Collection of Class B topologies <100mA Idle and Sound closest by Class A

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ontoaba

ontoaba

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Joined 2009
Jon Lord said:
The Technics SE-A100 uses not very good OPamps for driving the power stage. With more recent ones like the LME series, you get better performance. The Class AA circuit also suffers from a kind of "thinking error", which let it operate only at sub optimal performance. The reason of this i don't know, probably patent infringement issues or whatsoever.
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Thanks John.
I am also has experience using opamp buffering output stages. I found that using TL082 is more pleasant than 4580, but 4580 has better high freq result.
I need both pleasant and better, so I am decide to use bc557b (only 1xBC557B, 4x1N4148, 2x4k7R, 1x22R, 1x195R, 1x220uF, in floating sullpy) in SE classA and it better than 4580 and still very pleasant.

Hi, Tief,
ClassA and SEclassA has very different character. SE is natural for half and not for half. The most natural sound from loudspeaker is when you tap it, underdamped, and damped with resistor will sounds most natural and very pleasant.
 
nigelwright7557

nigelwright7557

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Joined 2008
murtonpikesystems.co.uk
tiefbassuebertr said:
Until now, it is still a challenge, to create a solid state power amplifier with <100 mA quiescence current through the power output devices and sound quality like pure class A at the same time.
)
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My class AB designs have all had very low bias currents yet sounded great.
I run about 10ma through the output MOSFETs.
Peavey have a similar approach to low bias currents.
 
tiefbassuebertr

tiefbassuebertr

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Joined 2005
tiefbassuebertragung.de
ontoaba said:
Hi, Tief,
ClassA and SEclassA has very different character.
SE is natural for half and not for half.
The most natural sound from loudspeaker is when you tap it, underdamped, and damped with resistor will sounds most natural and very pleasant.
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I don't understand this marked term. But perhaps you mean the same as to read about the first mentioned URLs by post #1 from URL
http://www.diyaudio.com/forums/pass...s-basic-description-italians-400-000-amp.html
nigelwright7557 said:
My class AB designs have all had very low bias currents yet sounded great.
I run about 10ma through the output MOSFETs.
Peavey have a similar approach to low bias currents.
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Without direct comparison for checking sound charakter several other Class AB designs sounds good. An example are the topologies from the diyaudio member X-pro (Creek, Cambridge Audio), have a look to the URL
http://www.diyaudio.com/forums/solid-state/122378-cambridge-audio-a3i-repairs-mods.html
But what say the listeners in case of direct comparisons against single ended class A like ZEN or DOZ?

BTW - 10mA idle current through the output MOSFETs - this sounds more to Class-D than Class-B, does't it ?
Please let us know an URL for schematics from this topologies.
You say, that Peavey have a similar approach to low bias currents. Which models from
http://www.peavey.com/support/searchmanuals/archived.cfm?page=M
you mean ??
 
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ontoaba

ontoaba

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Joined 2009
tiefbassuebertr said:
I don't understand this marked term. But perhaps you mean the same as to read about the first mentioned URLs by post #1 from URL
http://www.diyaudio.com/forums/pass...s-basic-description-italians-400-000-amp.html
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I think that water and air is similar, if you shake your hand or something in water, you may feel natural movement of your hand. SE is not 100% natural, and it need more to move the loudspeaker more natural.
Voltage driving is when your hand moving according its position, current driving is its force, power is VxI. Natural driving for complex waveform is none of that three, You could calculate it from physics rules. When you tap your loudspeaker, when maximum displacement, when maximum velocity, when maximum force. Then, find the formula of natural sound. Many people are really wrong in driving loudspeaker, they think it is just a resistor.
 
ontoaba

ontoaba

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Joined 2009
Yes, so easy. SE is the most natural but only half, some enhancement will make it very pleasant. My buffer with bc557b is handle the loudspeaker through a power gain output stages, driving loudspeaker directly from SE classA is waste power.
SE classA alone isn't enough. I am using another secret buffer and non linear damper. Still I can't reach as good as if my amp driving headphone directly. Headphone with my output stage is so beautiful. Much beautiful when compared to CDROM headphone output, or when using my soundcard or opamp based buffer.
 
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ontoaba

ontoaba

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Joined 2009
Yes it is a secret, because it using different way to handle loudspeaker than currently available. Too soon to be shared.

The buffer is simple but waste more power than SE classA, not suitable for direct loudspeaker driving. I am using power gain with only 11nS small signal lagging. The other fascinating is power amplifier cost without power supply only ~$30 with 200W output and sounds better than SEclassA. The other pity is I am not sell it here;).
 
ontoaba

ontoaba

Member
Joined 2009
Try with this for starting (see pict). Add some diode, resistors and some elco. Then, give both that SE, secret buffer each. They will sounds good and will more sounds good after secret buffer given. And more sounds good if it has good damper. But sadly still not as real as real sound.
 

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tiefbassuebertr

tiefbassuebertr

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Joined 2005
tiefbassuebertragung.de
moschfet said:
I have a simple MOSFET amplifier from me, which runs in class-ac. The amplifiers sound absolutely excellent:) I will improve the circuit and build something with bipolar.

Bemos - Eine verzerrungsarme Mosfetendstufe in class-B, Elektronik-Selbstbauprojekte - HIFI-FORUM
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Interesting project. I would like to know the diagrams of the gate currents from the output MOSFETs in case of normal operating mode (sine wave and square wave) and in case of clipping - both from LTspice and in real live.

What about the sonic differences between the topologies about
http://www.diyaudio.com/forums/solid-state/192173-poweramp-irfp4668.html
and
http://www.diyaudio.com/forums/solid-state/202701-simple-circlotron-2sk1058.html
 
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