Indeed, and there's a whole lot more of it made than top-notch Burgundy
But it's still pretty great stuff in good years when properly transported, stored and aged.
Of you could try reading the data sheet and see what the device is intended to do!
There are a lot of people in the audio game, I was not aware of her before; quite a character it seems! I guess I'm flattered ... and, in looking around for mentions of her found this piece by John Atkinson: Is It Real? Or Is It... | Stereophile.com. Don't agree with everything here, but it has some interesting points ...
One sentiment therein I severely disagree with ...
That's precisely what I am after, and when achieved is very satisfying. But, you have to be as fussy as me, and seemingly Enid, to get there ..
Frank
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Reminds of the little dinner party I attended when Bob Dylan brought a bottle of 1970 Mouton Rothschild. Unfortunately the year was 1974 and the wine was ridiculously unready to drink. He liked what I brought, something a good deal less exalted but eminently ready to drink.
At least he didn't need to feel remorse one way or the other, as he could well afford the Mouton
The Bordeaux crash happened around then all 1970 firsts were ~$200 a CASE.
It might be worthwhile to talk about the differences between relay contacts, solid state switches, and finally silver on silver rotary controls. Obviously, I have designed preamps with multiple versions of all three. Perhaps others of you out there might give me your experience on the subject.
He paid about 40 locally iirc for the bottle. I tried to suggest it was a gift for the host to lay down, and there were bits of grumbling at the idea, so I acquiesced.
The sillier example, oddly again Mouton, was a Wine House tasting that ended with a 1975. Utterly hard as nails, and people grabbing at the bottle aggressively because it was expensive. That was the last tasting at the WH I attended.
My input relates to the use of relays. I would guess 700 relays a month for 22 years is almost 185,000 Panasonic DS series alone with less than 10 failures. Pretty good quality parts not quite as good as Toshiba fets but close and very good for electromechanical. Mechanical switches not even close to that but it could be brand related.
Well, I guess I can start.
The worst contacts that I ever came across were sealed mercury relays in an ABX box. The best contacts I have used are Shalco silver rotary switches that we used in the CTC Blowtorch.
Everything else is somewhere in between, with gold on gold relays ranking slightly better than solid state contacts. Every solid state switch that I have ever personally tested has some measurable distortion and a limited voltage range.
The worst contacts that I ever came across were sealed mercury relays in an ABX box. The best contacts I have used are Shalco silver rotary switches that we used in the CTC Blowtorch.
Everything else is somewhere in between, with gold on gold relays ranking slightly better than solid state contacts. Every solid state switch that I have ever personally tested has some measurable distortion and a limited voltage range.
I wasn't up yet
I've used all but the pure silver rotaries, which sound promising if pricey. Silver is great since even the oxide is still fairly conductive. Unfortunately the sulphides and some other compounds are not, so the wiping action is essential.
When I was in the switching system business we used Switchcraft interlocking pushbutton switches, which had silver posts and silver-plated contacts with lots of wiping action. Moreover they were lubricated with a substance that prevented tarnish for quite a while. My father worked with the company to engineer a lockout for multiple positions being detented, which permitted a single switch in series with a given source, loudspeaker, or amplifier output, compared to the competition who daisy-chained to prevent simultaneous selection and shorting together. So for their equipment, the position in the array produced variable results. We also used real wire instead of PCB traces, typically 18 gauge.
For a more modular system we used relays with bifurcated gold-plated contacts, for some redundancy. However the 6 pole ones were often unreliable, so the relays were socketed. The great mistake was to use the same style pushbutton for actuation of a local module used by another company famous for poor reliability. Anyone seeing the PB would assume the system was a POS.
For solid-state switching of line-level sources on a new system (for a deal that insured our demise, as it was woefully underbid) I used discrete ~15 ohm JFETs and discrete drive. It sounded o.k. but the expectations were not all that high --- it was for an autosound display.
At UCLA I had to toggle between two preamp outputs rapidly and with good isolation. The resulting switch occupied an entire ~4" x 6" board and was a "T" arrangement, again with discrete devices throughout. At the time a friend who had worked with Steve Schectman at Caltech said that, when they couldn't find a single JFET with low-enough on resistance for a somewhat comparable task, they had given up. Shectman's system was popular because it could be readily cloned, having been laid out on PCBs. Mine was entirely hand-wired.
On the subject of solid-state switching, if one is not feedback-averse too much, the most effective approach for accuracy that vastly improves on the use of a compensating FET in the feedback, is to switch among entire input and feedback networks at the opamp inverting input. If you use as well a T-switch arrangement (two FETs in series and one to common between them) the isolation will be excellent. For the selected network the loss in the switch will be negligible to the extent the opamp input Z is high. The drawbacks include the need to drive all of the networks whether they are selected or not. And of course you have to be happy with your opamp, however realized.
For the Harman speaker-mover switched attenuator I was using mercury-wetted reeds for the rather low-Z resistor networks (Vishay bulk metal foils), and initially suggested mercury displacement relays for switching loudspeakers. The system was completed to the board level and some parts built before the group started feeling poor, and when we estimated that it would take another 20k to finish it the project was shelved. I don't even know what they wound up using for preset level-matching. They use individual amplifiers for the loudspeakers I believe.
Since the project from my perspective was never completed, I have little experience with listening through the Hg-wetted relays. They do have rather higher resistance and with a larger temperature coefficient that simple metal-on-metal reeds, and there was a bit of an analysis of the effects in my 1997 AES paper on the system from the perspective of errors in the attenuation. Of course the purpose of the mercury was to insure no dry contact problems developing.
At one point (jumping back to the switching company days) some work was done on solenoid actuation of the pushbutton switches. It was a messy proposition, probably comparable to the difficulties of electromechanical actuation of a big rotary switch.
Yep, and sometimes you need additional switches to GND a the T input to avoid exceeding voltage specs, mostly of course when using integrated analog switches with +-5V supplies and less. As of yet I typically managed to get away with "half-T's" when using these, being driven from moderate network impedances.
How was the test set up? And were these the same specific relays used in the ABX box?
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