Yeah, but realistically, just how strong does it really need to be? Unless you're loading it with heavy transformers or big-*** caps and it needs to survive the rigors of shipping, it's a perfectly good material for audio. Also, FR1 and FR2, which are paper/phenolic based are fire resistant, though they're not the beautiful dark brown like the old XP and XXP materials.
se
SE,
I have a sheet of some of that in 1/4" thickness that I just so happened to use to mount some crossovers on, a bit of overkill I would have to say. Looks much more like standard pcb board color though with a slight greenish tint.
Back to audio for now and trouble shooting a car problem no mechanic can find. Of course it is an electrical problem, intermittent at that, heat related under the hood.
I have a sheet of some of that in 1/4" thickness that I just so happened to use to mount some crossovers on, a bit of overkill I would have to say. Looks much more like standard pcb board color though with a slight greenish tint.
Back to audio for now and trouble shooting a car problem no mechanic can find. Of course it is an electrical problem, intermittent at that, heat related under the hood.
Some are so soft they can be stripped from the wire with a fingernail if not too thick...
My pleasure. How about calculating an ~9awg star quad (12awg per conductor) that is moderately constrained (0.030 between conductors, Teflon insualted) and 5-6 twists per foot?
Using a GR 1689M LCR meter down near the bottom end of the Ls range is challenging. To get repeatable numbers I use a 4 wire - to - 2 wire fixture and have to re-zero at each new frequency.
By "parasitic inductance" are you referring to proximity effects from things like metal benchs, loops made in the cable under test, etc.?
As an aside, do cable AC parameters change appreciably at higher currents other than IR losses? Instead of testing cables at 1mA or 10mA for example, what happens with the increased fields at 1A? 10A? higher?
Thanks,
Dave
No that's not Bakelite. That's phenolic board, as explained by SY. Bakelite is a different material - I believe, for instance used in the past for light switches, kettle handles, that sort of thing.
Jan
Wasn't that a sort of standard by the Institute for HiFidelity (IHF) in an attempt to make apples-apples comparisons possible?
Jan
IIRC, it suffered a bit of credibility problem early on, when people found out there was straw in it. Try convincing the average layman that the straw wasn't added as a bulk filler to reduce costs, but actually made it stronger.
Real Bakelite can be very beautiful, and in the '50's was often swirled of two colors for consumer goods. It can be cast very smooth and take detailed shapes, like some Kodak cameras and lots of "Art Deco" radios. Hand-held 35mm slide viewers are sometimes magnificent little jewels. Beautiful stuff of an earlier age; too expensive nowdays.
Find a 1950's, early '60's, Leitz Wetzlar slide projector and look at its detachable power cord's connectors, with integral switch, and enjoy real engineering beauty.
Thanks,
Chris
Find a 1950's, early '60's, Leitz Wetzlar slide projector and look at its detachable power cord's connectors, with integral switch, and enjoy real engineering beauty.
Thanks,
Chris
It gets worse (or is it better?
). All cheap hand held LC measuring instruments I have used do not test with a sinusoidal signal but with a pulsed, irregular squarewave one.This is my experience with cheap LC meters too.
For L measurements at the low scales on cables, I get a rather broad range of readings say +/- 10-20% of the calculated expected value and this with only some instruments, while for C measurements the range is much narrower~ +/-2-3% with all instruments.
To quote:
"inductance can only be properly understood if it is realised that it is only defined for a closed circuit.
What is usually meant by a statement about inductance is incremental inductance, such as that
caused by a length of wire if it were to be inserted into a closed circuit."
Jn will come and provide his valuable comment on this.
My side-comments: If higher current increases the network losses, measurement system’s noise figure will worsen.
I want to hint on the –measuring instrument dependent-risk that the resulting higher voltages at the input of the instrument may increase intermodulation distortion products. This effect is not as easily verified as the effect of input overloading, which may also occur.
Cube test (high amplitude pulse sweep excitation) is a realistic hard test, no?
Not to mention some TT-arm beauties
George
So true. An autotransformer, like a typical OT transformer, is a matching impedance device.
In addition to this, it is a delicate to tune L/C LP filter for HF signal rejection (HF generated either at the amp or at the load side).
Tuning the transformer with a capacitor that shunts the primary or secondary winding (taps for an autotransformer) can make it.
The inductance of each winding (taps) is the decisive element in that tuning .
George
With modern hypercompressed music releases that also have heavy low bass content that's easy. Think some techno, speedmetal and similar. Kids don't listen that audiophile 'cr*p', they want REAL music. Throw a loud party while daddy is not home and watch his posh amp go up in smoke
With modern hypercompressed music releases that also have heavy low bass content that's easy. Think some techno, speedmetal and similar. Kids don't listen that audiophile 'cr*p', they want REAL music. Throw a loud party while daddy is not home and watch his posh amp go up in smoke
Another reason to have good protection circuitry like Mac does. My kid is scared to death to touch Dad's stereo, which is also effective protection.
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