2 smd transistors and no labels. How do i know which is which ? [Solved]

[eh la bas ma]

Hello,

I am building a  Fairfield Circuitry Shallow Water clone.

https://docs.pedalpcb.com/project/LowTide-PedalPCB.pdf

It's a full kit from musikding.

Unfortunately they didn't write the names of the 2 smd transistors.

One is a J201, the other is a 2SK208.

How do i figure it out ? Does it even matter in this circuit ?

I have other builds with J201 transistors. I thought maybe I could try one of the unknown smd transistor in one of them and see if it changes anything.

But i suspect 2SK208 should sound quite close to a J201...

Every suggestions are welcome !

Edit : Both are soldered on smd adaptor boards. I tried them at both locations.

All i can notice is that the boost (from the internal DPDT)  is louder with one of them.

Any idea which one would be louder ?

[idy]

No schematic in the build doc. "Coming soon." Have a heart, pedalpcb. Can make a board and sell it but can't add a schematic.

[Rob Strand]

One is a J201, the other is a 2SK208.

How do i figure it out ? Does it even matter in this circuit ?

From Build doc:
Q1 2SK208-Y JFET transistor, N-channel
Q4 J201 JFET transistor, N-channel

Don't need part names on the PCB just Q1 & Q4 positions on the layout.

If the problem is you can't identify the parts themselves.

smd J201 might have a marking of 62P on the top
2SK208-Y  might have a marking JY on the top

You could also measure VP using fig 10 circuit:
https://runoffgroove.com/fetzervalve.html

J201 will have a lower VP.

[eh la bas ma]

One is a J201, the other is a 2SK208.

How do i figure it out ? Does it even matter in this circuit ?

From Build doc:
Q1 2SK208-Y JFET transistor, N-channel
Q4 J201 JFET transistor, N-channel

Don't need part names on the PCB just Q1 & Q4 positions on the layout.

If the problem is you can't identify the parts themselves.

smd J201 might have a marking of 62P on the top
2SK208-Y  might have a marking JY on the top

You could also measure VP using fig 11 circuit:
https://runoffgroove.com/fetzervalve.html

J201 will have a lower VP.

Thanks a lot !

I managed to read 62P on one of them, with the help of my phone. Problem solved.

Glad i could avoid building some extra circuit, just to tell them apart...

Now, all i have to do is calibrate this thing, and it's going to be quite difficult.