How do I use Computer Modern product symbol together with txfonts package?

Question

I use the package txfonts but I don't like this symbol

I would like to use Computer Modern symbol for the product symbol.

Answer 1

Variation on my answer here: Different Sum signs

\documentclass{article}
\usepackage{mathtools,txfonts}
% =============================================
%Import symbols from font cmex without importing the whole package
% =============================================
\DeclareFontFamily{U} {cmex}{}

\DeclareFontShape{U}{cmex}{m}{n}{
  <-6> cmex5
  <6-7> cmex6
  <7-8> cmex7
  <8-9> cmex8
  <9-10> cmex9
  <10-12> cmex10
  <12-> cmex12}{}

\DeclareSymbolFont{Xcmex} {U} {cmex}{m}{n}

\DeclareMathSymbol{\Xdprod}{\mathop}{Xcmex}{89}
\DeclareMathSymbol{\Xtprod}{\mathop}{Xcmex}{81}
\DeclareMathOperator*{\Xprod}{\mathchoice{\Xdprod}{\Xtprod}{\Xtprod}{\Xtprod}}
% =============================================
%\usepackage{fonttable}
\begin{document}
\centering
prod under txfonts:\par
$\prod_{i=1}^2 x_i $
\[\prod_{i=1}^2 x_i \]
Defined Xprod from cmex:\par
$\Xprod_{i=1}^2 x_i $
\[\Xprod_{i=1}^2 x_i \]
%\tiny\fonttable{cmex8}
\end{document}

Answer 2

In the modern toolchain, with unicode-math, you could write:

\usepackage{unicode-math}

%% There is also a TeX Gyre Termes X that’s a more exact clone of
%% newtxtext, or any Times font would work here:
\setmainfont{TeX Gyre Termes}
\setmathfont{TeX Gyre Termes Math}
\setmathfont[range=\prod, Scale=MatchUppercase]{Latin Modern Math}