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Old 4th August 2006, 12:29 AM   #11
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You realize also that tripath uses a mixed sort of feedback, pre and post filter? Usually that ends up giving you a load sensitive frequency response, so part of that may be due to the speakers used as well... unless they used a zobel?

In case anyone should volunteer to do these tests, I trust almost any well regarded amp would be good for comparison? Perhaps with different loads and zobels.
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Old 4th August 2006, 12:30 AM   #12
Solve is offline Solve  Sweden
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"What's your threshold for considering it off phase anyway."
I mixed around with an tune in cubase- a tecno song- and changed the time between left and right.
Very small differences before i got the swing i thought,
But, it reminds me about the T-amp i listning to now.
The difference is the whole mix is phased i think.
Just proof me.
I could be wrong.

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Old 4th August 2006, 09:41 AM   #13
Pano is offline Pano  United States
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Quote:
Originally posted by Solve
Just proof me.
Why don't you test it? That way you will know for sure.

I'll try to run my own test as soon as I can. Phase between channels is something I have not tested over a wide frequency range. IIRC, at 1KHz, the channles are in phase on a sawtooth wave.

Testing 2 channels at once on the bridged amps will be tricky, as the outputs can't be tied to ground. Maybe with the scope in differential mode the phase between each positive side could be measured. Or maybe I'll make an resistor bridge and try that.

Something like this:

amp+plus---^^^^---P---^^^^---G---^^^^---amp-minus left
amp+plus---^^^^---P---^^^^---G---^^^^---amp-minus right

Where ---^^^^--- are resistors and P-G stand for scope Probe and Ground.
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Old 4th August 2006, 02:05 PM   #14
soongsc is offline soongsc  Taiwan
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I would also be interesting to find how the phase differences compare with phase differences in speakers.
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Old 5th August 2006, 05:36 PM   #15
fredos is offline fredos  Canada
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Easy to check phase between your 2 channel..Just send the same inpuit signal to booth input and with a scope in mode in1-in2 check if you get signal at different frequency! Just make a ''differential'' of booth output...You will see rally fast if they are a phase change of your ''stereo'' amplifier in function of frequency!

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Old 6th August 2006, 01:18 AM   #16
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I agree to Fredos suggestion, or if you dont have a scope you can use cheapo CMOS PLL chip like CD4046 or the very popular 2 inputs "EXclussive nor gate" as the phase detector.
If the two channels are not in sync on phase, the o/p of the EXnor will give "high", if in phase, it will give "low". BTW the o/p of the exnor must be filtered out by a RC filter for smoothing ripples.

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Old 6th August 2006, 01:20 AM   #17
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HHmmm I for some reason think it unreasonable to expect any two amps to be perfectly in phase with each other. Should establish a normal tolerance, if there isn't a known one already. High/low just isn't going to cut it from the way I see it.
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Old 6th August 2006, 01:36 AM   #18
KBK is offline KBK  Canada
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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?

Point being, a item that has clocking system, specifically if it is used in a digitally based re-construction of the signal, will suffer micro phase shift from (ie, x+y= the 'point' of the signal.x is the 'timing'component and is suspect, in terms of timing, therefore it becomes a phase issue) the clocking component. A free running osc used in such a system, depending on it's function, will cause SEVERE micro detail and micro transient issues (positional-locational issues in waveform reconstruction). The devil is in the details.

No mistake, these things are great, as long as the signal is simple. They really fall apart under complex signal loads, IMHO.

I have bought 3 amps so far, to investigate this technology. A sonic impact (2 of them) and modded the crap out of them. Then, the Ref T amp from the same folk. Modded it to the point that I can't sell it to anyone, it's got some semi-secret stuff in it, but it still does this 'thing', during complex passages. One of the secrets to removing this as an issue is, to use a battery system, supposedly. This kinda makes sense, as these are essentially current drive devices. My business partner has the whole max level Red Wine Tripath set-up, as well.

Now, I've got the boards I bought from Brian and am going to make one from scratch, with my own parts choices, again, similar to the ref t amp. I'll give them another shot, but as Conan said in Conan the Barbarian, "This better not be Hagga".

If the loss of detail during complex passages is -still- there, then the whole Tripath thing is a waste of time in my book.
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Old 6th August 2006, 02:21 AM   #19
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You guys crack me up!
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Old 6th August 2006, 03:22 AM   #20
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Quote:
Originally posted by KBK
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?

Point being, a item that has clocking system, specifically if it is used in a digitally based re-construction of the signal, will suffer micro phase shift from (ie, x+y= the 'point' of the signal.x is the 'timing'component and is suspect, in terms of timing, therefore it becomes a phase issue) the clocking component. A free running osc used in such a system, depending on it's function, will cause SEVERE micro detail and micro transient issues (positional-locational issues in waveform reconstruction). The devil is in the details.

No mistake, these things are great, as long as the signal is simple. They really fall apart under complex signal loads, IMHO.

I have bought 3 amps so far, to investigate this technology. A sonic impact (2 of them) and modded the crap out of them. Then, the Ref T amp from the same folk. Modded it to the point that I can't sell it to anyone, it's got some semi-secret stuff in it, but it still does this 'thing', during complex passages. One of the secrets to removing this as an issue is, to use a battery system, supposedly. This kinda makes sense, as these are essentially current drive devices. My business partner has the whole max level Red Wine Tripath set-up, as well.

Now, I've got the boards I bought from Brian and am going to make one from scratch, with my own parts choices, again, similar to the ref t amp. I'll give them another shot, but as Conan said in Conan the Barbarian, "This better not be Hagga".

If the loss of detail during complex passages is -still- there, then the whole Tripath thing is a waste of time in my book.

To be honest it's a waste of time in my book too. Step into the now?

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