Russellc
Addicted Member
My unscientific method would be to use a radio shack sound meter and compare to a known driver.
Russellc
Zilch's AK Design Collaborative - Econowave Speaker
- Thread starter Zilch
- Start date
My unscientific method would be to use a radio shack sound meter and compare to a known driver.
Russellc
Duffinator
Spin The Black Circle
So what you've moved your office to ZilchLab? :scratch2:
If only. Picture was provided for a bass bin reference. I'm stuck at work tonight. I would far prefer to be building at the Zilchlab right about now.
I saw it with my own eyes and heard it with the sine sweep at 18k but not above. I think you will like what you hear with the B&C
In your reply, please be kind. Even after reading Greg's writings, I still have extremely limited circuit knowledge...
Is the area between the caps really at 9V+?
If there is no continuity at DC, how is there a potential difference?
However, to me, it seems there can be no point of raised voltage level because there is no direct continuity. It would be like saying there is 9V positive between the caps even if the negative side of the battery were never connected to the circuit... You'd have to bypass the cap to measure voltage and the cap appears in the circuit as open at DC...
I am hopelessly confused.
skywave-rider
Slumming in Akihabara
Hi Cosmos,
You don't need continuity to have potential, or voltage. Just like the 2 terminals of any battery, not connected to anything, have no continuity, no current, but there is voltage (assuming it's not dead.)
So the cap is like an open circuit to DC across it -- no continuity, but has voltage (the bias) and it passes AC.
Hope this helps.:yes:
Or maybe I've added murk.
Say, "shut-up Skywave."
You don't need continuity to have potential, or voltage. Just like the 2 terminals of any battery, not connected to anything, have no continuity, no current, but there is voltage (assuming it's not dead.)
So the cap is like an open circuit to DC across it -- no continuity, but has voltage (the bias) and it passes AC.
Hope this helps.:yes:
Or maybe I've added murk.
Say, "shut-up Skywave."
No unkindness intended here, ever. :thmbsp:
Yes, what Skywave said: it sits at +9V, referenced to common, where the battery (-) is connected. That is also AC common, which is the trick here.... :yes:
First listen, no tweaks yet, mated with LE14A, violet curve here:I think you will like what you hear with the B&C
Smooth like BMS polyester, with clarity and delicate detail.
900ss looked it up; polyimide = Kapton.... :thmbsp:
Russellc
Addicted Member
First listen, no tweaks yet, mated with LE14A, violet curve here:
Smooth like BMS polyester, with clarity and delicate detail.
900ss looked it up; polyimide = Kapton.... :thmbsp:
Nice! Very nice in "untweeked" form, can hardly wait to see tweeked. Looking pretty flat except the little hump around 3200-3300.( Or is that a trough at around 2000?) Very nice.
Russellc
Paratima
E'Wavin'
My problem with the JBL white paper is that it doesn't address cause and effect. We know that when you pass AC through a cap, capacitive reactance resists the change in voltage by drawing current ahead of the voltage change. This begets phase shift of up to 90 degrees, dependent on frequency. Fine.Hi Cosmos, You don't need continuity to have potential, or voltage. Just like the 2 terminals of any battery, not connected to anything, have no continuity, no current, but there is voltage (assuming it's not dead.)
So the cap is like an open circuit to DC across it -- no continuity, but has voltage (the bias) and it passes AC.
Hope this helps.:yes:
Or maybe I've added murk.
Say, "shut-up Skywave."
Does phase shift, in and of itself, cause distortion? Does the combination of phase shifts, occurring at different places throughout the crossover, cause distortion because of different paths through different numbers of caps? In other words, what exactly is the problem or problems that cap charging is supposed to alleviate? Does it happen at all frequencies and drive conditions? If not, why not? When is it a problem?
Once you've answered those questions, then you can look at CC and say, ah, CC bias improves the sound because... And then you can figure out how it actually affects circuit operation and at what frequencies and/or drive conditions. First, you have to define the problem. Otherwise it's just good guju: "Rub these batteries on your tweeters twice a day and the music will be warm and airy."
Russellc
Addicted Member
I found it improved the sound, like Rob said, not lightning and thunderclaps, but a decided increase in clarity and detail, particularly on decay portion of sounds. Also, the Selenium sounds smoother. Enough of an improvement that I found mys elf listening to things I was already familiar with, and enjoying them more. always a good sign to me! Rather than speculate on all the reasons it wont work, give it a try! Then you can answer the question for yourselves. Its not that many parts, give it a try. Each side only needs ( in addition to the existing resistors and coils, whose value and number stay the same) dayton 5.1mfd and 4.0mfd, a 10mfd, then either (2) 1.0mfd or (2) 3mfd, depending on which compensation, < or > than 95 db. That's it for the high freq, for the low: (2) 20 mfd and (2) 4 mfd. Not that big a deal, and you'll be treated to what I sense, and I think you would also sense, as an improvement.
I dont know why it works, and really dont care. Its a good idea put out by those that know, which makes it a little better bet than a pig in a poke. I may try this on some of my other speakers as an experiment. Hmmmmm just in time for the Indignia build I'm in the middle of.
russellc
I dont know why it works, and really dont care. Its a good idea put out by those that know, which makes it a little better bet than a pig in a poke. I may try this on some of my other speakers as an experiment. Hmmmmm just in time for the Indignia build I'm in the middle of.
russellc
tubino
A guy with too many tubes
The stuff I read by Greg Timbers directly addresses cause and effect. If they weren't jpgs, I'd cut and paste the relevant parts.
http://www.lansingheritage.org/images/jbl/specs/home-speakers/1993-k2-s5500/page10.jpg
http://www.lansingheritage.org/images/jbl/specs/home-speakers/1993-k2-s5500/page11.jpg
http://www.lansingheritage.org/images/jbl/specs/home-speakers/1993-k2-s5500/page12.jpg
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I wish I could get more out of those graphs, but being color blind they just end
up being nifty designs...
all the same it looks like the B&C driver could be a contender for the next logical step up from the 220ti.
That crossover witchcraft is also interesting. Maybe I will incorporate it when
I upgrade my drivers. Or maybe it would take the place of upgrading my drivers! So many decisions... I feel pretty lucky to have decisions like this to make!
up being nifty designs...
all the same it looks like the B&C driver could be a contender for the next logical step up from the 220ti.
That crossover witchcraft is also interesting. Maybe I will incorporate it when
I upgrade my drivers. Or maybe it would take the place of upgrading my drivers! So many decisions...
I feel pretty lucky to have decisions like this to make!
The problem is that a capacitor has a "memory". The dielectric material doesn't allow the signal to smoothly pass through 0 volts. When a cap is charged in a + direction the dielectric is stable. As the voltage goes down it discharges until you get to 0. At 0 there is a sticky point where it has to start recharging. Then you go in the - direction. The same will happen as you cross 0 going from - to +.
It's somewhat like static friction in a sliding joint. You have to overcome that threshhold before the joint will slide smoothly. Think of pushing a car. It's hard to get it going, but once it's moving it's not so hard to keep it going. It's the same type of effect. If you were going to vary the speed of a car you were pushing by 1mph peak to peak it would be easier and smoother to use 2mph as your reference and vary the speed between 1 and 3mph than it would to start from a stop, go up to 1mph, stop, pull backwards to 1mph, etc.
That's the same principal as in the CC crossover. You're keeping the capacitors from that 0 crossing where they stall.
Did that help any?
Ray
skywave-rider
Slumming in Akihabara
Cc
From reading those brief Timbers pages, he's boiling it down to two ideas, which I assume are supported in more detail elsewhere.
1. Stabilizing the dielectric via the charge, reducing capacitive "hysteresis."
2. Applying DC bias to move the waveform above the zero crossing.
When you think about it, both points make sense. Paratima wants to see cause and effect, however. How to measure this? In #1, IIRC, he's making more of a subjective evaluation. For #2, I assume a sine wave test will settle it. Am I missing something?
From reading those brief Timbers pages, he's boiling it down to two ideas, which I assume are supported in more detail elsewhere.
1. Stabilizing the dielectric via the charge, reducing capacitive "hysteresis."
2. Applying DC bias to move the waveform above the zero crossing.
When you think about it, both points make sense. Paratima wants to see cause and effect, however. How to measure this? In #1, IIRC, he's making more of a subjective evaluation. For #2, I assume a sine wave test will settle it. Am I missing something?
Paratima
E'Wavin'
I believe that it made a positive difference for you, Russell, and I'm happy for you.
I fully intend to give it a try, perhaps several.
I do care. I want to know why everything works, one thing at a time. First, I want to know what the problem is that's being fixed and be able to measure it. Second, I want to know why cap charging fixes the problem and be able to measure the amount of change. Y'see, if we can measure it, it's science and we can understand it. If we can't, it's voodoo, like Monster Cables at $100 per foot. Trust me; it works! Just hand over your cash and sign here.
Tubino: I've read it several times. Greg Timbers saying, "Trust me".
Ray and Skywave: Most of my o'scope work was with digital circuits. OK, make that "All".
Never had any problems with 0 changing into 1's or vice-versa. Is there actually a "sticking point" at 0 volts? It seems to me that that would tend to distort the signal pretty severely, maybe even affect the frequency. Surely that is testable. I sold my scope many moons ago, when I stopped designing (digital) circuits, but I may just go on the 'Bay and pick one up to settle this. It shouldn't be that tough.As an aside, sort of, I know that I get better mileage from my car if I don't stop, but just coast down and then speed back up. I'm changing from deceleration to acceleration and not going through zero (stopped). That fits Ray's description. I just don't know how (or if) it applies to capacitive reactance. Guess I should have stayed awake during that course, huh? :worried:
Bauhausler
Rational Subjectivist
RusselC: There are good reasons that people are not just trying this despite the small parts count. It's a technical change that does increase the cost of the crossover. Many of us would undertake that only with a sound scientific basis behind the idea. I understand from reading the white paper on the K2.S5500 what they SAY it does but they don't cite any evidence that the capacitor bias produces measurable effects that have audible consequences. This is the hallmark of sound technology: measurable results that can be repeated by anyone. I'm not saying it's snake oil, just that they should at least send a sample to the lab and show us that the composition lacks all reptile ingredients.
Lots of us have been down this road before with unsupported audiophile tweaks. I've spent fortunes on power cords, speaker cables, interconnects, green paint for CDs, contact treatments, record weights, tube dampers, special plugs, footers, shelves, tuning cones and myriad audiophile folderol. Those products ranged from moderately useful to outright lies. The best and most reliable tweaks are those that have some science behind them.
When I built my EWave crossovers I spent an extra hour sorting resistors and capacitors to match them up within a couple of percent between channels. I know the differences between the drivers and other variables in the system swamp the small variations in the crossovers, but component values are one thing that I can control so I make sure my parts are in tight tolerance.
I'm not saying I won't try the biased crossover for my next pair of ewaves but I probably won't devote much cost or time to the experiment unless some hard evidence comes up.
The seriesed capacitors issue brings up another possibility for testing for the audibility of the bias effect. Since they're seriesed, polarized caps could be used in this circuit. All of the crossovers we've been building have used film caps so far because the values are small. In place of the .47 film cap, a pair of 1uf 25V electrolytics could be used. The positive terminals would be placed together and that would be the +9vdc bias point. 1uf 25VDC electrolytics are WAY smaller than film caps. They should have advantages in terms of inductance. Also, the dielectric should have a much less linear characteristic around zero than a film cap. This means that if there is any audible effect from biasing it should be very clearly heard using back to back electrolytics. If the sound of back to back electrolytics did not improve with biasing then I would seriously doubt that biasing film caps could have an audible effect in that application.
You could even raise the stakes: in place of a .47uf film cap use a .5uf film cap in series with a 100uf 25V polar electrolytic. If there's a benefit to polarizing a dielectric, you'd definitely hear it there.
Lots of us have been down this road before with unsupported audiophile tweaks. I've spent fortunes on power cords, speaker cables, interconnects, green paint for CDs, contact treatments, record weights, tube dampers, special plugs, footers, shelves, tuning cones and myriad audiophile folderol. Those products ranged from moderately useful to outright lies. The best and most reliable tweaks are those that have some science behind them.
When I built my EWave crossovers I spent an extra hour sorting resistors and capacitors to match them up within a couple of percent between channels. I know the differences between the drivers and other variables in the system swamp the small variations in the crossovers, but component values are one thing that I can control so I make sure my parts are in tight tolerance.
I'm not saying I won't try the biased crossover for my next pair of ewaves but I probably won't devote much cost or time to the experiment unless some hard evidence comes up.
The seriesed capacitors issue brings up another possibility for testing for the audibility of the bias effect. Since they're seriesed, polarized caps could be used in this circuit. All of the crossovers we've been building have used film caps so far because the values are small. In place of the .47 film cap, a pair of 1uf 25V electrolytics could be used. The positive terminals would be placed together and that would be the +9vdc bias point. 1uf 25VDC electrolytics are WAY smaller than film caps. They should have advantages in terms of inductance. Also, the dielectric should have a much less linear characteristic around zero than a film cap. This means that if there is any audible effect from biasing it should be very clearly heard using back to back electrolytics. If the sound of back to back electrolytics did not improve with biasing then I would seriously doubt that biasing film caps could have an audible effect in that application.
You could even raise the stakes: in place of a .47uf film cap use a .5uf film cap in series with a 100uf 25V polar electrolytic. If there's a benefit to polarizing a dielectric, you'd definitely hear it there.
skywave-rider
Slumming in Akihabara
:thmbsp: