Sorry if a bit off topic but can you give me an example of one of these mosfets? I've considered the idea of super cooling high idle current mosfets for fun but I haven't been able to find a justifiable purpose until I saw your post.
A small chunk of a curve of any active device tend to be more linear the smaller is the chunk. But again, there are other worms in the can that grow bigger as the result...
I wonder if you give too much credit. Maybe it is not chosen but just happened. There is always that story given of endless listening tests and circuit optimisation and picking of every single minute component. Down the line it's a billion tube amplifiers copied from the RCA and Mullard manual, every now and then with a change in driver and/or output tube. Coming up with an RC coupled circuit with Trans. - Rect. - CRCRC filter power supplies takes way less time than designing the brochure and the fancy casing.
In the RDH4 article they reference a source called Bass Without Big Baffles. In case anyone is interested in it the link is below. I very much plan on building it just to give it a try. They talk about having harmonics of bass notes without the fundamentals so you don't need large speakers and boxes to give the sound of deeper notes.
http://www.keith-snook.info/wireless-world-magazine/Wireless-World-1950/Bass%20Without%20Big%20Baffles.pdf
Granted, likely swapping the EL33 for a 6V6 since the EL33 looks to be one expensive valve...
http://www.keith-snook.info/wireless-world-magazine/Wireless-World-1950/Bass%20Without%20Big%20Baffles.pdf
Granted, likely swapping the EL33 for a 6V6 since the EL33 looks to be one expensive valve...
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The link above it is accessible (Wireless world Nov 1950), and the one after it (Wireless World Mar 1950) but I can't access the linked article (Wireless World Apr 1950).
Anyone else having problems?
Anyone else having problems?
"Who made this ultra-linear tube?"
The triode is a DHP, triode wired, small signal (1.5 Watt). Many old directly heated tubes will make great triodes.
The beam pentode is a TV Sweep tube (most TV sweeps work well for this), using Crazy/Twin drive (still evolving). Details begin here:
http://www.diyaudio.com/forums/tube...nificent-television-tubes-47.html#post4574362
The triode is a DHP, triode wired, small signal (1.5 Watt). Many old directly heated tubes will make great triodes.
The beam pentode is a TV Sweep tube (most TV sweeps work well for this), using Crazy/Twin drive (still evolving). Details begin here:
http://www.diyaudio.com/forums/tube...nificent-television-tubes-47.html#post4574362
The term "hi-fi" is the level of faithful reproduction of sound. Higher the better in that world. What that world doesn't represent is whether it's perfect or not.
Sure Evenharmonics, that may make the distortion perfectly acceptable (I have very high efficiency old Tannoys) but you couldn't say it was minimised.
People keep complaining about amp thd 0,00..%, but nobody asks speakerboxes mfg´s, to provide data. Bigger numbers in general.
Doubtless the IMD produced by the speakers is just as annoying. Maybe the amp IMD is easier to design out.
The speakers being the bottleneck, that's where the target should be when determining what minimizing is.
Our definition of Hi-Fi has changed a lot in the last few decades as well. Solid state amps able to push DC to 100+KHz have set a new standard. RDH4 has a section on "The target of high fidelity" which gives specifications that most Hi-Fi amplifiers of 1969 would have aimed for at a minimum and "values in brackets are rather extreme":
Frequency Range: 40-15,000 (30-20,000)Hz.
Variation in output +- 1db (+-0.5db) at three levels.
Total harmonic distortion not more than 1% (0.7%).
Intermodulation distortion not more than 3% (2%), measured at 40Hz and, say, 7000Hz-RMS sum.
Power output sufficient to ensure that overloading does not occur.
Phase angle as small as possible.
The desired degree of damping on loudspeaker at bass resonant frequency.
Hum inaudible.
Noise to give specified dynamic range 70 (80)db; total noise 52 (62) below mad RMS peak signal.
By todays standards an amplifier built to these standards wouldn't be Hi-Fi even if it might sound amazing.
Frequency Range: 40-15,000 (30-20,000)Hz.
Variation in output +- 1db (+-0.5db) at three levels.
Total harmonic distortion not more than 1% (0.7%).
Intermodulation distortion not more than 3% (2%), measured at 40Hz and, say, 7000Hz-RMS sum.
Power output sufficient to ensure that overloading does not occur.
Phase angle as small as possible.
The desired degree of damping on loudspeaker at bass resonant frequency.
Hum inaudible.
Noise to give specified dynamic range 70 (80)db; total noise 52 (62) below mad RMS peak signal.
By todays standards an amplifier built to these standards wouldn't be Hi-Fi even if it might sound amazing.
Distortions of mechanical and electrical systems are not compatible by THD numbers. Absolutely. Our perception did not learn during evolution (neither was created by God) to ignore electrical distortions. That's why SE amp distortions are less audible than PP class B ones, because they are closer to mechanical distortions.