Ultimate sounded Class D for diy without custom made IC's like Tripath TA2020

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#42
indeed they are, they are also using the SEMELAB diffused laterals, same basic type and manufacturer as the ones used in 'the wire' Class AB power amp (not the little one already linked)

the Class D label printed on one of the sets of fets is simply a brand name, not the topology. semelab has diffused these fets under license to a number of companies
 
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#43
Any news?

qusp said:
indeed they are, they are also using the SEMELAB diffused laterals, same basic type and manufacturer as the ones used in 'the wire' Class AB power amp (not the little one already linked)

the Class D label printed on one of the sets of fets is simply a brand name, not the topology. semelab has diffused these fets under license to a number of companies
Click to expand...
Interesting fact. Without schematic this isn't easy to know.
 
#44
marce said:
Can I ask why a discrete version would be better! It goes against a lot of design technigues required for Class d amps (effectively a modulated SMPS). A discrete design would be more spread out introducing parasitic inductances amongs other gremlins IMO.
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Because at intregrated solutions there is no possibility to reach the inside components for matching resp. correcting the values (e. g. in order to the background noise requirements).
Check out this thread:
http://www.diyaudio.com/forums/class-d/286090-noise-smsl-sa-50-tda7492-low-level.html

what about this class-D concepts (in order to the sound quality) ?
http://www.diyaudio.com/forums/clas...-much-trouble-used-lot-models-harman-jbl.html
Seven Transistor Labs, LLC: Class D Ampifier
http://www.lf-pro.net/mbittner/ClassD/Classd_sch_4.GIF
Hypex Electronics BV - UcD

Also of interest for understanding class-D is this website:
Class-D Amplifiers
 
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#45
I can't say I like SMD and for DIY I have avoided working with them, usually by buying pre-assembled pcbs. However the march of "progress" is inevitable. And with less people even interested in DIY electronics nowadays it makes the problem even worse. I think the MUSES72320 volume attenuation chip may end up being the ic that forces me to pop my SMD cherry, or possibly the TPA3251D2.

Class-d has some unique problems, people have talked about the parasitic inductance already that requires short traces. Also the problem it may stop oscillating, for me at least means I want DC protection. Also shorted terminal protection is a good idea along with thermal protection. All this ends up meaning that you need a lot of circuitry, but with the ic this is all built in and cheep.

Warning this is subjective:
Also I don't want acceptable sound, I want very good audiophile-class sound that sounds good on my full range drivers. We had Tripath, which was the first family of chips that demonstrated class-d is not only relegated to driving cheep subwoofers but can actually make nice sound. When they went bankrupt, I thought we lost good sounding class-d for the foreseeable future, which justifies discreet class-d, but TI has now come along with there TPA3110 family which is also very good. I don't know if they snapped up the IP from Tripath, they are both 2nd order delta sigma modulators. In my opinion you need at least a 2nd order modulator for it to sound good. One strange exception was the TPA3122, it's a dip chip, and yes it starts with TPA but the highs are shrill. Maybe it's the board implementation, or maybe the legs were just too far apart with the dip package.
 
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