Needs some 3.5mm jack..
Good night.
Hi, why a 3.5 mm jack ? For headphones or, heaven forbid, for the inputs ? Worst connector since ages, alway bad contacts and crackling. I replaced so many of them that I never use them in my own designs.
edit: just checked your web page and it seems you use them for inputs. Bad choice compared to RCA. Sorry. Using RCA is standard and RCA to 3.5 mm cables can be bought. It would make your design way more user friendly, maybe you can use both ? With a power amp as this chip crackling seems to be very unwished for.
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Because i can.
I never had any issues for the last 40 amp boards. So maybe yours where all from poor quality or not properly used/soldered. I use them always in a self grounding configuration to mute/ground the inputs when no connection is made.
Well, even RCA is not GND before Signal when making a connection, so RCA is far from optimal as well. As my normal amp designs are made to be small and portable, i did not used RCA connectors mainly because of their size. Those amps are 50*50mm²..
If you will have a look again, you may notice that there's normally a pinheader for an alternative input.
Millions of millions of mobiles,mp3-players etc. worldwide get stressed/stretched/used every day with lots of force on the 3.5mm connectors. Quality ones wont fail, cheap ones will.
But in the end, there will be RCA (at least) on this board.
Beside this, do you prefer an opamp differential input stage or a PNP differential amp with constant current?
GND before signal has not been the primary goal of RCA and who plugs in connectors on a live power amp ?
I have used many different 3.5 mm jacks and if the connector does not fail then the cable will. Also in mobile phones it is one of the most failing connectors with micro USB as a good second one. These connectors were not designed for high quality but for low cost. Talk to a repairman (I was one myself) and I know what answer you'll get
The quality ones just last a bit longer. I am not an advocate for RCA but when do you see an RCA plug/jack fail ? Of course you can use 3.5 mm "because you can". You can also design 50 x 50 mm2 boards to keep costs low but isn't this hobby meant to get the best out of a design ? Since when is very small size obligatory ? To be able to use 3.5 mm connectors and leave out the coils ? Just joking, I understand you only want portable stuff and thus you do some concessions but TPA3251D2 won't be for portable designs I guess.
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I'd actually argue that 3.5mm connectors are just as reliable as RCA jacks, if not more so. However 3.5mm jacks end up being subjected to far more mechanical cycling just because of the application they end up being used in (headphone jacks on MP3 players) which is why you see many more of them go bad.
In a fixed amplifier like doctormord's, the jack might only get plugged/unplugged a few dozen times over the lifetime of the amplifier. Assuming a good quality jack is used, and the customer plugs in a good quality plug, it'll be fine.
Oh well, alot of people who don't know better.
I thought micro USB where designed to be small, not especially for being low cost.
Talk to a repairman (I was one myself) and I know what answer you'll get
Not that often, but, as stated, i'm not seeing a "3o5" fail that often.
Sure, but does size matters? Or do bigger design usually perform better? I.e. there are alot chinese TPA3116 boards out there, which are bigger and perform worse.
Since when is very small size obligatory ? To be able to use 3.5 mm connectors and leave out the coils ?
To me, its obligatory as the most things i do at my job/study are small and even alot smaller than those amps.
Beside this, leaving the coils off is not usually a bad thing if you can make sure noone gets "hurt" (EMV/EMI whise).
Because noone did it right now. There are ppl who use 300/600W TAS amps on their bikes. To me, a 100x100mm² board is "huge".
So lets see, what there will be in the end.
Regards,
doc
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They are made to be cycled often by design and they have switches inside so moving parts and we know what happens to moving parts. They are used for portable stuff as they are small and cheap. The are definitely NOT more reliable than RCA connectors. No manufacturer burns his fingers on them in normal consumer HiFi equipment. But after having seen RCA being used for SPDIF as a standard and for example the older Iphone connector nothing surprises me anymore, so let the 3.5 mm plug be the new standard in HiFi
as HiFi is going down the drain anyway. I am glad you acknowledge that many of them go bad. They almost always do, it is just a matter of time. The nature of them makes people plugging them in and out a lot and the contact area is quite small compared to RCA, RCA is at the back of stuff so many just leave them as "they work". Install and forget .... as a reliability freak I like stuff that does not break down by design. But it is good that not many like that otherwise we would see Lemo connectors on consumer equipment. I have many types Lemo connectors in stock but never dared to create my own standard I have a technical education and followed quite some courses in telecom and just one thing keeps returning: "gentlemen, please remember that connectors are chosen by the industry as long as they're cheap !"Now I will retreat and plug in my headphones (6.3 mm jack....).
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Lemo is a different story, i got some stuff equiped with them. Nice and "expensive" but built for life². Offtopic:
I like/use the Binder 620/720 series alot, even if they are made of plastic.
Snap-in connectors IP 67 - Franz Binder GmbH & Co. Elektrische Bauelemente KG
(As seen on the pictures from another project)
Attachments
This is KiCAD VRML export with custom 3d-models in a HDR renderer + some postprocessing in Photoshop.
Btw.
Beside those Coilcraft wirewound inductors here:
http://www.mouser.ee/ProductDetail/Coilcraft/MA5172-AE/?qs=ZYnrCdKdyedMvVvFAobk3w==
What do you think about those:
http://www.mouser.ee/ProductDetail/...GAEpiMZZMsg%2by3WlYCkU4PzPTkpdogh7gwLG/FOMSk=
and especially these:
http://www.mouser.ee/ProductDetail/...EpiMZZMsg%2by3WlYCkU3WuiCT54zcgYN7U25CV%2bGU=
Btw.
Beside those Coilcraft wirewound inductors here:
http://www.mouser.ee/ProductDetail/Coilcraft/MA5172-AE/?qs=ZYnrCdKdyedMvVvFAobk3w==
What do you think about those:
http://www.mouser.ee/ProductDetail/...GAEpiMZZMsg%2by3WlYCkU4PzPTkpdogh7gwLG/FOMSk=
and especially these:
http://www.mouser.ee/ProductDetail/...EpiMZZMsg%2by3WlYCkU3WuiCT54zcgYN7U25CV%2bGU=
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Nice. I've tried learning KiCAD on a few occasions but ultimately the requirement to get things done puts me back into using Eagle.
The L versus I curve has a slope on both of those inductors, which will cause L to change with the audio waveform, I'm not too fond of that since there's no post filter feedback on the TPA. The Coilcraft toroid and the VER2923 have a flat L value up until the point of saturation, I greatly prefer that.
The L versus I curve has a slope on both of those inductors, which will cause L to change with the audio waveform, I'm not too fond of that since there's no post filter feedback on the TPA. The Coilcraft toroid and the VER2923 have a flat L value up until the point of saturation, I greatly prefer that.