Some "knobless" Vox/Thomas booster schematics.

[anotherjim]

I don't know how I missed them before now, but these old Vox/Thomas Organ boosters are new to me...

I think I've seen the treble boost before, but not the others.
Careful with that bypass switching Eugene!
More info...
https://www.voxac100.org.uk/jennings_musical_industries_treble_booster.htm

[Electric Warrior]

Schematics for these have been around for ages.

However, the Thomas Organ ones are not the only Vox boosters.
There are british made variants as well.

The british distortion booster started out as a Fz-1 based circuit (but with only two transistors). Later on they used something with a MK1.5/Fuzz Face topology (but different from the Thomas Organ version). And then there's an italian made distortion booster with yet another different MK1.5 based circuit.

There are british made germanium versions of the treble and bass boosters as well...

[willienillie]

The only list the Thomas Organ house number for the Qs.  Are they silicon?

[anotherjim]

Both Vox and Thomas types were silicon NPN negative ground. 2N2924 has been suggested.
Apparently, the switch in the UK Vox ones has 3-pole operated as a true bypass...
http://voxshowroom.com/uk/misc/boosters.html

[willienillie]

TO seemed to have several part numbers for 2N2924 (86-5044-2, 86-5050-2, 86-5114-2, maybe more).

[R.G.]

Vox in the UK and Thomas Organ in the USA also put collections of one to four of these little effects inside guitars.The US versions even had little circuit lumps on a "motherboard" inside the guitars, and one version even included the "repeat percussion" effect. There were several versions, as noted.

I got all hot about these at one time and did some PCBs for exact-repro. Fun.