johnego :
HEXFET vs MOSFET | difference between HEXFET and MOSFET
Well, I know what the cutting-edge technology is about to use in your new designs.
It would be very enlightening if you attach the circuit design in which you use this technological novelty (any circuit that currently uses it, something already known, I understand that you want to protect your own development)
HEXFET vs MOSFET | difference between HEXFET and MOSFET
Well, I know what the cutting-edge technology is about to use in your new designs.
It would be very enlightening if you attach the circuit design in which you use this technological novelty (any circuit that currently uses it, something already known, I understand that you want to protect your own development)
I'm not currently using HEXFET/MOSFET because I'm just doing class B. But I'm using LATFET, with its low transconductance problem, and if paralleling is part of the solution, then its a financial problem
I don't know yet if I'm satisfied or not with my class B. I need to use better source to find out. If I'm satisfied then I will not go the class A way...
When I'm not satisfied with class-B then I'm going to design a class-A amp with HEXFET. I think best of HEXFET/MOSFET parts are dominated by smaller packages like TO-220 and even SMD... I think my best part was something like STP10N bla-bla-bla (I forget) which is hard to find the P-channel part (and I have only a few). But I have a lot of IRFZ34/IRFZ934 which is/was my second best part.
My very good result with class B is because I do know something about the evils of global feedback. Nothing 'spectacular' like new error correction or something. In class A with no GNFB I have no added value that enable me to design better amps than others, I think. But I will try, as not many examples I can find or copy anyway... But BTW, AKSA-LENDER-ALEPH Class A looks like a good candidate that I can use as reference... Or may be CFA that I'm already familiar with.
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It is not a must at all. Many commercial offerings, some in the high end work in class AB with no global NFB.
Actually i disagree with your general class related statements. Class A, both with valves and SS sounds different to me, better in some aspects, worse in others. It probably depends on what qualities of sound you consider musically important. Soundstaging, where class A excels is for me a lot less important than PRAT.
Ah! I forgot the DartZeel. I must build such amp. Do you have a schematic?
I don't know where we disagree...?
Yes, but which schematic? I have heard about online circuit that doesn't work, unstable, etc., not to mention bad review (beside good ones of course). I wasn't interested because my standard for THD was (and still is) high. I have only simulated one circuit, a DartZeel, but never decided to build one and then I forgot...
Which one is the best between those non GNFB amps? I just want to hear how it sounded now. I think there must be a 'secret' schematic, otherwise I don't think it will work well enough...
The VAS, yes, down to component values, which seems a bit ridiculous. Apparently Mr Delatraz owned an extensive Revox collection and clearly liked something about the sound of that particular amp.
The overall concept is still different. The diamond output, the lack of loop fb. There is even a ridiculous patent attached to it.
Not sure if any of this matters. Attaining good sound is not a result of engineering excellence. Good ears and an open mind are far more important. Engineering has its place mostly for making sure things don't blow up. And of course for marketing to the gullible.
CFA do have unique performance, and it was not so popular (may be a secret among high quality amp manufacturers). May be he's just fond of the CFA characteristics and nothing more. Today, CFA has been more popular, especially with internet and LTspice, I doubt those old circuits are special...
Well, the o/p stage is not part of it, that's all. It is a very nice amp for the parts count and effort but of course not perfect or universal.
General sound signature is more suited for soft and mellow music, rather than dynamics, control and lightning fast leading edges. Performance in low impedance speakers is very disappointing but hardly surprising. A SS equivalent to a PP 300B with slightly better bass, more resolution and less bloom.
Except high power solid state, I do not see any amplifier being accurate without GNF, even with a lot of local feedbacks, lot of distortions are left behind.
This is a myth of the 1940-1950 when drivers were paper, alnico sensitive magnets and 95 db sensitivity, 0.01 watt was sufficient, recordings were not extended and broadband like today.
I have also a big problem with the 'best' amplifier. The current market amplifiers all sound alright, from basic receivers to super costly class A behemoths. It is rare that I find an amplifier that I dislike and same for speakers.
People should listen with their ears and measure, try to corroborate. Choosing by circuit topologies is ridiculous. I would be happy with a fully digital and class D system. I am into the tube gears because it is a personal choice, not the best.
This is a myth of the 1940-1950 when drivers were paper, alnico sensitive magnets and 95 db sensitivity, 0.01 watt was sufficient, recordings were not extended and broadband like today.
I have also a big problem with the 'best' amplifier. The current market amplifiers all sound alright, from basic receivers to super costly class A behemoths. It is rare that I find an amplifier that I dislike and same for speakers.
People should listen with their ears and measure, try to corroborate. Choosing by circuit topologies is ridiculous. I would be happy with a fully digital and class D system. I am into the tube gears because it is a personal choice, not the best.
What do the science guys working in this field have to say about getting good sound?
Iow what is the outcome of properly conducted listening tests.
1 it's the transducers that are the bottle neck of the reproduction chain. The electronics are completely transparent, with some exceptions.
2 speakers that come out on top in double blind listening tests all have a simular character and measure alike: No audible resonances and a uniform off axis response. I think that the prediction rate is 86% based on spinorama measurements alone and 99% when bass is excluded. That is a stunning result if you ask me.
Iow what is the outcome of properly conducted listening tests.
1 it's the transducers that are the bottle neck of the reproduction chain. The electronics are completely transparent, with some exceptions.
2 speakers that come out on top in double blind listening tests all have a simular character and measure alike: No audible resonances and a uniform off axis response. I think that the prediction rate is 86% based on spinorama measurements alone and 99% when bass is excluded. That is a stunning result if you ask me.
ok..scottjoplin said:
You must think I like high efficiency because it is an easy load for an amp, otherwise why would I build them?
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