capacitor phools

[W3SLK]

Don said:

I once heard a tale about when the old VOA transmitter site in Mason, OH lost an antenna wire on their big array.  The transmitter was on the air when a support cable or insulator broke.  As the wire separated, it left a tremendous rf arc for a brief instant, caused by tens of kilowatts of modulated AM.  Supposedly, the modulation was clearly audible for miles.

There's an AMer out of Kingston, NC, (name & call escape me now), who used to work for the VOA down there. He too said that when an insulator on the feed-line would crack, you could hear, (and see) the modulation. He said that the insulators would explode soon after in a display of sparks.

[Steve - WB3HUZ]

W4KBQ?

Don said:

I once heard a tale about when the old VOA transmitter site in Mason, OH lost an antenna wire on their big array.  The transmitter was on the air when a support cable or insulator broke.  As the wire separated, it left a tremendous rf arc for a brief instant, caused by tens of kilowatts of modulated AM.  Supposedly, the modulation was clearly audible for miles.

There's an AMer out of Kingston, NC, (name & call escape me now), who used to work for the VOA down there. He too said that when an insulator on the feed-line would crack, you could hear, (and see) the modulation. He said that the insulators would explode soon after in a display of sparks.

[W3SLK]

That be him Steve!

[WBear2GCR]

Yeah Don,

There are quite a few DIYers sites on this and more sophisticated units.

This guy is typical:

DISADVANTAGES
-Can start fires
-Arc is a veritable nitric acid factory; must be in    ventilated area
-Extremely inefficient
-Causes RF interference
-Multiple HV voltages required

Nitric acid? Really? I mean maybe, but that's the first I've heard of it.
How about Ozone.

and "Causes RF interference"
Yeah, because you didn't bother to put a grounded screen around it? Duh.

And, he is running on an illegal frequency. They have to be run on 27.xxMhz. at least in the USA, the freq assigned for these various home RF generating things.

If you do a google you can find the Magnat tweeter from Germany and although I can't recall the name at the moment there is a current production horn loaded unit also from Germany that is beautifully built.

[k4kyv]

And, he is running on an illegal frequency. They have to be run on 27.xxMhz. at least in the USA, the freq assigned for these various home RF generating things.

Yes, the ISM band (industrial-scientific-medical).  Our old 11m band, that had to accept interference from those devices.  Later became CB.

An old good-buddy rig would make a cheap, readily available, ready-to-go rf exciter for the device.

[VE7 Kilohertz]

Yeah Don,

That was likely the Ionofane or Ionovac.

There are/were many other "plasma" tweeters and speakers.
The king of all was the Hill Plasmatronic. Google it.

Today there are still a number of plasma speakers, the downside for most of them is twofold, first the plasma makes a small but discernable hiss, and they generally require a horn to match to the air.

          _-_-bear

Woooo, you guys are stirring the ol' memory bank. I HAD a set of those tweeters, sort of a hammer tone blue paint finish, like the door on a GE 250 watt TX.  Horn loaded, seperate power supplies...way cool.  Not much good below about 8-10KC IIRC.

Anyone have the Dayton Wright pre-preamp?  Many dozens of xstrs all paralelled to make a really low Z moving coil preamp.
How about the old Quad seat back ESL speakers?

Cool stuff

Paul

[WBear2GCR]

Right, and a constant hiss... if you still had any HF hearing left...

The Dayton-Wright preamp used a standard technique for gettin lower noise out of devices - works for toobes too!

The Quad ESL is to this very day an outstanding performer. The designer Peter Walker really knew his stuff. The limitation of the Quad 57 is output level and bass, but the rest is almost as good as you can get even today!

              _-_-bear

[Opcom]

a review of this tube type car stereo amplifier:
http://milbert.com/bam235ab

The critic writes:
"...The sound of this amplifier is exceptional, far beyond anything I expected from a state-of-the-art car stereo. How can I describe the sound? With shrieks and tears and screams."

- This is the kind of claptrap I find humorous.. Maybe he stuck his finger into the amp and was describing the sounds he made.

The unique thing is that the tubes drive a mosfet buck converter to convert their high-Z signal to low-Z to run the speakers. What good is that? no iron!! In defense of the amp, it does have "Auto-Plasma-Bias ™"

[WBear2GCR]

I did not see a mention of the mosfet buck converter... did I miss it?
Says: "10 tubes no transistors..."

Depending on how (if?) they did the above trick, it could be a violation of a patent by David Berning - although I doubt that they are as clever as Berning is, or else his patent expired.

                          _-_-bear

[Opcom]

I thought it was the Berning design, recalling the schematic in the patent. Maybe I have the wrong amp cited. I've read that the BaM is the 12VDC operated version of the Berning EA-230.

http://www.davidberning.com/products/qz

notice the voltage warning on the PC board..

So, are they the same? There was a picture of the Milbert amp with the cover off, but don't see it now. I believe it had the two HF output transformers, could have been looking at the EA-230, but did not see any large plate transformer which would be expected in a home stereo amp.

Could the Milbert be just a parallel set of totem pole tubes? We've seen that design for decades as the transformerless amp with three 6080's or 6AS7's and a couple of voltage doublers operating right of the 120V line.
http://k-amps.8m.com/cgi-bin/i/PowerAmps/Vacuum/6AS7OTL.gif

Another of Berning's patents seems to copy the old screen-driven class B 807 modulator from the ARRL handbook. Probably sounds better though.
http://www.davidberning.com/technology/patent3995226


In any case it was the review I was citing for amusement. the shrieking and screaming.. too funny.

[WBear2GCR]

Dunno I didn't see much on the Milbert page/site... did I miss it??
Where?

The Berning design is clever, but not without some issues regarding the lag of the switching supply vs the input signal to the upper tube...

And, for $29 grand, I think I want a cleaner, better built and laid out implementation...


                 _-_-bear

[w3jn]

Here's an article on a full range flame loudspeaker.  I remember mention of same in an old Audio Cyclopedia, but this article has a lot mroe detail.

http://www.4x4pride.org/Flame/Docs/FlameAmp/FlameAmp.html

[Opcom]

      one morning on 75 AM Nick KG2IR, who was an engineer at Harmon Kardon explained exactly why they used certain "Black Beauty" caps in a famous high end amp they desinged. it had something to do with low price and availability. i'll try to remember to have him tell that story again, and record it. it really sets the record straight. it's the truth, and the "audiophillies" ain't gonna like it. Bear- if you make you living off these folks and make happy runs to the bank with their money, well then more power to ya OM! personally i think most of it is hogwash.

      have any of my fellow gunners on AM tried Oxygen Free Copper bullets for handloads yet? do they increase muzzle velocity and energy? do they give more consistent groups? should i cryogenically treat my brass cases before they hit the resizing dies? this could be a new market for metalurgical tomfoolery! plenty of shooters are like audiophillies and will buy about anything claiming to make their irons shoot better. these also are the same folks who couldn't hit a deer six feet in front of them with a 20MM cannon... i like to keep it simple. simple and low tech just works. my 100 year old Mausers hit coffee cans at 100 yards easily, and the ceramic caps i use in my audio chains sound just fine thank you.

I've always wanted to load some saboted shotgun shells with aerodynamic machined steel sabots tipped with a bit of tool steel. Alas, I cannot get depleted uranium. I think maybe for po folks, drilling the center of the lead slug and fixing a ball bearing could improve hitting power. For the rifles, there is always steel core ammo. Hard to get (or costly) now. Once upon a time, there was a kind of shotgun ammo called "Blammo". Had a primer in each end. One must protect one's costly AM station.
check this, completely different  - http://www.youtube.com/watch?v=xNPGvPa9NeQ&NR=1

[Opcom]

But back to the capacitors - I try to use plastic 'brick' (poly whatever -no electrolytics) and old oil-filled caps whenever possible when doing coupling or bypassing in audio amplifiers and loudspeakers, respectively. That goes for air core coils in crossovers too. I will use orange drops and look-alikes as well and I like their performance just fine in my audio amplifiers. I believe that using a higher voltage plastic or otherwise monolithic capacitor (like 2x-3x the required value) improves the performance, but I cannot prove it.

It is true that putting better components in a system improves the fidelity. There are white papers concerning capacitor selection for ADSL modems that dig into this in detail, even differentiating between different constructions and materials of otherwise identical-seeming monolithic capacitors, and while DSL techniqies are not audio, they are extremely demaning of linearity and symmetry to keep the data rate high. One thing noted was that the best performance seemed to come from the more costly capacitors.

For radio, it comes down to the bottom line, that on the other end of the transmission, after your signal is detected and goes though whatever electrolytics, ricebox DSP, and snazzy 2-way speaker with 6" woofer and 1" dome tweeter the other guy is listening with, he will not hear or measure the difference. There's nothing wrong with using better quality parts on one's TX end, as long as one understands that the point of diminishing return has been passed once the signal leaves the antenna. Anything more is grape nuts and fruit.

[k4kyv]

Are those alleged subtle and minuscule improvements resulting from such things as silk dielectric capacitors, oxygen-free copper wire, gold-plated connectors, $600 power cords, high-end speaker cable and other questionable-but-expensive audiophoolery, supposed to actually make the music-listening experience more enjoyable, or is this simply to satisfy the desire of a hobbyist cult to gain a little more "perfection" in reproduction, whether real or imagined?

A noteworthy analogy lies within the amateur radio AM community.  We may take pride that our AM transmitters are capable of transmitting an undistorted frequency response at 100% modulation that goes down to 30 Hz or lower, and spend many hours experimenting and modifying our rigs to achieve that goal.  In reality, for voice transmission, undistorted low end down to maybe 80 Hz is more than sufficient for near-perfect voice  reproduction.  The only benefit from undistorted 20 Hz capability would be for music reproduction, which is not legal to transmit via amateur radio.  We work towards this goal solely for the sake of pride of accomplishment, since it will unlikely make an iota of improvement to what our audio actually sounds like at the other end of a QSO, except for incidental improvements to the audio response and distortion characteristics that would likely accompany our careful and prolonged efforts.

Many of the UTC Linear Standard series transformers tout frequency responses down to 7 Hz.  The fine print in the catalogues explains that for distortion-free low end, you need the response to be essentially flat down to about one third the lowest frequency the transformer is actually expected to handle.  So, for distortion-free voice response down to 80 Hz, this implies that the transformers and other components in the modulator need to be flat down to about 26 Hz.  Many converted broadcast rigs, or homebrew rigs constructed from broadcast components should be capable of going down to at least 30~, but I doubt that many of us have a flat response all way down to 7 Hz.

OTOH, doesn't this imply that with "communications grade" audio that has all those "useless lows" sharply cut off below 300 Hz, that everything below about 900 Hz is going to sound like crap?

[WBear2GCR]

Don,

The stuff has an effect.
Some is bogus, but really not all that much...

The only questions are:
- is the effect good?
- is it worth the money?
- can you hear it?
- and do you care?

Otherwise it is just fancy art/sculpture for your room...

                        _-_-bear

[WBear2GCR]

Hope this helps:

http://gboers.xs4all.nl/daisy/home/g3/139/measure/capacitor-comparison.html

          _-_-

[kb3nqd]

AudioPhiles kill me...I used to be one (it was a very expensive hobby).  My college roommate was much more serious about the hobby than me.  I have fond memories of him trying to drive his flat ribbon speakers with a woefully underpowered Carver amp that made all the lights in our apartment go dim.  Many audiophiles spend 100s of thousands of dollars in pursuit of the perfect "live" concert hall sound.  My opinion is that it would be cheaper for them to go to concert halls on a regular basis.  What I find the most amazing though is the same people that will pay 2K or better for monster cables usually won't spend a penny remodeling their home for improved acoustic response.  There are exceptions to this rule but they tend to be rare.  I guess we all need something to spend our money on.  I'll stick to boatanchors for now.

[Opcom]

Are those alleged subtle and minuscule improvements resulting from such things as silk dielectric capacitors, oxygen-free copper wire, gold-plated connectors, $600 power cords, high-end speaker cable and other questionable-but-expensive audiophoolery, supposed to actually make the music-listening experience more enjoyable, or is this simply to satisfy the desire of a hobbyist cult to gain a little more "perfection" in reproduction, whether real or imagined?

Oh heck no. what we did in the lab was measurable science. No snake oil, only good parts from major manufacturers with fully documented specifications and guaranted performance.

[KI4YAN]

Let's see this Disputed:

http://members.aol.com/sbench102/caps.html

Steve Bench, by the way, is a competent audio designer. Zero Bullshit on his pages, although he does cater to the audiophool types with this No R no C designs-Which, by the way, were done just to prove a point, not to specifically eliminate anything.

Now, do I believe in the "Magic Capacitors"? No, nothing is magic. But some types of capacitors are better suited to different services. I certainly don't use my Sr-Ti doorknob caps as DC blocking caps in a transmitter, but rather in the Nitrogen laser sitting on the bench across the room...

[WBear2GCR]

Steve Bench's tests that you linked show some things, and not others.
SInce he was not on axis with his camera, and it appears to be a non-flat CRT, it's really difficult to compare visually what he tested.

I'd think that there needs to be some expansion, or magnification of the curves, perhaps an overlay to visually see some differences.

Also he used rather LF for testing, not sure that is optimal for revealing cap diffs...

Regardless, there have been some other tests that perhaps are more telling...

In most ham applications, it is all moot...

            _-_-bear

[WU2D]

Listen to Capacitor Girl - she knows...
http://www.oldsoundequipment.com/capacitor%20girl.html

Mike WU2D

[Opcom]

she'd be OK if she'd trim those nails! They look like big square chisels!

[wavebourn]

Speaking of capacitors and more;

Do you know what happens when distance between plates change?

Do you know about repulsion and attraction of plates under a voltage?

Do you know about mechanical resonances in capacitors?

Do you know about change of dielectric properties mechanically and electrically?

If at least you answered "Yes" on one of my questions above, why you don't believe that capacitors add specific distortions and character of them depends on how particular capacitor was made, and what materials were used?

Now, do you know that current heats a conductor?

Do you know that heat changes resistance of conductors?

Do you believe now that resistors add distortions?

[k4kyv]

she'd be OK if she'd trim those nails! They look like big square chisels!

I like the Battery Girls at Dayton better than this Capacitor Girl.