Bif Muff Diode Switch problem

[PieterPost]

Hi there,

I am new to the pedal building world. After messing around with some guitar rewiring I decided to pick up this lovely hobby. I've been reading around alot, and started building my first pedal (a veroboard Analogman 108BC Sun Face).
While waiting for some parts to arrive I decided to get some practise in by doing a simple mod. I decided on the diode switch for big muff circuit. To keep it simple, I only modded the first clipping stage for now.

I wired everything as per the image below (removed D1 and D2 first). The DPDT switch works perfectly in the no-diodes mode (wonderful sound btw), but when set to the 2x 1N4148, the sound just sort of cuts. I understand that the no-diodes option is supposed to be way louder, but the diodes option barely lets any sound through.
I've tried wiring up the diodes in various ways (connecting them both to two lengths of hoopkup, twisting one over the other and soldering in place, even a dedicated small piece of vero to run them in parallel) but the problem persists. Did I just misunderstand the way the switch is supposed to be wired? With each wiring option, I used a fresh pair of diodes (ordered a whole bunch), so I'm pretty sure I didn't fry ALL of them. Alas, my multimeter hasn't arrived yet, so I cannot use that to debug.
Any ideas? Thanks in advance!

[Nocentelli]

The diode mod should be to remove the diodes - that diagram shows them being shorted instead. I suspect the sound you like is actually the stock BMP diodes, and the very quiet sound has the diodes shorted which would leave a 100n cap directly across collector and base which would lead to a massive cut in level.

Snip the jumper that connects the top lugs of the DPDT and see if that helps

[PieterPost]

That might explain the problem!
I'm gonna give it a go when I get home.