After riaa nonsense had to put gabdx into ignore bucket...
Me too, now I got two an39. Built second one for a friend, after he heard my system. But he was affraid of running it so hot.
When the strings decay with different warbles in the sound, it likely means the strings are stretched out unevenly. When that happens with guitar strings the fix is to replace them.
I agree with this. More or less said same in my previous post.
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All amplifiers with particular harmonic profile will sound good. And all amplifiers with low distortion will not sound good is little hard to agree upon.
'Does THD accurately predict good sound quality?' Right now, as I am listening to music using the 'KISS' headphone amplifier, imo, probably.
A DC servo can also add THD at LF. The solution is to increase the filter slope. That adds an additional RC. Not a big cost.
Tom
Maybe... I think it happens because the string has a spiral wire around it to mimic a very long string, but you can clearly hear the string inside 'solo' and it causes a peak of high harmonics just after you hit the string, I could take pictures next time.
Some strings have more the problem are single, but replacing 1 you can't, its a piano and I want all the strings to be the same age.
What I meant by RIAA is that some transistors high gain input stage (to reach 100Watts types) utilize the full rail voltage and for reasons which I am not familiar but read in books , the gain in Open-loop is like RIAA either when the signal is small or too high.
Someone can simulate it in Spice, I am too busy. T
The JLH input stage didn't suffer from this disease in the quest for over 50 watts amps. That is what crippled its power and what caused it to be one of the best designs ever.
For example this (diamond?)
Someone can simulate it in Spice, I am too busy. T
The JLH input stage didn't suffer from this disease in the quest for over 50 watts amps. That is what crippled its power and what caused it to be one of the best designs ever.
For example this (diamond?)
If you only hear sound system with one kind of amplifier (example: high distortion amplifier) then your opinion is useless.
You should experience with many kind amplifiers and many kind of speakers to make such opinion.
I design many amplifiers for small groups and they experiment with many parts. Some use ordinary parts, some use very expensive parts, sand some use combine of them. When we gathered together and listen same sound system, their perception slightly different.
In stereo system, imaging and sound stage must be the most important. If you do not right imaging and sound stage what the meaning of stereo?
After designing many amplifier, I have confident but not 100% sure that the most important in amplifier is higher slew rate and then the low distortion of high frequency. But simple class A amplifier with high slew rate always sound good. My conclusion is if I can not achieve very low distortion in ALL audio frequency, make it class A 🙂
Some people have opinion that they love low frequency quality of high open loop gain amplifier rather than low open loop gain amplifier (of course they do not know which the high open loop gain and which is not, but I know because I designed it).
THD is PARTIALY show that amplifier sound (subjectively) good or not.
You should experience with many kind amplifiers and many kind of speakers to make such opinion.
I design many amplifiers for small groups and they experiment with many parts. Some use ordinary parts, some use very expensive parts, sand some use combine of them. When we gathered together and listen same sound system, their perception slightly different.
In stereo system, imaging and sound stage must be the most important. If you do not right imaging and sound stage what the meaning of stereo?
After designing many amplifier, I have confident but not 100% sure that the most important in amplifier is higher slew rate and then the low distortion of high frequency. But simple class A amplifier with high slew rate always sound good. My conclusion is if I can not achieve very low distortion in ALL audio frequency, make it class A 🙂
Some people have opinion that they love low frequency quality of high open loop gain amplifier rather than low open loop gain amplifier (of course they do not know which the high open loop gain and which is not, but I know because I designed it).
THD is PARTIALY show that amplifier sound (subjectively) good or not.
I experimented with bias of amplifier because I didn't like the sound of the class AB,
As I augmented the class A bias, the sound was more of what I didn't like of the bad input stage,
High slew rate all the way!! + high frequency stability (otherwise it will self destroy!)
At one point when the design reach its perfection the 'quality' of the parts mean almost nothing because it is all properly addressed in feedback which works flawlessly.
(if you can hear the bootstrap cap, something is wrong with your feedback loop, etc.)
Rolling parts and 'listening' for improvements is a huge red flag and signify something is very wrong in the audio chain.
As I augmented the class A bias, the sound was more of what I didn't like of the bad input stage,
High slew rate all the way!! + high frequency stability (otherwise it will self destroy!)
At one point when the design reach its perfection the 'quality' of the parts mean almost nothing because it is all properly addressed in feedback which works flawlessly.
(if you can hear the bootstrap cap, something is wrong with your feedback loop, etc.)
Rolling parts and 'listening' for improvements is a huge red flag and signify something is very wrong in the audio chain.
What are you even trying to describe? The input stage needs to provide the drivers and output stage with enough voltage to drive the output to as close to the supply rails as possible. This necessitates that the input stage is connected to the full rail voltage.
What do you mean by, "is like RIAA"? Are you saying that the open loop gain of an amp typically follows the same curve as RIAA compensation? Because that makes no sense at all. Most amps have a first-order rolloff (-20 dB/dec) starting at some relatively low frequency. 10 Hz maybe. Around the frequency where the loop gain approaches unity you'll sometimes see some kind of compensation kick in, so there'll be a slight wobble in the amplitude response. Like this:
This is what RIAA compensation looks like:
The only commonality is that both slopes are downward trending.
Tom
Once you find the distortion profile that sounds good to you in your system, the measurements would come into play to ensure amplifier/speakers/room acoustics would preserve that profile even at high output... and that is pure science... because the amplifier would change the harmonics profile differently from the speakers, at high sound pressure/output. Then you have to couple that amp/speakers combo with the room acoustics that has an opinion of its own at high output... This, together with the rise in popularity of streaming services and cheap Watt/dollar amplification, resulted in an explosion of room correction software usage and associated measuring equipment.
I think a good start is to know what you personally like... and how that looks on the AP measurement screens. Of course, staying on that path is not easy because everybody else will try to convince you that you've no clue.
I think a good start is to know what you personally like... and how that looks on the AP measurement screens. Of course, staying on that path is not easy because everybody else will try to convince you that you've no clue.
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Simple.... THD is not a good measurement as it bundles all kind of distortion together.
Also, we don't know exactly what makes stuff sound good, our psychoacoustics are incomplete therefore we don't know what to measure.
If we did, we wouldn't have High End Audio.
Your question, unfortunately, is way too simplistic and the answer is evident in this forum.
Also, we don't know exactly what makes stuff sound good, our psychoacoustics are incomplete therefore we don't know what to measure.
If we did, we wouldn't have High End Audio.
Your question, unfortunately, is way too simplistic and the answer is evident in this forum.
My engineering mind says there cannot be anything better than “wire with gain”.
In practice, I cannot listen to extremely low HD amps for as long. Amps with a bit of HD, I can listen to for longer continuous sessions.
I don’t know why.
In practice, I cannot listen to extremely low HD amps for as long. Amps with a bit of HD, I can listen to for longer continuous sessions.
I don’t know why.
"extremely low" HD? What the number? It is only at 1 kHz or the whole audio band? It is only one level or all level before clipping?
What a totally Bzarre question! 🙄
Why is that important?
He says he's "listening". I suggest that means he's listening to music! 🙄 (Not a signal generator.)
A truly outstanding question (not!). (Perhaps "a truly nitpicking" question is a more appropriate description?)
Why is that important?
He says he's "listening". I suggest that means he's listening to music! 🙄 (Not a signal generator.)
A truly outstanding question (not!). (Perhaps "a truly nitpicking" question is a more appropriate description?)
One person in my group complain after built one of my amplifier. He said the different is not significant with his previous amplifier. Other member of the group suggested him to change the speaker with better speaker. I do not remember which speaker but the drivers used SB Acoustics. The he said the different is huge and he cannot listen his previous amplifier anymore.