That's actually exactly what I need for work. I was actually considering building a slightly modified clone of your version, but at 300 CHF this device seems like a no brainer. Lets hope that procurement lets me buy from a Swiss startup...
honestly the way we Swiss love our bureaucracy, I'm willing to bet the house that they will be ready to comply with whatever paper trail your procurement requires.
As an audio guy, I know exactly where that "DC Servo" moniker comes from. Glad to hear there's actually something interesting happening with it, and it wasn't solely marketing wankery.
We are engineers through and through and despise marketing wankery too 😉. Nevertheless I must say that good engineering marketing is very nice, like it was in the past.
Since there is an audio servo used the question of audio grade caps from nichicon (muse) comes to mind. Those are rather lower grade caps . The effect of voltage rating also is of interest in that application . The cost difference is small in case .
@@johnwilliamson467 Exactly. It means they are rated to work within specifications for a given amount of time at that temperature. In the case of this amplifier 105oC caps are going to work for a much longer time at lower temperatures.
@@zsigmondkara For these caps the rule of thumb is 2x per 10c work for about a 40 c range thus 120c over 85 c is aprox 16 times the life given the test I have watched.
I personally enjoy my own naturally occurring noise sources. You have an approximate 2kHz noise source whenever unmuting your mic. This may be from test equipment active in a lab, not studio environment.
0:30 The "BNC Polarity" is just a bit 'funny'(being an AC coupled device), but I guess they're referring to the battery charging function. Poor label layout, that BNC Polarity advice should have been printed directly adjacent to the battery charging note for it to make immediate sense.
I love this stuff. However, I'm not a fan of the DC cancelation circuit. My approach was to build a composit LNA with minimal gain and use a very low noise SAR like the AD4630-24. I put a brick wall on the .1 to 10hz bins and ifft to get the RMS. No settling is really needed since there are no AC caps. Also, it's nice that the SAR has a little bit of over rang, so you can measure the same reference noise.
With 10V Input Voltage and 24 bit resolution you will have 600nV LSB resolution. How do you want to measure 10nV or less? You need a gain of 100 or more.
BNC charging is a bit ... silly ... however i am reminded that the end user is an idiot and would gladly keep a device like this plugged in while using it so its a nice cheap lockout mechanism
Swiss startup? Hmm, let's see where they from ... and of course, they are two villages over from where I live. 😅 Even though it's mostly villages here just at the border, for some reason this is tech central of Switzerland.
One very simple method of achieving similar fast-settling LNA performance is to split the overall gain into two stages. An ultralow noise first stage gain of about 250x is plenty to get the signal of interest well above the noise floor, but is low enough to prevent the first stage from railing due to input electrolytic leakage. If you follow that stage up with a high-pass filter, the DC offset is removed and the signal can be safely amplified further. I'm glad that you mentioned input voltage safety, since with such a large input electrolytic it is very easy to overload the input, even with the input clamp diodes. Many opamps don't allow more than 5mA, so either higher than desired input resistors, or JFET current limiters are required. My design uses the OPA2182, which does not have input back-to-back clamp diodes, so it can handle differential inputs up to the VDD/VSS span. I also included a series mosfet voltage limiting circuit, so the input is fully safe for hot plugging into anything up to 30V, regardless if the LNA is powered on! I'm on rev 2 of such a design, and have gotten a 72nVpp / 10.6nV RMS shorted input noise floor! Current consumption is only 7mA total, so it gives plenty of life from a 9V battery. If you search the eevblog metrology page for "DIY 0.1 to 10Hz Noise Amplifier", posted June 12th 2023, that's the build log of my initial design, which I will be updating with the second revision very soon! *The EEVblog post is updated with my Rev X2 results! 78nVp-p typical and 10.54nV RMS typical noise floor with a shorted input
To measure how noisy is the DC volatge reference. The less noise it has the more exactly you can measure its voltage, nowadays possible to 7 places which is 0.1 ppm.
So cool. I wonder how the guys at welectron handle your humor. I'm in Canada a purchased a bm869s recently and they were about as helpful to me as the dolphins were to the fish population before they left earth haha
AVX makes Wet tantalum capacitors with ultra low DC leakage (less than 1uA). I believe Mr. Williams used a few of them for some ultra low noise preamplifier (AN 124 July 2009).
@@DanielHeineck yeah its about 60-150 euros per piece. Ive been on excursion in AVX where they make it but they didnt want to give me a samples :( I would gladly accomodate some nice 4700uF wet tantalum cap :)
There's me expecting a huge InterFET FET - I've seen they have some running at >50 euros a piece but low noise is the name of the game there. I'll stick to the LSK389 and similar.
Ich fange erst zu staunen an, wenn der Verstärker von 10 Hz bis 10 Ghz einen Amplitudengang von +/- 0,1 dB hat und der Rauschpegel unter der Messgrenze liegt. 😂
