Suggestions on low noise JFETs and OPAMPs???

[vanessa]

I really like the Orange Squeezer build I made (GGG), but it seems with the stock opamp (4558) and JFETs (2N5457's) it seems to have a bit of distortion to it (I've read others complaints of the same thing), worse with humbuckers. I put a TL072 into it and it seemed to help a bit.

Are there any better JFETs and OPAMPs that could help make this thing crystal clear or close (heck maybe just better?)?

Hi-Fi is the direction I'd like to go.

:roll:

[littlegreiger]

Try an OPA2134 for the opamp they are supposed to be low noise Hi-Fi parts but they are more expensive. As for Jfets I'm not sure. Maybe some one else knows a low noise one. You could try a J201 , not sure if it's any better but it's different.

[KORGULL]

Check out the NJM2068D chips at BG Micro - part#ICS1014, 3 for $1.00.
They are like a low noise version of a 4558.

A low noise chip might not solve your problem though, ...you probably need a way to increase the headroom.
Maybe your pickups are too hot - I can't get a totally clean sound with my EMGs unless I back off the guitar's volume quite a bit.
*Last edit for punctuation*

[lovekraft0]

If you're having distortion problems, you could try trimming down the input level, so the OS doesn't have to work so hard.

[zeta55]

Try an OPA2134 for the opamp they are supposed to be low noise Hi-Fi parts but they are more expensive. As for Jfets I'm not sure. Maybe some one else knows a low noise one. You could try a J201 , not sure if it's any better but it's different.

I tried TL072 and the OPA2134 in my SS amp. The OPA2134 made a huge difference.

[bigjonny]

If you're having distortion problems, you could try trimming down the input level, so the OS doesn't have to work so hard.

...and perhaps increase the value of the output potentiometer, if your overall volume gets too low...

[Paul Marossy]

An OP275 is a pretty quiet opamp...

[Mark F]

I believe FET's are inherently low noise.

[petemoore]

I know, just typing anyway...use higher voltage supply[?].
 My OS does that too.

[nelson]

trim down the input volume then use a gain recovery stage at teh end (LPB2 or other) then you have a compressor and possible boost in one pedal

[grapefruit]

Depends whhere the distortion is happening. If it's in the FET's then, like others have said, trim down the input. Try with your guitar volume first, but you could replace R1 WITH A 2.2M and put another 2.2M between R1 and the input switch. That will halve the input level. Adjust the ratio to reduce or increase the input level. You could use to other half of the op amp to boost the output level if necessary.

If the op amp is distorting you can either do the above,  increase the supply voltage, or use a rail to rail op amp. I haven't  built the orange squeezer but my guess is the FET's would be causing at least some of the distortion.

There are probably other tweaks you can do to improve it. hopefully someone with experience with this will chime in...

Stew.

[Noplasticrobots]

What about using a TL082, would that work?

[bwanasonic]

A Burr Brown OPA2134 works well for an opamp, but be sure to search the archives here for Orange Squeezer info, especially posts by Mark Hammer. Part of what you may be hearing as distortion, could be envelope *ripple*.

Kerry M

[Jered]

  For JFET's try different 2N3819's, but the pinout is different. 2N5457 is D-S-G, 2N3819 is S-G-D
  Jered

[R.G.]

You mentioned noise in the title of the post, then your question says distortion which is worse with humbuckers.

If it's really the distortion, then the cause is most likely the distortion of the JFET gain modulation itself, either with the signal itself or with the ripple on the envelope detector.

The OS is a remarkably capable compressor for something so simple - but it may be about at its limit of performance.

A much better low distortion compressor can be made from the NE570/571 or SE571 chips. They are used in a lot of hifi equipment.

The THAT company chips are going to do even better at this. But all of these will be much more complicated designs.