[jpelg]

I've got an ASL MG Head OTL32 coming in the next days, complete with a nice compliment of extra tubes to roll with it. This is my first tube amp.

How exactly do you all assess your tube rolling process? I mean, it's not like you can just switch tubes instantly and do quick comparisons. Tubes get hot. They have to cool down before removing, etc. Hearing memory can be swayed just by the knowledge of equipment changes too.

My general plan is to use the stock tubes that come with the amp to begin with for a few weeks - getting to know how that sounds, on recordings with which I am familiar. This should give me a fairly decent "ear memory". Then when I am feeling ambitious, and have some quality time available, try out the other tubes, with as few variables as possible (no source, or cable changes, etc.).

I imagine that some tube changes will be like night & day, while others may be more subtle. Does this sound like a decent plan? Any recommendations from you experienced valve rollers?

 

[ServinginEcuador]

jpelg,

The best thing to do is sit down with a pen and paper and take notes while you listen. Listen to the same Cd a few times and keep adding to your notes. Write down things like where the notes are coming from; how realistic they sound; any harshness, stringency, ease, etc; how does the bass sound, etc.? Then take a hot pad from the kitchen and use it to pop out the tube you are using, pop in the next tube and immediately fire up the amp again. Now, listen to the sound you just heard with what you are hearing after the tube has had a good 5-10 munites to warm-up. Then, compare the notes from before to what you hear now.

I will also look for a certain characteristic like great highs, lows, wide soundstage, great voccals, etc, in a recording of a track of music. Then I listen to several of these tracks and listen for a while and take notes. I then swap tubes and go at it again and compare what I am hearing to what I just heard and my notes.

 

[Hirsch]

I just listen to music. If I feel something's missing, I try to figure out what it is, and then try another set of tubes. It will take a set of tubes that has been sitting on a shelf for 40 or 50 years at least a day or two to burn-in and reach their sonic potential. There's no way to hurry this process. The 15 minute warm-up won't even give you a clue of what a NOS tube can do.

 

[lan]

I look for differences in frequency response, detail, soundstage, and transients. At first, I choose more obscure pieces that I don't normally listen to which have a lot detail and of course well recorded. Sometimes when the differences are so minimal, I'd go by feeling on the music. After upgrading something like cables (even powercords), I'd listen for the differences again. Somtimes the difference between tubes may not show up as much as something else in the system was holding you back before.

If your tubes are already burned in, you could just warm them up and go at it. If not, I'd burn them in each for a few days each then compare after that.

Have fun!

 

[Dusty Chalk]

Pretty much what Hirsch said. I listen to a set of tubes for weeks at a time. It's quite frustrating, without two sets of the exact same amps, and the ability to make the rest of the system exactly the same.

I'm not a hardcore believer in A/B tests, anyway. I wouldn't be able to tell the difference between CD, HDCD, and upsampling, one right up against the other, but I have been able to tell subconsciously.

 

[carlo]

jpelg,

Congrats on the new amp man. I think your plan is an excellent one. Here are a couple more thoughts to add to the others here:

Since your amp will be breaking in (I do believe in break-in for caps and the like) your stock tubes idea for a while is best, this way no unnecessary wear on other tubes and it removes another variable from the comparison.

When comparing different tubes I don't get too caught up in how they sound, but rather try to pinpoint the character of the amp itself. I find this helps me narrow down the traits I'm looking for, which helps me narrow down the tubes I want to try, and my life is easier. Since you're driving K1000s I think its a good idea to look at the output tubes first, I try to get the dynamics and slam first and then getting the flavor of input tubes is usually more dramatic. I haven't heard the OTL32, suggestion based on my experience based with tube speaker amps (K1000 being more like a speaker than a headphone).

Remember warm-up when comparing, since tubes need to be on for a while to sound their best its impossible to do quick a/b's and actually have an idea of what the system will sound like. I agree with whats been said here about a few days between tube swaps, its the only way thats worked for me.

About dramatic changes: at times it floors me how a tube can change a component. Every now and again I find combinations that give me so much music I don't care about comparisons anymore. Then switching to a mediocre tube is dramatic but not pleasing: my point is there are far more okay tubes than great ones. My advice to those looking to tube roll with one amp is not to have a large collection of various tubes but rather have a stash of the tubes they like. If someone can find one or two that give them the music its better to stockpile them instead of getting a diverse collection. Especially if the tube is no longer in production, it'll only get more expensive.

Hopefully the 12au7 rolling pack andrezjpw was trying to assemble comes to fruition and it makes its way to your place.

hop you post the progress and results of your experiments.

 

[kuma]

Quote:

Originally posted by Hirsch I just listen to music. If I feel something's missing, I try to figure out what it is, and then try another set of tubes.

Amen to that. To learn not to listen to *sound* but to listen to msuic is probably the heardest thing when you evaluate anything.

 

[kuma]

Carlo is right.

Your amp needs some runnin in. Depending on the amps, but typicaly new tubes take few hundred hours to fully break in.

Don't start tube rolling till you get the handle on what the stock tubes sound like.

 

[PinkFloyd]

A valve, like any electronic component, will require an extensive period in the circuit before it performs to its optimum potential.

As a general rule, most equipment requires several hundred hours of playing to fully break-in. There are several factors that determine the extensive length of "break-in", such as charging of capacitors, establishing the electron flow on the PC board, cables, soldering joints, etc. External conditions, such as the power quality and stability of your power in your listening room, the kind of music you are listening to (more or less dynamics), and many more factors will contribute to the break-in process. It is important to note, that the more a given electronic unit has been played, the smaller the audible differences get.

Simply swapping one valve for another and trying to reach a conclusion as to which is best isn't an ideal way to conduct a comparitive test. When I tested the valves for the X-Cans I firstly burn't in each valve for 48 hours with continuous music ... Ideally you would burn in each valve for a few weeks and "then" roll them in to audition them.

I was fortunate in having 2 X-Can V2's when I conducted my valve test and could go from X-Can to X-can in a second and listen to the differences..... even this is not an accurate way of evaluating the sonic differences an individual valve will bring about as no two amps sound the same.

At the end of the day, if it sounds good to you then go with that valve............... you could easily find yourself listening to the components rather than enjoying the music.

Life's too short......... enjoy the music!

Pinkie.

 

[tom hankins]

jpelg: I wouldn't worry about the amp being burned in. The stock tubes are the J&J ECC82 the amp has about 100 hours with these tubes, about 60 hours with the RCA cleartops, and 2-3 hours with the siemens chrome plate's. I have not tried any of the other tubes I sent but they are matched. Have fun!