YAP - Yet Another PowerAmp

[Edmond Stuart]

Re: post 221

Hi Edmond,

From your previous post:

''What are C8,C13, R6 and R13 for? Looks like TMC, but it certainly doesn't improve THD. Without these components, I finally get 1.6ppm, almost the same value as Mr P. has measured.
This exercise leaves us with two questions:...''


Can you clarify your reasoning on YAP's front end compensation? When you said 'without this' did you mean no compensation at all for front end?

Cheers.

Atiq

Hi Atiq,

As far as I can follow Mr P's reasoning, C8,C13, R6 and R13 are NOT meant as a TMC network, rather as an attempt to improve the phase margin of the compensation loop.

edit: Also look here: http://www.diyaudio.com/forums/showthread.php?postid=1756663#post1756663



By 'without this' I meant without the additional components that look like TMC (C8, C13, R6 and R13). Of course, C9 and C12 will still be needed.

BTW, don't copy YAP, as it is a botch job, and don't build my PMP/PCP amps either, as they are obsolete by now and will superseded by a simpler topology.

Regards,
Edmond.

 

[jacco vermeulen]

it is a b job

On a more amusing level, rumor has it that the CEO of Quebec's major pension fund stated he used to run Botch Canadian enterprises.
.....after his own private pension plan deal turned sour.

 

[Bonsai]

" . . . BTW, don't copy YAP, as it is a botch job . . . ."

Was that really necessary Edmond?

 

[syn08]

" . . . BTW, don't copy YAP, as it is a botch job . . . ."

Was that really necessary Edmond?

Huh? Of course it was necessary

 

[Edmond Stuart]

" . . . BTW, don't copy YAP, as it is a botch job . . . ."

Was that really necessary Edmond?

If Mr P. says it's necessary, then it's really necessary.

 

[Iain McNeill]

Re: Re: Re: Re: Re: PSU

Edmond, unless you radically change your tone I am not willing to continue this discussion, I don't have the time and mood for another mudsling. BTW, I was very confortable on your ignore list.

Frankly speaking, I'm not particular charmed by some of your remarks either. Perhaps we both should change our tone.

Your bickering must stop. It reflects poorly on both the forum and the pair of you. Keep your comments on topic.

 

[syn08]

Re: Re: Re: Re: Re: Re: PSU

Your bickering must stop. It reflects poorly on both the forum and the pair of you. Keep your comments on topic.

I'm sorry, I can't do more than this:

http://www.diyaudio.com/forums/showthread.php?postid=1802900#post1802900

I really hope there will be extra ignore options in the next forum upgrade (like hiding your own replies from other members, private replies, hiding replies to an ignored member, etc...). The only other alternative, which is always an option, is to move my stuff elsewhere.

 

[Iain McNeill]

Exactly my objection, making personal statements about your feelings regarding other members has no relevance to this otherwise very interesting thread.

I can't help think that you and Edmond are responding emotionally without trying to understand the point the other is trying to make.

This is an international forum in English and not everyone's English skills are the same. The written word is even more removed from the intended thought. Before assuming a response is an insult, we should try to find alternate meaning or ask for clarification.

 

[Edmond Stuart]

botch job

Your bickering must stop. It reflects poorly on both the forum and the pair of you. Keep your comments on topic.

Whose bickering must stop? Mine or from that person who says things like: "Only if you promise to avoid PMSing again" or other insults like that.

As for 'on topic', please read all my comments on YAP and you will see that calling that thingie a 'botch job' is far from off topic.

 

[Edmond Stuart]

clean hands?????

I'm sorry, I can't do more than this:

http://www.diyaudio.com/forums/showthread.php?postid=1802900#post1802900

I really hope there will be extra ignore options in the next forum upgrade (like hiding your own replies from other members, private replies, hiding replies to an ignored member, etc...). The only other alternative, which is always an option, is to move my stuff elsewhere.

Using your own words, 'your not an angle'. As a matter of fact, you are the most cynical an nasty person on this forum. So please stop whining about comments that are provoked by yourself and don't try to wash your hands of this.

 

[stinius]

Re: clean hands?????

As a matter of fact, you are the most cynical an nasty person on this forum. So please stop whining about comments that are provoked by yourself and don't try to wash your hands of this.

What the heck is your problem Edmond?
If you have something you would like to tell Ovidiu, why don’t you just send him an email or a letter?
To use such words that you are using now on an open forum is not good practice.

 

[michaelkiwanuka]

Common sense (and theory) tells us that TPC (two pole compensation) reduces both the distortion of front-end and OPS as well, while TMC (transitional Miller compensation) reduces only the distortion of the OPS.

So one may wonder why using TMC at all. The point is that the phase response of TMC is much better (TPC shows a nasty dip).

Since -generally!- the OPS contributes the most to distortion, little is gained by a further distortion reduction of the front-end. In this regard, TPC has no advantage over TMC, it only spoils the phase response, resulting in overshoot. So far so good.

No. TMC (or preferably "local two pole compensation") reduces distortion in the second and output stages.

Further, given the same forward path unity gain frequency, TPC and TMC both give exactly the same total loop gain (two-pole single zero, with the same "nasty" phase dip in both cases) about the output stage, implying that the reduction in distortion about the output stage is the same.

Since, given the same forward path unity gain frequency, TPC provides the same total loop gain about the WHOLE amplier as TMC provides about only the second stage and output stage, TPC is in principal more effective at overall distortion reduction.

The so-called "nasty" phase dip in frequency response due to the coincident double poles in TPC is completely innocous provided the circuit is correctly designed.

Moreover, the overshoot in the transient response of a TPC compensated amplifier is easily tweaked out by imploying lead compesation in the global feedback loop.

Note that such lead compensation does not necesarily introduce RFI into the amplifier courtesy of the loudspeaker leads, as is routinely suggested, if a correctly designed LCR network is used as a filter at the output of the amplifier.

Most such LCR networks that I have encountered are incorrectly designed.

 

[michaelkiwanuka]

With all due respect to Edmond and others here, I was unable to identify any advantage of a TMC compensation schema over TPC.

True.

 

[michaelkiwanuka]

The HEC output stage was anything but flexible and the requirements for precision resistors and on board tuning is really annoying.I've seen recently on this forum a DIYer fighting the HEC battle, it's very hard to distingu ish between an out of balance HEC stage and some external issues, like power lines induced 2nd harmonics.

Far better to use a diff. stage for HEC. Greater precision is afforded and, if well designed, there is no need for pots.

 

[Bob Cordell]

Far better to use a diff. stage for HEC. Greater precision is afforded and, if well designed, there is no need for pots.

Hi Mike,

I agree with your points about HEC. When properly executed it is very effective. People in high-end audio should not be complaining about using 1% metal film resistors if they care about quality in audio-path circuits. With 1% resistors, where the nonimal value has been optimzed once, at design time (e.g., design centering), HEC will be able to deliver about 40 dB of distortion reduction at low frequencies as limited by component tolerances.

Even with a perfect trim, HEC distortion reduction at high frequencies (e..g., 20 kHz) is limited by the HEC loop compensation required for stability.

Cheers,
Bob

 

[dimitri]

Hello Michael,
I don't know what your intent was and why you decided to resurrect this controversial thread. You mentioned your views on TPC many times. I believe it is right time to show your design and to proof your point, otherwise it looks like commercial (you are not trying to sell something here, are you? )
BR