Found out the circuit of THX 789. It's nothing new.

[JohnYang1997]

It's basically a composite amplifier or a nested feedback amplifier. They put a opa546 in the feedback loop of opa1602. That's it. The so called feed forward technology is purely BS. They added a resistor of 37.4ohm which only decreased the feedback factor at lowest frequency. And they call this innovative, new, patented "technology". Na.
The performance is respectable, the marketing, not so much.

 

[Wombat]

It's basically a composite amplifier or a nested feedback amplifier. They put a opa546 in the feedback loop of opa1602. That's it. The so called feed forward technology is purely BS. They added a resistor of 37.4ohm which only decreased the feedback factor at lowest frequency. And they call this innovative, new, patented "technology". Na.
The performance is respectable, the marketing, not so much.

You know too much.

 

[JohnYang1997]

You know too much.

I just hate unrealistic unfaithful marketing.

 

[boXem]

It's basically a composite amplifier or a nested feedback amplifier. They put a opa546 in the feedback loop of opa1602. That's it. The so called feed forward technology is purely BS. They added a resistor of 37.4ohm which only decreased the feedback factor at lowest frequency. And they call this innovative, new, patented "technology". Na.
The performance is respectable, the marketing, not so much.

The fact is that it is patented, worldwide. Meaning that something was considered as new by several patent offices (in most cases, EU ones are stricter than US ones).
So maybe not just marketing, even if I have personally hard time to understand what is fundamentally new with this patent.

 

[JohnYang1997]

The fact is that it is patented, worldwide. Meaning that something was considered as new by several patent offices (in most cases, EU ones are stricter than US ones).
So maybe not just marketing, even if I have personally hard time to understand what is fundamentally new with this patent.

The patent is not related to the 789 circuit. They are not remotely similar in any means.

 

[boXem]

The patent is not related to the 789 circuit. They are not remotely similar in any means.

Then, marketing

 

[ThomasXia]

A pity that they are just boasting.
Waiting for your Topping amps.

 

[pos]

What about the ahb2 amp?

 

[JohnYang1997]

What about the ahb2 amp?

The ahb2 amp uses discrete circuits. It's hard to tell. There is very big chance to implement the patented circuit. However the patented circuit does not show feedforward. The fundamental topology should still be feedback. And as they achieved great performance. I do not have much to say.

 

[thaitao2702]

Are you sure it doesn't use feedforward? Have you reserve-engineering it?

 

[AnalogDE]

Just taking a quick glance at the diagram there appears to be feedforward through the cap in Z3.
Obviously there is still NFB.

 

[LTig]

Just taking a quick glance at the diagram there appears to be feedforward through the cap in Z3.
Obviously there is still NFB.

I have seen similar circuits before, to enhance current output of opamps. There Z3 was connected from output of X1 to the emitters of Q1 and Q2. The only difference to the patent is the existence of Z1.

 

[Ron Texas]

It works, doesn't it?

 

[JohnYang1997]

It works, doesn't it?

Yep. It works, just like any other well designed composite amplifiers, well, a bit better still. I'll give them that. It's really great well engineered amp. The power/ground section is even more mind blowing. We can learn a lot from the circuit.

 

[w1000i]

I don't understand much but do you think schitt latest magni heresy is better than THX implementation to get high power w/lower noise ?
https://www.audiosciencereview.com/...it-magni-heresy-headphone-amp-teardown.10330/

 

[FrantzM]

Hi

I don't know enough about audio circuits to make a strong case. I am not defending the THX people:
Any circuit must have those 3 basic elements:
Resistor
Inductance
Capacitors

How you arrange/use. these components is where the "genius"/results are. Sometimes the arrangements can be simple. sometimes more complex. Western Music use 7 notes... From Beethoven to Kanye West ...

 

[JohnYang1997]

Hi

I don't know enough about audio circuits to make a strong case. I am not defending the THX people:
Any circuit must have those 3 basic elements:
Resistor
Inductance
Capacitors

How you arrange/use. these components is where the "genius"/results are. Sometimes the arrangements can be simple. sometimes more complex. Western Music use 7 notes... From Beethoven to Kanye West ...

Despite there are non linear elements, I get what you are saying.
That's where the issue lies. It's the way they claim the circuit operates. Instead of being an feedforward error correction circuit, which should be very different, it's a fully feedback circuit with feedforward path that might help stability. So basically it's more of a stabilization technique, among many others, than else. They marketed the circuit to be ground breaking, unique, which is misleading at best.

 

[JohnYang1997]

The point is, apart from criticizing THX for their marketing, that most good performing amps measured on this site are actually more similar than different from THX's topology. Namely, Atom, neurochrome hp1, TCA HPA-1, Geshelli Archel 2, Fiio A5 etc.

 

[Celty]

I care about price to performance, not marketing, unless the marketing actually states false performance data (which amir has shown to be true in some instances). From Intel to Apple - from Ford to Nvidia, all these companies engage in marketing babble and misleading nonsense. Good gosh audio is probably among the worst of all (see marketing ads on cables, DACs, you name it).

That is why we need actual test results as we find here at ASR. Bottom line, THX amps do perform, so the rest is not issue to me.

 

[JohnYang1997]

I care about price to performance, not marketing, unless the marketing actually states false performance data (which amir has shown to be true in some instances). From Intel to Apple - from Ford to Nvidia, all these companies engage in marketing babble and misleading nonsense. Good gosh audio is probably among the worst of all (see marketing ads on cables, DACs, you name it).

That is why we need actual test results as we find here at ASR. Bottom line, THX amps do perform, so the rest is not issue to me.

I do not represent you. So if you are ok with this then fine. This is just an opinion. What I'm stating is for people who care somewhat about the circuit and how they achieve the performance.
Like I stated later, the meaning of this is not forcing you not buying thx related products but to inform the fact this level of performance is achieved with already available topology and techniques.
I have higher standards for companies like THX, Benchmark, JDS. I expect them to be better and more honest than many others. Hence why.