buffer is noisy what can i do?

[ninjadave7]

i built jack orman's opamp buffer on vero and it works fine but is very hissy and noisy.  i'm powering it with a pp2 and it's on it's own plug, no sharing.  the buffer sits in a true bypass looper.  any ideas?

[kvb]

all I can say is that I asked this question once and the answer was runaway feedback.

In part of a buffered distortion I had an output that was too close to an input.
The problem could be a layout issue
The solution could be some shielded wire.
hope that helps

[ayayay!]

I see 3 variants of his opamp buffer.  I advise getting intimate with them, especially the part under "miscellaneous" that talks about power supply noise rejection.    What I mean is, what kind of PS filtering did you use?  You still need it even with a good power supply.  It's not about the supply, it's about the pedal.   

http://www.muzique.com/lab/buffers.htm

Oh my, I just realized I hit 1000! 

[brett]

Hi
choose your opamp carefully.  The ME5532 is very quiet, but has low input impedance, so it's not an buffer (!), the 741s and 4558s* hiss a lot.  In general, it's hard to beat a TL071/2/4. However, keep the input resistance low (resistor to Vref for a non-inverting confidguration) or you'll pick up RFI and other cable noise.
cheers


* 4558s are simply dual 741s.  Popular opinion has it that they contain enormous amounts of mojo (esp as feedback clippers), while 741s contain none.  I conclude that popular opinion is popular, not smart.

[igor12]

My buffers are a little noisy too but clean up when I put them on a real circuit board with proper grounding and stuff.  Also 4558 are quieter than tl072.  Look up the datasheet  at mouser and look for the nV/Hz spec.  Also, look at different brand 4558's. Some are quiter than others.

[oldrocker]

I put Jacks AMZ Simple Jfet Buffer on board my flying V.  Very low noise and works quite well.