lol. Any known bad sounding schematics ?
Alright, fire up the links, I'm interested.
Standard lab practice, ask syn08, I don't care what the audiophile magazines do.
Again a simple sketch of input source, DUT circuit, and what you are calling this offset injection would help clarify.
BTW I presented current injection into the output to measure input referred error at an AES conference 30yr. ago.
Again a simple sketch of input source, DUT circuit, and what you are calling this offset injection would help clarify.
BTW I presented current injection into the output to measure input referred error at an AES conference 30yr. ago.
Last edited:
Hi peufeu,
I agree, dumpster fire. People are trying to win arguments by picking things said apart rather than looking at the truths.
There is one fact that is true these days. If you can hear it, it can be measured and quantified. In fact, I can do this in my lab and have been doing it for years.
Most folks don't know how to interpret what the readings are, and I am getting better at it every day. But, I am measuring things well below your ability to hear it.
Scott Wurcer designs ICs for audio and other. This man knows precisely what he is talking about. I'd listen to what he has to say and work through very carefully what he says before trying to argue the point. There are others who likewise know exactly what they are talking about here. Most I suspect will not post in this silly thread. Examples would be Doug Self, Nelson Pass and John Curl. They all design differently and to different design goals, but they are all experts. I haven't seen Morgan Jones around, but he too knows what he is doing.
By taking specific examples you can use them to "prove" any point. Doing this therefore isn't useful and is a waste of time. Another thing I should clarify is that test equipment give consistent answers. If it doesn't, it is broken and needs repair / replacement. Ether that or the test performed did not eliminate all other variables than the quantity under test. I replaced a flaky HP 34401 (27 years old) with a new Keysight 34465A. I cannot afford to have the wrong answer, period. When it's mate's display started to go, it was replaced with a Keysight 34461A (one model down). I can't stress how important test equipment is and your expectations of it. Using something less quality and expecting higher accuracy than it is capable of is the same as having broken test gear. That is why equipment is calibrated (compared against known standards) and optimized as needed. You should know the limits of accuracy for your equipment. Often the LSD in a meter is pure fiction once you figure out the error budget for that function, range and frequency of signal.
Sound complicated? I guess it can be. That's one reason why a good technician or engineer is well worth what they pay them. It's also why someone who doesn't spend the time to understand what they are doing will argue endlessly with someone who does. Doesn't matter the trade, this is a universal truth. We just happen to be involved with electronics. That means electronic measuring tools.
Any audio engineer or good technician I have ever met has good equipment and listens to things carefully. The while package. If you only listen, you have less than 1/2 the story, yet people will still consider they have superior knowledge.
-Chris
I agree, dumpster fire. People are trying to win arguments by picking things said apart rather than looking at the truths.
There is one fact that is true these days. If you can hear it, it can be measured and quantified. In fact, I can do this in my lab and have been doing it for years.
Most folks don't know how to interpret what the readings are, and I am getting better at it every day. But, I am measuring things well below your ability to hear it.
Scott Wurcer designs ICs for audio and other. This man knows precisely what he is talking about. I'd listen to what he has to say and work through very carefully what he says before trying to argue the point. There are others who likewise know exactly what they are talking about here. Most I suspect will not post in this silly thread. Examples would be Doug Self, Nelson Pass and John Curl. They all design differently and to different design goals, but they are all experts. I haven't seen Morgan Jones around, but he too knows what he is doing.
By taking specific examples you can use them to "prove" any point. Doing this therefore isn't useful and is a waste of time. Another thing I should clarify is that test equipment give consistent answers. If it doesn't, it is broken and needs repair / replacement. Ether that or the test performed did not eliminate all other variables than the quantity under test. I replaced a flaky HP 34401 (27 years old) with a new Keysight 34465A. I cannot afford to have the wrong answer, period. When it's mate's display started to go, it was replaced with a Keysight 34461A (one model down). I can't stress how important test equipment is and your expectations of it. Using something less quality and expecting higher accuracy than it is capable of is the same as having broken test gear. That is why equipment is calibrated (compared against known standards) and optimized as needed. You should know the limits of accuracy for your equipment. Often the LSD in a meter is pure fiction once you figure out the error budget for that function, range and frequency of signal.
Sound complicated? I guess it can be. That's one reason why a good technician or engineer is well worth what they pay them. It's also why someone who doesn't spend the time to understand what they are doing will argue endlessly with someone who does. Doesn't matter the trade, this is a universal truth. We just happen to be involved with electronics. That means electronic measuring tools.
Any audio engineer or good technician I have ever met has good equipment and listens to things carefully. The while package. If you only listen, you have less than 1/2 the story, yet people will still consider they have superior knowledge.
-Chris
Hi Scott,
Depends greatly on the test setup and suitability of the test signal.
The null test can tell you if or what you have a problem with something - done properly. What it won't do is quantify anything. But, you still have to resort to using a suite of test gear in a lab at some point.
Like everything, the skill that the test was designed and set up with is paramount, and the execution of course!
-Chris
Depends greatly on the test setup and suitability of the test signal.
The null test can tell you if or what you have a problem with something - done properly. What it won't do is quantify anything. But, you still have to resort to using a suite of test gear in a lab at some point.
Like everything, the skill that the test was designed and set up with is paramount, and the execution of course!
-Chris
I can only speculate he's thinking about op amps and injecting an extra DC current in the output node. For certain devices (usually the old ones, with limited open loop gain and with lateral PNPs) this helps reducing the distortions, by displacing the bias and as a result avoiding the gm doubling effect.
I have never seen something similar for audio power amplifiers.
"a lot of us" is a broad term. This crowd is not part of that group, me thinks. When I listen it's always an event, music and all. I don't separate the two. Looking forward to various aspects of various recordings, I enjoy it all. I'm analytical regarding everything. Just listening is when somebody has a radio on somewhere and I overhear it.
btw, titanium is far too harsh.
- Status
- Not open for further replies.