Tube rolling How to

[joessportster]

I have read countless threads on tube rolling where people spew countless attributes of this or that tube, Some will tell of the differences between several tubes and so I have a ???

 

It has been my (recent) experience that tubes definitely have a BURN IN period (I am not talking about the warm up phase of all tube amps) I am talking about after hours of use the tube comes into its sweet spot , of course after more hours the tube will start to decline  

 

My question is then this:  If you are rolling tubes how can one render a decision as to what this or that tube does ? or is this decision made off initial warm up and BURN IN is a non issue ??

 

I ask because after maybe 200 hours I heard a definite difference in SQ with my Kenzie and swapping the tubes has taken the amp backwards a tad.......................Is the answer to burn in several tubes and then roll ??

 

Just curious how some here approach this

[tube fanatic]

Joe, you realize that you're opening up a discussion that's likely to get very passionate quite quickly!  Most sonic differences in tubes of the same type are attributable to differences in interelectrode capacitance (often due to significant variation in electrode spacing, particularly in some beam power types), and cathode emission (which affects current draw and can vary enough to affect biasing, depending on the circuit).  This is usually noticeable from the outset.  Some claim that the type of heat dissipation coating on the plate affects the sound (i.e. black vs. gray plate), and that freezing the tube for some arbitrary length of time affects the sound as well.  Tubes do not have a burn-in period.  What can change over a 200 hour use span is the emission of the cathode which can affect the operating parameters (bias, plate/screen voltage) which in turn can affect the distortion produced since it results in a change in the operating point of the tube.  Keep in mind though that in a new, robust, tube which has a potential life span of, say, 10,000 hours, 200 hours is quite insignificant.  Also, after listening to an amp for 200 hours, you tend to get used to the sound, and often find it more pleasing as a result.  Lastly, unless you are doing the comparison between tubes with careful listening level matching, it's impossible to render a decision.  I've always advised that if a piece of equipment sounds wonderful as it is, leave it alone and save the money of buying countless other tubes in an effort to chase that always elusive "sonic nirvana."  So, that's just my take on the situation.  Looking forward to the other opinions!

Maynard

[joessportster]

Hey Maynard, I am aware that some folks are passionate about this stuff, Me I am just curious  , I have rolled tubes in the past and frankly only rarely heard a difference

 

"Tubes do not have a burn-in period.  What can change over a 200 hour use span is the emission of the cathode which can affect the operating parameters"

 

My way of looking at this would be your above statement = Burn in, I am sure this does not fit the typical definition of BURN IN, I would say that the changes in the tube that occur due to use regardless how it ends up affecting the sound could be construed as Burn In......................In fact that is exactly what I wanted to convey though I did not say it as well as you  

 

I agree 100% if it sounds good leave it, (I just have never been physically able to do that, its like an illness  ) 

 

I think headphones have allowed me to hear  more into the music, and that has peaked my interest in tube rolling, I mainly buy tubes to have as a backup, especially with the Kenzie as it is my only headphone amp and frankly with my experience in this hobby I am convinced any further amp swapping would at best be give and take, I plan to live with the Kenzie a long time, I also have it in the back of my mind that once we get settled I want to set up a bi-amp speaker using a kenzie for the mids and highs..........the tubes for the Kenzie are currently on the cheap side and when I can afford a pair I want to stock up as once tubes become more popular and less avail the price skyrockets

 

Thanks for your thoughts

[jimjimbo]

Joe, what tubes are in your Kenzie?

[joessportster]

Joe, what tubes are in your Kenzie?

I have what Justin sent with it

 

1626=national Union

12sl7gt=RCA

 

The spares I Have are, 

 

1626=RCA, KenRad, TungSol

12sl7= TungSol, RCA and a Raytheon 2c52

 

The raytheon is an alternate that some folks use in the darling circuit and swear by, I have collected the tubes over the past year of owning the amp and frankly am done unless something really interesting pops up real cheap

 

I am currently using a pair of the TungSol 1626 and the Raytheon 2c52, detail seems finer however sibilance also seems more pronounced

 

Talking with Justin about this he feels the 1626 are a null point and only difference in sound is realized with the 12sl7, I can say the biggest difference I have heard is with the 2c52 which of course affirms exactly what Maynard said

 

Justin mentioned that he finds alot of microphonics in the various 12sl7, I have not experienced that issue to date

 

Mark nice to hear from you, have not seen you posting much lately Hope all is well

 

Jim do you have a kenzie ??

Edited December 21, 2014 by joessportster

[jimjimbo]

Joe, no, don't have a Kenzie.   I have Justin's original Stereo 15 Special Edition, but was just wondering what other tubes you were rolling with....

[joessportster]

Really just playing around 

[Taz]

Really just playing around 

 

Don't let the wife catch you!  You gotta sleep sometime...

[Audible Nectar]

As one who is sensitive to tube rolling (as well as capacitors in the audio path) I'll throw in my two dollars' worth.

 

First, I want to be educated about the gear itself - to learn about what tubes serve what purpose in the circuit, what the potential risk to the gear is if a tube fails (always a risk when rolling), and read up on what others have used in the same gear to get educated impressions as to what specific tubes impart good sonic results in that piece of gear.

 

If it is a unit lots of people have - like Mac MC30s or VRDs (common around here) it's easy to get impressions on what people like and why. I did lots of reading before doing any trials.

 

What I like to focus on is what slots make the most sonic difference. In an amp like MC30s, all of the small signal tubes (there are four) affect the sonic signature, as all of them are in the audio path. The power/outputs matter too. Rectifiers, not so much, assuming that I stay within 5U4GB tube types. Needless to say I read 'til I was blue to try to get a handle on THAT many variables.

 

VRDs were an easier study, two smalls and power tubes being the primary rolling concerns, and lots of users here to get opinions from.

 

A JM peach is even easier - one linestage tube being the primary variable. Picky circuit for a 6dj8, though - had to have a QUIET one. But again, easy to get opinions.

 

Then it's a matter of procuring thoroughly tested tubes to use in trials. Fortunately I am lucky to have a local tube pro with an array of top flight testing gear to weed out the "questionables." He has screened 90% of my tube collection and only once did I find a tube that didn't work that was supposed to. I kept the best and returned or threw out the rest. I kept nothing that didn't test like NOS - in fact most IS NOS, but I do have some stock that would be considered "light use".

 

So now I have an idea as to what tubes might be of interest, those tubes in hand, and the gear to be rolled.

 

I make sure the tube pins have been cleaned - I use DeOxit to clean off any deposits, then allow to dry thoroughly.

 

I roll ONE position at a time. If you are a tech or in the presence of one, you can take more "liberties" - but I always roll in one position at a time to make sure that if there is a "fault" I know which "roll" did it. Once I get the combo I want to try and the unit is running stable, I listen for an extended period - several weeks, several sessions, lots of different listening material and sources.

 

Your first impression might not be what you think it is. Give it time - the subtle nuances of these changes will not become totally evident until you spend time listening. Be patient. Unless it's a total sonic failure (which indicates something else might be amiss) I let 'em run for several sessions.

 

Tubes tend to reach "optimum" in my experience in an hour or two. There's a reason you don't bias a set of VRDs, for example, until the amp has been on a while, the circuit and tubes up to temperature and stable. You will get 95% of it in 10 minutes - the rest within 2 hours. Before I listen, I'll often let my gears warm up for an hour or so with no music whatsoever, just to have them in top sonic form when I begin. It is also an opportunity to assure operating stability, especially if rolls have been done recently or service performed.

 

On the subject of "break-in". This can occur, especially on truly unused tubes. Not so much if they have been used. I have found that many of the Shuguang and Russian tubes (especially the 6L6GC "winged C") need some time in circuit to show you what they really are sonically. I don't notice it as much on the NOS varieties from the peak of tube manufacture.

 

So why roll anyway?

 

There is a lot to be said for the idea that Maynard states - that if a piece of gear sounds great as it is why worry? But that is EXACTLY the kind of gear I want to "tweak". The KEEPERS. If it sounds just "OK" - tube rolling probably isn't going to help enough to make it a keeper. When I was sold on VRDs, it was with the stock tubes. So I'm thinking - if I am going to own a pair, I want to take 'em all the way, make them the best they can be, as I'm going to live with them for a long time. So they get the best caps and tubes I can afford.

 

Same with the Peach. Sounds very good with that EI furnished 6dj8 - sounds even better with that NOS Philips Holland 6922.

 

The MC30s were a different story - I went through a loooooong road of rebuilds, cap evaluations and tube rolling to get the absolute best out of them. It was like having kids. Finally got them to fully mature status and ready to unleash on the world Doubt that I would go through all of that again - although I did definitely enjoy the journey, and much appreciated the help I got on that project. And to this day they are a prized part of my audio stable.

 

All of which is to say, tube rolling is about the finishing details - that "something extra" that I would only go through for the true "keepers" - the gear I want to keep for a long time.

[The Dude]

Joe you just remove the tubes from the amp and.

https://vimeo.com/115137971

[tube fanatic]

Duder, I love your video clip!!!  I think you should contact Music Direct and develop a special tube rolling mat ("specially treated to isolate the tube from the effects of the Earth's magnetic field, and cause the electrons to travel from the cathode at faster than the speed of light resulting in the best possible sound available from your system.  Only $5000 which includes a set of magic cable trestles and electromagnetic stabilizer stones!").  

Maynard

[Marvel]

A JM peach is even easier - one linestage tube being the primary variable. Picky circuit for a 6dj8, though - had to have a QUIET one.

True statement. I think my JM Merlin is one of the best preamps out there, regardless of price, but a quiet tube can be hard to find.

 

Bruce