Tripath a phase fake?

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KBK said:
The tripath amps have a free running 300khz (at least in the 2024 chip info that I have poured over) osc. I'm not quite sure of it's function yet, even though I've read some of the technical papers. Could some one point to the full educational info on such, or clear that up for me?


That free running 300khz info is in regards to the on board charge pump. The charge pump provides a voltage greater than the supply voltage from which the gates of the high side mosfets are driven. The frequency the charge pump operates at has nothing to do with the switching frequency of the amp.
 
Tripath can be decent, but falls short compared to better designs. Why keep kicking the same ol horse?

I can think of one reason...... price.

Take my setup for example. I have three AMP1-B's, thats 6 channels of amplification that cost less than $200. A 6 channel setup using ColdAmp, Hypex, ZAPulse, or anything else thats considered superior to TriPath would break my bank.

If money isn't an issue, I would agree that there are far better choices than TriPath.
 
panomaniac Why don't you test it? That way you will know for sure.[/B][/QUOTE] I dont have the equipment or the knowledge to do it. [QUOTE][i]Originally posted by soongsc said:
I would also be interesting to find how the phase differences compare with phase differences in speakers.

Yes!Maybe its only out to the speakers?
Im no expert...


classd4sure said:



Tripath can be decent, but falls short compared to better designs.
Why keep kicking the same ol horse?

I dont have so much experiance of good sounding hifi so T-amp
was a realy nice kick for me!
So, realy i dont know what to compare with?
You tell me?

But.
Still we talking stereo?
Ok.
I dont know...but for me its an very wide stereo in Tripath.
I never heard so wide stereo!
Maybe thats why i like it.
But my complains is thats it maybe to wide.
You know those cheap stereos with presets of wide stereo effects?
So, just asking if somebody with equipment could measure if its
something fishy between Left and Right in phase.

:)

Solve
 
The very best conventional amps(non Class D) may have as little as one or two degree(s ) phase shift in the audio band.
A coil (inductor) in the output pathway of a conventional amp may cause a phaseshift(delay), in the feedback loop , if the amp is a NFB one.
Which may very well effect the sound.
Some manufacturer claimed that phaseshifts in amps, first of all effected our perception of the bass. I don´t know at all, if this is true, but some may investigate.
On the contrary , many swear the bass to be the forte of class D amps....

An input filter, with a low and steep corner frequency, may also effect an amps phase response.
 
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I had a qucik look at a Fenice20 amp today. This uses the same chip as the Sonic Impact Amps.

I see NO phase difference between channels over most of the audio spectrum.
There was a little phase trouble in the top octaves, but not much.

The amp is a little tricky to measue in XY mode, as the speaker actually does not see ground. I tested between positive and negative output posts on both channels and found the 2 poles to be 180 degrees out of phase, as one would expect. Then phase was measured between L+/R+ and they were in phase. Same for L-/R- in phase. I assume that means all is well.

I did, of course, first measure phase between left and right at the amp inputs. No problems. Sine waves and worble tones were used.

As I said, there was a slight phase problem up high, I will look into it further. Will also measure phase after the input caps.

But at first look, the phase seems to track very well between Left and Right.
 
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The outputs are bridged so one speaker output will swing toward the positive rail while the other output will swing toward the negative rail. Or you can say the waveform on the - output is 180 degrees out of phase with the waveform on the + output.
 
I am interested in how much phase shift exists for all the class D amps mainly for subwoofer integration. Wouldn't phase shifts have the largest effect in the bass region? IIRC, Nuuk said he had problems with his tripath amp working with his sub amp.
 
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That would be phase shift between input and output. Not the same as between channels.

I think there is a lot of phase shift going on between input and output, and it's not linear with frequency - that's the problem. If I figure out a good way to measure it, I'll let you know.
 
This would only be dependent on the filter used though right? So even with the same chip but with different filters we would have different phase shifts, right?

If the phase is occuring in the chips themselves than I think that would be more difficult problem.
 
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I would depend on the input filter, yes. But as we use rather large input caps, there shouldn't be any real phase problem above 15Hz.

The input/output phase shift (If there really is one) is likely coming from the chip, and/or the output filter. I think it is the modulator on the chip.

Need to test it.
 
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