BV,
The subject has been investigated thoroughly for everyone who wants to know. PMA has unlikely the means to carry out a trustworthy scientific research.
Sound quality has no quantifiable and expressible quantities. Nevertheless, people will continue to turn subjective values into figures and graphs to infinity, fooling themselves and others.
"Sound quality has no quantifiable and expressible quantities. Nevertheless, people will continue to turn subjective values into figures and graphs to infinity, fooling themselves and others. "
Nonsense.
The number help us make sense of the realities. And, If the numbers cannot expLain everything we experience, then we have to investigate some more until we find the cause. However, I doubt we are missing some fundamental insights in Audio . . . it is a mature and well understood branch of engineering. Period.
Nonsense.
The number help us make sense of the realities. And, If the numbers cannot expLain everything we experience, then we have to investigate some more until we find the cause. However, I doubt we are missing some fundamental insights in Audio . . . it is a mature and well understood branch of engineering. Period.
... well understood branch of engineering ??? Hard to believe for me.
The perceived sonic differences between different audio high end amplifiers are today still identify than 20 until 30 years ago - even within the same price class and even by nearly identical measured distortion behavior.
And it may well happen that an vintage amp with 2N3055 or 2N3773 (very slow speed) sounds better than some similar device from currently production (if it is properly restored).
The Braun "Regie 450" and Regie 510 are examples therefore
http://upload.wikimedia.org/wikipedia/commons/d/d8/Braun_regie_510.jpg
Would now be developed as thoroughly as in the early jears of hifi, then it would be a clear and verifiable progress present - not only by measuring thd
Only the MJL21193/94 specified for THD. 0.08% for 100W/8ohm.
And how about the linearity????
Sajti
MESA Transistor
(′mā·sə tran′zis·tər)
(electronics) A transistor in which a germanium or silicon wafer is etched down in steps
so the base and emitter regions appear as physical plateaus above the collector region.
mesa transistor: Definition from Answers.com
like Panasonic's 2SB713/2SD751
http://stock.hqbew.com/pdf/PANASONIC/34644_2SB713.pdf
with no precision about the testing conditions,
this is meaningless...at which quiescent current?...
anyway,onsemi own models doesnt coroborate this..
at this rated output power, wich i presume is
at 1KHZ, toshiba 2SA1943/2SC5200 are clearly better..
Wahab,
I note quiescent here is 240mA, pretty deep Class AB; not sure what output, but is that around 20Vp?
Can you inform us of the emitter resistor used here?
It's interesting to see that odd order is always higher than even order until about the 15th harmonic. It's a tough one to resolve, the DEF output stage.
Hugh
I note quiescent here is 240mA, pretty deep Class AB; not sure what output, but is that around 20Vp?
Can you inform us of the emitter resistor used here?
It's interesting to see that odd order is always higher than even order until about the 15th harmonic. It's a tough one to resolve, the DEF output stage.
Hugh
the schematic displayed is pretty unclear...
we know nothing about the quiescent current although it s
a key parameter in output stage THD...
the test is done with a 40 V PP sine, very close to the
supply rail voltage , as the emitter degeneration 0.5r add a
further 2.5 V gap per rail, so the quiescent current you measured
is quite on the range expected for low THD at this level..
with on semi quiet about this parameter, i ll simply check wich current give this figures of distorsion..
so far, the sims i made doesn t agree with on semi unless the current is in the range you measured or even more...the figures are about 0.3% ..
i hadn t had the time to go further for now, but i ll soon check
this deeper...
anyway, although the toshiba 1943/5200 give more odd harmonics, their level
is significantly lower than the ones diplayed by onsemi s 21193/21194...
wahab
Certainly not true, Lumba. An outstanding example is the ThermalTrak line of power transistors by OnSemi. Arguably THE BEST audio power BJTs on the market. Their far superior thermal tracking ability is a virtual game-changer. They have outstanding ft and excellent SOA.
Cheers,
Bob
Making switching transistors is also a difficult challenge, maybe even more challenging than linear ones. A good example from On-Semi is MJE13009, 400V 12A, it features excellent switching times and low Vce-sat for a 400V NPN. It really does 12A, I got up to 1800W in a regulated SMPS with four of these (TO-220!!), and cost was ridiculously low. Eight IRFP460 TO-247s were required back then to get similar efficiency when better high voltage MOSFET were not available.