Starting my first project.

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#42
Active Xover PCB

Navin..i plan to keep it vented...will try and post a sketch of the enclosure layout(without bracing) in a couple of days...

i have ordered for the 4780 and the 3886 PCBs(Peter Daniel's) and have decided to go active to bypass baffle step and other problems....will be getting the boards on the first week of July..

in the meantime i want to get started on the crossover.. ..can u give me ur thoughts on this active crossover (the one in siliconchip.com)

http://www.diyaudio.com/forums/showthread.php?s=&postid=661936#post661936

If u can atleast tell me that the circuit will work and that it is not a dud(u know,like the kind of circuits we get in our Indian Electroincs magazines)...
If it loooks alrioght then i will give it for etching...
The sooner the better.
Thanks,
Cheers,
Sachi
 
#43
if you want me to validate the active XO I think it will work. I would replace teh opamps with sockets though so I could compare other opamps. I have a feeling your best option woth the OP827.

what drivers are you intend to use. i worry about the mid here as it has to cover 200-6k well. this will put less strain on the tweeter though.
 
#44
WEll if it is goin to work then i'll give it for etching today..
The drivers are the following
midrange-
http://www.partsexpress.com/pe/show...tnumber=299-492
tweeter-
http://www.partsexpress.com/pe/show...tnumber=264-526
LF Driver-
http://www.partsexpress.com/pe/show...tnumber=295-315

The crossover frequencies can be varied and i want to first try out the crossover at 450 hz and 4500 hz .
Sockets can be accomodated,i think...i will check out the opamp u have suggested..



anyone got a different view please put them accross..
Thanks,
Sachi

p.s:the drivers have been broken in for 50 hours now at 20Hz.i will start on the enclosure by this weekend(after i get the enclosure drawings verified on the forum)
 
#47
see http://www.tymphany.com/prodvifa.php

i would look at XO values of about 250 and 3500Hz. 450Hz is where the ear is very critical. I dont think this driver will work smoothly above 5K and you want to roll off before that.

Since the tweeter Fs is 650Hz it should be ok.

I think the mid chosen should be better.

options if you are looking at a XO fo 450hz are:
Vifa's M10 (parts express K10)
or if you are looking at an XO of say 250hz
Vifa's PL11MH, PL11WH

Dont know if these meet your price point though.

When I build my speakers I evaluate the cost of other materials, cabinet, XO, labour, accessories and assume my drivers sould cost atleast as much as all these combined. So if my cabinet is Rs. 3000, my XO is Rs. 1000, labour is Rs. 2000 and accessories is Rs. 500 = 6500 the drivers should cost rs. 6500 too. this is just a thumb rule I work with.
 
#48
When I build my speakers I evaluate the cost of other materials, cabinet, XO, labour, accessories and assume my drivers sould cost atleast as much as all these combined. So if my cabinet is Rs. 3000, my XO is Rs. 1000, labour is Rs. 2000 and accessories is Rs. 500 = 6500 the drivers should cost rs. 6500 too. this is just a thumb rule I work with.
Click to expand...

That's pretty much what i have earmarked...
i have already bought the drivers and have no other go....

250s a bit close cause the fs of the midrange is 110hz....
maybe 350 would be an improvement.

am leavin in an hour to give the crossover layout to be etched.
 
#51
sachi said:
i plan to use the PCB layout as specified in the article ..

http://www.siliconchip.com.au/cms/A_30278/article.html
Click to expand...


my apologies, i didn't realize you were going active,

.. have fun ,

when you experiment, remember that active x-overs are great to play with but just keep in mind that x-overs are intended to shape and control driver response, rather than merely limiting their response. you may yet need some passive components in there (or an equalizer module, .. but that seems like overkill and may not be desirable in terms of the speakers' musicality)



when you have this project working, be sure to measure and tweak what your loudspeaker system is doing, but trust your ears in the end.

cheers
 
#57
Hey navin, what abt the TL074.are their any differences in them ..i mean the same IC from different manufactureers..i got a quote of 12.rs/each

Regarding the transformer.. are there any other torroidal manufacturers other than Miracle.. i was quoted 200.rs for the 20VA with 15V secondaries...Their place is very close to mine(just a couple of km)...Please advise..
 
#58
i suspect the TL074 mightbe better than the 324. there a lot of voodoo out there and some of these voodoo guys swear by Burr Brown. I figure if one can afford them why not.

I get my trannies from Rcore. they are more expensive Rs.600 for 600VA and Rs. 1000 for 1200 VA. Buy local. as long as the quality is good.
 
#59
Trans!!

Hi Sachi,

Regarding the transformer.. are there any other torroidal manufacturers other than Miracle.. i was quoted 200.rs for the 20VA with 15V secondaries...Their place is very close to mine(just a couple of km)...Please advise..
Click to expand...

I get regularly my trans from MIRACLE , They are very helpfull for Diy guys,I think you can go ahead for those transformer, quality is assured, they can test the trans for you, I get the Inductors also from them , Belive me Absolute Quality

😀 😀 😀

Thanks
Arasuk😉
 
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