old autoformers....

[Deang]

I rebuilt some Type A's for someone who opted to keep his T2A's. The networks were built with identical parts as my Type A's with the exception of the autotransformers. My Klipschorns had been loaded with my Type A's for about a week, and I pulled them out to put the newly built ones in for a listen. When I turned it up, the highs sounded compressed and the cymbals sounded splashy and dry. I listened to the CD the rest of the way through, and then loaded my Type A's back in -- different. I initially put it down to cap break-in, but since everyone insists there's no such thing, I decided it probably did make more sense to attribute it to the only thing on the boards that wasn't the same -- the autotransformers. I don't mean to hear these things -- I just do.

[awsjr]

thanks to everyone for their thoughts and experience......in the

crossovers I have rebuilt I have replaced the autoformers with ones

from BEC......I always like new....caps, wire, inductors.....the

works.....now I have a collection of old stuff....by the way, off topic

but I changed the tweeters in my Belles to JBL 2404s and they are

awesome (with ALK crossovers).....thanks again -Al

[BEC]

Guess I should make a serious comment to this thread. I have not found a T2A that I thought needed replacing out of the few hundred crossovers I have rebuilt. I do test every one of them for attenuation and frequency response. I would catch one that was as much as 1 db out. The new 3619s and 3636s are technically better built than the original T2A but that is not saying that the T2A is not "good enough".

Dean,

How can the autotransformer effect the highs in a type A crossover?

End of serious comment.

Having said all that, I think replacing the T2As is a good thing to do. I have 25 more new autotransformers arriving today from the factory and need to move them.

Bob Crites

[3dzapper]

Bob, you crass selfpromoter![]

I have been following this thread with great interest. Soon I will be rebuilding or replacing the type AAs in my "new" Belles. I think that Dean has convinced me to go with all new components including the inductors and autoformer. Now I must ask myself if I am going to build A/AA convertable networks or spend a little more to build new ALK type As. The latter would match the networks in my Khorns and LaScala.

Rick

[D-MAN]

I'll see that and raise you $500...

Do you guys think that subjecting passive components to vibration (as in the Khorn back chamber; pressure changes + vibration) effects the sound? Decreased component life seems like a given, to me.

Here's another: does vibrating wiring alter the sound?

DM

[Deang]

How can the autotransformer effect the highs in a type A crossover?

Bob -- the fundamental notes of cymbals sit between 300Hz and 1kHz. The shimmer at the very tippy top sits at 7.5kHz. Regardless of the network -- the majority of what we hear in cymbal work is actually covered by the squawker. In the old networks, the squawker is still generating considerable output at 7kHz, and that 2uF cap on the tweeter is just starting to bring the tweeter to a level above the squawker. Try it -- terminate your tweeters with 8 ohm resistors and listen.

I don't know, it just seems to me that "upgrading" a network should entail upgrading the whole network. To me, that means the best parts and/or a better circuit. I haven't done hundreds of rebuilds like you have, but the ones that have been sent to me had autotransformers that amounted to being nothing more than rust-buckets. When the windings are so loose that you can swivel the solder tabs I think they're ready for the trash can. Wire wound around a core should be tight/solid -- and able to withstand mechanical stresses without impacting its performance (Cornwall and Heresy). I see the autotransformer as a part that passes four octaves of music -- and I just think it's a good idea to go with the best built part available. If there is a performance edge -- I want it.

[BEC]

Dean,

Dang it! You are trying to make me argue against my own interest.

Yes, I have seen a good number of "rust bucket" T2As in my rebuilds. But, they have without exception run right on up from the crossover point to 20 Khz straight as an arrow and flat as a pancake. I just can't see the mechanism that would cause what you describe.

Honestly, I thought by now I would have found some that would not pass. I think the oldest ones I have tested were from 1963. They must have used pretty good coatings on the windings from early days and until those coatings deteriorate and cause a short in the windings, looks to me like they will be good as they were when new.

Bob

[Deang]

Bob -- I read somewhere that an inductor with loose windings will go all over the place when subjected to vibration. But like Dennis said, an autoformer isn't acting as an inductor but as an attenuator. Maybe I shouldn't have assumed the difference I heard was related to the different autoformers. Hey, I'm much more comfortable putting it down to cap break-in anyways.

After I posted I got to thinking about cymbals and where the tweeter comes in at with the 2uF cap. After I got done doing some things around the house I grabbed a bunch of caps, some lead wires with alligator clips attached, and one of your K-77's. I hooked a speaker cable up to my little Teac, and just put the 2uF cap in between the amp and tweeter. I fired up the RTA, sat the tweeter on the floor in front of me, and put the mic on my knee. If I can trust the Behringer and the microphone -- it shows the tweeter well into the game at 5kHz. Just looking at numbers, I never would have imagined there being that much output at that point.

With that out of the way, I thought it would be a good time to check out Hardhead's theory about harshness coming from the tweeter -- so I took the volume control to 11. There wasn't any harshness that I could detect -- so I called Deb upstairs for a listen and asked her if it "hurt" her ears. She said it was just annoying listening only to a tweeter, but didn't hear anything objectionable. She started to leave and I asked her to hang on a minute -- and I pulled the 2uF Kimber off the clips and stuck in a 3.3uF Solen film and foil. "That's too much". "What do you mean that's too much?". "It hurts my ears".

If you set out the crow, I'll eat it.

Edited 12:01AM: I'm only going to eat a little bit of crow, not all of it. I just realized how much power I was running into that tweeter. Someone would have to drop a 100 wpc into their Klipschorns before they hear that tweeter the way Deb and me were listening to it earlier.

[WMcD]

I liked DeanG's test protocol. Another board member reported that his daughter, a teen at the time, commented on the change in sound with the addition of the P-Trap without any notice of the modification to her. As you know the, P-Trap notches out the 9 kHz artifact in the K-55-V.

So my guess is that our female friends do have more sensitve hearing to treble, if not other frequencies.

Regarding the effect of vibration on wires. I will not get cranky on this one, i.e. say that it is up to the one proposing there a change should prove it with hard data. Forgive my "attitude" elsewhere.

This is because I think we have all the testing we need: The winding in the voice coils of our drivers are subject to intense vibration. They in fact cause it. Remeber, the voice coil pushes and pulls against the magnetic field of the magent. The magnet is stationar.

Further, the wire in the voice coil is most likely similar or the same as used in transformer / inductor / autotransformer windings. In this case the wire is prone to heating, too. Then you have the winding in generators and motors spinning around 'til it is dizzy. No problems.

Of course if you want to argue that the wire used to wire point to point in the x-over is different and could wear out or develope the electrical equivalent of a nervous breakdown . . . I just wouldn't know.

Smile,

Gil

[D-MAN]

Ok, I'll try to point out some issues. I have no empirical data to show.

First, everyone has heard that subjecting amplifiers (pre and power) to vibration alters the performance. Hence aftermarket "feet", "points" and "cones" amongst various other pads, stands, cushions, etc. This sets up the point that vibration of electronic components can cause sonic degredation. Since they have virtually no moving parts to speak of, how can that possibly be the case? Anyone who has experimented with this already knows that it is quite true.

Second, mechanical movement caused by vibration causes stress. Metal fatigue, stress fractures, solder joint failure, component failure. Add heat, current flow and its effects on metalugy (i.e., magnetization) and oxidation to that. Now even wires can experience problems with efficient conduction, even breaking, but if even a few strands break or become overly resistive in a small wire...

Third, everyone has heard of the various studies concerning EMF especially about the high-power transmission lines causing potential health problems by living in proximity. It's measurable. So the fact that wires act as inductive sources of EMF (magnetic fields of flux) around themselves is inarguable, is it not?

The US Navy used inductive pickups to monitor underwater telephone cables in Soviet waters in the 80's. No physical contact needed with the conductor itself. Just a close proximity...

Wire acts as an inductor regardless of the amount of current being transmitted, although of course, the strength of the field flux is directly proportional to the amount of current flow, and it ALWAYS produces an electromagnetic field around itself when current is flowing, efforts at shielding notwithstanding. It may be small, but it is there, and is measurable. Vibrating the source of that flux field alters the field "size" in that the flux field is reasonably stationary and the wire producing it moves within the field due to vibration, of course, and that takes (builds) or gives (collapses) EM energy depending on the geometry involved. The "motor" effect, in other words. I suspect that the field could not be acurately measured if the wire producing it is vibrating, and it should be understood that the field will have a lag in following the vibrating wire again dependent on field strength (ie. distance from the conductor).

For example, the EF is not physically connected to the wire, but the wire, being physical, can move due to other forces and disrupt the expanded field by proximal changes REGARDLESS of signal current. That is, the field blossom is dependent on proximity to current flow and will exibit lag time in building or collapsing to a degree (also measurable). The question remains; how is the blossomed flux field effected by the source inductor moving within the blossomed field due to vibration? What is the effect on the signal from intermitant EM field behaviour (i.e., not due to signal current) due to inductor movements?

Now this assumes that the EM flux field is interactive with the inductive source current flow, rather than a passive proportional artifact of current flow itself. It would conceivably be more "passive" with a stationary wire.

The bottom line is that all wires as well as all other components in the signal path, active or passive, should be as stable as possible for the best sonic effect as well as promoting component longevity.

I know that some of you think that wire is immaterial to what you perceive in hearing, and I do not. Consider wire important, if you want an edge in performance. Otherwise, my system will always sound better than yours! nah-na-na-na-na-nah (childish yet seemingly universal taunt heard in every playground around the world).

DM

[BEC]

D-MAN,

In the immortal words of Lee Iacocca speaking to Snoop Dogg in the current Chrysler commercial:

"You know, I'm not too sure what you just said."

Bob

[D-MAN]

Dang, Bob! that was alot of typing - I went to alot of trouble!

Sheesh!

DM[]

[WMcD]

D-Man. After reading your post several times, I do have a gruding respect. Really. Yeah I know, the printed screen here screams sarcasm. But it is not.

I'm not quite sure we've hit all areas of physics which affect phyical objects.

Electric fields.

Magnetic fields.

Inertia.

Gravity.

Relativistic effects.

Strong and weak forces (though I think E and M fields are the weak forces). The strong nuclear forces overcome the electric fieds which would cause protons in the nucleus to repel each other.

But all of these are so small (as unaccounted influences) that that can't have any real effect on pererformance of our equipment.

The effect of aftermarket cones . . . I leave to you.

Smile,

Gil

[D-MAN]

Hi Gil, I'm NOT contentious - I'm "opinionated"!

But really, I did leave out the effects of sunspots. Maybe I'm just getting lazy![]

DM

[IB Slammin]

Oh, I get it!. The electrons get tired of being pushed around. So they go on strike. Then you have to bring in new scab electrons to do the work. And then ...

Terry,

You sure are easy to entertain.[]

Malcolm,

After three pages.........I just saw the righting on the wall[]

Regards,

Terry

[pauln]

I must step in here...

D-Man Wrote: As for the physics, electrical current causes time-based molecular change, not only in the valence portion but in the latice structure of conductive materials. PERIOD.

DeanG wrote: Bob -- the fundamental notes of cymbals sit between 300Hz and 1kHz. The shimmer at the very tippy top sits at 7.5kHz. Regardless of the network -- the majority of what we hear in cymbal work is actually covered by the squawker.

D-Man,
I assume we are thinking of copper, which is not molecular.
I'm not sure what you mean by 'valence portion', but all the copper atoms within a wire have the same valence for their entire existence.
[ed] Copper does have a lattice structure.

DeanG,
The Zildjian cymbal company has recorded and analized the harmonic structure of cymbal overtones up to 90KHz, not that much power is in that region.

Paul

[Malcolm]

God, as much as I hate to agree with D-Man, copper does indeed have a

lattice structure, and it is face centered cubic. Sometimes such

cr*p gets spread here!

[D-MAN]

It comes part and parcel of a particular element's ability to conduct electricity. Any iron-based inclusions in the copper wire (for instance) would be subject to becoming magnetically charged and exhibit polarity at a molecular level eventually. Also it is considered that oxygen molecules in the copper wire (for instance) would cause bonding irregularities which interfere with element-to-element valence bonding, the means by which current is actually conducted through the molecular chain.

Add to that the residues caused by oxidation, and the wires will eventually become MORE resistive to current flow in particular to very low signal (what we call "transients"). No, not the cymbal being struck, but perhaps the "shimmer" or the harmonics produced, i.e., the extremely tiny signal portion which is very hard to describe but what determines how "realistic" it sounds.

DM

[Duke Spinner]

So ...DMAn ...

you are saying you are going to calculate the area of the wire in Circular Mills ...

pick a frequency,

and show me how wire "hardened" by low voltage / amperage ;; is affected ...

or ...

you are going to tell me that You "Hear" the difference ....

Which is it ...??