Re: A Challenge for Stewart Pinkerton

Hi-

Your comments about this being a tube group are well-taken;
however there are people who find their way here and are qualified to
comment.
I have an active Google alert for "amplifier input current noise"
which frequently brings me here to read the prognostications of the
tube afficondidos.
I am afraid that, as an analog consultant who designs commercial
equipment, such as seismometers having noise floors of -120dBm, the
idea of using a tube for an amlifier right now would never cross my
mind.
Tubes are for the most part not even specified for several types
of noise which are critical (voltage, current, 1/f) plus from a
knowledge of their inner structure (a shaky grid susceptible to
mechanical feedback and vibrations, a red-hot cathode thrumming with
1/f noise) I cannot how anyone could even defend the use of the tube
amplifier except in the power stage of an amplifier.

Regards-
Charles Gilbert
Consultant
NonDigital.Netfirms.com

.

Relevant Pages

  • Re: Relationshp of Vk to Rk and noise?
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    (alt.guitar.amps)
  • Re: basic understanding of how electric guitar gear works
    ... Fender Frontman 15R Amp ... amp I can't get them last that long (say, I'd like the sound to last as ... amplifying initial small noise as well). ... I'm older, have been playing for a while, and have accumulated some tube amps. ...
    (alt.guitar.beginner)
  • Re: Relationshp of Vk to Rk and noise?
    ... a shield over the tube all helped, but there is room for significant ... I'm assuming that the hiss you are referring to is ... Resistor and tube noise is White Noise, at equal energy throughout the bandwidth. ... Even at the same gm FETs have a 6dB advantage from the get go due to ...
    (alt.guitar.amps)
  • Re: MC PHONO PREAMP
    ... gives a calculated effective input noise resistance of 1250 ohms which ... Draw a vertical line through a wanted Ea for the tube and plot where Eg1 ... Its input noise ... that's why I am suggesting a 40dB amp before it. ...
    (rec.audio.tubes)
  • Re: MC PHONO PREAMP
    ... equivalent input noise resistance for a tube. ... The EINR isn't the only source of tube noise. ... In my case the following amp has gain of 1,500, so this becomes 180mV, ...
    (rec.audio.tubes)