I see he still left the option open for you....😉
In the USofA, and elsewhere for that matter, do you get handed feedback forms at the end of courses?
In the USofA, and elsewhere for that matter, do you get handed feedback forms at the end of courses?
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And the logician's small son playing with his toy horse announced "This is not a red fire truck."
Not sure I fully grasp the slime on the barrel part, might be an idiom I haven't met.
But, yeah, my posting volume tends to correlate dirextly with the amount of time I'm doing simulation work, which is infinitely less over the weekends. 😀 Some of us aren't retired and are actually trying to develop new tech in our respective fields, rather than try to prove our worth for things done ages ago. 😉 (Which have their merit, no doubt, but should be leveraged as a tremendous foundation to understand and improve the latest and greatest. Audio electronics seems more an afterthought in development nowadays, other than the continual pursuit of lower and lower power envelope at good enough)
Not sure the context of yours and PMA's exchange, but it's ground hog day whenever Joe comes back to the thread. I cannot get myself to have the patience to read what he writes, because anything that could be said in half a sentence takes 2 paragraphs of gobblygook. I don't think we're covering any new ground here anyway (and I mean Joe's ideas gaining sophistication and understanding of the fundamentals).
And yes, the whole lot of orangutans throwing poop from their respective cages gets tiresome so I skip all those posts. Not sure what I missed but I'm sure I'm better for it. Which is to say, been there, done that, will invest my energy elsewhere.
It's been a trend now for the online courses. They are starting to do so for the classroom work as well now.
jn
^if by starting you mean in full swing in the institutions I've attended since the early 2000's. 😉
I was a popular TA with much of the feedback being "I learned more from him than the professor", which is a low bar, but nonetheless one I'm happy I cleared.
I was a popular TA with much of the feedback being "I learned more from him than the professor", which is a low bar, but nonetheless one I'm happy I cleared.
@billshurv
Yes, many now use square or rectangular wire for the voice coils. But if a vendor is big enough, they can simply purchase a die at the wire vendor and have them put chamfers on two or four edges of the square wire prior to coating the wire with enamel or polyimide.
The triangular or diamond shape void is where the round pickup wire would nest, and it wouldn't compromise the cross section that much.
jn
ps. I would prefer 4 chamfers only because it eliminates operator error at the winding setup.
Yes, many now use square or rectangular wire for the voice coils. But if a vendor is big enough, they can simply purchase a die at the wire vendor and have them put chamfers on two or four edges of the square wire prior to coating the wire with enamel or polyimide.
The triangular or diamond shape void is where the round pickup wire would nest, and it wouldn't compromise the cross section that much.
jn
ps. I would prefer 4 chamfers only because it eliminates operator error at the winding setup.
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Hi John,
Everything you can share with us about Bybee devices is that:
1.) you use them because they make your system sound better
2.) you have zero idea how they could function
I think I see some snake oil running down your leg there John.
-Chris
Given how many ways you can design a tube signal circuit, did you have anything specific in mind? Or can you let us know which commercially sold unit you are thinking of.
And there it is. The secret that no one can explain reasonably how they function. Why do you even bring these up on a continual basis John? All you are doing is acting like a dumb ad campaign for Mr. Bybee.
Everything you can share with us about Bybee devices is that:
1.) you use them because they make your system sound better
2.) you have zero idea how they could function
I think I see some snake oil running down your leg there John.
-Chris
Idly mulling I wondered if you could turn a groove into the former so square wire would sit on edge so you could drop a square sense wire into the gaps. I then realised that the former is probably not deep enough and you lose turns per inch on the drive winding. Oh and probably a biatch to wind.
I should sacrifice a speaker to the god of getting a clue.
I would co-wind the large and small together on the teflon 3 piece split mandrel, put the former over that, then co-wind back to the starting point. Two layer, start and stop at the cone end. So the inner layer sense wire is buried next to the former, the outer layer sense is visible on top of the coil.
I would consider either a glasscloth former the epoxy fills, or a graphite unidirectional weave cloth, as I'd worry about the expansion coefficient.
jn
A split mandrel, I would have the center as a wedge with two outer D shapes. clamp together and machine the outer diameter. You can build the winding stop as a lip on one end, or a hole down the middle to clamp the end plates (teflon coated aluminum, teflon tape with sticky side is common for woodworking fixturing. After the thing has cured, the wedge can be pushed out and your done..
jn
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For most commercial drivers you see two layer or 4 layer voice coils wound with round copper or copper coated aluminium. Its a good compromise for getting lots of copper in the gap. And these drivers need to deal with looser gaps etc. to be commercially viable.
Other issues would be underhug or overhung voice coil. Underhung means lots more magnet etc. to get the same Xmax.
If I were not up to my eyeballs in headphone work I would get one of these: Amazon.com: Goldwood Sound Dual Voice Coil 6.5" Replacement Speaker Woofer Black (GW-406D): Home Audio & Theater and test the concept. You could have a good sense of how well it will work by the weekend.
Commercial voice coils are usually wound on Nomex or sometimes aluminium (with a split). They are often self supporting for tweeters. Edge wound coils are premium and one layer with the return laying flat up the center if I remember. You then need leadout wires which are there own specialty, usually a tinsel covered length of nylon thread.
There has been nearly 100 years of development on this technology so few new tricks to bring. The autosound market taught the industry how to make durable drivers.
I would go with fully non conductive just to eliminate the eddy dragging in the gap.
I do have some nomex sample stuff somewhere, some calendared and some not calendared.
glasscloth is also easy.
Do you know if the goldwood is bifilar?
If I were going to re-coil a woofer, I'd carefully remove the vc form and leave a length of the wire that goes from the vc to the litz attach points. Once the vc dimensions are known, the mandrel can be turned, the coil made. The only thing left would be a centering shim to center the coil, then reattach the cone.
In fact, why not just buy a reconing kit I assume the dustcap is glued on after remount, or just buy a new dustcap..
jn
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A funny story: Last Sunday, I attended I attended the LA&OC Audio Society Awards Banquet where I was introduced as one of the greatest vacuum tube designers in the world today. I had to correct the president of the society that I only design solid state, but I really liked tubes for audio anyway.
The best 'fix' for digital sound using a tube interface was designed by my nearly 50 year old comrade and competitor Bascom King where he added tubes as front end to his PS Power amp. I first heard it recently at the Rocky Mountain Audio Festival in October, driven by a PS digital source. It was really nice. I was envious, compared to my JC-5, digital driven presentation presented upstairs. Analog driven, my design was OK as well.
JN, Max was referring to a BYBEE PURIFIER, didn't you realize that? However, he was just testing you for your mathematical 'chops' because the Bybee does not work because the resistor is inside the ceramic tube. In fact the first Bybee devices, (most of which that I use today) have the resistor placed side by side the actual ceramic device, and they still work OK.
The best 'fix' for digital sound using a tube interface was designed by my nearly 50 year old comrade and competitor Bascom King where he added tubes as front end to his PS Power amp. I first heard it recently at the Rocky Mountain Audio Festival in October, driven by a PS digital source. It was really nice. I was envious, compared to my JC-5, digital driven presentation presented upstairs. Analog driven, my design was OK as well.
JN, Max was referring to a BYBEE PURIFIER, didn't you realize that? However, he was just testing you for your mathematical 'chops' because the Bybee does not work because the resistor is inside the ceramic tube. In fact the first Bybee devices, (most of which that I use today) have the resistor placed side by side the actual ceramic device, and they still work OK.
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diyAudio Forums Archive - Simple MFB woofer project
file:///C:/Users/Richard/Downloads/BAP_Thesis_Theory_final.pdf
Motional feedback: dual voice coil signal
Voice coil *former* generates motional feedback voltage?
a few ideas... This last one is interesting idea.... use the metal VC former as a single turn pickup.... maybe a redesign of the metal vc former will have benefit as a pickup?
THx-RNMarsh
file:///C:/Users/Richard/Downloads/BAP_Thesis_Theory_final.pdf
Motional feedback: dual voice coil signal
Voice coil *former* generates motional feedback voltage?
a few ideas... This last one is interesting idea.... use the metal VC former as a single turn pickup.... maybe a redesign of the metal vc former will have benefit as a pickup?
THx-RNMarsh
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I already knew that, I never even asked for my money back. In fact it's still here not working (unless of course the battery's shelf life has been reached).
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