Which op amps do you use for active filters??

[zx3chris]

just curious what everyone uses for active filters.. ive only fooled around and never actually used one for musical purposes, so ive only used 741s... whats good and cheap??

-chris

[svokke]

Well, I'm also designing an active crossover.
For testing if the thing blows up I use the cheapest dual op amps avalable here in Belgium: TL072. For more serious work I change for the NE5532, pin-compatible with the tl072 and many others. This is a standard hifi opamp.
I wouldn't use the 741, it's a quit old opamp. in school we use that opamp to learn about opamp limitations, because they are so obvious. Even measurable with budget measuring gear.
A lot of people say other opamps are better, like the AD826 and AD712, but I don't have experience with those yet.
I guess there will be a sonical benefit but I don't think it will be a day-and-night difference.

Regards, svokke

[trwh]

Hi Chris

As svokke says, the TL07x and the NE553x are both very good sounding opamps that are very cheap. I have just constructed a small 4 band equaliser for 'party duty' around a TL074 and TL072 - it sounds just fine, and was perfectly stable first time.

Both of these devices can be found in abundance in many pro audio mixing consoles and outboard units, etc. However, if you only need a few opamps, you could choose a more expensive device, such as the OPx134, or the OPAx604, which have significantly better 'specs, and are said to offer a worthwhile sonic improvement.

Hope this helps,
Tim.

[mm]

Hi Chris
I have used a number of well known inexpensive op amps in various capacities including TL072,TL082, NE5532. These were my favourites for different reasons. I was partial in particular to the TL072 for a number of years. However, after trying the opa2604, I am no longer interested in my old stand bys. They may cost a dollar or two more, and you may need to order by mail, but I have found the opa604 to be way more than worth it. With all due respect to svokke, dare I say "Day and Night"?
Have fun!
mm

[peranders]

To make it easy for you, you can use almost any opamp with slew rate more than 10 V/µs and noise less than 15 nV/Hz and stable at the gain of 1. If you use opamp J FET's inputs you don't have to worry about resistor values.

NE5534/32 and TL7x, TL8x are cheap and easy to get working

My favorites at the moment is AD8610 and OPAx134, excellent chips and not so expensive