Just wondering as I read all your posts. Care to point me to any units I can read about online you designed?
Hi morinix,
I haven't put up anything I've done. The period for builds stretches from late high school to now. Nothing I have done is either remarkable or noteworthy. I've also done some speaker builds for nightclubs and for people at home. Again, nothing to write home about. My current project will hopefully be a commercial one, so I can put that stuff up once done.
I have also designed tons of modifications of other commercial equipment that required PCBs for companies like Tascam and a few others. I like doing that more because if the add-on fits inside a unit, I'm done with it before having to deal with safety people and cabinets.
I designed and installed a complete communications system with paging for water plants in Mississauga. They like to have every little thing labeled. The last one required 1 MDF and 4 IDF's where wiring is organised and taken to where it needs to be. These were 100% my own work with no outside help. Surely those large systems are more of an achievement than a little box. One system has about 3,500 watts worth of amplification for paging. 5 racks full of mostly Bogen amplifiers (HTA-250), and they are expanding.
-Chris
I haven't put up anything I've done. The period for builds stretches from late high school to now. Nothing I have done is either remarkable or noteworthy. I've also done some speaker builds for nightclubs and for people at home. Again, nothing to write home about. My current project will hopefully be a commercial one, so I can put that stuff up once done.
I have also designed tons of modifications of other commercial equipment that required PCBs for companies like Tascam and a few others. I like doing that more because if the add-on fits inside a unit, I'm done with it before having to deal with safety people and cabinets.
I designed and installed a complete communications system with paging for water plants in Mississauga. They like to have every little thing labeled. The last one required 1 MDF and 4 IDF's where wiring is organised and taken to where it needs to be. These were 100% my own work with no outside help. Surely those large systems are more of an achievement than a little box. One system has about 3,500 watts worth of amplification for paging. 5 racks full of mostly Bogen amplifiers (HTA-250), and they are expanding.
-Chris
The thing that gets forgotten is that Jan is not a native English speaker. He is so fluent we often gergelflesrh it.
In most areas of electronics I work in the test/repair guys are an important part of the overall design team, as are production. The test/repair guys work with some pretty sophisticated kit and often have to build kit to interface with it or bespoke kit for testing, having to measure, test and repair the kit equipment that is being designed. Complex product design is a team effort these days.
Yes.
I always consider that:
- Amplifiers and power supplies do not have 0 Ohms output impedance and infinite current capacity.
- Amplifiers do not have infinite ripple rejection.
- Speaker's cable and passive filters don't have 0 Ohms impedances.
Trying to linearize everything (response curve, phase curves, impedance curves, distortion curves, feedback level curves ...) as much as we can and everywhere we can don't seems to me such a stupid approach.
Now, when we have to make compromises, everybody is free to chose its own priorities.
Because the absolute thresholds of inaudibility for all those criteria had not been published yet, at the end, the judge will be the listening preferences of the user. Subjective ? Oh yes.
After all, it's about *musical* reproduction, no ?
Originally Posted by Speedskater :
In past decades, Stereophile did do some weekend blind loudspeaker tests. But their Golden Ear reviewers couldn't repeat their opinions on the second day, so the magazine found excesses not to do anymore blind tests. A magazine has to keep Golden Ear reviewers and advertisers happy.
There were other tests. Maybe in issues Vol 14 #7, Vol.15 #5, Vol.16 #1, Vol.16 #9.
In past decades, Stereophile did do some weekend blind loudspeaker tests. But their Golden Ear reviewers couldn't repeat their opinions on the second day, so the magazine found excesses not to do anymore blind tests. A magazine has to keep Golden Ear reviewers and advertisers happy.
The August 1994 issue Vol.17 #8 pages 103 thru 160 (including 25+ full page ads).
There were other tests. Maybe in issues Vol 14 #7, Vol.15 #5, Vol.16 #1, Vol.16 #9.
This is an interesting PA design. I hope it gets written up in Linear Audio or better.
Here is 2 Ohm data some one asked about.... limited by the bench supply ->
The distortion hardly changes with load Z and output level and freq. (!)
View attachment CFA 2 Ohm.pdf
THx-RNMarsh
Here is 2 Ohm data some one asked about.... limited by the bench supply ->
The distortion hardly changes with load Z and output level and freq. (!)
View attachment CFA 2 Ohm.pdf
THx-RNMarsh
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Me too.
I also think in terms of 'energy' flow and direction, forms of energy storage and consequence of energy storage and consequence of energy transduction.
Further to this is consideration of energy 'spectrum' due to materials and interactions by proximity or connection.....every material is a 'filter' of sorts.
Lack of direct experience of subjective benefits (reliance on naysayer hearsay), reliance on NFB as the cure all and economics are causes.
Yes, but such compromises are not an intelligent/properly considered choice unless the subjective effects of all the parameters you quote above are known and understood.
From this comes ordering of priorities.
You are saying 'trust your ears'....that is strictly verboten here, against forum rules and inviting disciplinary actions.
No, here it's all about arguing, and such arguments usually from 'hearsay' point of view.
And yes, of course it is.
In my experiments with 2 way loudspeaker flattening each driver rising impedance to 40+kHz, the subjective change is substantial and the subjective improvement of a couple of RC networks far outweighs the modest cost.
Bass driver resonance caused impedance hump is not so problematic as the inductive energy return at higher frequencies.
This return energy causes (subtle) chaotic noise and mayhem and distinctly contributes to fatigue.
Making the loudspeaker system electrically 'correct' is quite the first thing to do and renders a host of amplifier/cable shortcomings less objectionable.
Electrically correct sounds electrically correct, and is necessary for 'correct' and properly enjoyable reproduction.
Dan.
Can you translate that into English please?
All amplifiers employ NFB. Every, single one. Even those that claim not to use NFB (typically, Single Ended Triode amplifiers) employ NFB. The triode, itself, utilises internal NFB to operate.
What can be important is the TYPE and AMOUNT of NFB and how it is applied. Like most things in life, a little is often good and a lot can be bad.
Really? Are sure about that?
Huh?
"Return energy"?
There is no such thing as "electrically correct". There are simply design choices.
Say what again? Since when is 'trust your ears' against the rules? I see some version of that all the time around here.
Just had another look at the forum rules, and it doesn't mention this.
I ***|u|me that Max is referring to back EMF (which I wouldn't personally characterize as "chaotic," but, hey).
EDIT: OK, so just for the record, "cocknocker" is no problem, but "***|u|me" gets censored. Got it.
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.[/QUOTE]
No, but you appear to, but all waffle and then when asked to back it up have oddly got nothing as it was so long ago. You didn't even keep a lab book?
As has been pointed out, if you linearise the drive unit, you change the T-S parameters. It becomes in effect a different drive unit which possibly then drives a different set of compromises. Other than when we get the regular dive down the rabbit hole of current drive vs voltage drive this doesn't get discussed much which is a shame as it's far more interesting than debating whether a power amp can be taken seriously if it can't melt a 4" nail or be used to jumpstart a car.
Back EMF ?
[edit] Jim the Oldbie gave the same answer. First.
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I ***|u|me that Max is referring to back EMF (which I wouldn't personally characterize as "chaotic," but, hey).
EDIT: OK, so just for the record, "cocknocker" is no problem, but "***|u|me" gets censored. Got it.
Back EMF does not occur in a properly designed and aligned speaker system. However, as we have discussed in this thread, not all speaker systems are perfect. In that case, any back EMF produced will be absorbed by the output impedance of the amplifier. IOW: It is a non-problem in a properly designed speaker and/or when using a properly designed amplifier.
Of course, if one is using an improperly designed speaker system and a poorly designed amplifier....
You probably are not totally used to Max's take on Vogon poetry.
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