In DAC, Anything audible but unable to be measured(so far)?

[Bamboszek]

Frequency compensation techniques, stability and whole control theory is not that simple matter so it is completly understandable someone might have questions. Here is interesting read about driving capacitive loads, including multi feedback topology proposed by you. Especially notes below slides. Things get even more complicated when we consider current feedback amplifier like TPA6120A2. I'm working on composite headphone amp project. I have few prototypes already, next week I'm excepting to try few configurations - with Riso in feedback loop vs simple air core inductor at output. I have access to vector network analyzer and APx525 so I will be able to compare stability and THD performance of both methods. I can publish results here if there is any interest.

 

[JohnYang1997]

Frequency compensation techniques, stability and whole control theory is not that simple matter. Here is interesting read about driving capacitive loads, including multi feedback topology proposed by you. Especially notes below slides. Things get even more complicated when we consider current feedback amplifier like TPA6120A2. I'm working on composite headphone amp project. I have few prototypes already, next week I'm excepting to try few configurations - with Riso in feedback loop vs simple air core inductor at output. I have access to vector network analyser and APx525 so I will be able to compare stability and THD performance of both methods. I can publish results here if there is any interest.

I have done fully working composite amplifier with lme49600, tpa6120. I even did 3 opamp cascade nested feedback + feedforward circuit. The circuit above is no where near the chips limitation in terms of stability. The thing that needs mentioning are already mentioned. You don't need to teach control theory, electronics, different topology, input impedance, bode plot all of those all over again in order to share one simple modification. The person who read the modification only need to know the values and the related considerations. It's VERY SIMPLE.

 

[amirm]

I'd buy one and ship it to Amir, but there's the problem of 110v/220v version... I'd need the EU-compatible one .

My lab AC supply can generate anything so that is not a barrier. The barrier would be the high cost of shipping it back to you in EU. So how about those of you who are interested buy it and just send one to me to test? Sending cheap stuff back and forth doesn't make sense.

 

[Bamboszek]

It might be very simple for someone proficient in electronics. Before making any modifications for my gear I would prefer to have some insight on topic instead blindly trusting someone over the internet. I think thats wise and normal reaction to ask some questions instead of potentially risking unstable amplfier or even damaging headphones.

 

[amirm]

Frequency compensation techniques, stability and whole control theory is not that simple matter so it is completly understandable someone might have questions. Here is interesting read about driving capacitive loads, including multi feedback topology proposed by you. Especially notes below slides. Things get even more complicated when we consider current feedback amplifier like TPA6120A2. I'm working on composite headphone amp project. I have few prototypes already, next week I'm excepting to try few configurations - with Riso in feedback loop vs simple air core inductor at output. I have access to vector network analyzer and APx525 so I will be able to compare stability and THD performance of both methods. I can publish results here if there is any interest.

I would be interested. Please post it in the DIY forum.

 

[JohnYang1997]

It might be very simple for someone proficient in electronics. Before making any modifications for my gear I would prefer to have some insight on topic instead blindly trusting someone over the internet. I think thats wise and normal reaction to ask some questions instead of potentially risking unstable amplfier or even damaging headphones.

I would assume everyone who read modification and has confidence to do so has at least cheap earbuds and oscilloscope to test.
Also for people like you who have the ability to simulate and test can just test it.
Simply put, I stated fully tested stable, one can take it or leave it. I'm not responsible for further knowledge. Certainly most people wouldn't even ask questions like you guys do while you guys are the ones that can test yourself.

 

[solderdude]

'We guys' might have some experience in the field of designing electronics and realize there can be discrepancies between simulations and real world applications. That's why I asked.
The TPA6120 is one of those devices.
No need to get in a knot over it.

 

[Joachim Herbert]

The challenge then would be for the sound engineer to master the recording so that it can render the most pleasing sound spatially for the listener; and for the audio equipment that plays the sound to reproduce that 3d sound field with fidelity.

How do you measure that?

No need to measure that. Transparent equipment. makes sure everything is passed on as intended (or recorded). End of story.

 

[Morpheus85]

The thread is a bit older. I am considering buying this amp. I currently have a topping A50 and am considering whether the E600 is better.

 

[solderdude]

We can't know where they differ unless they have had extensive testing on the same test rig &circumstances.
Most likely differences between both amps are far below audible levels.
It's more about looks, functionality, price and availability as well as 'service' when something is wrong within the warranty period than one being 'better' than the other.

 

[Veri]

The thread is a bit older. I am considering buying this amp. I currently have a topping A50 and am considering whether the E600 is better.

What are you looking for after the A50? If you want lower output impedance and cleaner power look at the THX amps. The E600 is another high output impedance amp just like your A50, at best it will be similar at worst it will be a worse performer. Don't bother.

 

[Morpheus85]

Okay. Thanks. Then I will keep the A50