That's not disputed at all.
Whether his success is due to less vibration because of the massive case is speculation.
jan didden
Corian, or maybe marble, if you want to target the weight-lifter market.
Don't forget though - this would have to serve only for the lining!
John insists on the heavy metal for screening as well as mechanical properties, and I have no doubt about the problems caused by ambient EMI
The Tap Test could be the greeting of choice at ETF - check your senses before the listening starts....
Why not hogged out depleted uranium for added mass??? ;-)
or plutonium... now that'd be exotic... call it the Fukushima -1...marketing could have a field day 8x the mass of el-cheapo aluminum
Mass, Weight, Density or Specific Gravity of Different Metals
or plutonium... now that'd be exotic... call it the Fukushima -1...marketing could have a field day 8x the mass of el-cheapo aluminum
Mass, Weight, Density or Specific Gravity of Different Metals
That's why I suggested that would-be designers should investigate the mechanical vs audio performance relationship for themselves. Speculation is only a bad thing if that's all that one can do. the DESIGN process, which John does get right, clearly is what makes the difference.
For instance, Thorsten's Bravura performance just now highlights the working of the Design process, as actually performed by a properly equipped [i.e. Tools and Talent] professional, and gives a glimpse of the real level of attention to detail required in the best products.
Bravura! That was the name of the preamp I couldn't remember a few weeks back during a discussion here. A real cult item, beloved of the Fultonites. Totally oddball circuit which allegedly self-destructed when anything other than a Shure V15 III was connected to it. I don't know if it could sense that someone didn't use the G version of the cartridge and pre-emptively break out into oscillation...
Does anyone know what circuitry they used?
Thanks for the memory jog, Rod!
Does anyone know what circuitry they used?
Thanks for the memory jog, Rod!
If you like. But the designer himself stated that it was important for reasons of mechanical-acoustic properties.
So, whether it is only speculation, or whether it is a fact, the only reasonable thing is to conduct one's own experiments to find out whether it it useful in another design context.
Of course, if one does not respect the design achievements of John Curl, one could just ignore what he says.... but then, there would be little reason to haunt this thread.
Or are you simply looking for a dispute in logic?
So, whether it is only speculation, or whether it is a fact, the only reasonable thing is to conduct one's own experiments to find out whether it it useful in another design context.
Of course, if one does not respect the design achievements of John Curl, one could just ignore what he says.... but then, there would be little reason to haunt this thread.
Or are you simply looking for a dispute in logic?
Everyone, please try the 'fingernail test' on suspect test equipment, however, virtually any solid state part is microphonic to some degree.
YET, the really important reasons for the heavy case are still not considered:
1. Structural stability, in order to mount the switches and pots, and safely use them without buckling the front panel.
2. Shield thickness, with a NON-MAGNETIC material, in order to reduce as much low impedance EMI at audible frequencies, as possible.
Side note: We did not START with a 'hogged out' chassis. Our prototype was a welded chassis. However, Bob Crump, watching the welder in action, decided that too many reject chassis would be made that way. We could not afford to have marred or rough chassis. We could not sell them to discerning customers that way, any more than you could sell a Mercedes with a hand applied paint job (you know, with a paint brush). Fit and finish was part of the package.
In recent years, I have made chassis without 'hogging' them out, BUT they are just as expensive and actually more complicated to make 'properly'. In fact, the machinist recommended 'hogging' it out, next time, if we ever went into production.
YET, the really important reasons for the heavy case are still not considered:
1. Structural stability, in order to mount the switches and pots, and safely use them without buckling the front panel.
2. Shield thickness, with a NON-MAGNETIC material, in order to reduce as much low impedance EMI at audible frequencies, as possible.
Side note: We did not START with a 'hogged out' chassis. Our prototype was a welded chassis. However, Bob Crump, watching the welder in action, decided that too many reject chassis would be made that way. We could not afford to have marred or rough chassis. We could not sell them to discerning customers that way, any more than you could sell a Mercedes with a hand applied paint job (you know, with a paint brush). Fit and finish was part of the package.
In recent years, I have made chassis without 'hogging' them out, BUT they are just as expensive and actually more complicated to make 'properly'. In fact, the machinist recommended 'hogging' it out, next time, if we ever went into production.
The crossover looks like "low pressure moulding" has been used. Used widely in automotive and other areas to protect components etc from vibration, moisture etc. We use it for the same reasons. You can get almost the same result at home with hot melt glue. Personally for solid state based electronics in a home environment, I would be surprised if the vibration levels from air borne sources are ever going to be high enough to cause distortion, before your ears bleed, mechanical and delicate based devices are another story. We use MIL-STD-810 table 8, and have noticed some problems, with ferrite based components as the ferrite cores move (differential Vibration) and a MLCC (X5R) that got put in a signal path, but very little else (apart from the odd assembly problem, like bits falling off), but constant vibration is one of the (main) causes of electronics failure and any moves to reduce it or attenuate it should be used.
As well as machining, there is investment casting and moulding, depending on quantities.
As well as machining, there is investment casting and moulding, depending on quantities.
Hi,
These are already copper foil types, with tight windings and impregnation. So they benefit a lot less than most.
However overall turning the crossover into a solid block still measurably helps. We use clear resin so no-one says we only pot the crossover to hide what we do.(BTW, the crossover is passive Chebychev 10th order)
Ciao T
Mr. Thorsten, it is a very nice solution in some respects to turn the crossover into a solid block. However, I doubt your claim that this is a 10th order filter, given that I count only 4 coils and something like 10 capacitors.
Vac
Absolutely so! Yet so much here is but mere speculation; speculation on each tiny aspect of component - often without any reference to the circuits in which the praised or criticised components are to be used.
We all know that any chain is as strong as it's weakest link: JC and the other successful designers writing here attempt to cover all aspects in their designs by ensuring that each aspect of the design is executed as well as possible within the specification brief achieving thereby a chain of balanced strengths.
What worries me here is that there are so many "contributors" who are themselves supposedly well qualified and who demonstrate a heady mixture of talents, yet continually snipe at JC, TL etc. with such dedication that any normal reader would suspect that jealousy rather than valid criticism was their underlying motive. Thank goodness JC has enough sense to ignore most of this and that TL has the capability to take them down a peg or three. It is the lack of grace of some individuals which lets them down.
Valid criticism is one thing, but ongoing campaigns - bordering and even crossing over into the personal - are entirely another. A change of attitude from "what can I criticise" to "how can I advance this debate" is in order for some. IF there is a personal grievance then take into the private domain.
For many DIY audio is a pastime/hobby. Others have professional interests in audio and as such behave exceptionally well. But others have either been in the industry or wish they were and behave as dramatically and badly as any actor manqué.
EDIT: Jan - this is not directed at you.
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First .33 ohms is the maximum resistance you should see on an AC outlet. Some measure much lower. A fuse in normal use will double it's resistance. So the fuse contribution may be as much as 20% of the power line losses.
Non linear resistance in the power supply side may or may not be a problem! It tends to extend the charging time available for the main filter capacitors. A very low line resistance and a stiff power transformer can have a very short charging time and very high peak currents!
A very simple power supply may be as good as a really whiz bang one if you have a circuit that is very resistant to power supply issues. An example would be a mosfet power amplifier with global feedback.
The other extreme when power supply is a big issue would be a bipolar junction transistor MC phono preamp.
So power supply issues are related to many other items.
When you hog out a block of aluminum you increase the number of resonant modes. They also go up in frequency. At higher frequencies the movement is more easily reduced by mass and other absorption mechanisms. That is why i install silica gel inside my critical cases. It not only keeps moisture down it also damps vibrations.
A sheet metal case has more panel flexing as the metal is usually thinner. The solution to that issue is to emboss a pattern in the metal. You often see this in Japanese mass-fi gear.
Non linear resistance in the power supply side may or may not be a problem! It tends to extend the charging time available for the main filter capacitors. A very low line resistance and a stiff power transformer can have a very short charging time and very high peak currents!
A very simple power supply may be as good as a really whiz bang one if you have a circuit that is very resistant to power supply issues. An example would be a mosfet power amplifier with global feedback.
The other extreme when power supply is a big issue would be a bipolar junction transistor MC phono preamp.
So power supply issues are related to many other items.
When you hog out a block of aluminum you increase the number of resonant modes. They also go up in frequency. At higher frequencies the movement is more easily reduced by mass and other absorption mechanisms. That is why i install silica gel inside my critical cases. It not only keeps moisture down it also damps vibrations.
A sheet metal case has more panel flexing as the metal is usually thinner. The solution to that issue is to emboss a pattern in the metal. You often see this in Japanese mass-fi gear.
Hi,
Thank you, we do try and we are not all gold fuses and the like, we do know our basic engineering...
Now why would you doubt me? Surely my word is good enough, right?
Even if you do not take my word, as I mentioned it is a Chebychev (Type II to be precise) I really cannot see the reasons for you demurring...
Well, I designed and measured the filters and they are > 60dB/Octave for the first 30dB or so attenuation.
There are number of proponents of similar approaches, Neville Thiele has his Neville Thiele Methode, Jeff Joseph calls it infinite slope, Jason Cuadra had some nice articles. What I added to this is not a lot, but my adjusted methode does have advantages.
You can see a bit more on this page:
Abbingdon Music Research - Product - LS - 77 Features
Ciao T
Thank you, we do try and we are not all gold fuses and the like, we do know our basic engineering...
Now why would you doubt me? Surely my word is good enough, right?
Even if you do not take my word, as I mentioned it is a Chebychev (Type II to be precise) I really cannot see the reasons for you demurring...
Well, I designed and measured the filters and they are > 60dB/Octave for the first 30dB or so attenuation.
There are number of proponents of similar approaches, Neville Thiele has his Neville Thiele Methode, Jeff Joseph calls it infinite slope, Jason Cuadra had some nice articles. What I added to this is not a lot, but my adjusted methode does have advantages.
You can see a bit more on this page:
Abbingdon Music Research - Product - LS - 77 Features
Ciao T
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Shorted inputs? Cables are certainly microphonic, but how about comparing a complete phono setup with cart down on a statioary LP.
tch tch
hmmnn... and this only occurs in one direction??? methinks not
Really?? Do they mine the metals and semiconductors, refine them to the professed degrees deemed necessary, verify the quality of the doping profile in the active devices that are discussed to such exhaustive detail, confirm the conjectural hpotheses stated as FACT as to such mechanisms as crystal orientation in wires, etc... or do thay mock and patronize those that do (or have done or debunked) this sort of research and state such as naive and uninformed of the superiority of their insight. [/QUOTE]
Sorry, but I just don't see this as being as one-sided as you present it here. Both sides engage in your stated behaviors to a greater or lesser extent; it's a shame that the snippets of truly useful information are buried in attempted character assassinations and obfuscated pompous pronouncements and intentional misrepresentations of fact.
Or maybe it's all in good fun (ala 15 year old boyz during recess)
IMHO
John L.
hmmnn... and this only occurs in one direction??? methinks not
Really?? Do they mine the metals and semiconductors, refine them to the professed degrees deemed necessary, verify the quality of the doping profile in the active devices that are discussed to such exhaustive detail, confirm the conjectural hpotheses stated as FACT as to such mechanisms as crystal orientation in wires, etc... or do thay mock and patronize those that do (or have done or debunked) this sort of research and state such as naive and uninformed of the superiority of their insight. [/QUOTE]
Sorry, but I just don't see this as being as one-sided as you present it here. Both sides engage in your stated behaviors to a greater or lesser extent; it's a shame that the snippets of truly useful information are buried in attempted character assassinations and obfuscated pompous pronouncements and intentional misrepresentations of fact.
Or maybe it's all in good fun (ala 15 year old boyz during recess)
IMHO
John L.
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