Q on signal path and LFO circuit seperation

[Ice-9]

Hi again. just a quick question for you knowlegable people.

I have just got hold of some smd tl084's quad opamp chips. I am intending to use them on a phaser that i am working on. My complete circuit will use 8 op amps, so i could use 2 X TL084's . The thing is, the signal path uses 6 op amps ( 1 buffer stage, 4 op amps in the phaser filter stage and 1 op amp as a mix/ output buffer) that leaves me with 2 op amps left for the LFO circuit. Does anyone know if using the 2 remaining op amps in the TL084 as the LFO generator whilst the other 2 in the same chip will be carrying signals (input/ ouptut buffer/ mixer) will cause any clocking /  noise problems in the signal path.

Should i use a seperate chip for the LFO.

I do have some smd 4558d chips so i could use 1 X TL084 for the filer /phase section, 1 X 4558d for the input/ output and 1 X 4558d for the LFO.

Just in case anyone is wondering why i'm using smd components, It's just cause i have them and i want to do some experimenting using these.

[Mark Hammer]

The ticking occurs because one part of the circuit draws current away from another in short punctate bursts.  Isolating that part of the circuit so that it has its own emergency reservoir is very helpful in reducing tick.  You will also note that many circuits will use lower current dual op-amps for the LFO, such as an LM358, a TL062, or TL022.  Good practice because if that part of the circuit needs less current, it won't be as obtrusive at those moments when it most needs current.

So, save those extra op-amps for other things that don't have an LFO, score yourself an LM358 or equivalent, stick a 100R resistor between V+ and pin 8 on the LM358, and a 100uf cap from pin 8 to ground.

[Ice-9]

Thanks Mark ,
That information is exactly what i was looking for, and also sorry i missed the post which dealt with exactly the same question coincidentally posted while i was typing my post.  I will get some of the low power op amps and start working out my pcb.