2019年8月13日 · As Scott implies, IME noise rise and fall with temperature, especially at audio frequencies, is often due to other noise sources than basic resistive thermal (Johnson) noise. Years ago a fellow engineer used some wideband (microwave) GaAs devices and then later SiGe HBTs from an RF LNA (low noise amplifier) design of mine to (attempt to) create ...

2025年1月12日 · Ditto noise with an actual cartridge attached for reasons I posted about (and provided data for) a couple years ago. For the S/N freaks out there, remember that, putting aside mechanical issues, cartridges have Johnson noise, and at higher frequencies where the inductance becomes a significant part of the source impedance, there's increased ...

2025年1月15日 · The thermal noise of a 47k MM load resistor shunted by a typical MM cart (taken as 500mH in series with 1.3k Ohms) is 3.1uV. This sets the absolute best case SnR to 76 to 77 dB ref 5 mV. To achieve that level of performance, the input devices will have to be carefully selected for lowest noise voltage and importantly, very low noise current.

2019年3月18日 · Analog output buffers add noise, of course, but how much depends upon the design. A perfect DAC would have no other noise sources and meet the equation above. Noise sources like thermal/Johnson/Nyquist, shot noise, flicker noise, and the zillion or so other sources is probably beyond an Internet post.

2023年5月27日 · Now I emphasize "baseline" noise, that is, the noise that physics enforces for perfectly ideal systems. In the real world, it's inevitably worse- for example, preamp current noise (which Amir does not measure) will degrade things further. If the cartridge is not connected to anything (in case this is an eristic exercise) it still has Johnson noise.

2019年3月24日 · The lowest, as defined here, is the noise floor. With electronics, it can be relatively low, as Johnson noise, Op Amp's noise etc' with analog sources (vinyl or tape) is the rumble or hiss (-50dB) or CD with S/N of -100dB or better. Mostly, such dynamic ranges, also need to consider the lowest sound (music) ref. to the noise floor.

2018年2月28日 · This chip actually acts as a mixer which is buffered on the outputs by a low-noise NJM2068MD (M - stands for the small DMP8 socket, D - stands for very low noise). However, when CD-DIRECT is pressed the YD953A0 and the NJM2068MD are bypassed, this way an even lower background noise is achieved, hence a better SNR and THD+N.

2019年7月29日 · If we choose to use 1ET7040SA(~14μV(A)), even though 1ET400A has lower noise(~11.5μV(A)) and lower price, we must be able to get enough benefits(the Output power) for justification. Then, we can look Marchaudio's in house data.

2018年11月6日 · And you couldn't resolve 32 bits going out (ADC), also not possible. For a bunch of reasons. you'd not only be ay under the Johnson-Nyquist noise, but you'd be into shot noise—I'd be temped to estimate electrons flowing per unit time at the 32-bit extreme if...er, I lost my sanity and thought it was a fun idea.

2022年4月28日 · If it's passive it still can introduce noise. Actually resistors are main noise source in audio electronics due thermal (Johnson–Nyquist) noise. Modern opamps are less noisy than 100 ohms resistor. So THD vs freq and THD vs voltage graphs could be interesting to see, even for passive filter.