Quote:After some burn in time on the unit (I think it had sat unused for sometime) and the tube, things seem to be improving. By swapping it in and out, I don't think it's hurting anything now, but still trying to decide if it adds anything. (this is as a buffer, not passive pre) I'm not wowed yet, but I'm not PO'd anymore. Believe me, I WANT to like this thing! I'm not out to play gotcha.
Based on my experience, I would not list a 12AX7 as a viable option, unless there is a vast difference between Sovtek and NOS versions. With the the AX tube, it really sounded horrid. Vast improvement w/ the Mullard 12AU.
cheers,
joe
Joe,
The ZOX is always shipped with the 12AU7 or 12AU7a. The 12AX7 will easily saturate if it see's a full 2 volts at it's input. With a high output dac of 3 volts or more it would not be usable This is why an input gain control was designed into the ZBOX so that you can turn a high output source down to normal. A 12AU7 is far more forgiving and will work with the ZBOX gain control all the way up in almost all cases. 12AT7 falls in the middle of the two. The 12AU7 has the lowest output impedance while the 12AX7 is going to have the highest. This means that the 12AX7 will not drive an amplifier with a 10K input impedance very well. There would be no bass. On the flip side it may drive a 100K input impedance wonderfully. This is why some people report it sounds good with a particular tube and others report just the opposite.
I'd be curious to know exactly what the signal path consists of and where the ZBOX is placed in your system.
- Steve
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Zbox questions (Read 4656 times)
