If you put the whole contraption it in the refrigerator overnight, I am sure the noise would be even lower the next day.
Hey Ed, you could try putting your pico-Volt preamp into a flask of Helium
(I dunno if the batteries will work down there though . . . )
Since the input is a pair of transformers that would work. But liquid nitrogen is probably enough, cheap and easy to get. Now what to measure?
The pair at -200C should do about 4 PV.
Last edited:
No and no and no again, the lossless is in their imagination and hype. There is only one lossless, diff yields zero at all bits.
.
Profit for sales guys and the IRS.
Over the last dozen and a half years under VW ownership, Bentley hasn't made as much as a dime return, BAU for the top of the food chain.
(the last place on earth you'd buy a Bentley is Australia, 2/3d higher than US list)
Yacht broker commission on a newbuild is 6 percent of the contract price, of which the actual sales person receives 1 percent, on top of a base salary.
But 1 percent of a 100 million superyacht makes 1 million dollars
(Overhere in '92, an AD797 cost $15/pc. Inflation corrected to present day, makes some 27 dollars. An opamp which still is top of the range, currently at a third of the original rate, sounds like value for money to me. Wish I could say the same for a Bentley)
Yes carrier freezeout is real and already important at 77 Kelvin. Some experimental physics people used to shine light from a "grain-of-wheat" incandescent bulb on bipolar transistors to get them to work at 4.2 K. Another nuclear sci guy made a helium-cooled charge preamp using Germanium JFETs, although it still had so much excess noise it wasn't particularly high performance. That was a long time ago.Or how well the transistors will work! Dopants like a little heat to do their job.
If you put the whole contraption it in the refrigerator overnight, I am sure the noise would be even lower the next day.
Hey Ed, you could try putting your pico-Volt preamp into a flask of Helium
(I dunno if the batteries will work down there though . . . )
I think you're mixing threads up. Ed's project and my microphones are two different things. The mechanical and acoustic damping properties of beach sand are amazing, it's just that you don't actually want the sand to get in your mic so you use a ziplock bag as the first layer.
Ok its in their imagination. Well, we shall see later what falls out from it. if I have a chance, I'll listen to it. Maybe more will be divulged in time.
-RM
That is only the electrical noise the brownian motion of the air is dominant in most mics so the air load is needed. My refs of the B&K literature is all one needs, brilliant stuff no need to re-invent anything.
No issues with static from the bags? That'd be my concern. (Evidently not, though)
I just bought some 797 today -- a dozen -- for about $3 each. Going to see how they perform and where they blow up at with PS> than Absolute Max rating. Just curious.... looks to me like in order to get maximum yield the mfr has to allow as many as possible to pass.... thus a lower max rating. I'm just curious in the opamps I would use in projects.... 4-5 of them.
The Bentley..... I have a caddy CTS-V [improved]..... but the Bentley is better made and is amazing in many ways. That W12 TT engine, transmission and Audi-like 4 wheel drive, --- too much to list.... The CTS-V is lighter and more horse power so it is better in some other ways. Bentley's 650 ft/# at 1600 rpm get the heavy weight moving very easily. My GF wanted the Bentley ... It is her's but I like to drive it. She just goes to the grocery store with it. So you can blame her that i have it parked in my drive way.
THx-RNMarsh
Last edited:
i have it parked in my drive way.
THx-RNMarsh
Car stuff is wasted on me, I don't have a clue as to what you are talking about. I'm still trying to get the speaker lights on my Kia Soul to light up at less than deafening levels.
Absol Max PS voltage test for the AD797...... works just fine all day at +/-24vdc...... but thd goes up sharply if either supply goes above 25vdc. Very different from the LM7171 which has a slowly increasing thd above its' 28v. I havent tested either to the smoke level. Yet. Others to do.
Burning them over night.
THx-RNMarsh
Burning them over night.
THx-RNMarsh
Last edited:
Yes that was in the days when Janesik discovered that the output amplifier on the chips was a faint light source.
- Status
- Not open for further replies.