mystery crybaby transistor

[numpty]

Could anybody identify this transistor from mid 70's cry baby located at the edge of the circuit board, its
SFP5172 or STP5172, its not 2N5172. I'm  sure its not the transistor originally intended for that board
because the three holes in the board do not align with the configuration on the lead out from this transistor as two of the leads cross each other.
The board contains a red fasel inductor and green ARCO caps and retailed in the UK.I would like to replace it as I'm sure its noisy.

[R.G.]

Someone may know.

Here's what to do until they pop up.

Is this a negative ground unit? That is, does the negative battery lead get connected to signal ground when the unit is operating?

It almost certainly is, but you do have to check.

If it's negative ground, get yourself a 2N5088. Quiet, low noise, well behaved. If it's positive ground, get yourself a 2N5087 or 2N4250.

[numpty]

I've since discovered from a weblink "fattening the tone of a vintage vox wah pedal" that its actually an SIP5172 which can be replaced by a BC109 does that sound right?

[Dai H.]

maybe it is a 2N5172  that is marked a bit differently since some wahs apparently used them. Otherwise a random house number that happens to match with a type used in some old wahs. Also I've heard of crossed over legs in stock wahs, so iirc if it's a 2N5172 and the legs are crossed over now, (if you want to put in a BC109), then a BC should go right in.