Questions from a Tube Preamp newbie

@aberyclark

1. I leave my 12AU7 based line stage on 24/7 and the tubes just go on and on.

2. Yes, in my experience. After about a week they are where they will stay.

3. Don’t know as I have never had a tube power amp. With a total of 5 tubes in my system, I have found tube rolling to make a difference in sound quality.

4. Not a fan of JJ tubes in my experience. I use all Gold Lion 12AU7 tubes sourced from Cryoset. The tubes are cryogenically treated and seem, again to last forever. When you are ready to "roll" I would strongly encourage you to contact Ron Sheldon at Cryoset and give the Gold Lions a chance.  You can always talk to Ron and see what tubes his customers have had success with in a Rogue preamp like your's.

When I called Rogue to inquire about tubes for my RP-5 preamp, NOS Mullards were recommended to me.  I purchased a matched set of 5 (1 spare) from Uncle Kevin at Upscale for 60.00 each.  It truly brought the preamp up a few notches and I have used them ever since.

+1 hifiman

I also like the Gold Lion from Cryoset lifespan approximately 5000 hours

@stereo5  Good to hear that the NOS Mullards are working for you.  I sourced NOS Mullards from Upscale several years ago, and they sounded good but they just didn't last very long in my circuit.  No catastrophic  failures, just the tubes got very noisy.

1) Some pre-amps are 'hard on tubes' - usually the manufacturers will acknowledge this and will recommend using only very rugged tubes (Audible Illusions and Audio Research come to mind. ) Under normal conditions with most tubed pre-amps you should be able to get at least 3000 hours. (You can do a search on line to find out Rogue's reputation on this unit, or call Rogue for the real skinny.) Some a lot more! 10,000 hours is not unheard of.

2) For small tubes 24 hours will reveal their sonic signature. Change thereafter will be nominal until old age sets in.

3) Small tubes in both pre-amps and power amps are influential on the output, the pre-amp perhaps more so because it output is dependent on one tube type, but with a power amp its sound is based on a matching between the power tubes and the small tubes which gives a lot more flexibility in the sound of its output, i.e. you can fine tune it more easily. 

4) JJ tubes can be fine if you like their sound and they are low noise. I have used them often without problems. I usually change them out only to change tone. Good life expectancy and they are cheap(!) so you can have a few spares around should you need them. Since you already have them just enjoy and wait for the time you want to explore sound changes using different tubes.

JJ tubes are a fine budget tube (~$15/tube).

I once had a preamp that used 12AU7 tubes that came with JJ’s. I found the sound to be pretty uninspiring so I changed them to Psvane 12AU7-TII.

At US$50 each, they were a significant step up sonically from the JJ’s.

Here's a review of them on AudioAsylum.

What are the sound signatures of the Gold Lions vs the stock JJ's? The NOS Mullards are pricey plus, I hear they do not last as long

1. Most preamp tubes will last 3000-5000 hours. Some are speced out to 10,000 hours, so there are exceptions.

2. 40-50 hours, there are exceptions.

3. Depends on how the circuit is designed and how the tube(s) are implemented within that circuit. Tube rolling can make a huge difference or none at all.

4. Never been a fan of the JJ tubes.

I have quite a few of the Mullards and have never experienced a premature failure or an increase in noise?  Excellent tube.  The Pvsane tubes are also very, very good.

@stereo5   My previous post should have been stated more accurately.  The NOS Mullards I used were 4003s not 12AU7.  They were recommended by Upscale for my line stage.  Glad to hear you're having good luck with your NOS Mullards.  The 4003s I used yielded an amazingly smooth texture to the music.

@aberyclark   I only used one pair of JJs.  I abandoned them because of what I perceived to be a "hardness" to the sound.  The new production Gold Lions in my circuit yield an expansive soundscape, smooth textures and great dynamic swing.  This is referring to the Cryoset Gold Lions which are cryogenically treated.  I have no idea what the GL sound like without that treatment.  The JJs are inexpensive but when you have five figures in your system it seems foolhardy to cheap out on the tubes whose influence will be heard at all times.

@stereo5   Wow.  I'd have to check receipts but when I bought the CV 4003 about 15 or so years ago they were about $100.00 for a matched pair.  That was back in my early days with my tube line stage and just went with the advice I was given.  Perhaps I might have obtained better results with the Mullard 12AU7.

I never leave tube amps on when I'm not around as I've had small signal (preamp) tube commit "tubicide"…once in a guitar amp I left on after a rehearsal (for a week) and that amp never really recovered (sad), and another time a well regarded new-ish NOS Phillips AT7 killed itself right on front of me during a listening session…jumped up and shut down the amp before any damage happened. If tubes have a break-in period I'm not aware of that as they seem to display whatever their tonal characteristics are pretty much right off the bat, although the rest of the amp might need warm up. I noticed this when swapping out tubes having just shut an amp down to let it cool a bit…many many hours can be gleaned from a hard driven signal tube, proven by guitar players everywhere when you'd just forget about 'em until the amp starts to get weird…years...

I have a lot of the CV4003s from Upscale.  They used to be $35 each for the Platinum Grade.  These are the ones that I've had no problems with.  I've used them in DACs, preamps, phono stages, all over.

I also have several other types of Mullard 12AU7/equiv.

I'm a tube newbie like you and it looks like you're getting great recommendations specific to your preamp. When I got the tube rolling itch, I contacted Aric at Aric Audio directly and he recommended a specific set of tube brands and models; rectifier, voltage regulators, and 12ax7 signals, and I swapped them one at a time over a month period just to gauge the improvement. Collectively, they took the preamp to an entirely new/better level. His recommendation was based on his own personal experience rolling many different brands/models in the same unit he uses regularly in his own system. So sometimes asking the designer may be a good approach. Mine came with JJ 12ax7 signal tubes and apparently the Electro Harmonix Gold pins work best in this particular model. Total cost was $85 for 5 tubes. By the way, in my case, the overall difference after the swap was not subtle or just a matter of taste, etc. It just made the music sound better. I asked him why doesn't he sell them with these tubes and his response was I was the first person who contacted him for tube suggestions and secondly most people have a favorite brand/model in mind and just go ahead and roll tubes regardless of what comes with the unit so why put more expensive tubes in. By the way, he also gave me some recommendations for upgrading a small number of the capacitors to Audyn Copper to make it sound "crazy" good. That's my next plan.
Good luck and enjoy the music.

What was the problem with your Rogue preamp? If I remember correctly there was a lot of hiss, etc. What did Rogue do to it besides change tubes?

They told me that they repalced some Op-amps and added some grounding to the LED display

@aberyclark , there's no rule that says that all four tubes need to be the same type. When I owned a Perseus Magnum, I had 2 RCA Blackplates in the front Gain position, and Mullards as Cathode Followers. The RCA's provided open, dynamic sonics, while the Mullards provided warmth and classic tube bloom.

The best deal that I've come across is the Brimar CV4003 at Upscale. These are British tubes with warmth, but have more extension than Mullard at the top and low-end.

Picked up a pair of Telefunken 12au7's and a single 12ax7 from Andy Bouwman at Vintage Tube Services this past summer for my integrated amp. (not a Rouge)  Andy is extremely knowledgeable and fair in his pricing. He is a straight shooter and won't just sell you something for the sake of it. All of his tubes are tested before shipping and have a return policy.
Check him out at:http://vintagetubeservices.com/

I think the Brimars are Kevins favorite. The smooth mids of mullard without high end roll off. Plus, cheaper than mullards

I wonder if the Brimars add more sparkle on the top end vs the JJ's. I hope not. I think the JJ's top end (and low end) is perfect. Just a little more silk on the mids would be nice.

I wouldn't use the term sparkle to describe the Brimars, I would say they have a nice amount of "air" in the highs, a very realistic sound. 
RCA Cleartops and Amperex have sparkle, meaning extended highs. Never tried JJs.

I used to be a "solid state bigot" but about a year ago replaced my solid state preamp with a tube model.
1.  How long do they last?  I suspect it depends on how much current is running thru them.  In my experience, tubes seem to start to sound "dull" in power amps after a year or so, but in preamps, last much longer, being that they don't flow so much current.  I have a friend whose preamp tubes are 8 or 9 years old.
2.  When I got my new tube preamp it seemed that the tubes seemed to "settle in" in about 100 hours of playing time.
3.  I replaced the stock tubes with Gold Lions, and I found the sound improved immediately, especially female vocals, acoustic piano and violin.  After the Gold Lions broke in, they sounded even better than the stock tubes.
4.  For the preamp I own, most people seem to enjoy the Gold Lions.  My preamp came new with JJ tubes and they were OK, but not as "musical" as the Gold Lions.

@ejr1953   Did you get your Gold Lions from Cryoset?

I wouldn't use the term sparkle to describe the Brimars, I would say they have a nice amount of "air" in the highs, a very realistic sound.
RCA Cleartops and Amperex have sparkle, meaning extended highs. Never tried JJs.

My zus have the super tweeters and I do not want to add more sparkle. Now “air” should be fine. I may try a set. I guess if i thought they were a smidge too bright, i could always just use two and use two jjs

Yes, using a different tube type as cathode follower gives you an almost endless variation of sonics. Rogue responds very well to tube rolling and  there are many different 12AU7's.

Hi , I have a Rogue RP-1, not as nice  , but some similarities. I replaced the JJ’s after about 10 hours . I use medical grade NOS Telefunkens . I have 3 sets. I started with NOS RCA 12AU7WA tripple mica’s. Nice sound . I have NOS Mullards ECC 82’s , sounds like somebody threw a blanket over my system . Kinda like pushing the Dolby button on a cassette player . I also have 2 pairs of Seimens nickel plates and Amperex Holland . For my taste and in my system the Telefunkens are hands down my favorites . The Seimens are second , very linear and defined , but a little bright on the top . The Amperex are even brighter . Unless I change speakers , I’ll stay with the Telefunkens . I just took a pair out with about 5000 hrs . The Tectronix labels had changed color from the heat . Popped in a new pair and could tell a difference . I feel about 100 hours on the tubes have them settled in . Also I like NOS Tungsram and the E I crossed swords too . So for me , I spend on good NOS Telefunkens and for budget Tungsram . Although the Seimens are pretty sweet . I assume you have a quality power cord ? I also have had good results with Morrow MA5 interconnects, after 600 hrs . As far as Rogue, they tell most people to run Mullards . They even suggested them to my buddy for his 180 mono blocs . I’ve had Hiss Problems too . I just had hiss on one side , so I changed Tubes . I didn’t bother to see if just needed reseating, I just replaced them . Also with four Tubes , if one is gain and one is phase ( ask them ) changing just one tube per side will have a big influence . The JJ’s are cheap and reliable , perfect for mass sales . So happy listening and I’ve babbled enough . Regards , Mike. 

Hi Abery,

1. It really depends upon the preamp and the quality of the tubes.

2. NOT that I have noted, but I am no expert.

3. A tremendous difference. I'd seriously look for some Telefunkens. I can't be sure about the 12AU7's, but I think Telefunken's pretty much own the 12A-whatever family. 6DG8's I tend to prefer Bugle Boys for warmth and Siemens for detail, YMMV.

4. JJ's are likely pretty good for the mostly crappy tubes made today. While most things, like cars, televisions, etc. have improved, I suppose due to low demand tubes have gotten worse, much worse in some cases than the really good older tubes. Mind you, I said really good older tubes, many brands were no better than what you can buy new today.

Hope this helps.

@lous One current tube brand you may want to consider are Genalex Gold Lions sourced from Cryoset. I have yet to find any 12AU7s that work as well in my line stage as the GL’s. besides the fact that they have a neutral, dynamic, open sound, they last a l o n g time!

I've heard good things about the gold lions

Unless someone owns the same preamp, recommendations may help, but a different circuit will result in different sound.
I had a preamp that used 12au7 that was meant to stay on 24/7, it has been so long, I can't remember what I was running. But those tubes, in that circuit lasted for years.
I mostly wanted to comment on CJ, the preamps that run 6H30s, I have one a CT5, are easy on these tubes, I just replaced the tubes for the second time, after +7000 hours, and if they had deteriorated, it was so slight as I could not swear to it. The 6H30 is one of those tubes that there are only 3 options. NOS, hard to find, and if you do, a minimum of $250 for a pair, if lucky. The EH gold pins from Cyroset run me about $90, shipping included. I found about 75 hours to settle in. They get a little bright around 50hrs, then by about 75 hrs, they are done.
I used to have a preamp, that used 6CG7/6FQ7, that I rolled at least 10 different tubes through. At that time, almost everyone recommended RCA Cleartops, I found the RCA Blackplates, Toshibas, and the winner to be Mazda. If you can find someone with the same preamp, their advice will be most helpful.
Maybe I am a minority, but after a lot of rolling in two different preamps, I got tired of it. I prefer to listen to music, not tubes. My CT5 makes that easy. No fretting over is there a better choice.

I have NOS Mullards ECC 82’s , sounds like somebody threw a blanket over my system . Kinda like pushing the Dolby button on a cassette player .

As always, YMMV.
Regarding Mullard and other NOS brands, if they are noise-tested they should sound good for many hours. There are several types of Mullards; longplates, shortplates, ladder plates, with square getter or with halo getter. ECC82 labelled "Made in Great Britain" are of the highest build-quality.

There is a "house sound" to these tubes, warmth with a relaxed top-end (since they are British they should be called valves).
1950’s ECC82 longplate square getters present open and warm sonics with rich textures; I own several pairs. The CV4003 is a military-spec boxplate with a wide soundstage, and to my ears, sound more "lively," whereas the short plate sounds more "closed-in."

Philips tubes made in the UK factory will have the same sonic signature as Mullard. Phillips Holland was the parent company of Mullard and Amperex.

Regarding #4, JJ tubes do not have a good reputation among audio tube people.  However, Rogue may have built their preamp to sound good with them and if it is hard on tubes, JJs may be stout enough to handle the punishment, while other tubes may not.  Best bet is to talk to Rogue about it.   See if they recommend any other tubes. 

rodge827 ++++++++++
Andy has the best tube test equipment on the planet

OP get started with this, no need to wait till your JJ need replaced
you will find it adds an interesting aspect to learning to listen for small differences and sometimes massive change

all for relatively small $ and have others have said get you some spares in the process

NOS Tubes - Go to Brent Jessee! http://www.audiotubes.com

However, I have been amazed with Gold Lion signal tubes, I have no reason to go back to NOS.

Thumbs up to both Brent Jesse and Andy at Vintage Tubes . These places have quality product and a wealth of knowledge . Also of interest is Brent Jesse’s site that explains the sounds of various NOS Tubes . I find the descriptions to be spot on . Also sorry if I ruffled any feathers on my Mullard description . I also appreciate the number of knowledgeable Goners that have chimed in on the New Production Gold Lion Signal Tubes . I have their KT-77’s and KT-88’s and found them to be excellent. Somebody mentioned Cryo ? Was the change noticeable? I also appreciate Wolf and Lowrider . Good info guys , thanks .

@buellrider97  I mentioned using Cryo'd Gold Lion 12AU7s from Cryoset.  I don't know if the cryogenic treatment has improved the sound of the stock tubes but I can attest to how long they remain quiet in circuit.  Ron Sheldon at Cryoset also tests the tubes carefully to supply you with matched pairs if needed.  

The JJ's are still running strong after over a year of everyday listening. After new years I think I will try Gold Lions from Cryost or from Upscale Audio with their CJ/Rogue match option.

As an aside, I like all the JJs I’ve had (all preamp or driver small tubes) except the KT77s, as they lasted about one day in my Dennis Had se amp before I rejected them. They are cheap however...after I recovered from that experience with 77s I eventually bought a pair of the Gold Lions and they’re the best of any type (88s, 120s, 150s, etc.) of anything I’ve tried in that amp...a very nice tube indeed.

JUST A NOTE ABOUT CRYOSET...Ron Sheldon is very ill and has sold off his tubes and other gear.  A terrible shame.  I have had great performance from his cryo'd tubes.  Unfortunately bad things do happen to good people.😔

I left my VAC Standard on 24/7/365 for three years and the (2) 12AX7 and (2) 12AU7 were fine, Plus the case was sealed. (and still only became a little warm._ so if a tube exploded. it would be kept in the case. All otehr preamps I own have open slots or grillwork, or a plexiglass cage (CJ.)                     
I played music every day all day.                
For the (3) 6DJ8 in my ARC SP-15 I leave it off since I do not use it a lot. I want them to last a long time.                      
For the Conrad Johnson ACT2 which is a oven when on, I turn it off due to the heat.                        
The Audible Illusions Modulus 3A I turn off to save the tubes also.    
                       

So sorry to hear about Ron Sheldon. I hope he improves

would agree with hifiman, the 12au7 series of tubes should last a very long time; not like power tubes where you'll get a few years out of them and they need to be  replaced.

would also suggest not to rule out the industrial grade tubes such as the 6189, and 5814. The GE triple mica 5814 black plate is a fine sounding tube. Many of these carried the 5 star rating, for broadcast use. similar to RCA's Command line of tubes.