So some of them are incorrect.
Deaf or delusional, that is the question ! (with apologies to Shakespeare) 😀
Deaf or delusional, that is the question ! (with apologies to Shakespeare) 😀
Joshua_G said:
Bratislav said:
I don’t see a problem using relays, if you are using the right relays, at the right place and know how to use them, no problem.
If you are using wrong relays, at wrong place and don’t how to use them, big problem.
Cheers
Stinius
Hi John, all,
As unpopular as a mercury relay would seem to be, have you tried any of these? They would seem to promise better contact.
One wonders about tiny audio signals. I can imagine that the smallest signals could possibly not be able to get from one solder pad, through the relay and out again. That's assuming some (probable) oxide layer that the signal can't punch through until it has attained enough emf. Could we even be talking about the tiny emf caused by dissimilar metal contact?
The same issues would seem to plague mechanical rotary switches. Those switches that you like John, are they heavily plated with silver, or silver from the contacts to the terminals used for soldering. Given that the connection may be an issue, wouldn't a crimped connection between silver terminal and silver wire not be a superior way to go?
To consider such tiny electrical signals, perhaps a look at instrumentation used for particle physics might shed some light on what we are doing. Experiments that have to capture tiny charges reliably and quantify them reliably. One would think that these people know all about connections and possibly switching.
Think about Keithly. They have instruments that resolve down to 20 uV (the 1801 nanovolt preamp) and another that measures down below 1 fA (the 6517 electrometers). The current figure is especially impressive. They must know how to treat a signal. I am going to bet that they use some pretty good relays as their equipment often operates under software control.
Looking at this evidence, it would seem that their are some very capable relays out there.
-Chris
As unpopular as a mercury relay would seem to be, have you tried any of these? They would seem to promise better contact.
One wonders about tiny audio signals. I can imagine that the smallest signals could possibly not be able to get from one solder pad, through the relay and out again. That's assuming some (probable) oxide layer that the signal can't punch through until it has attained enough emf. Could we even be talking about the tiny emf caused by dissimilar metal contact?
The same issues would seem to plague mechanical rotary switches. Those switches that you like John, are they heavily plated with silver, or silver from the contacts to the terminals used for soldering. Given that the connection may be an issue, wouldn't a crimped connection between silver terminal and silver wire not be a superior way to go?
To consider such tiny electrical signals, perhaps a look at instrumentation used for particle physics might shed some light on what we are doing. Experiments that have to capture tiny charges reliably and quantify them reliably. One would think that these people know all about connections and possibly switching.
Think about Keithly. They have instruments that resolve down to 20 uV (the 1801 nanovolt preamp) and another that measures down below 1 fA (the 6517 electrometers). The current figure is especially impressive. They must know how to treat a signal. I am going to bet that they use some pretty good relays as their equipment often operates under software control.
Looking at this evidence, it would seem that their are some very capable relays out there.
-Chris
A good bit of charged particle detection in physics and chemistry is done by pulse counting. At higher charged particle flux, analog systems are used.
Hi PH104,
Yes, but you have to detect the event and move the information to the device used to process the sensor information. Same problem.
-Chris
Edit: Imagine a thermocouple output around 0 °C. We are talking some very small voltages where the temperature of the connection point must be corrected for. That seems to rate as well.
Yes, but you have to detect the event and move the information to the device used to process the sensor information. Same problem.
-Chris
Edit: Imagine a thermocouple output around 0 °C. We are talking some very small voltages where the temperature of the connection point must be corrected for. That seems to rate as well.
Hi Chris --
Good point. In the systems I've used, the preamp or preamp/discriminator was mounted on the back side of a vacuum flange, directly opposite the detector (analog or pulse counting electron multiplier) which was inside an ultra-high vacuum system. The entire back of flange with preamp was then doubly shielded. The interconnecting wire between the EM and preamp was nothing more than a coaxial vacuum feedthrough. The basic philosophy was to keep the connection short, rigid, and tight between detector and preamp. It would have been better but impractical to put the preamp inside the vacuum system.
I guess the audio equivalent would be a MC preamp soldered directly to the pins on the cartridge. 🙂
Phil
Good point. In the systems I've used, the preamp or preamp/discriminator was mounted on the back side of a vacuum flange, directly opposite the detector (analog or pulse counting electron multiplier) which was inside an ultra-high vacuum system. The entire back of flange with preamp was then doubly shielded. The interconnecting wire between the EM and preamp was nothing more than a coaxial vacuum feedthrough. The basic philosophy was to keep the connection short, rigid, and tight between detector and preamp. It would have been better but impractical to put the preamp inside the vacuum system.
I guess the audio equivalent would be a MC preamp soldered directly to the pins on the cartridge. 🙂
Phil
Hi Phil,
Yep. Good analogy.
Still, there are many natural phenomena that require analog conditioning before you can process the signal. Often times the signal may be in the form of a tiny pulse, or it may represent a slowly drifting "DC" voltage. A signal so small that moving air currents may generate enough of a current to totally swamp the signal of interest. Choppers may work well here, but then they generate noise and may still be completely unsuitable.
And we think audio is hard! 😉
-Chris
Yep. Good analogy.
Still, there are many natural phenomena that require analog conditioning before you can process the signal. Often times the signal may be in the form of a tiny pulse, or it may represent a slowly drifting "DC" voltage. A signal so small that moving air currents may generate enough of a current to totally swamp the signal of interest. Choppers may work well here, but then they generate noise and may still be completely unsuitable.
And we think audio is hard! 😉
-Chris
yep. I remember - vaguely now - using chopper amplifiers, phase-sensitive detectors, and other cool things. I spent a fun couple of hours on Saturday wandering through the "Black Hole", a surplus place with decades worth of surplus scientific equipment from Los Alamos National Lab. Every once in a while I get lucky and score some big heatsinks.
Bratislav said:
Amusingly you are probably right when you mention "better ears". None of the listed companies (no experience with Halcro)make any serious attempt for sonic transparency. They rather create a specific, likeable sound. Relay colourations become unimportant as they are swamped by capacitor and other distortions. And it's not necessarily the designers with the poor hearing - it's their targeted customers.
Per example a very slight increase in component quality and sound leads to almost doubling of the price along the Audio Research line-up. Let's say $200 worth of better components is the difference between a $3k and $5k preamp. And both of these use a $10 volume control. How much would a motorized Shallco add? 🙂
anatech said:
The following taken from my post #7511 in this thread may shed some light on the matter, and I made some other relevant comments in post#7517.
Regards,
"On the matter of Shallcos (and the similarly-constructed Blore Edwards) one of the most important issues here is the overall 'integrity' of the signal-path through these 'good-sounding' switches, by which I mean the least detrimental to the signal. The input/output connections are soldered directly to the rear of a small single solid piece of silver, the other end of which is the actual stationary contact. The wiper arrangements are similarly 'minimal', and there are no dissimilar metals riveted to each other nor convoluted signal-paths which one finds in most relays which I have inspected internally."
john curl said:
John you undermined just about all your arguments here. The 911 is the traditional rear engined Porsche and the 944 is so completely different being front engined and with a watercooled 2.5 Litre strraight four engine to the air cooled 3.0 flat six boxer of the "real" Porsches as to be almost a different brand.
Anyone who couldn't tell the difference would not be in the car, let alone driving it.
As a comparision you might as well have said you can hear the difference between speaker cables when ther unit is switched off.
If you don't know the difference between a 944 and a 911 then why bother with a Porsche at all?
jacco vermeulen said:
To be honest it makes excellent reading and i agree with most but how much of it is just hot air? So, what does BAT use? Obviously this price range does not allow for a bulk foil ladder, so it has to be shunt to be affordable for the average Joe 🙂 One nice resistor per attenuator. Me, being a notorious cheap skate do exactly the same. And what about the switching elements? We learn that most of them either sound bad or are just too difficult and expensive. There are obviously no relays which leaves some form of discrete analogue switches. Assuming these don't use tubes what does it leave?
The last 3.0L 911's were made in early 80's. And yes, the rear-engine 911's - especially those prior to the 911(996) series - were notorious for their under-steer. Much different feel than the 944, although it is a great car.
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