op-amps with high gain

Hi Imno,
Have a search for Dual op-amp or in-amp. Is that what you mean by "two channel"?
Read the datasheets to find the one that you require. Most have a wide range of voltage input (that I read). 3v -30v, so your 18v supply would be perfect. But Dual supply does seem to be 16v.
Here is a dual op-amp datasheet to read.

Martin

 

The gain of a typical op amp is around 100,000 to 1,000,000. The thing you are actually interested in is the gain bandwidth product or GBP.

This number represents the max gain they can produce at any frequency. Divide the GBP by the max frequency you will need and that tells you the max gain you can have. Of course, the actual gain is set by the feedback network. You never run an op amp open-loop unless you are using it as a comparator.

For example, the popular LM324 has a GBP of 1.2M.

So if your max frequency is 1 KHz you can have a gain up to 1200, and if the max is 100 KHz you an have a max gain of 12. At 1.2MHz or above, it will have no gain.

Bob