No, the key is for safety. It has about kilovolt of B+ inside. Unfortunately tubes need such voltage.
By the way, Gu-50 output tubes look like trash cans. Otherwise they would cost 10-20 times higher. 😀
By the way, Gu-50 output tubes look like trash cans. Otherwise they would cost 10-20 times higher. 😀
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No wonder you don't have one,, deh wife would never allow that in her house...😀 Anyway whenever you switch to tubes at home , i will too .....😛
You are wrong. My wife is actually spoiled by their sound, and would like to have some at home.
OK, when you get one to replace the Denon let me know ....😎
It is hard to tell, I took a job of a System/Network admin to have some money for living. No time for projects.
Yes life ..... Always farking with the Audio ...damn 🙁 😛.
Can you explain , why GU50 tube and not say KT88/KT120 and whatever happened to the 6LQ6 type power tubes..?
Can you explain , why GU50 tube and not say KT88/KT120 and whatever happened to the 6LQ6 type power tubes..?
Yes, if you can explain, why crappy non-linear steam engine age 6L6 clone instead of designed by Telefunken much more linear LS-50 pentode. 🙂
No. Because Gu-50 look like trash cans. And were unobtanium for manufacturers of mass production of guitar and hi-fi amps when everything, from crap to jewels, was made on tubes. LS-50 was designed and manufactured by Telefunken for military and government applications. Later after WW-II it was captured and redesigned for Soviet military applications, like aircraft transmitters. The tube requires more precision equipment to align grids, and uses more expensive materials, like nickel alloy for anodes. That's why after being red dissipating 100+W shortly it still works as if it never happened.
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That is not always true and not a surprise, my N2 has low feedback and only 9 transistors including the power mosfet and its current source, it could operating also with 8transistors in total. There are no easy way to get stable high NFB that could reach 1ppm THD and less, with only 7 transistors driving mosfet output. Low distortion in solidstate isn't always high feedback but the output stages could be linearized with good design.
Why need 1ppm? because it need to work as linear current amplifier that has linear forward and reverse transfer. 1ppmTHD V-amp results in around 0.01%THD I-amp (depend on I sense resistor used). 0.01% THD is the margin that my ears start to hear differences for H3 and up, H2 is 0.02%.
In N2. It just have crossover distortion rises when operating in 10kHz and up with high current 2ohm load.
Attached shows 800mA biased N2, crossover at 10kHz is only in micro volts. I am choosing 200mA because that crossover distortion is already inaudible in around 100mA. Test is also easily do with biasing switch.
You know? This kind of buffer (I call it power gain in the past, but not a good name) has linear load transfer from output to input that makes it sounds like what is at the input.
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Marantz was pentodes? Dynaco? Fisher? Quad? Leak? Luxman? (just to name a few power amps he reviewed back in the day)
For preamps with which Holt was intimately familiar, I can't think of any that were pentodes.
For preamps with which Holt was intimately familiar, I can't think of any that were pentodes.
Marantz was triode-connected. Fisher ditto. Dyna, ultralinear. Quad, ditto. Leak, ditto. Luxman, triodes. For the preamps, the Leak Point 1 was pentode, every other one I can think of from that time was triode.
Careful, SY, you are being inaccurate in your statement about triodes vs pentodes (or beam tetrodes). For example, Marantz COULD be connected to triode with a switch, but it was usually used in 'Ultralinear' which is equally triode and pentode.
In 1965, we used to modify Fisher 500C receivers to triode operation, from PENTODE operation. Dyna was Ultralinear, and could be beat sonically by either Radiocraftsman (triode) or Marantz 9 in triode mode. Even Ultralinear is not perfect, just a good compromise between power and performance.
In 1965, we used to modify Fisher 500C receivers to triode operation, from PENTODE operation. Dyna was Ultralinear, and could be beat sonically by either Radiocraftsman (triode) or Marantz 9 in triode mode. Even Ultralinear is not perfect, just a good compromise between power and performance.
Gordon Holt never published a negative review? Are you kidding?
Irrelevant anyway, here was a guy who INVENTED so-called subjective reviewing and had far more experience and knowledge than anyone else doing it, then or since. So how do you explain away the change in the perception of "tube sound?" Or was Holt effectively deaf?
Irrelevant anyway, here was a guy who INVENTED so-called subjective reviewing and had far more experience and knowledge than anyone else doing it, then or since. So how do you explain away the change in the perception of "tube sound?" Or was Holt effectively deaf?
Oh, OK, Gordon Holt didn't know how to use a switch. Never listened to a triode amp. Sure.
How many Fisher 50A did you modify to triode?
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