Orange Squeezer JFET question

[scotsman]

I'm about to get started on the TonePad version of the Orange Squeezer.  Just finishing up the BOM in Mousers project manager (what a great tool) and had one question that I was not able to find an answer to after doing the search of the board.  I've seen other "boutique" versions of this pedal mention that the JFET's (2n5457) were matched.  Does this really matter?

Thanks in advance. 

[R.G.]

I've seen other "boutique" versions of this pedal mention that the JFET's (2n5457) were matched.  Does this really matter?

Absolutely.

NOT.

The two JFETs in the OS have nothing in common in how they're used. One is a variable resistor, like used in phasers. the other is used as a constant current source.

Someone telling you that they matched the JFETs in the OS are telling you that either they don't know what they're doing or that they do know what they're doing but think that YOU don't.

[scotsman]

I've seen other "boutique" versions of this pedal mention that the JFET's (2n5457) were matched.  Does this really matter?

Absolutely.

NOT.

The two JFETs in the OS have nothing in common in how they're used. One is a variable resistor, like used in phasers. the other is used as a constant current source.

Someone telling you that they matched the JFETs in the OS are telling you that either they don't know what they're doing or that they do know what they're doing but think that YOU don't.

Thanks again R.G. ! 

[burnt fingers]

Boy I'm glad this question was asked.  I have been putting off a OS build because I thought that FET's needed to be matched and haven't gotten around to building a JFET matcher.

I guess an OS is on the bench soon then.

Scott

[George Giblet]

>The two JFETs in the OS have nothing in common in how they're used. One is a variable resistor, like used in phasers. the other is used as a constant current source.

On the surface that's true but oddly enough it's not entirely true.  A long time ago I contemplated putting up at OS version that used a BJT for the current source - because BJT's are cheaper.  It turns out that if the JFETs are matched the amount you have to vary the 10k resistor for the correct sound varies over a range of something like 1.5 to 1.  If you replace the current source with a BJT the 10k needs to be adjusted over a range of 5 to 1, which makes it a little more difficult to adjust.  If you buy JFETs from the same batch they aren't matched but they often tend to have ball-park similar characteristics so the 10k resistor would still require a smaller range of adjustment to the BJT version - so for that reason I didn't bother putting it up the BJT version.

This is a purely a tolerance and ease of adjustment issue it has nothing to do with the sound or mojo of the unit.  If you don't know what I'm talking about just accept RGs comments!   More importantly, as RG said,  don't bother matching your JFETs.