Conrard-Johnson CT5 tube rolling?

Anyone out there have experience using NOS with the CT5? Are they better than the $200 a pair tubes CJ sells? My tubes are about ready for a rotation, so I thought I'd check with fellow owners.
Damn this iPad auto- correcting keyboard! That's C-o-n-r-a-d. Sorry.
Hmmm, after 10 days and more than 100 views of the question, I'm beginning to believe that CJ tubes are the best choice for the CT5.
c-j likes to say that you cannot find tubes that will make your preamp sound better than those they supply. Some people agree saying that the preamp will sound best with the tubes it was designed to use.

My experience with a c-j 17ls2 is that different tubes will change the sound of the preamp and I have found tubes that I prefer to the stock electro harmonix 6922s. This will not come as a shock to tube rollers.

I have not heard the CT5 but I don't think it would hurt to try some different good quality tubes and see what you think.

If you search some of the threads on tube rolling you will find the names of reputable tube sellers who can make recomendations based on what changes you would like to make to the CT5's sound.
Well I live with CJ Act 2 for about 2years without changing stock tubes after I was told by CJ customer service it's not necessary . Well, after 2 years , 1 purchased 2 pairs of NOS tube, no contest and wish I have change tube earlier . Similarly when I purchased a Tron Reference phono stage I was strongly discouraged by the designer to change tube. So trust your ears not what the manufacturers say
Audio blazer,

I put new tubes in last week and was blown away by the I agree that refreshing tubes is a good idea.

One thing about the Ct5 is that it's tough on tubes. Even CJ customer service recommends every 1500 hours.


The ct5 uses the Sovtek 6H30p "super" tube and there aren't many sources for compatible and reliable alternatives I've recently learned.
Hi Vhiner, you are right, I don't think there is a substitute for the 6h30 other than the 6h30-DR which is a premium quality 6h30 that is no longer made.

They are for sale here on Audiogon for $280 a pair. I think it would be worth the investment to see how they work with your c-j. Considering what a CT5 costs it's a good idea to pay a little more for tubes that get the best out of it. I am not saying that you will like the 6h30-DR better though. I've never heard a CT5 with either tube.

Merry Christmas!

Thanks so much for the tip! I will check the DR version out. If anyone knows of the most " reliable" source let me know.
To my knowledge there is no readily available alternative to the 6H30.

I have heard the 6H30-DR lend a positive improvement (vs the 6H30-EB) in ARC Reference gear, but not so much in a CJ ACT2 or Premier 140. Even then the result was no where as dramatic as, say, swapping contemporary EH 6922s for NOS 6DJ8 family. Strictly my opinion re CJ: at current prices the DR does not warrant the premium over stock. If you still want to spring for the DRs, I've had good results from Eugene at If you do get them, let us know how they work out for you.
Vhiner, check out parts connexion . 6H30DR is selling for much cheaper than you can get elsewhere as far as I know
Thanks for the referrals, guys!
Vhiner, would you care to share your experience? I recently snapped up a CT5.

Congrats on the CT5! It's a marvelous preamp. I bet you got an amazing deal now that the ET 5 is out.

I decided to stick with CJ's supplied Sovtek tubes because the majority of posts I've read around the forums and boards indicate the expensive alternatives for the CT5 don't yield much bang for the buck. I'd love to hear if you have a different experience. How do you like the unit so far?

I *do* have one tip: Try a Hifi Tuning Supreme fuse in place of the stock fuse supplied by CJ. The fuse is accessible from the rear and relatively easy to swap out. Let the new fuse burn in for about 50 hours and then reverse the direction. You'll hear a difference and then you can know which direction you prefer. The fuse runs around $55 and is worth every penny, IMHO. I also use a Shunyata Python CX power cord (*far* better soundstage and transparency than the stock cord).
Hi Vhiner
Am curious about your comment that CJ service recommends changing the tubes in a CT5 after 1500 hrs. My CT 5 is 5+ yrs old with 3000+ hrs with the original tubes and it sounds sublime !
Am I missing something ?

I'm tempted to just say, "Yup!" LOL.

Ed, the very model of modern major tech guy at conrad-johnson, has told me several times that the tubes will operate well into the 3,000 hour range but that the sonic degradation at that point will be obvious if you replace them. When I replaced mine after 2,000 I was floored. A pair runs $135 right now and is *well* worth the price, IMHO. Tube degradation occurs very slowly and, therefore, seldom noticed until one begins to seriously fade.

When I replaced mine I fell in love with preamp all over again....gorgeous bloom, sparkling highs, prodigious lows, etc.
Many thanks. What's the best source for the 6H30 tube? Did you buy from CJ or online ? I think my tubes are fine for now but not sure for how long.

I buy directly from CJ because they stand behind their tubes and test them rigorously. Put'em on your holiday wish list...I think you'll like what you hear!


Thanks. I had to replace a 6550 on my CJ LP 70S , power amp,a few years back and found online prices to be way cheaper. CJ doesn't manufacture the tubes and the mark up by the CJ dealer was absurd.
I have a pair of 6H30 on order and will swap them and report on the difference.

Look forward to hearing your impressions!

Hi Vance
Replaced the stock Sovtek 6H30 in the CT 5 with a brand new pair of EH 6H30.Its the same tube except it has gold plated pins with makes for better contact. As for sonic differences its sooo miniscule, though I suspect the newer tubes have more clarity/air. What made a fairly dramatic difference was the use of the CJ supplied damper rings. Without there was grain and etchiness.
Many thanks to you and others on this thread for all your inputs/advise

Sorry the new tubes weren't a bigger bang for you, but at least you now know you're cooking with a full tank of gas. I agree that the damping rings are a must.
Vhiner: Sorry for responding late as I didnt browse the forum on a regular basis.

Tube dampening: the original rings do a great job but Herbie's tube dampener add a bit more focus, at $10 a pop, they are worth a try

Tube rolling: the DR versions are indeed better in my CT-5 and did the job in an even more liquid midrange, which I was after, w/o rolling too much off in the highs as the stock version.

Thanks for the tip on the fuse! I will order some (also for my LP140 mono blocks)