JFET phaser distortion

Started by Cotoletta, November 01, 2014, 09:38:47 AM

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Cotoletta

Hello guys,
I'm building a phase 90 clone, but I have way too much distortion even with the feedback loop disconnected. I have my 2N5952 well matched, but I always have the same issue. I even tried to modify the schematic adding the RC network for each JFET from the phase 45 schematic, it distort a little less but still.
I have a few sets of 2N5952 with Vgs from around -1.3V to -1.8V if that helps.
If I disconnect the wet signal from the last phasing stage everything goes fine, so the input buffer and the output transistor are fine.
Oh, and I'm using a 78L05 regulator instead of the 5,1V zener diode.

Any thoughts?

duck_arse

I've used a regulator in place of a zener in fet bias circuits on the breadboard before. I found the regulator is sometimes the source of lots and lots of hisss. perhaps it is also the problem here, but you should probably also go here and follow instructions .....

http://www.diystompboxes.com/smfforum/index.php?topic=29816.0
You hold the small basket while I strain the gnat.

Cotoletta

Just tried with a 5,1V and 4,7V zener, rebiased the LFO but same thing, still distortion in the lower end of the sweep...
Also i have triple checked everything, no wrong components or connections. I've read about other people complaining similar issues with phase 90/45 clones.

PRR

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