Try to get some 6n23p Voskhods 74-79 period and you will never look back, problem is to find a good and trusty vendor for these. They have a better pricing compared to other 88 family nos, have less tedency to microphonics, and generate less heat around the tube. I have tried nearly all in that family and i am happy to have a good stock of these and selling nearly all my nos stock of ecc88/e88cc/e188cc. Just kept some Holland ecc88, e88cc, e188cc, Siemens e188cc A frames (which i find better voiced than CCa's). D-getter Bugle Boys ecc88 and Amperex Holland e88cc straight D-getter 1958-1959 period are special but can become noisy. All depends on your gear and how hard it drives the tubes.
Another nice and linear sounding tube is Mullard e88cc-01, equivalent to CCa but unfortunately same pricing and more rare.
G
Another nice and linear sounding tube is Mullard e88cc-01, equivalent to CCa but unfortunately same pricing and more rare.
G