Line Stage Tube Replacement for CJ ET3

This is more of a comment than question but I thought it bears mentioning to the community for comment.

I have owned an ET3 preamp for about 7 months now and about 5 months in, I noticed a high frequency hiss coming from the right channel. I emailed CJ who promptly responded with a replacement line stage tube which they sent me for about $60. Great customer service by the way.

Before I go on any further, I have to confess that I was never that impressed with the ET3 or the sound of my system in general. It always sounded a little "off" although it was difficult to pinpoint what the problem was. I played with speaker placement, cables, audio sources, etc. Nothing made a huge difference. I was left with a sinking feeling that I spent a lot of dough for ho hum sound. I was also regretting going with an all-tube setup (amp and preamp).

With a newly installed line stage tube I turned on the system for a test and was immediately floored. My system went from mediocre to stunningly incredible. It's been several days with the new tube and I'm still in shock. Every track I've played sounds amazing!

How many people have had this same experience? It slays me to think that I spent thousands on a new audio system only to find that the entire experience was at the mercy of a $60 part. Furthermore, without the hiss, I would have never thought to email CJ, prompting a replacement tube.

So my overall question is this: How does one know if the tubes in an amp or preamp are in peak condition other than a hunch that things sound "off"? How many of us are settling for less than great sound because the new gear we purchased came with defective or rapidly degrading vacuum tubes?
You don't know as most of the time the tubes die gradually until they get noisy like yours did. Some amps like Audio Research have hour meters programmed into the display so you can keep track of tube life. That way and just change them out at recommended intervals.

And yes cj makes nice sounding and well designed equipment along with great customer service.

I guess I'm a little bit tweakier than you are. I bought a new tube preamp about 5 weeks ago, and the new tubes I ordered arrived before the preamp did. My preamp uses 8 tubes, I haven't even opened the package that the original tubes came in. I've tried 2 different NOS 6SN7's and the new Psvane CV-181 TII's with the 6SN7's, I've already tried (2) different pairs of NOS 12AX7's and 12AU7's.

I've heard brand new tubes that don't sound right. I make changes as soon as I hear anything wrong. Hell, many times I make changes when everything sounds great.
7 months without being impressed with the sound? I wish I had your patience. :)
Consider you just changed one of the three tubes in your pre-amp. My bet is that new tube you have is nothing special. If you had a complete set of NOS matched tubes you could really hear your CJ sing. Contact Andy at and see what he recommends.