John Curl's Blowtorch preamplifier part II

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The "blue thingie" in the center of the paper cone tweeter is a "phase plug".
Originally I think it was a wood dowel. Remove the stock dust cap and put a bit of rod with a rounded edge - voila! "Phase plug".
(oh, it is glued to the pole piece, and it looks "exotic" and special)

Ok, NS-10s.
Rotten speakers.
Not a thing "good" about them. Nothing.
Stock caps in the xover are horrid, change them out and the highs actually sound almost good.

Why are they used?
The very same reason that Auratone was popular.

It happened like this.
Some producer had a BIG HIT, or a string, or that was in a particular studio. Back-in-the-day. People saw that he was using NS-10s instead of Auratone, or perhaps in addition to. Now, others wanting part of the "secret sauce" started to use NS-10s.

They were adjudged back in the day to be roughly equivalent to some random home stereo speakers - that's why they were used, to see how a mix might sound on rotten, no good, cheap home speakers.

No magic.
 
Reference 86702 above...
Not just resistance but inductance as ac signals like to follow the path of least inductance more than the path of least resistance as they get higher in frequency So its the inductance we care about, resistive at low frequency, inductive as the frequency increases... Understanding this is a great help in understanding ground loops in audio and why they can be created quite easily without people suspecting they are there.
The app note also shows the importance of proper decoupling (especially again as the frequency increases0 and why decoupling capacitors should be on the same "ground" as the signal.
Of course with audio we are in the lower end of the frequency spectrum, but even here the low frequency stuff (20-100Hz) can find a different return path than the high frequency stuff, usually the low stuff can go round the chassis connection and PE lead of the mains cable, whilst the higher stuff will go down the interconnect shield, especially if its a naff shield (cheep braid).
Figure 11 shows why I like LOTS of ground planes on my layouts, preferably 10 layer for a top notch analogue/digital layout, not always possible due to cost restraints though...
 
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just some comments on skin effect...... I asked if there was a phase componenet at various depths... I couldnt find an answer here. But I did find the answer and it is what i suspected. yes, there is a phase effect with the skin effect. Not too surprising for an equiv RL circuit.


In regard to my including audio freqs with skin effect.... it takes about 4 skin depths to contain 98% of the signal.

Richard
It’s all governed by Lenz's law.

The word 'standard' in depth of penetration denotes plane wave electromagnetic field excitation within the metal. This is not the case in practice but δ (Standard depth of penetration) values are good enough for our needs ( see attachment)

George
 

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Eddy current Capacitors! In the 90's I remember seeing a schematic with large value electrolytic caps tied from plus rail to minus rail near an op amp. I asked an EE back then and he said "That is to cancel out eddy currents"

Can't find out much on the WWW.

Can anyone shed some light?

Wrong explanation from that EE.
Such a capacitor is used to confine ( reduce the loop area of) electrical circuit’s unbalanced circulating currents.

Now, eddy currents are not to be found in electrical circuits but within electrical conductors.
Also, all eddy currents are circulating currents but not all circulating currents are eddy currents



George
 
The "blue thingie" in the center of the paper cone tweeter is a "phase plug".
Originally I think it was a wood dowel. Remove the stock dust cap and put a bit of rod with a rounded edge - voila! "Phase plug".
(oh, it is glued to the pole piece, and it looks "exotic" and special)

Ok, NS-10s.
Rotten speakers.
Not a thing "good" about them. Nothing.
Stock caps in the xover are horrid, change them out and the highs actually sound almost good.

They were adjudged back in the day to be roughly equivalent to some random home stereo speakers - that's why they were used, to see how a mix might sound on rotten, no good, cheap home speakers.
One useful bug/feature of factory NS10's is the 'shred your ears' highs if there is any MF/HF dirt in the mix.
Ferrite inductors and lousy caps is 'the magic'.
Those tweeters when zobeled and fed with good caps become clean and go way past hearing range, and with stunning detail.

Dan.
 
And, fwiw, many of the people here that you seem or appear to be referring to actually have built their own gear... I bought trashed Quad57s and rebuilt them. Cheap compared to the usual used prices.

So, the $5k thing is a bogus argument.

The price of gear is not commensurate with the performance, not at all. No direct correlation. Personally, when I was younger and essentially broke all the time, I frequently saw and heard systems that cost more than I made in a few years (I was broke - no kidding) that sounded like utter doggie poopie.

So the question is QUALITY not price.
If you have no point of reference that includes an experience of (for lack of a better phrase) a "transcendent presentation", then there is no point of reference that you could relate to.

_-_-
 
So what?


With a 10kHz square wave it would have to be 70, 90 or 110kHz. Bats might hear it.


Much of the noise on this forum comes from people, including some of those commercially involved in audio"

.

.

.

Having a bad day?

Quite frankly, I don't give a damn what the bats hear or what I can't. A decent square wave is coming out of my amp and by the time it gets to the end of 10 feet of cable it looks indecent. Period.

If a square wave rings at the end of a long cable, we know how to make it look decent again with an RC network - that's all.

The real problem with this forum is that we have an abundance of miserable old codgers . . .

😉
 
One useful bug/feature of factory NS10's is the 'shred your ears' highs if there is any MF/HF dirt in the mix.
Ferrite inductors and lousy caps is 'the magic'.
Those tweeters when zobeled and fed with good caps become clean and go way past hearing range, and with stunning detail.

Dan.

Nah.

They just have their native freq response without the added hash added when you mod the tweeter xover. They're really not great tweeters at all.
For that matter nor were the original woofers anything special.

Basic Japanese mid/low level "hi-fi" speakers that got a following because, as I said, studios copied other studios and producers copied other producers. I was on that scene when they first showed up... 😀

(before that, there were all sorts of other speakers of similar sizes in studios...fwiw)

Another reason they got a following is that because they were small and cheap, producers and engineers who moved from
studio room to studio room and studio to studio when having a pair of NS-10s in the room actually had a point of sonic reference to
work from. Unknown room, but with a known speaker. Cheap, affordable, portable.

The "tissue paper" mod, which was famous/infamous is part of the whole NS-10 thing... fwiw I did that to those and others,
probably before whomever first did it in a big studio did it, but I not be well-known/famous.

_-_-
 
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The NS-10 and later NS-10M (nearfield monitors) didn't stand up too well to monitor use. I've replaced woofers more often than I can count. But various people are correct in that they represented inexpensive speakers (there are no shortages of worse speakers out there!). That's because they NS-10 was a shelf speaker for home use. After noticing their popularity in the music studios, Yamaha corrected the response for nearfield monitor use. We stopped seeing Kleanex / paper towels and socks stuffed in front of the tweeters. The dead woofers continued to march in through our doors.

I was told by mixing engineers that the "awful tones" and NS-10 represented what people heard from TV, radio speakers and that they were good for setting levels. The reason almost every studio used them was so that recording engineers and producers would hear close to the same thing from studio to studio. For the main monitors, there wasn't really a standard, but I saw big black JBL speakers hanging from the ceilings of many control rooms.

The monitors weren't supposed to sound good, they represented what engineers felt that most people actually listened to similar performing speakers. This is pretty terrible junk many people have, sadly true. No, NS-10 speakers are not what I would choose to listen to, but they work well for the job they were picked for. I don't know what replaced the NS-10M speakers, but I'm told they sound much better. Anyone know?

-Chris
 
.....The price of gear is not commensurate with the performance, not at all. No direct correlation. Personally, when I was younger and essentially broke all the time, I frequently saw and heard systems that cost more than I made in a few years (I was broke - no kidding) that sounded like utter doggie poopie.
There are also very expensive systems that DO sound good/correct.
That said, I have also heard numerous expensive systems that just don't quite 'get there'.

So the question is QUALITY not price.
If you have no point of reference that includes an experience of (for lack of a better phrase) a "transcendent presentation", then there is no point of reference that you could relate to.
I suspect that there are many here who have not heard a 'holographically' real sounding system.
When you do, that sound sticks in the memory and is never forgotten.....and nothing else quite compares, but it does raise the understanding of what is attainable.

Dan.
 
Having a bad day?

Quite frankly, I don't give a damn what the bats hear or what I can't. A decent square wave is coming out of my amp and by the time it gets to the end of 10 feet of cable it looks indecent. Period.

If a square wave rings at the end of a long cable, we know how to make it look decent again with an RC network - that's all.

The real problem with this forum is that we have an abundance of miserable old codgers . . .

😉

Oh?
Nothing to do with the load?
Or if it does it with a resistor on the end, best change the cables??
 
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