Although thanked for the answer given – I suspect Tweed was looking for an off the self solution (without having to resort to soldering).
I’m guessing that you want a stand alone stereo volume control with phono in and out on each channel.
I have taken a quick look at the usual outlets on the web (ebay, maplin, CPC etc) without success.
I have in the past seen such items on ebay – so it might pay to keep searching.
The reason for their rarity is that they are normally used on high-end power amplifiers that do not include integral volume control.
If you can’t wait and don’t want to build you own – my advice would be to purchase a mini stereo mixer to do the job. These can be purchased for under £30 and would have the advantage of allowing other inputs to your power amp.
(most mixers use ¼ inch jack in/out – converter plugs (to phono) are readily available)