The KillerDAC Audio forum

Telefunken 12AX7.  They have a reputation and the price to match, but i find in general these valves overrated, the smooth plates 12AX7 have the typical telefunken house sound, pretty, sweet,  light, clean, and airy, and in the right place beautiful, but lacking a little in body and warmth and most importantly timbre, apparently they say the rib plate is fuller with more body than the smooth plate, and they sell a little cheaper. Because they have a very distinctive sound they can be very handy in tuning a system. I found they worked brilliantly in my old Convergent audio technology (CAT) mark 2 preamp, just by putting in a single smooth plate 12AX7 in one of the CATs 10 valve positions, without it the preamp was ordinary, that valve just had the correct flavor in the CAT. The rule is you cannot use a full house of telefunkens in any superbly tuned system as with all valve brands, it's always a mix and match scenario. I own telefunken 12AX7s because they are important in my tuning arsenal but generally keep away from buying too many, problem is you must own them to understand them, and that is the key to use them in the right place. Picture of a smooth, then a rib plate Telefunken 12AX7. Always look for the diamond logo between the pins before buying.

Let's talk about a mullard 12ax7, 14mm short plate 1960s plus, these are very good sounding valves, and the one to get has copper rods, they are much harder to find than the non copper variety. These 12AX7s usually sell for half the price (or less) than the long plate versions. Again look for the Mullard Blackburn code on the glass and as you can see in the 3rd picture these 2 non copper versions are dated Blackburn 1969, These mullards copper and non copper are a very good all round 12ax7 and well worth the money.

A few have brought these after reading bryans comments, and then did the comparison, But ultimately there wasn't one. it is a good sounding DAC, but not magical. Shame because its Cheap. But hotted up it may cut it.

Like all great DACs, its really depends on the system, the type of music you play, the quality of the CD, Your own prejudices, it is often so CD dependant.  Never ends.  There is often no best with the top contenders, and even then, ten people with 4 different winners.

Does this DAC sound as good as the KillerDac?