Class A amplifier

[dualazmak]

Any real measurements instead of a spec sheet typed up by the manufacturer? Would be interested to see same.

JSmith

Just for our reference, Accuphase always shows their "guaranteed" THD and Fq response spec data in their users manuals, like this for Class-A amp A-75;
https://www.accuphase.co.jp/manual_pdf/a-75_manual_j.pdf

 

[gene_stl]

Some manufacturer's are more credible than others. Sometimes Amir states his measurements agree (or ocassionally disagree) with those of the manufacturer.

 

[solderdude]

All you need to listen to 2C3D setup. Nothing much to say if you don't listen. Keith Johnson already opened the door of wide bandwidth. Look at this look just fine again. The transistor actually switching into 1.2mHz and no more reading. It is 500 times more bandwidth than you need in audio.

Lot of the spec are worst than AHB2 other than Frequency Respond and speed. It is one of the top well engineered amp in the world. If really choosing for reference, I will definitely choose Spectral.

I'll ask again because you avoided the real question...

Why does one have to listen to an amp with a 1MHz bandwidth and what would the MIT cable add if the speakers and source don't have much (sine wave shaped) frequencies above 40kHz anyway.

 

[voodooless]

All you need to listen to 2C3D setup.

Oh no, now the cables come in.. looks like those Spectral amps need special cables to remain stable. The design if totally flawed!

Nothing much to say if you don't listen.

Please do so, double blind, perfectly level matched.

The transistor actually switching into 1.2mHz and no more reading. It is 500 times more bandwidth than you need in audio.

Class D switching frequency != audio bandwidth.

 

[JSmith]

info

Thanks for finding... this looks a bit average though around 50Hz etc.

JSmith

 

[voodooless]

Thanks for finding... this looks a bit average though around 50Hz etc.

To be fair, since this was an older amp there might have been an issue with the power supply caps.

 

[kongwee]

I'll ask again because you avoided the real question...

Why does one have to listen to an amp with a 1MHz bandwidth and what would the MIT cable add if the speakers and source don't have much (sine wave shaped) frequencies above 40kHz anyway.

Oh no, now the cables come in.. looks like those Spectral amps need special cables to remain stable. The design if totally flawed!

Why don't throw the question at Bruce Brisson? I am not the designer. Capacitance sure it is. The thing core cable is not cut into half unlike transparent cable. many resistor, cap are running in parallel . All other cable manufacture their cable is inductive having a parallel core with PVC or whatever skins. Well, I may be wrong for decades I never remember all these theory. I guess all cable are naturally inductive because of capacitance skin. MIT Cable run extra wire in series with capacitor. Naturally that section is capacitive. You can see all these caps in the box all over google. This way you are correcting power factor of the cable which no other cable maker will touch except Transparent cable. This is how it done your nearby substation work. After the high tension cable flying to your substation, you get capacitor bank to correct the power factor after step down transformer. In higher series of MIT Cable even inductor are used.

In hifi show, if you meet Bruce, perhaps he can explain better.

Spectral MIT cable are especially made and get better result using Avalon Acoustic speaker. Three company work together to create their 2C3D. Go and listen to it when Keith Johnson amps are still selling. I don't think Rick Flyer will continue Spectral Audio, it is not his main business according to my ex boss.

Of course, you can read his white paper.

MIT Technical/Whitepapers - MIT Cables - Music Interface Technologies

MIT Whitepapers and Technical Writings MIT Technical Note 101— Transportable Power in Audio Cables: Energy Storage Elements and the Power

mitcables.com

 

[solderdude]

Why does one have to listen to an amp with a 1MHz bandwidth if the speakers and source don't have much (sine wave shaped) frequencies above 40kHz anyway.

What would be the reason you need such a bandwidth ?

 

[SIY]

Well, I may be wrong for decades

Indeed.

 

[voodooless]

Of course, you can read his white paper.

MIT Technical/Whitepapers - MIT Cables - Music Interface Technologies

MIT Whitepapers and Technical Writings MIT Technical Note 101— Transportable Power in Audio Cables: Energy Storage Elements and the Power

mitcables.com

All I see is a load of pseudoscience non-sense...

Funny though, how one needs a high bandwidth amplifier, and then needs to attach a super high capacitance cable to filter away all that high-frequency crap again. Why have it there in the first place? Why not just build the filter right into the amp, as normal designers would do?

 

[kongwee]

Why does one have to listen to an amp with a 1MHz bandwidth if the speakers and source don't have much (sine wave shaped) frequencies above 40kHz anyway.

What would be the reason you need such a bandwidth ?

I don't if I explain this earlier, I can repeat it again. Square wave is good explain. When rising or falling of the square wave, a perfect the horizontal straight line is having you transistor at work infinite frequency. You have slew rate in real world, rise or fall time. They are measure in volt over micro or even nano second. Nano second mean 1 MHz. You open electronic engineering to read about BJT, MOSFET.....other transistor. You can read more how square wave are form. I really throw out all the theories decades ago.

Funny though, how one needs a high bandwidth amplifier, and then needs to attach a super high capacitance cable to filter away all that high-frequency crap again. Why have it there in the first place? Why not just build the filter right into the amp, as normal designers would do?

If you really measure MIT Cable is capacitance over all, it is high pass filer actually. Capacitor is not capacitance depending how you insert in a AC circuit.

 

[SIY]

I don't if I explain this earlier, I can repeat it again. Square wave is good explain. When rising or falling of the square wave, a perfect the horizontal straight line is having you transistor at work infinite frequency. You have slew rate in real world, rise or fall time. They are measure in volt over micro or even nano second. Nano second mean 1 MHz. You open electronic engineering to read about BJT, MOSFET.....other transistor. You can read more how square wave are form. I really throw out all the theories decades ago.

If you really measure MIT Cable is capacitance over all, it is high pass filer actually. Capacitor is not capacitance depending how you insert in a AC circuit.

Uh huh.

 

[sergeauckland]

Kongwee said
" I really throw out all the theories decades ago."




And replaced them with total bollocks.

S

 

[voodooless]

If you really measure MIT Cable is capacitance over all, it is high pass filer actually. Capacitor is not capacitance depending how you insert in a AC circuit.

High pass? How does it let audio through then?

 

[solderdude]

I don't if I explain this earlier, I can repeat it again. Square wave is good explain. When rising or falling of the square wave, a perfect the horizontal straight line is having you transistor at work infinite frequency. You have slew rate in real world, rise or fall time. They are measure in volt over micro or even nano second. Nano second mean 1 MHz. You open electronic engineering to read about BJT, MOSFET.....other transistor. You can read more how square wave are form. I really throw out all the theories decades ago.

I know about square waves and why they are used to test amps (I design amp myself)
It seems like you have no idea what a square wave is nor what semiconductors properties are, what feedback is etc. nor why a ridiculously high BW would not be beneficial nor needed. 100kHz is wide enough.
The fact that amps can be designed to have a super high BW does not mean it is needed.
Funny how audiophiles that love tube amps are never worried about BW and square waves yet they claim superior sound quality despite the poor BW of most of these amps.

 

[SIY]

High pass? How does it let audio through then?

The same way a nanosecond is a megahertz.

 

[Geert]

You open electronic engineering to read about BJT, MOSFET.....other transistor. You can read more how square wave are form. I really throw out all the theories decades ago.

Funny things happen when someone is so unknowledgeable on a topic he can't even assess and understand the knowledge level of the other party.

 

[kongwee]

Funny though, how one needs a high bandwidth amplifier, and then needs to attach a super high capacitance cable to filter away all that high-frequency crap again. Why have it there in the first place? Why not just build the filter right into the amp, as normal designers would do?

If you really measure MIT Cable is capacitance over all. It is high pass filer actually.

High pass? How does it let audio through then?

If you define MIT Cable is one big capacitor C, aren't you are going to take your load R as speaker load? Who pass you this diagram to debunk MIT Cable?

If your diagram can treat as a normal cable, where C is actually the insulator between the two conductor. So normal cable are low pass filter. Just conductor and insulator.

 

[SIY]

If you really measure MIT Cable is capacitance over all. It is high pass filer actually.

If you define MIT Cable is one big capacitor C, aren't you are going to take your load R as speaker load? Who pass you this diagram to debunk MIT Cable?

If your diagram can treat as a normal cable, where C is actually the insulator between the two conductor. So normal cable are low pass filter. Just conductor and insulator.

Congratulations, every time I think you can’t post anything stupider, you prove me wrong.

 

[kongwee]

Congratulations, every time I think you can’t post anything stupider, you prove me wrong.

Proved to me then if you have a digram of MIT Cable just putting capacitors just a cross their terminals. Best have the actual diagrams.