Recently hooked up a second Arjen Helder t-2020 amp board to my living room system. It sounds great at usual listening volumes. In fact, I don't hear the power limitations until I get close to too loud. I'm also noticing for the first time that it just doesn't sound good at very low as in barely audible volumes.
I know with traditional class a and a/b, distortion usually goes up as the power increases. I remember seeing a claim that class D goes the other way and there's more distortion at low volume. I've never attempted to measure, but do remember a similar phenomenon with my sonic impact amps.
It could also be that there's some source of noise in my system that isn't masked by lower volume music.
We rarely talk about listening at low volume. Usually, when I evaluate electronics I turn things up. Am I the only one who hears this?
I know with traditional class a and a/b, distortion usually goes up as the power increases. I remember seeing a claim that class D goes the other way and there's more distortion at low volume. I've never attempted to measure, but do remember a similar phenomenon with my sonic impact amps.
It could also be that there's some source of noise in my system that isn't masked by lower volume music.
We rarely talk about listening at low volume. Usually, when I evaluate electronics I turn things up. Am I the only one who hears this?
Have a look at the THD+N vs output power plots (usually only given at a specific frequency) for any amp. In general, the distortion gradually drops as output power rises then sharply increases as the amp reaches its maximum output power. That doesn't necessarily mean that most amps will sound bad at low volume levels. Your speakers are just as much a part of the equation.
The problem is, that the T-amp uses fully digital processing. And if it does even has 24 bits DSP, then at low level there will be used only 5-6 bits maybe, which is not enough.
Non-digital class-D amps (UcD, for example, as mentioned by Workhorse) are having more deep resolution, and their theoretical lower limit is only the noise level of the devices used...
Non-digital class-D amps (UcD, for example, as mentioned by Workhorse) are having more deep resolution, and their theoretical lower limit is only the noise level of the devices used...
The problem is, that the T-amp uses fully digital processing. And if it does even has 24 bits DSP, then at low level there will be used only 5-6 bits maybe, which is not enough.
ERRRRRRRR........................
From which angle T 2020-amp becomes digital and from where these 24 bits DSP came in jumping for resolution
http://www.kafka.elektroda.eu/pdf/tripath/TA2020.pdf
T-amp uses spread spectrum analog modulation, no DSP with 24 bits
Low listening level
I have noticed this with my modified Sure 2X100 amps as well. The sound seems to be a little less than satisfying at early morning (other people are asleep) listening levels. The good news is that at normal (loud) listening levels, this is the best sounding amp I have ever heard. Much better than my Ucd180.
I have noticed this with my modified Sure 2X100 amps as well. The sound seems to be a little less than satisfying at early morning (other people are asleep) listening levels. The good news is that at normal (loud) listening levels, this is the best sounding amp I have ever heard. Much better than my Ucd180.
ERRRRRRRR........................
From which angle T 2020-amp becomes digital and from where these 24 bits DSP came in jumping for resolution
http://www.kafka.elektroda.eu/pdf/tripath/TA2020.pdf
T-amp uses spread spectrum analog modulation, no DSP with 24 bits
Anyway, they DO have some hi freq internal clock, making their modulation NON-contiguous or discrete, with limited resolution. Please, do not mix it with triangle wave, which is also some kind of clock, but is NOT an discrete modulation.
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Tripath's amps work in complete other way. Typical square output from T-amp:
This is very similar to the delta-sigma modulator output, but it is NOT an delta-sigma modulator...
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It looks as if the high time period is constant, which would effectively be pulse density modulation.
I must say that I thought the tripath amps were another self-oscillating design, with a more complex than usual feedback modulator. If they really were PDM, then a bridged version would need to use 3-level modulation. Are you really sure this is the case?
I must say that I thought the tripath amps were another self-oscillating design, with a more complex than usual feedback modulator. If they really were PDM, then a bridged version would need to use 3-level modulation. Are you really sure this is the case?
To make it clear, this 'pattern' is shown for the moment, when the input voltage is constant. In usual class D amp, when the input voltage is constant, the duty cycle is constant also.
Little knowledge is dangerous thing.
If the duty cycle with no signal condition is not uniform (means 50-50%) in tripath amps, then you will get considerable DC OFFSET AFTER INDUCTOR at output...............
Little knowledge is dangerous thing.
If the duty cycle with no signal condition is not uniform (means 50-50%) in tripath amps, then you will get considerable DC OFFSET AFTER INDUCTOR at output...............
Can you please read the messages carefully, before posting the answers in red color? I have said about the CONSTANT input voltage, not about absence of the input signal
And the following square wave will NOT produce any DC after lowpass filter, although it does NOT have 50% duty cycle:
____-_____------_------_____-_____-----_-----_____-_____-----_-----_____-_____-----_-----
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Tripath sounds excellent
See the link for a comparison to a newer TI driver amp.
http://www.diyaudio.com/forums/class-d/152980-class-d-audio-who-these-guys-22.html#post2081056
Whatever topology the Tripath driver chip uses, it is sonic genius. At louder listening levels, the modified Sure 2X100 amp with a MeanWell switch mode supply is by far the best sounding amp I have ever had home. Transparency, dynamics, and speed like no other. For $100.00!!! Too bad they went out of business. Luckily, there still seems to be good availability of chips.Tripath amps are defenitely NOT the self oscillating amps...
See the link for a comparison to a newer TI driver amp.
http://www.diyaudio.com/forums/class-d/152980-class-d-audio-who-these-guys-22.html#post2081056
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