Originally Posted by Wolfbane
After 20 hours with the Telefunken ECC88 I've installed an Amperex ECC88 'pinched waist' gold pin tube. Initial impression of this combination is also very favorable!
Update to follow.
With more then 20 hours of listening to music through the DAC-11 and Amperex ECC88 'pinched waist' tube combination I've (almost) reluctantly moved on to a Mullard gold pin (relabled Phillips) E88CC-01 tube in it's place.
The pinched waist Amperex was a step up from the Telefunken it replaced. I found it to be more detailed and revealing then the Telefunken and a really great match for the DAC-11! Unfortunately I only have one of these tubes and I could certainly be satisfied to listen to this combination for a long time.