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.
>