JFet Tolerances for Surfy Bear Reverb

[spacecommandant]

I'll be building a couple of spring-tank reverbs, one of which is the Surfy Bear, and in the build docs it specifies using 5457 Jfets "selected for Vp: -1.58V, Idss: 3.27mA, +/- 10%" for Q4, Q5, Q6.
What would likely be the result of using 5457s that fall outside of those tolerances?
Also, for those who have experience using/measuring 5457s, how common are these specs (assuming they are from reliable seller... Mouser, etc.)?
I'm happy to use either through hole or SMD.
Here's a link to the schematic:
https://schematicsonline.com/schematic/surfy-bear-fet-reverb/

[FSFX]

Also, for those who have experience using/measuring 5457s, how common are these specs (assuming they are from reliable seller...

This is the characteristics of a typical 2N5457 that I have in my JFET stock.


I have both the SMD MMBF5457 and the THT 2N5457 and both types measure within 10% of that in the graph with typical VP of -1.4v so the values you quote would be a little higher compared to the ones I have.  But, of course JFETs are notorious for having wide spans of characteristic values so it is just a matter of measure and see. I have seen -1.58v and 3.27mA quoted as typical for 2N5457 devices and those are actually the values for a typical one mentioned on the bias calculator spreadsheet I posted a link to earlier on another thread.

[spacecommandant]

Also, for those who have experience using/measuring 5457s, how common are these specs (assuming they are from reliable seller...

This is the characteristics of a typical 2N5457 that I have in my JFET stock.


I have both the SMD MMBF5457 and the THT 2N5457 and both types measure within 10% of that in the graph with typical VP of -1.4v so the values you quote would be a little higher compared to the ones I have.  But, of course JFETs are notorious for having wide spans of characteristic values so it is just a matter of measure and see. I have seen -1.58v and 3.27mA quoted as typical for 2N5457 devices and those are actually the values for a typical one mentioned on the bias calculator spreadsheet I posted a link to earlier on another thread.

That's good to hear. Thanks for the response.

[sarakisof]

I'll be building a couple of spring-tank reverbs, one of which is the Surfy Bear, and in the build docs it specifies using 5457 Jfets "selected for Vp: -1.58V, Idss: 3.27mA, +/- 10%" for Q4, Q5, Q6.
What would likely be the result of using 5457s that fall outside of those tolerances?
Also, for those who have experience using/measuring 5457s, how common are these specs (assuming they are from reliable seller... Mouser, etc.)?
I'm happy to use either through hole or SMD.
Here's a link to the schematic:
https://schematicsonline.com/schematic/surfy-bear-fet-reverb/

I've built a couple of those units. THT. I've created my own PCBs.
Used 4AB3C1B tanks. Couldn't hear a significant difference between jfets, even with chinese 5457s from eBay couldn't tell a big difference at all.
I'd say use whatever 5457 from Mouser or your local reliable seller and be happy with it. It's a great unit.

I left it as is, finished but not enclosed because i was too tired trying to find the ideal enclosure for me. I'd like to put it in a 60s suitcase , old flute's case etc. I was looking to find smthng to be (not just look) real, with its original relic and true age worn from past decades. It had to be rectangle to fit the tank etc. Was close but never found smthng good enough, then I quit. I use my Twin and Farfisa FR40 tube amp's spring rvrb since then.

[antonis]

I left it as is, finished but not enclosed

I wouldn't dare to step down to your basement, Sofoklis..

[sarakisof]

I left it as is, finished but not enclosed

I wouldn't dare to step down to your basement, Sofoklis..

Specially while being drunk from tsipouro.