Interesting, completely the other way for me. I have a collection of really "nasty" recordings, as in that on most systems they sound pretty horrendous, unlistenable to in an enjoyable way, and it takes mere seconds to assess a completely unknown setup this way -- the faults absolutely scream at you; I'm speaking of the components working as a complete entity, not the recording ...
Frank
Well, I spoke about evaluating gear on my own setup.
When a piece of gear doesn't sound good, it's quite obvious very soon. It takes prolonged listening to find out that something really sounds good, without drawbacks.
I didn't like the majority of other setups I heard. Indeed, at times it takes few minutes to find out that you don't like a certain setup. On one case I found it out only after a whole listening session. Only after the second listening session I could pin point the reason for it: it is a setup (a fairly expensive one, about 4 times than my own setup) which has a great "Wow! Effect", but all music on it sound the same, and it is very far from being musical.
Ferrous metals increase thd -
Current flowing thru ferrous metals create a non-linear Z which translates into distortion... Ferrous metals within 2-3cm (1 inch) of a signal carrying wire is sufficient to measure the thd increase.
Thus, keep ferrous metals like the chassis might be - 1 inch or more away from the signal wires and pcb/circuitry. And, of course dont, therefore, use parts with ferrous metals in them.
The research done on this came from Japan... I think I recall who/company but not sure. -Dick Marsh
Current flowing thru ferrous metals create a non-linear Z which translates into distortion... Ferrous metals within 2-3cm (1 inch) of a signal carrying wire is sufficient to measure the thd increase.
Thus, keep ferrous metals like the chassis might be - 1 inch or more away from the signal wires and pcb/circuitry. And, of course dont, therefore, use parts with ferrous metals in them.
The research done on this came from Japan... I think I recall who/company but not sure. -Dick Marsh
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Great...thanks. I can tig weld stainless and if I can get paint to stck to it, powdercoat it and bake it in Mrs. Aeronautical's oven.
One parameter resolved.
I've already mentioned driving boogie rock with strong cymbal content, rock with studio injected cavernous soundstages in another post. 80's new wave pop with layers and layers of synthesiser sounds and heavy reverb and other effects in the mix are hard work for a lot of systems.
In another direction, early 30's swing orchestras, with rows of brass blasting out crescendos well back in the soundstage
An Ambisonics recording by Nimbus of Franck and Faure chamber music, an extremely distant acoustic is conjured up.
The Essential Odette on Vanguard, live recording at Carnegie Hall, mastered at an extremely low level: full volume is just barely loud enough.
Ike & Tina Turner in concert, very, very dirty sound, plus full blown studio mixes on one CD. Massively energetic, raw sound, would be diabolical on most setups.
Jimi Hendrix Experience's Voodoo Chile recorded live, and done superbly. The drum kit is captured perfectly, and the Marshall amp growls and grinds menacingly. With excellent audience ambience. But will your system show it?
The list goes on and on ...
Frank
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I think I still have a connection for stainless sheet metal. If so I can build my chassis out of that.
Now for the trivial things...like electrical properties.
Come on guys...lighten up...i WAS JUST KIDDING
I am trying to come up with some design goals but heck, I just want it to sound good, last a long time, and be within my abilities to build. Mr. Curl, I am looking at the schematic you posted earlier today. I would need a little bit of guidance but am willing to have a go at it. In the next few days I will try to figure out if I can buy the parts. I wish there would be others out there that would build this along with me...it would be a shame for these guys to waste good energy on something productive like building the best preramp we can build.
That's the number 1 criterion for me, the worst of the worst recordings have to be musical, in that sense I'm totally on your side here. And this musn't be achieved by doing the equivalent of throwing a thick blanket over the speakers, I've heard this system "sound" many times, and it is not the correct way ...
Frank
Of course it isn't the way to attain 'musicality' of a sound setup.
Though I cannot pinpoint exactly what is it that contribute to the 'musicality' of a sound setup, I have a feeling that it has much to do with the sense of realism, perhaps alongside with some other attributes.
Anyhow, when a setup is 'musical', I hear only the music, I'm being swept and captured by the music, I don't hear any of the 'audiophile' attributes of the setup. This is what I have a sound setup to begin with – to enjoy listening to music (reproduced).
Do the magnet test on your proposed chassis -- if it isnt magnetic (ferrous) then it is OK to use.
Generally, a steel shell around a transformer is OK and aids in shielding low freq fields. But it is better to do as John does and use aluminium for the rest of the chassis -- thought it costs more than a steel chassis.
Thanks Dick,
I have family in the sheet metal biz so I'm hoping I can score a 4 x 8 sheet of 18 guage stainless reasonably. But I take what you guys say to heart...well shielded with the right metal...grounded of course.
I am exploring the schematic Mr. Curl posted today and yes...frankly, I am intimidated. So I will either need to get on my big boy pants or find a kit to build. I can absolutely execute it effectively if I can get the parts. Any input is greatly appreciated.
Mike
I believe it is extremely simple: that it is a lack of low level, high frequency distortion. Obviously the recording will have certain quantities of this, but if the playback setup adds an extra, clashing variant of this then it becomes too much for the ear/brain and you can't enjoy the musical message, emotional fatigue sets in very quickly.
A very simple test that I have alluded to a number of times: put on a difficult recording, like the ones I've just mentioned; how close can you move towards the tweeter driver of one of the channels while playing at normal volume before the sound coming from the tweeter sounds obnoxious? If you can go all the way and it still sounds clean, pleasant, musical, then you're on a roll ...
Frank
The Parasound JC-2? Not to be discouraging, but Mr. Curl has often said in this thread that many of his designs would be too difficult for home constructors. Parts aren't really available, etc. I think this one qualifies.
To devote that much effort to a flat gain of less than 20 dB (which can easily be designed completely *out* of a custom construction) without planning on putting a hundred times as much effort into speakers is, IMO, wrong.
Just my opinion, but there it is,
Chris
Thick conductive material is a shield against magnetic fields. Superconductors would be ideal, but they are a little hard to source, particularly the room-temp ones. Stainless is unfortunately not very conductive. Fine for electric fields, pretty poor for magnetic.
Aluminum is eminently machinable and available in good-sized billets for hogout. Copper is gummy (particularly the oxygen-free high conductivity stuff, which would otherwise be the best, except for silver) and very expensive and very cumbersome to machine.
But for low-frequency mag field shielding, the material must be THICK. Otherwise, the best strategy is to put distance between the product and the interfering field, and keep loop areas small. The near field EM approximation helps a lot here: for a loop emitter, the magnetic component of the near field falls off as the CUBE of the distance. This helps a lot and in a hurry.
Don't worry, I don't expect any of you to make the Para JC-2. I put it up as an example of the DIFFICULTY of doing a Class A design. It would be better to buy a used Para JC-2. Less hassle. This makes the JC-80 a 'piece of cake' by comparison to build, doesn't it? And the BLOWTORCH is even harder to make right.
Thanks Chris, I am definitely going to have to go in another direction. I am doing this for fun...I need to keep reminding myself of that fact.
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