[jdandy]

Originally Posted by W9TR

Tubes for the MC 2301.....I've found that changing out the KT-88's make a subtle difference, the 12AT7's much more so. I am currently running Gold Lion re-issues (thanks Bob!) in my amps. I also like the vintage Mullard CV4024 in this application but haven't done an a/b test.
Tom

Tom.......That is a fine combination of tubes in the MC2301's. I currently have my pair of 2301's loaded with Gold Lion KT88 power tubes and Siemens ECC801S driver tubes. I have compared the Siemens driver tubes against the Gold Lion B739/ECC81/12AT7 tubes, the Mullard CV4024, the Telefunken 12AT7/ECC81, and the Tung-Sol 12AT7/6201 tubes. All of these tubes sound excellent with only minor differences in the upper midrage presentation. I kept returning to the Siemens ECC801S tubes because they seemed to present the most balanced presentation across the full frequency spectrum. About three months ago I swapped the Siemens tubes for the Gold Lion tubes for a week, then returned to the Siemens ECC801S. To my ears the Siemens delivers the cleanest, most resolved presentation of all the above mentioned tubes. TubeMonger.com sells the Seimens ECC801S. I also have a quad of Siemens E81CC/12AT7 tubes but haven't rolled them into the MC2301's yet. The Siemens ECC801S tubes sound so good I don't want to mess with perfection.

Contrast my current impressions to my 12AT7 tube rolling review and you will notice that four years ago I had a preference for the Telefunken ECC801S and the Gold Lion 12AT7 driver tubes over the Siemens ECC801S. Since that time I have changed DAC's twice, now using the Esoteric K-01X, and replaced the Olive 04HD music server with the Aurender N10. In addition, I have replaced some of the studio's absorption panels with Vicoustic Wavewood diffusion panels that improved the room's acoustic signature. As the sound system is presently configured the Siemens ECC801S driver tube in my MC2301's are delivering outstanding sound.