For the simple question what is produced these days can I say that the delta sigma is coming and promissing. I did read self oscillating did sound sometimes nice, but unstability and max frequentie is a issue, a delta sigma can with modern mosfets go to 1.5 mhz, one of the best sounding T amps use a delta sigma with feedback, is mentioned here and the maker is out of bussiness.
regards
regards
Self oscillating class-d amplifiers can deliver great performance. But like any othertechnology, it will not perform, if you do not know how to implement it.
I would say that the old ICEPower "A"-modules are still among the best.
As i mentioned in my first reply, self oscillating class-d design are typically build around a op-amp based integrator. This works as a analog delta sigma modulator.
Digital delta sigma modulators are cheap to build, since the complete amplifier can be put into a single chip. And that may be the most positive thing to say about these....
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I got the impression that the sound quality depends a lot on the output filter, the quality of the output inductor that is, rather than the 'chip'. ?
Both. The output filter is a critical part but it can't make up for something that's not delivered into it. Any distortion/non-linearities in the system adds up (or even multiply), no matter at which stage they happen.
Well ....... some still do ! Like some TI and Philips Class-d chips for instance.
Regards
Charles
He said while with most class-D amps an increased voltage improves the sound, the with the Sure AA-AB32313 the sound was much smoother and precise with the lower voltage.
(-> Gremlin- kleiner Class-T Amp- ganz groß. - DIY-HIFI-Forum )
Since the amp runs very hot with the higher voltage - it's most likely heat related.
Using a opamp with very high slew rate can make a very good integrator making the amp more liniair, good quality pcb and parts, I am not busy with digital amps but read about she involve very well and people dare to compare with single ended tube amps.
Most trouble is not in modulation however but are in speed of mosfets and deathtime and demodulator coil.
regards
Wile my circlotron amp is under test I did burn mosfets with runaway) I was curious about the D amp and did sim a kind of modulator with very fast opamps (freq 800 khz), did give a nice sinusoidal back with this smal test schematic. Middle picture is 80 Khz demodualted test signal.
Maybe in future I do also go get deeper in it as I do hear some sound very good these days.
regards
Maybe in future I do also go get deeper in it as I do hear some sound very good these days.
regards
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Volume control
Guys, what about a volume control in front of the AA-AB32512 (or AB32313) ?? I think they have a rather lowish input impedance (10K?) so just a passive pot might not work well enough. Sure Electronics sells three models of "digital volume control"...starting at $5 to $30...specs are impressive for the $30 model...anybody tried any of those ??
Thank you, Alex
Guys, what about a volume control in front of the AA-AB32512 (or AB32313) ?? I think they have a rather lowish input impedance (10K?) so just a passive pot might not work well enough. Sure Electronics sells three models of "digital volume control"...starting at $5 to $30...specs are impressive for the $30 model...anybody tried any of those ??
Thank you, Alex
Hi Alex,
Hi, I have the $5 model with the AA-AB32313. I was skeptical because of this low price. I compared it with my passive pre-amp LDR3x, and for the need I have it. It is in bi-amplification mode, so the Sure with its pot and a pre-amp tube, allows fine tune.
Hi, I have the $5 model with the AA-AB32313. I was skeptical because of this low price. I compared it with my passive pre-amp LDR3x, and for the need I have it. It is in bi-amplification mode, so the Sure with its pot and a pre-amp tube, allows fine tune.
I think this will fit here, I am quite new to D amps and now I have spare time and circlotron is in rust until new year I spent my time on these D amps, I go look with how to get them liniair as possible with or delta sigma or self oscilating, last I did now, however why I get such a low oscillation frequention. I did use the tap before the coil and that give high frequentie oscil but whenm put on other side of coil it drops to 80 khz or so, that is to low.
But maybe I do something wrong as I proberly do.
Sorry by break in here.
regards
But maybe I do something wrong as I proberly do.
Sorry by break in here.
regards
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For people who has bright sound from class D you need to use gooed opamps like the alfet opamps from burr brown like the opa 2365 or for single the opa365 who sound very well and is high speed, the AD versions do all sound very bright, for the comparators thing is different because she do only output pwm, I experiment with a lt serie 2.9 nS comparator,.
regards
regards
I was testing with some things and a power comparator, it is a lot of fun but after new year I get go on with the liniair circlotron.
Class D amps are still under development, extreme low HD costs mucho calculations and time, and still when overdriven, very nasty effects.
regards
Class D amps are still under development, extreme low HD costs mucho calculations and time, and still when overdriven, very nasty effects.
regards
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I may have mentioned that a pair of quad 63s tookout my hifimediy 150W T3 monoblocks. On receiving replacement T3 modules one fails after 5mins of use. After many emails to hifimediy they kindly sent three replacement modules.
My T3 monoblocks are now up and going and sounding as good as I remember them. Hifimediy are very helpful and I think their class D amp modules are the best. My T3s - "Tutu" are the best sounding Tripath class Ds I have made and heard and possibly the best amps I have heard anywhere. The Sanders Magtech may be better but I have not compared. Glad to have Tutu back.
I hear you ask "Tutu"? Well it is in answer to Bruno's Mola Mola brand name for his Kalugas. I wanted a double sounding name. Not only that there is two of them - Two Two.
My T3 monoblocks are now up and going and sounding as good as I remember them. Hifimediy are very helpful and I think their class D amp modules are the best. My T3s - "Tutu" are the best sounding Tripath class Ds I have made and heard and possibly the best amps I have heard anywhere. The Sanders Magtech may be better but I have not compared. Glad to have Tutu back.
I hear you ask "Tutu"? Well it is in answer to Bruno's Mola Mola brand name for his Kalugas. I wanted a double sounding name. Not only that there is two of them - Two Two.
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what ?
Rating the Hifimediy T3S very low is quite a stupidity . This amp is very good, i have 2, they deliver amazing sound, tested in a lab they give exactly the output they say. Also it will not cost more than 170 euros to have a complete stereo amp. Maybe he tested a faulty unit or did not match it with proper speaker loads.
Rating the Hifimediy T3S very low is quite a stupidity . This amp is very good, i have 2, they deliver amazing sound, tested in a lab they give exactly the output they say. Also it will not cost more than 170 euros to have a complete stereo amp. Maybe he tested a faulty unit or did not match it with proper speaker loads.
I have to wait for parts, so I did some sims on class D.
I can get low distortion however I see that on negative sinus output signal it get shoot through, and not on positive output signal.
Version with the IR2011 I think I have to include a deadtime generator but need to see how to do it in ltspice.
I did read about gate resistors as setup for dead time but I think it is better with a gate driver, I did use a discrete comparator like the phillips, it had pretty low HD with use of poles.
regards
I can get low distortion however I see that on negative sinus output signal it get shoot through, and not on positive output signal.
Version with the IR2011 I think I have to include a deadtime generator but need to see how to do it in ltspice.I did read about gate resistors as setup for dead time but I think it is better with a gate driver, I did use a discrete comparator like the phillips, it had pretty low HD with use of poles.
regards
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Hi,
I don't think this can be stable. you have to put square signal at input and see if output is stable in time domain.
Low THD is good, but who cares about 0,1 or 0,001 % THD (probably cant be heared), my opinion, but unstable amplifier can be heared I would say.
What about "russian design", uses different feedback ? (other threads there), forum member SOUS
full differential UcD modulator with extra integrator
He use HYPEX topology with extra integrator, but special circuit that "kills" additioanl poles to get amplifier to be stable... hmm
I don't think this can be stable. you have to put square signal at input and see if output is stable in time domain.
Low THD is good, but who cares about 0,1 or 0,001 % THD (probably cant be heared), my opinion, but unstable amplifier can be heared I would say.
What about "russian design", uses different feedback ? (other threads there), forum member SOUS
full differential UcD modulator with extra integrator
He use HYPEX topology with extra integrator, but special circuit that "kills" additioanl poles to get amplifier to be stable... hmm
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Afcouse we try to diy our own amps, that is the challence. making amps from other members do not.
You say 0.0 or 0.001 do not hear, this is dependent of the kind of distortion, if it is even harmomics the amp get warmer with it, if it is other stuff it sounds bad, I try high end, so need very low distortion, I try to make the modulation liniar with poles, I have that from a paper, the power comparator is a existing one who is stable.
Thanks for the tips, I try a square, but then I get a lot of mudulation interfacts, who as I presume is needed to see how it is with stability.
regards
You say 0.0 or 0.001 do not hear, this is dependent of the kind of distortion, if it is even harmomics the amp get warmer with it, if it is other stuff it sounds bad, I try high end, so need very low distortion, I try to make the modulation liniar with poles, I have that from a paper, the power comparator is a existing one who is stable.
Thanks for the tips, I try a square, but then I get a lot of mudulation interfacts, who as I presume is needed to see how it is with stability.
regards
MOST basic UCD (Putzeys patent version) gives about 0,1 % thd, and I measure mostly even harmonics.
But it is completely sable with square input... if you add more poles/zeroes.. it is not..
I would say that stable simple ucd must sound better then unstable one with very low simulated thd..
But it is completely sable with square input... if you add more poles/zeroes.. it is not..
I would say that stable simple ucd must sound better then unstable one with very low simulated thd..