Homebrew PCBs

Since most active crossovers are unity gain filters with a fairly high
impedance and input drive level, the TL07x opamps should work just
fine, better than a low impedance bi-polar input opamp like the NE553x
series and as well as a 'boutique' high dollar FET opamp that probably
won't gain you much, if anything, especially at a cost vs performance
ratio

JR


--- In Homebrew_PCBs@yahoogroups.com, "david_mcauliffe"
<david.mcauliffe@...> wrote:
>
> (Sorry if this is a dupe- I didn't see it show up)
> 
> Hi,
> 
> I'm looking for some help with a PCB, and its schematic. I'm not 
> feeling very confident at the moment.
> 
> It comes from a stereo 3-way active crossover, which is twice as many 
> channels as I need. This send the signal to three amplifiers, not 
> three speakers. I'm also looking at a couple of little changes as 
> it's going to be used on an instrument rather than an audio system- 1/
> 4" jacks instead of RCA, that sort of thing.
> 
> I've managed to get the schematic for one channel, and the power 
> supply, and an image of the stereo PCB. I'm looking for some help 
> putting the channel and the power supply together, and then onto a 
> PCB.
> 
> It uses three quad op-amp TL074s, and I was also hoping to get some 
> advice on whether there is anything newer and quiter. Or maybe even 
> changing this to six quieter op amps (the chip number escapes me 
> right at this moment - I've got 5534s or similar echoing in my 
> mind??? My notes are elsewhere!)
> 
> I'm not willing to post the info I've got openly yet. While the 
> design was originally published in a magazine and the PCB is 
> available on their web site, I'm not too sure about the copyright 
> status and throwing it open to the group.
> 
> If anyone feels like they want to and can help, can you drop me a 
> line on this email.
> 
> Hoping to hear from someone soon,
> 
> Cheers,
> 
> David.
>