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Are Your Capacitors Installed Backwards ??


Kreg

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4 hours ago, wvu80 said:

Anyone is allowed to take on any of my opinions by saying "I disagree with you Dave because you said "X."  No one has the right to say "Dave you're an idiot."  It's not OK.

 

BTW I'll be deleting my last few posts on the issue because I'd like to see a minor course correction away from personal attacks and I don't want to be guilty of the same thing I'm complaining about.

Thank you for posting this!!! I wondered why you deleted several posts in a discussion we were having after I pointed out something similar in your responses. 

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btw - at the High Efficiency section of Audio Asylum, Tom Danley says he will give a look for those files regarding his VOTT mod - of course they will only directly pertain to use of JBL2226 and BMS 4550 (IIRC?) but the crossover approach would be interesting and adaptable to the original drivers.  Tom tuned VOTT much lower - that may be a matter of taste as some like the original voicing more than a flatter response.

 

https://www.audioasylum.com/forums/hug/messages/18/183044.html

 

 "- - Keep in mind that normal crossovers like Butterworth, L&R and so on, normally do have a "time offset" (phase shift) between highs and lows at 90 degrees times the order of the slope so that when the acoustic centers are "time aligned", what results acoustically at the listening position has the low delayed relative to the highs, a normal condition which is listenable, technically does not preserve the signal wave shape for example.

An ideal truly coherent crossover is possible although more difficult to achieve but it will show no phase shift through crossover and ideally radiates that way on every direction, as if the upper and lower source were a single ideal source in time and space as Heyser once wrote of near the end of his life and has obviously been a target of mine for about 20 years now..

I saw your post about the A7 mods, I don't remember where those files are but if I can find them, I will send them to you. I do remember afterwards, it had about an octave more response at both ends and picked up some a little sensitivity (due to the driver change to a bms4550 hf and JBL2226 lf and re-tuning the ports . I had to move the horn back a couple inches but did end up with a Synergy style crossover (no no crossover phase shift) and it sounded quote good.
Hope you're doing well
Tom"
 

 

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Here's a page which should be helpful on measuring time delay with either ARTA, or Room EQ Wizard

https://www.diymobileaudio.com/forum/technical-advanced-car-audio-discussion/145484-measure-time-delay-t-arta-roomeq.html

 

Here's a page with a Hiraga take on VOTT crossover

http://www.vtaf.com/id107.html

 

When Tom Danley speaks of his Synergy series crossover,  I've not been able to hear any of those. (I've not driven for 25+ years, no mobility to travel to hear anything and my kid is paralyzed - so he can't drive) - but I do have Tom's old Unity prototype and in its range, its subjectively more coherent than a full range single driver  - lol - so if he can come up with that old VOTT info, that should be quite interesting.

 

A Unity horn biamped on top of a K-horn might be pretty good - is that arrangement used by some of the Klipsch-community?

 

 

 

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    I really enjoy the fresh ideas. Jeff has allowed a maybe one page topic grow to 29. Got to say many ideas do not appeal. The GTO caps, rats nest wiring, old VOTT speakers are all of no interest. 

  I gave up on SET amps a long time ago. Two have two in the attic. Do not like the distortion and colorations. Many prefer the effect over solid state.

 Will not make a three wire cable for use in the system. If one was made they would be braided together. The 8 ga single cable used by Decware is not the same as two 12’s and a 16 ga tied together. Decware is way out there also. 

  No golf balls, tape rolls, or pavers. 

  There are ideas of Jeff’s I did implement. 

  The composite 8a wire made me look at the 16 ga used initially. Paralleled two 16 ga to make 13 ga for the woofer and two 20 ga wires for a 17 ga to mid/tweeters. 

  The length needed to be 9 -10 feet to reach from the amp to the speakers. So made them a multiple of 57.1235 at 114.250 inches. Not sure how you measure this. So mine are exactly 114.25.

  I think the system does sound better. Cannot pinpoint if it is using a Star Quad speaker cable now, larger ga wiring, a length close to the magic length. 

  But without Jeff’s sharing of ideas I would still be using a 9’ pair of 16 ga cables on each speaker. 

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Many times just changing wires helps regardless of ga.  Wires can build up surface corrosion and connectors can loosen over time.  I've fixed several speakers just by loosening and tightening the screws on the crossover.   The difference wasn't subtle.

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Curious, silver in it self has a different tone to it, in my experience making a speaker brighter than with just pure copper.  So has this magic length wire been tested with pure conventional copper wire? Same deal with the "combo" wires, has there been any testing with a different "mix" of gauge wire with and without silver being used? Again has this been tested with the wire combo being braided or not?  I would venture to say that the silver content in the wire is by far the single most influential part and the rest has little to no value.

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It has yet to be established whether the magical length is between the amplifier output terminals and the speaker input terminals, or includes anything inside either of them.  Of course it's a rhetorical question because if there were any merit whatsoever to the concept, it would have to be from output device to input device or it would be utterly meaningless.  That means from the transistor lead (or output transformer) to the voice coil terminal.  Or would it be from the transistor junction to the place the voice coil lead initially forms the coil itself (likewise the case of an output transformer)?  And does it include the length of wire inside a crossover inductor, or exclude that?  And what do you do with a crossover capacitor which completely breaks the continuity of the run?

 

If the notion didn't seem ridiculous (for audio frequencies, especially!) at the outset, taking it to it's logical conclusion (rather, inclusion) as I've done above, must surely illuminate the utter nonsense of the whole idea.

 

I wonder what's to be done with any excess wire if the recipe is followed.  Is it haphazardly lain about or is it neatly coiled?  If coiled wouldn't it form an inductor?  Perhaps inconsequentially so if done in figure 8s with the crossings at right angles...

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44 minutes ago, glens said:

It has yet to be established whether the magical length is between the amplifier output terminals and the speaker input terminals, or includes anything inside either of them.  

  I have no idea how to measure the cables either. That is how I know they are exactly 114.25 inches. 

  It is starting to rub off on me.

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[ edit: add this note - Jeff's reply was not here yet when I started this one on my phone having a smoke in the garage -- the proper 1/4 of 57-1/8 is 14-9/32, not 14-1/4 -- but it still begs the question "is that tip-to-tip or center-of-terminal-to-center-of-terminal?"  ]

 

3 hours ago, Alexander said:

Jeffry, can you explain what your magic number (length) represents? 1/4, 1/2, a single wave or even a multiple of some given frequency? My amateur radio side is wanting to know what it might mean.  

 

One of his mentors was asked to improve the output of an audio driver at 60 kHz and that's how the magic number was derived.  Might've been around page 7?  I think it was for pest control.  On a side note I remember in the later '70s hearing a story about someone using that JBL tweeter that had a vertical slot with a clear plastic phase plug that came to a ridge down the middle being used for rat control at 40 kHz.  On the page in this thread where the magic number came up I pointed to the official time broadcast at that frequency and did the math on the wavelength.  It wasn't an exact factor of the frequency (though close-enough I suppose if amplifier internal wiring were added?).  I didn't think to check it against the 40 kHz frequency as I remember it being in the story.  Maybe I'll do that later...

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5 minutes ago, glens said:

 

One of his mentors was asked to improve the output of an audio driver at 60 kHz and that's how the magic number was derived.  Might've been around page 7?  I think it was for pest control.  On a side note I remember in the later '70s hearing a story about someone using that JBL tweeter that had a vertical slot with a clear plastic phase plug that came to a ridge down the middle being used for rat control at 40 kHz.  On the page in this thread where the magic number came up I pointed to the official time broadcast at that frequency and did the math on the wavelength.  It wasn't an exact factor of the frequency (though close-enough I suppose if amplifier internal wiring were added?).  I didn't think to check it against the 40 kHz frequency as I remember it being in the story.  Maybe I'll do that later...

And the wire length was? :D

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back in the 1980's Schitt's designer Mike Moffat used Teflon (IIRC) for his Theta 6dj8 phono preamplifier pc board's dielectric (guess that's quite cost prohibitive vs fiberglass plus issue of getting the copper to stick) .  Scott Frankland and Bruce Moore (subjectively) preferred point to point wiring in their tube preamp and amps to common pc board.  PC board sure makes things easier to service in tube equipment vs dense "rat's nests".  How do metal chassis ferrous and otherwise affect capacitors which are in proximity to the chassis' walls?

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4 hours ago, karlson3 said:

Alexander - is that roughly 50MHz 1/4 wave?

 

 

If 57.125" represents a 1/4 wave then yes it is just over 49MHz (just below the 6 meter band of 50-54MHz)

 

The formula is  468!/freq in MHz = 1/2 wave length in feet

 

! - 472 is some times used to adjust to real world antenna variables

 

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