New TM36 user here... Should i swap tubes right away?

Hi all and thank you for the great discussions on this forum.

I have a TM 36 on order from Thomann - which should be delivered tomorrow, along with the matching 1x12 HK cab. Can't wait to light it up! lol.

However, i'm new to tube amps and i'm reading a lot on the matter these days... getting acquainted with technical aspects like changing tubes and tone issues.

Now i'm wondering whether i should swap tubes right away on my expected TM36?

I read so many comments about this or that amp that got much 'better' after retubing, TM36 included.

I also read part of the "tube swapping thread" somewhere on this forum and got lost in all the subtleties of what various tube brands or models achieve in this or that position (V1, V2, V3) so i'm definitely not going to try this kind of voodoo right away. The most 'obvious' and simple swap i'm considering would be a set of JJs 12AX7/EL84 to start with.

What do you think?

Thanks for reading.

Some unpacking and setup picts:





Along a PRS CE24:


...and the classic lighted front panel pict:

Hi Pat, welcome to the world of H&K!  Here is my £400 worth.  

JJ full set - Yes.
Do you need them - No!
Will there be much change if you do get them - Not a lot!

There you have it.  The idea that different valves makes give a very different tonal balance is tosh!  The idea that you 'get a new amp' is BS!  Look at the Tube Swapping Thread again and go to page 5 and read from post #122 by VoodooJeff looking specifically at his comments.  I would have a look at the Wathen Valves' site too to see how much they currently cost!!!  Jeff is a pro guitarist and very feet on the ground guy who is straight talking in everything.  When he says "subtle at best" he means it.  It is a true depiction of the difference between a standard JJ 12AX7 and one costing 10x as much or more.  Remember, some people actually prefer the sound of the Chinese originals.  They have told me so in the past in PMs as they don't want to get involved in the fiery discussions this topic always starts.

At last someone has tried to prove the case that valves all sound different with very well specd equipment and highly accurate measurements.  Here is the result:  Valve Make Comparison.  Don't look at the pretty Red/Grey/Yellow bar graphs, they are set up to make it look like there are differences.  Go down to the bottom of the page and look at the "Frequency Sweep of Several 12AX7 Samples in the Same Preamp Circuit".  Click on it to get the enlarged version.  What you are seeing is undeniably the same basic curve repeated with absolute minimal differences in shape except for a flat level shift of less than 3dB, that's less than 0.7x which is nothing in electronics circuit variation terms.  The flat <3dB level shift to the curves means a hardly perceptible shift in volume and no shift in tonal character at all.

And remember, this guy was trying to show there ARE differences so there is no fear of someone frigging the results in a way that makes them just look the same.  He wanted to emphasise any differences he could.  In order to do that he invented a meaningless cheating method of displaying those results to try to make it show that there are differences.  That is what the pretty individual bargraphs are for.  They take the maximum minute difference and stretch all of those inside that limit to make them look much larger than they really are.  The maximum difference between any pair of graphs if they are slid over each other is actually a minute fraction of a dB.  That means no tonal difference whatsoever.

Suppose I have a difference between 3 valves of 0%, 0.1% and 0.2%.  That's hard to see and impossible to hear.  So I put the maximum difference of 0%-0.2% on a longish line.  That looks impressive.  And the 0.1% now fits exactly in the middle and looks so different to the values at the end of the line.  It's ridiculous and meaningless!

Swapping out your valves will mean the subtlest of changes and you may well like that.  When I first changes from Chinese stock to JJs I sensed a slight smoothing out of the top end.  I didn't get a new amp!  When I changed to different speakers I got a very different setup. So make sure you don't start going overboard with enthusiasm and feed fuel to the fire for others.  Honesty and a sense of balance are a valuable asset in our field.  Keep a sense of perspective and don't expect all you are fed by the "golden bat eared gurus" amongst us.

Hi bordonbert and thanks for the detailed answer. I kept reading the tube swapping thread and came to the same understanding... although some users feedback do pick my curiosity.

I also read the speaker setup does make a much more notable difference... as does the guitar and it's pickups - which does make sense.

One 'theme' that keep coming back about H&K amps is their perceived harshness or fizziness (does that word exist?) at high gain which may bother me at some point as i'm more of a classic 70s rock guy rather then the more modern metal styles.

Bottom line is i've just scratched the surface and have yet to get used to this amp and setup. I'll see how it goes and deal with it when i'm a bit more mature on the matter.

Thanks again.

You're right about the 'fizziness' of the top end Pat.  I think everyone knows what you mean when you say that, it's a good description of the effect.  I found that it can be helped very slightly by valve swaps but it is also not helped by too much twisting of the Gain control and sometimes the guitar volume control.  You may have seen one of the posts I have made about how the solid state input stage of the amps works and how you can overuse it by hitting it too hard at the same time as using too much Gain from the valve stages which follow it.  Here is a link to one version just in case you haven't caught up with that aspect yet:  Look at Post No #2.

Thanks again. Good read about the solid state input stage indeed. I don't really mind having some transistors in there as far as it stays analog. How did you get this level of understanding?

Somehow the TM36 looks like it contains three different kinds of tube amps with the clean channel being the most classic 'all tube' version, with it's tone and limitations. Crunch and lead emulating more modern designs?

In the end it's all gear talk... I think i read somewhere Keith Richards said something like "Give me any amp and i'll make it sound right". I never checked that quote and don't really mind whether it's true or not. But i like the meaning. Whatever the equipment, you can make it rock if you have the guts and spirit.