If you insist the difference has something to do with current drive then consult somebody you trust. Esa perhaps? Obviously you are not listening to the rest of us here. Otherwise you can explore and begin to investigate the real reason.
It could also represent energy loss not converted into acoustic output.
I do not think of you as aggressive, more of persistent in doing something that is unfruitful and hurtful to yourself while being useless to others.
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From an EMC point of view...(ground loop)
When I design an amp layout, I worry about where all the currents are flowing. When the amp has both positive and negative pass devices, I worry about where the speaker return current flows.
If it's simply the chassis, I can guess but it will be frequency dependent, flowing broadly at lf, tightening up to a thin path at hf in an attempt to reduce total path reactance. In this case, is the input differential pair anywhere close to that path? is it a simple common emitter input pair?
Did you put the .15 ohm near the input pair? If so, you have brought the output common much closer to the input pair common, so have removed a significant amount of ground loop. Recall a while back (probably 6 years or so ago) I mentioned this issue with the SWTPC tigersaurus.
If your input pair ground, or either base traps any rail or return fields, they can distort the output. If for example, only the positive rail communicates with the input pair via the pair's grounding conductor, the distortion will be asymmetrical. In your circuit, you have returned the speaker current to the reference point of your feedback divider so the divider reference point is not forming a loop with the normal return path.
Layout aspects and control of current send and return is a key element in EMC. For this post, my arbitrary hammer is magfield control, the nail is your circuit...
Do you have pictures of the layouts?
jn
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Would you repost your square wave measurement with a difficult load to see if the output is affected?
Whatever for John? Relax, you only live twice. One life for yourself and one for your dreams. 🙂
No, I am not. Saying such does not make it so.
I am not engaged in a discussion of estats. This is about magnetic field driven devices. I will not be sidetracked by the "look it's a squirrel" thing.
As I said, I am discussing electrodynamic speakers. Stick to the topic at hand.
It's bog standard, and the exact same applies with voltage drive. DF96 stated it quite well, I feel no need to add to his eloquent post.
I would recommend you find some good books on this, but alas, you have already pointed out that "you don't need no stinkin books" in a previous post.
ps. When I discuss actual motors and how they are designed, rated, nameplate specifications, operation...you glibly say "I don't listen to DC". News flash, nobody does on purpose.. course, many have experienced it..especially if you use radio shack blister pak output transistors..
A DC motor driven by nameplate voltage unloaded will simply spin at nameplate rating, or a linear will run at nameplate velocity.
Try to run nameplate current into either unloaded will result in destruction of the device.
A solenoidal force transducer driven voltage will proceed at a specific velocity. Driven by current, it will accelerate to failure.
jn
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That just makes it even more amazing. They can't get over the voltage model. I get that, trust me, I really do. Once I was there as well, but intuition told me that we needed to look again and harder. So I started to talk to people... it took time.
Sorry, but that makes no sense, the speaker is the load, so that is the point. You want me to change the speaker?
This speaker draws the same current at all frequencies from 30Hz upwards. This is the speaker that the measurement shows, that was 2KHz. I could have chosen other frequencies. Interestingly, with sine waves, the phase of voltage and current does not separate.
Does it make a difference to the sound? Yes indeed.
While I agree with you in concept... he is in an awkward position in any case, as he can't justify his results by saying "some arbitrary speaker". He is discussing his speaker. If he didn't specify what speaker it was, he would be gigged for not telling us..
On this, perhaps he should be cut a break..
jn
OK, you didn't understand the logic of my challenge, that's a shame.
But thank you for recognising this really is a topic at all. 😀
Never said that!
How can you put "quotation marks" around something I did not say? Please don't do that. That is not really an honest thing to do. Those words would never have come from my me.
Where have I ever spoken out against books? Only that when I quote legitimate authories, they get repeatedly smashed.
But I am getting used to it, so it doesn't hurt.
That speaker is completely free!!!
You don't like it and you haven't heard it?
Hmmmm....
So now DIY is discouraged in diyaudio.com - I wonder what Jason would think of that? 😱
It's been an interesting day, now almost midnight.
Bona notte!
Ok. Your measurement has shown that you did what you said. Sometimes however, I like to do things because it is neat, but a question remains..
PMA earlier today linked to a study which I found interesting. It set out with something to prove, and simply but thoroughly stepped its way to an answer. If it hadn't, then I would still have questions.
Yes, a little work with transistors will break a person out of that 😉
That's rather aggressive of you.
Again, rather aggressive of you. You don't listen to yourself, do you?
When I quote someone else, I do this:
perhaps you should switch to decaf..somebody who said something said:
The quotes were around "we don't need no stinkin....." because that is a standard tongue in cheek phrase used a bit on this side of the globe.
Go back and read your own posts. I'm sure you can find what you said if you bother.. You pick and choose books based on what you want to see, unfortunately that doesn't include standard engineering textbooks.
In a few years, hopefully you will look back on your own posts and say to yourself...was I really that obnoxious?
Until you come to that realization, you will treated as an obnoxious individual if you post obnoxiously.
jn
That speaker is completely free!!!
You don't like it and you haven't heard it?
Hmmmm....
So now DIY is discouraged in diyaudio.com - I wonder what Jason would think of that? 😱
It's been an interesting day, now almost midnight.
Bona notte!
Joe,
For some reason (nefarious or not), you seem to have attributed a post regarding you possibly selling your wares on this forum....to me. If you look carefully, you will find I defended your post.
jn
18 Ohm series resistor and the amplitude did not need to be readjusted? Was that done by ear and guestimation? A cable has an R, L, and C adding series R at the amplifier will always change the FR. As I said a fun exercise with little actual information.
Repeating that flattening the phase of the load will improve any amplifier won't make it true.
Sorry, of course, any amplifier with any speaker, it's a one size fits all solution, I forgot, the repetition is starting to confuse me, I'll go back to not reading his posts.
No, you have changed the amplifier current and it allegedly sounds different. "Better" would involve careful measurements.Joe Rasmussen said:
Once again I need to remind you that the conventional way of stating what I think you mean to say is "this speaker presents the same impedance at all frequencies from 30Hz upwards". To actually draw the same current whatever signal is presented would be difficult to achieve and likely to be very distorting. Why not try using technical English?
If your claim was simply 'amplifiers work better with a resistive load' then it would be hard to argue against that, although some might say that any good amplifier can handle most reactive loads adequately well so the claim is true but only trivially so. Instead of a clear statement like that you tell all your stories about F=BIl and current drive and parallel loads being driven from a pure voltage source affecting each other, then cannot understand when we point out all the flaws in your reasoning. Finally you accuse us of not understanding and claim that a number of unnamed experts agree with you. This we take with a pinch of salt; either they are not experts or they do not understand what you have said to them or you have told them something different from what you have told us.
Joe seems very capable of making decent plots of speaker FR, impedance, etc., but the distortion stuff seems to elude him. I suspect he knows full well that making the speaker look like a real R at all frequencies has little or none of the distortion reducing effect of true current drive.
I really don't know what to think about all this. In my opinion, NOBODY has studied loudspeakers well enough to carry on a discussion about them, EXCEPT as to how to make them sound perhaps better in a given situation. That includes me.
JN is going to get really nasty with Joe soon, just like he has done to me on occasion. JN just loves to 'lord over the monkeys' and he thinks that he can be a big fish here in a small pond. However, I don't get much from him that is useful, and I think that is because he doesn't know either.
Now, what Joe is putting forth, is it useful? Maybe. I don't know, and since I am not building my own speakers at the moment, and am using some very 'refined' ones, I don't think that I will try to add further passive devices to the amp output. That doesn't mean that Joe's info could not be useful to someone else here. I will leave it at that.
Now, what do I work with to further improve my hi fi? I add tweaks and mods as they come by, in order to improve the 'sound' of my hi fi. This is my latest:
discussion later.
JN is going to get really nasty with Joe soon, just like he has done to me on occasion. JN just loves to 'lord over the monkeys' and he thinks that he can be a big fish here in a small pond. However, I don't get much from him that is useful, and I think that is because he doesn't know either.
Now, what Joe is putting forth, is it useful? Maybe. I don't know, and since I am not building my own speakers at the moment, and am using some very 'refined' ones, I don't think that I will try to add further passive devices to the amp output. That doesn't mean that Joe's info could not be useful to someone else here. I will leave it at that.
Now, what do I work with to further improve my hi fi? I add tweaks and mods as they come by, in order to improve the 'sound' of my hi fi. This is my latest:
discussion later.
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