"Telefunken ECC88 RFT made, 1960's in AI M3A?

I would like to use these in my Audible Illusions M3A pre-amp. Has anyone else used them in theres?

I use Telefunken CCa's in mine and love them in the phono. I have also used NOS Telefunken 6922's also a super tube go and try you may like it . I like the sound with a Siemens 6922 or CCa's in the line stage but you could also try a 6922 Phillips Holland SQ miniwatt NOS or a Amperex PQ 6922 Holland NOS . This is what I use and love the sound just My two cents
I have not tried this tube, but I believe the RFT is not Telefunken. It IS a RFT, which is another brand all together.

There are many copies of Telefunken, some made in East Germany that are similar but do not offer the same performance.

A few years ago there were a number of posts about a German tube called the RSD brand. I bought several on the recommendation of a tube dealer and having read glowing reviews in posts like Audiogon.

In the end, after hearing the lackluster performance (among the ones that did not fail promptly) I disposed of them in the trash can rather than pass them on to another member.

If you can afford real Telefunken 6DJ8 (the tube you need), go for it. If you can't find it or refuse to pay the high price, try a Mullard 6922, Amperex 6922 or 7308.

Should you run across a Siemens 6DJ8 or 6922, it too is a gem. Good luck with the tube rolling.
I have just tried shooting out a bunch of 6922's .. Tele CCa's, 6 DJ8 Bugle Boys, Russian 6922's, Amperex Pinched Waist (Holland) 6922 and Siemens Halske 6922 Cca.. the Siemens was better by a significant margin.
Midareff, how long have you had the Siemens tubes in your Modulus now?