I need to convert a 6.3mm(1/4) to 2.5mm (3/32) TS jack. I figure the best way is to buy a 2.5mm TS cable, then solder a 6.3mm to the other end. I only need a short cable length, and think it's better to have a lighter cable on the 2.5mm end to avoid stress at the connection. Also soldering the small cable to a 6.3 (1/4) is going to be easier than soldering a bigger cable to the 2.5mm end.
 
Problem is, I'm fining it hard to find a 2.5mm TS cable, everywhere seems out of stock.
 
Can I rely on a TRS 2.5mm working in a mono  TS 2.5mm female socket

Afterthought: When I solder the stereo to the mono, solder both the ring and sleave of the stereo to the ring of the of the mono

Does your 2.5mm equipment receive or send? If it receives does it accept mono or stereo? If stereo it might be better to link the tip and ring.

2.5 is a female receiving. It's the input on my ABGs pre amp.
 
I figure as the 2.5 male jack will be pre wired on a stereo cable, if I connect both ring and sleeve to the 1/4 jack plug, then what ever contact (ring or sleeve) on the 2.5 female should be making a loop. As long as on a 2.5 ring (only) isn't the insulator between them, I can't see a problem. 

That is true. But it is also quite likely that the Sleeve (ground) in the 2.5 socket will only contact the sleeve and not the ring. Provided the jack is fully inserted. If your input device expects TS jack then either configuration will work. If your input device expects TRS (stereo) then you will only get one channel with the way you wired it.

Sorry for delay in replying. This forum seems to have stopped notifying when someone replied.

Finally tracked down a mono cable on Amazon, but Thomann doesn't work weekends, and didn't seem to process my Saturday order on Christmas Eve. So now looks like my new transducers won't arrive at my friends house until after her flight back to Vietnam. Now the situation will be reversed, I'll have the cable, but nothing to attach it too.

Is 2.5 bantam?

Bantam jacks are 4.4mm? I think he is referring to the very small version 2.5mm

Thanks