Solid State Preamp to replace tube unit

I agree with Marco1. Purchase tubes from CJ or a reputable dealer before you finalize your decision to go with a SS preamp. The ET5 is a nice pre. In fact, starting with the ET3se moving up to the ET7, the lineup is similar under the hood. Of course, the ET3SE doesn’t have two main outputs or a balance control and the additional tweaks made along the way.

I agree with those who point out that, generally speaking, preamp tubes will last for years, and that the CJ preamp you own is an anomaly or just cranky product design. There are a lot of fine tube preamps out there. I’m particularly fond of the 6SN7 tube for it’s open, natural and relaxed sound, as well as it’s sturdiness, longevity and relative affordability. A number of preamps are based around that tube, including the Black Ice Fusion F360, the Icon Audio Pure Valve, the Cary SLP-98 and the LTA MicroZOTL. Another option is a used Don Sachs Aikido preamp. I myself use my own version of the Aikido circuit, and it’s just a wonderful sound.  I'm currently using Sylvania 6SN7WGT's in it.  They weren't cheap, but I expect them to last four years or more before I need replacements.

But beyond the 6SN7, there are a lot of great and reliable tube preamps, some mentioned above. I’ve rarely encountered a tube preamp that "eats" tubes. I don’t see any reason to give up your preference for a tube preamp just because one particular model is giving you issues.

The answer is simple; Backert labs. I’ve owned both SS and tube preamps and never anything remotely like my Backert pre. The two 12AU7 tubes will last a lifetime. The pristine nature of the sound will blow your mind. I own the Rhythmn and it never fails to leave me in awe after 2 years of continuous listening. It’s paired with 300B mono blocks and the sound is very detailed but with the realism only possible by well designed tube power amps and DeVore O96’s. 

I can offer three suggestions to consider that are not the usual candidates.  All three can stay powered up all the time:

• SMc Audio VRE-1C - This is one of the most natural solid state preamps out there.  Unfortunately, it is above your price range and almost never comes up for sale used.  However, you can still have most of the magic with either one of SMc Audio's new stripped down versions, or by having them modify an old McCormack TLC-1 preamp (like mine).  These are active preamps with typically +6dB gain, (although mine is a unity gain version) and they provide all the bass and rich tonality you would ever want.  Contact Patrick at SMc Audio.
• Life-Changer Audio icOn 5 - These are passive AVC units using Dave Slagle's autoformers in copper or silver.  They sound very natural with very good bass, great tone, and just a touch of warmth.  Srajan at 6moons uses one in his main system.  I owned the 4Pro balanced unit and it sounded very good driving my amps with input impedance of only 10K ohms.  The icOn 5 uses a switchable input buffer to allow the full performance to take place with partnering equipment of any impedance. 
• Hattor Audio Ultimate Preamp - A very good sounding solid state preamp, and amazing for the price.  Get the dual mono, with AMRG resistors, and passive/active switchable gain (0, +3, +6, or +9 dB) using the op-amps of your choice (Staccato, OPA2134.  Great display, remote, and outboard power supply.  Other manufacturers use their volume controls.

I would echo the positive comments on the CODA 07X. The new FET version of this preamp is excellent. Absolutely silent, warm tube-like presentation, with great detail and resolution. I replaced a Classe preamp with the CODA 07X and the increase in detail was noticeable while maintaining a very a natural, musical sound.