Sorry, not correct. I am not ignoring you but I am not polluting this thread any further. I have no problem continuing discussion with you relevant to thread.
Then can you answer question I asked you, "Which precise comparison method did you use to discover this?".
You seriously did not know? Not making fun of me?
I believe Nelson Pass discover the effect. I read about this on his 2004 article "Current Source Amplifiers and Sensitive / Full-Range Drivers".
I have a Fostex FE206e for efficient driver, an SB Acoustic Satori for less efficient driver and some local speakers, no access to other exotic drivers mentioned in the article.
2 amps was prepared similar in design to Rod Elliot's "Project 56 - Variable Amplifier Impedance" using LM1875 chips, 1 amp with damping factor more than 10 and the other with convertible damping factor 0.5-2. System response was measured using a cheap condenser mic and AudioTester using mic laptop input, nothing fancy nor precise.
Frequency range measurement results and listening confirm findings mentioned in the article that efficient driver (like Fostex 206e) behave differently on amps with different damping factor while less sensitive driver (like Jordan J92) behave quite similarly on both amps.
If you feel you need more detail information or precision, I suggest starting a thread in Pass Forum, the nice gang there or perhaps even Mr. Pass himself will help you.
Nope.
I'm not sure what you mean by not precise. If you mean not precisely level matched, that's a flaw in the setup of test.
What kind of listening? Casual auditioning or objective A/B comparison? It makes a big difference in the meaningfulness of the results.
If the listening was one of those casual auditioning, its result isn't something to be used for confirming anything. It may be useful for entertainment though.
Like I said, if you prefer the sound of certain speaker, find amp that's compatible with it. If you prefer the sound of SET amp, find speaker that's compatible with it. If mismatch of amp to speaker or speaker to amp causes audible difference, then someone didn't do it right.
I thought you've been responding to me with your own existing knowledge, no?
For reference, links to article mentioned on post #123 Nelson Pass's Current Source Amplifiers and Full Range Drivers http://www.firstwatt.com/pdf/art_cs_amps.pdf and Rod Elliot's Project 56 - Variable Amplifier Impedance Variable Amplifier Impedance
Not precise meaning relative, not calibrated dB level of sound.
The amps in evaluation were level matched at 1 kHz prior to listening but are different in damping factors. I think finding a design of an amp to better match a speaker is the reason of this thread. Still searching for the right way to do it.
Like I said, I have no access to high precision calibrated equipments. I shared what I have. If you want more, feel free to try the Pass Forum.
Too late to bring the conversation around to SET amps. The thread's been moved into the bewildered zone.
Classic thread defecating. The best advice to come out of it is use the ignore button.
Bunch of recommendations were posted on first few pages. That's not enough for you guys? 🙄 You can always try "search" function.
To what precision level were they matched and which device was used for doing so?
This is what he said,
Bunch of posters gave recommendations on first few pages. What more do you want?
So I was right about your preconceived notions stemming from fiction.
During testing with the Fostex, they were electrically matched to 3-4%, 1kHz, 2V at speaker binding post using old Kenwood 20MHz scope and cheap Heles DVM. I shared what I have in the hope that what I have can help others.
Your response gave me an impression that something is preventing you to share certain parts of your experience. I can understand, I wish no inconvenience for you. Sorry to have offended you.
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Volume level need to be matched within 0.1 db. Using voltmeter, it has to be within 0.01 v variation. 3-4% variation of 2V is way off the the precision requirement that it's not considered level matched.
Some frustration may be but you didn't offend me. I have been sharing technical facts and experience on audio but somehow it feels like I'm talking to a brick wall. You need to watch that video again, as many times as it takes to understand the messages in it.
Thanks for the tip. I felt to have stepped into this discussion on the wrong foot. We in Indonesia was hit really hard at 1998 monetary crisis. Average engineer like me simply can not afford precise measuring equipments just to maintain a hobby. I was not in the least bit deluded to be able to meet a good standard, after a certain point where precision limit of measurement is reached, progress will just have to rely on a pair of grandpa's ears. Best thing expected to come out is just a nice sounding "effect box", as SY like to say.
I concur with your observation when typical loudspeaker is part of the test setup. I can not tell the 2 different DF amps apart with several multi way speakers tried. However, things are remarkably different when an untypical speaker is thrown in. The Fostex has a lot more bass response and a bit more the high end with the high DF amp, even when output level is lower than the high DF amp. Had you read Nelson Pass's Article art_cs_amps.pdf you may have got the gist of what I was saying, or even add a little bit more bits from your own experience.
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Digital multimeters that can do this job are not expensive at all.
You want real effect box? Get equalizer.
This has what to do with what I've been saying on this thread?
Mine can not be trusted better than 50mV accuracy on ACV reading at >400Hz. Maybe the one on your link is better.
Anything I said made you think I want an effect box? Currently designing an SE DHP driving PP LatFET OPS to mate with the Fostex. Maximizing frequency response and minimal phase shift by avoiding as many reactive elements as possible. Finding ways to measure better in the future to upgrade the effect box into hifi status.
Perhaps you know other methods to reduce audible differences due to mismatch of amp and speaker. Methods described by NP requires damping of speaker using reactive elements.
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I asked you if you want real effect box. If you do, equalizer is the answer.
You are going around circle. I already pointed out to you about your preconceived notion. If you run into a situation where audible difference was heard in an objective scientific test, then go ahead with your search for the proper amp or speaker. If you just want to change amps for the sake of changing amps, no one is stopping you.
Yes, it was very slow of me was'nt it. I think now I get what you were trying to say. Thanks for putting up with me.
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