#qi-hardware IRC log for Thursday, 2016-04-21

arossdotmeDocScrutinizer05, ok thanks for the education! :)00:10
arossdotmeI feel better about it now00:10
DocScrutinizer05yw :-)00:10
arossdotmecurrently i have soldered a short 15-20cm cable to it00:12
DocScrutinizer05then you probably can forget about the ferrites all together00:12
DocScrutinizer05mind you, the speaker itself is a huge inductivity00:12
arossdotmeand if it was few meters?00:13
DocScrutinizer05then you could tell from 50m distance if the speaker is on or not, by using a shortwave AM radio00:13
DocScrutinizer05worst case, prolly not00:13
arossdotmeoh right cool!00:14
DocScrutinizer05you should short the ferrite chokes if you plan to do that ;-)00:14
DocScrutinizer05then it might make for a poor AM transmitter00:14
arossdotmebut truely i want them to do there thing, but im conscious to see what it sounds like now.00:15
DocScrutinizer05just like any other switched mode PSU00:15
arossdotmelike those dc-dc boost and/or buck converters i have.... 00:16
DocScrutinizer05a class-D amp basically is nothing more than just a variable switched mode power supply00:16
arossdotmediff way of thinking about it, i thought about more like pwm light dimming...00:16
DocScrutinizer05roughly the same00:17
arossdotmehmm00:17
arossdotmemmh00:17
arossdotmei was going to use this mono amp for a subwoofer with a preamp bass/subwoofer frequency filter board 00:17
DocScrutinizer05sounds like an excellent idea00:18
arossdotmegot a good condition pc one but with built in amp but it was missing the ext vol controller so i count use it, looked up the datasheets but it wasnt clear what to do. it used a car ab amp chip. i decided it was easier to gut are replace with a nice little class d amp board00:20
arossdotmecount=couldnt00:20
DocScrutinizer05the volume controls would be in your preamp freq filter anyway, no?00:22
DocScrutinizer05but an AB is quite power hungry compared to D00:22
arossdotmein my diy dolution yes00:22
arossdotmeyea it had a large flat bent sheet of au attached to it00:23
DocScrutinizer05:nod:00:23
arossdotmeor via the pc surround sound subwoofer output vol ;)00:24
arossdotmeheh out with the old in with the new :)00:24
DocScrutinizer05sure. Yet I'd use the preamp incl vol control, even when you feed its input with 5/100:24
arossdotmeyea00:25
DocScrutinizer05just don't use the freq filter00:25
DocScrutinizer05when doing 5/100:25
DocScrutinizer05but the level controls (and tone controles) will still come in handy00:25
arossdotmeoh 00:25
arossdotmedont use freq filter?00:26
arossdotmewith using pc sub output?00:26
arossdotmewith=when00:26
DocScrutinizer05when you use 2/1 or 4/1 or 5/1? what for would you need the frequency filter there?00:26
DocScrutinizer05well, you still can feed the subwoofer output from PC to the lowpass filter in of your preamp00:27
arossdotmeso when im not using a source that is already filtered for a subwoofer which i assume the pc sub out is, it can work 00:27
DocScrutinizer05just don't feed subwoofer signal to the normal stereo inpuits or vice versa in that case00:27
arossdotmeoh by 2/1 ,etc you mean 2.1 surround sound.00:29
arossdotmenot vol level00:29
DocScrutinizer05when you feed normal stereo to your audio system, you mix both channels L+R and feed it to the input of the mono subwoofer lowpass filter00:29
arossdotmeyes00:29
DocScrutinizer05yes00:29
DocScrutinizer05for 2.1 or 4.1 or 5.1 you feed only .1 to that input00:30
arossdotmeyea, i know what you mean :)00:31
arossdotmesomething like this http://www.aliexpress.com/item/Low-pass-Filter-Finished-Board-Subwoofer-Crossover-Board-Deep-Bass-Single-Supply-DC10-24V-for-2/32461218097.html?ws_ab_test=searchweb201556_9,searchweb201602_2_10037_10034_507_10032_508_10020_10017_10005_10006_10021_10022_10018_10019,searchweb201603_7&btsid=bc9371c7-2125-49ad-9c26-d0e69b09b0fd00:31
DocScrutinizer05yep, exactly00:32
arossdotmesame but even cheeper. diff? no tracked shipping which is ok cus it makes it double the price but they also dont say if they use Phillips caps... hmm :/00:33
arossdotmehttp://www.aliexpress.com/item/Low-Pass-Filter-Plate-Subwoofer-Preamp-Board-2-1-3-Channel-DC-10-24V-22Hz-300Hz/32590327578.html?ws_ab_test=searchweb201556_9,searchweb201602_2_10017_10005_10006_10034_10021_507_10022_10020_10018_10019,searchweb201603_7&btsid=cc77f865-b72c-4a36-b7f5-2c767da007df00:33
arossdotmeonly one cap hmm :/ ? but nice and compact + its got a mid pot! :D but no balance... http://www.aliexpress.com/item/preamp-Stereo-NE5532-Tone-Board-Preamplifier-Volume-Treble-Bass-Super-LM1036/32613173971.html?ws_ab_test=searchweb201556_9,searchweb201602_2_10017_10005_10006_10034_10021_507_10022_10020_10018_9999_10019,searchweb201603_7&btsid=6c791000-8669-4f87-b60e-d76e54779cc800:35
arossdotme(not for subwoofer btw)00:35
arossdotmebut then i can use device software filters and same some weight00:36
arossdotmearr but then it is also a preamp which is good for weaker out vol devices...00:36
DocScrutinizer05(same but cheaper) yes, looks like.00:39
DocScrutinizer05the last one looks completely bogus. No or absolutely nonsensical specs00:43
DocScrutinizer05"function: power triode" WTF?!00:44
DocScrutinizer05"usage: Zener diode"00:44
DocScrutinizer05also a really decent design would filter out the subwoofer frequencies from the (normal) stereo branch, no not torture small mid/treble speakers with very low and high amplitude frequencies00:46
DocScrutinizer05s/ no / to /00:46
arossdotmeDocScrutinizer05, sorry i was ot, that last one was not for subwoofer but for my diy boombox. sorry. thats what i ment by "(not for subwoofer btw)"00:51
arossdotmeoh right i see the aliexpress specs selection has the wrong data in it urrg, someone was lazy00:56
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