No Differences When Changing Tubes?

Just wanted to drop in and say thank you to Cliff for the new 6CA7 and to the people on this thread for the discussion. I put the 6CA7 in my go-to Plexi and I liked it in some ways, but it wasn't quite right in others. After reading some stuff on here, I adjusted the Transformer Match and that gave me what I was looking for. I did it by ear and now one of my main tones is better than ever!
 
Just wanted to drop in and say thank you to Cliff for the new 6CA7 and to the people on this thread for the discussion. I put the 6CA7 in my go-to Plexi and I liked it in some ways, but it wasn't quite right in others. After reading some stuff on here, I adjusted the Transformer Match and that gave me what I was looking for. I did it by ear and now one of my main tones is better than ever!
Are you saying you noticed a difference in sound with a change in the power tube type parameter only (prior to changing Transformer Match only)? If yes, what differences did you hear?
 
Why is there a change tubes feature if it does not make any difference to the sound (preferably to match what would actually happen in a real world amp situation)? Not sure why anyone asking this question is being whiny and entitled either.
 
Just tried Transformer Match and Speaker Imp and, as Cliff stated, I heared some real differences.

Can't hear any differences with the Tubes Types, but I understand Cliff explanation...but would like to hear some differences... :D
 
Why is there a change tubes feature if it does not make any difference to the sound (preferably to match what would actually happen in a real world amp situation)? Not sure why anyone asking this question is being whiny and entitled either.
This long conversation about tube changes has already established that just changing the tube type parameter does not make a difference that most people can hear (It's so subtle you have to be trained to hear it), and, changing tube type alone does not result in the tonal changes one would expect in comparison to real world tube swaps. To make a significant audible difference (and one that reflects a real world tube swap) other parameters need to change along with the tube type parameter - the discussion moved on to: is there a way for users to know/learn how to make all the "tube change" related parameter tweaks to reflect a given real world tube swap (or, should there be some sort of new feature that makes all the related adjustments automatically when the tube type parameter is changed). I asked the question above because if someone can hear significant differences in sound based on just a change in tube parameter (other than to/from 300B) then I (and others) have missunderstood something somewhere along the line.

"whiney and entitled"?? Why? For trying to establish how the mechanism is working and/or to understand the process to correctly use it?
 
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It might also have something to do with cheaper modelers when you change tube types you hear a difference. Whether they are probably just applying an eq curve or not is debatable, but none the less you hear it.
 
It might also have something to do with cheaper modelers when you change tube types you hear a difference. Whether they are probably just applying an eq curve or not is debatable, but none the less you hear it.
ya - they are probably not realistically modelling such changes where as Axefx does with accuracy I suspect - but one needs to know how to make the changes (or maybe it's more accurate to say: one needs to know how to set up the resulting mismatches / incompatibilities that create a sonic difference once a tube is swapped). Anyway - this might be another dead horse that I should leave to rest in peace :p
 
Why is there a change tubes feature if it does not make any difference to the sound (preferably to match what would actually happen in a real world amp situation)? Not sure why anyone asking this question is being whiny and entitled either.

If transformer match is the only thing that is changing anything*, then why bother changing tube type at all? Just change the transformer match to whatever sound you’re after.

*i realize that’s not what you’re saying here.
 
Are you saying you noticed a difference in sound with a change in the power tube type parameter only (prior to changing Transformer Match only)? If yes, what differences did you hear?

Yes. I hear differences with basically all of them and, equally importantly, the feel is different. It varies, but there are differences in frequency response, the character and amount of power amp distortion, depth of the sound, how tight, loose, hard, soft, punchy, or spongey the notes are, etc.

In the grand scheme of the universe, it is subtle compared to changing amps or cabs, but it is definitely less subtle than some other advanced parameters.

A lot of the advanced parameters make a difference in the feel as much or more than the sound. I define "feel" as the difference between what you do with your hands and what you hear with your ears. For example, if you dig in and play hard with some amps, the volume actually goes down when you hit the initial transient that should be the loudest and the volume drifts up as the note sustains. People call that "sag" and that is a pronounced example "feel," especially if you compare that to an amp that is more faithful to the dynamics that your guitar is actually producing acoustically. Feel could be broken down into many, many different characteristics, but it ends up being hard to describe because the human brain is more capable of detecting these subtle differences than describing them in words.

When evaluating advanced parameters, I play a variety of things to gauge the feel. I play things hard and soft, full chords, partial chords, single notes, palm mutes, bends, high notes, low notes. You can't tell all the things changing in the feel if you stick to playing one thing when auditioning. You also can't tell the difference in feel by re-amping since you lose the interaction of playing and hearing at the same time.

I have a good pair of Sennheiser headphones I normally play through at home. What you listen through definitely affects what you hear and how much nuance/detail comes through.

My takeaway from this thread is: if I change the power amp tubes, my next step is to adjust the transformer match to taste.

If people can't tell the difference with the tubes or dial in the transformer response by ear currently, a different approach to the modeling might not help as much as some are thinking it will. If that's you, don't worry about it. A normal person can't wrap their head around 50 tone parameters and that is perfectly OK. Stick with default parameters, adjust the things you do hear a difference with, and make some good music. There are also people out there who spend inordinate amounts of time tweaking all the parameters and making those settings available for others to enjoy without going through the hassle.
 
Yes. I hear differences with basically all of them and, equally importantly, the feel is different. It varies, but there are differences in frequency response, the character and amount of power amp distortion, depth of the sound, how tight, loose, hard, soft, punchy, or spongey the notes are, etc.
Thanks for responding and the insight - if you are experiencing all those nuances with just a tube type parameter change then I am flabbergasted at my own complete inability to hear / feel anything at all given a similar change (other than with tube type 300B - and I can detect nuances in other advanced parameters and use them often with my descent quality rigs - it's not a complexity issue for me - it's simply that I hear/feel no difference when changing just tube type on it's own (absolutely 0). I won't belabour this further with more posts on my part as it's come full circle for me

Thanks Again!
 
Thanks for responding and the insight - if you are experiencing all those nuances with just a tube type parameter change then I am flabbergasted at my own complete inability to hear / feel anything at all given a similar change (other than with tube type 300B - and I can detect nuances in other advanced parameters and use them often with my descent quality rigs - it's not a complexity issue for me - it's simply that I hear/feel no difference when changing just tube type on it's own (absolutely 0). I won't belabour this further with more posts on my part as it's come full circle for me

Thanks Again!
K - now you're starting to sound whiney - shut up and play your guitar
 
At my band practice last night I swapped through a couple different power tube types on the FAS Brootalz through the PA at full jam volume. Some were boomier, some were tighter, the differences weren't huge but they were there.

For the people not hearing anything maybe they're subtleties your ear isn't attuned to yet (which sounds like a BS answer, but you definitely get better at critically listening to sounds as you train at it), or maybe it's just the environment you're testing them in. Are you at bedroom levels where the acoustic sound of your instrument is at an audible level to the Axe FX output, where the literal sound of your instrument can be masking some of your tone? Are you up at full gig volume? Are you using a speaker setup that does produce the full depth of lows to hear the difference?

Are you using a clean tone where it might be a much more subtle thing? are you using a crunch or gain tone that's fairly mid heavy which might be obscuring changes in the outer frequencies? Are you using the master volume high where power amp overdrive might be masking some of the tonal shifts, or low where the tubes might be working linearly and not having much discernible affect? I think my master was around 3-4, enough that it's mostly working as a clean amplifier but that might might be coloring the sound with some power tube OD.
 
I’m not saying I hear zero difference, but I don’t hear nearly as much as in the real world.

Plenty of others were though.

And that's kind of the crux of this thread:

In the real world, it's very hard to just change the tubes, because changing tubes and bias also affects the relationship with the transformer (which is simplified to transformer match in the Axe).

On the Axe you can change both these (tubes and transformer match) independently. Just the tubes or just the transformer match, or both.

And many people are wishing that the could be linked to automatically calculate, but we actually have more flexibility. Maybe you didn't actually like EL34s in your amp, you just liked the transformer mismatch more than you disliked the el34's tone. Maybe you want more or less mismatch than you really get in the real world.
 
In the real world, it's very hard to just change the tubes, because changing tubes and bias also affects the relationship with the transformer (which is simplified to transformer match in the Axe).

Believe me, I’ve built quite a few amps and I know that. I also have pretty good hearing. I don’t think I’ve heard anyone here saying they heard a big difference, except maybe with the 300B. If you’ve got good enough hearing to hear the changes as a huge difference in spite of the normalization of the circuit that FAS implemented, goodonya.

But I think what you wrote in the quoted section is the real crux of the thread, and the core of the wish I put in the wish list: If much of the difference in changing tubes is caused by the power amp circuit’s reaction to the change, I’d like the ability to have that change occur automatically, and then “optimize” the transformer match, etc., only if I want to. And a switch to use either approach as a choice. Short of that, a list of parameters to change in which direction to get back to the “mismatch” that would have happened if I had changed nothing in the circuit other than the tubes. I’m trying to get us to something that would please both camps.

Why these threads seem to take on such a polarizing vibe is puzzling to me.
 
Why these threads seem to take on such a polarizing vibe is puzzling to me.

It's a weird issue. It's on the borderline between a basic and advanced thing to do. On classic amps changing the to a new type and rebiasing or modding to support them is definitely something a qualified tech would be involved in, and is deep in the realm of "off the beaten track mods".

But at some point amp makers like Mesa Boogie starting doing A) fixed biases, B) tubes tested to match that bias, and C) 6L6/El34 switches. This made it pretty user serviceable to swap tube types. So it's a complicated change that was given a simple button thanks to a lot of engineering and business work on the companies side.

And there's a lot of mystique to people taking Marshalls and modding them to kt88s, etc.

Lots of people don't want to have to understand things at an amp tech levels, they just want to have one button that says "mod my amp to kt88s and tell me how it sounds", or "let me do the same thing I did with my dual rectifier when I flipped it to EL34".

But the flip side is that the real amp tech that modded that Marshall to KT88s probably did a handful of things to make it play nicely and sound good, maybe even did a transformer swap.

The other group seems to be people that have read and understood what the different aspects are of doing a swap and presumably come to the conclusion that "It can be done already and you just need to learn how".

So from Cliff's side I see three main things:
a) adjusting those things is all already possible, with finer control than people are asking for. Like replacing the Depth Mode switch on Bogners with a depth control.

b) How would you even automatically make the change for all amps? Some amps (like Mesas) have a standard configuration for both 6L6s and EL34s, but what's the "standard configuration" for a '59 Bassman with EL84s? A real amp would need a transformer swap, and now the transformer match parameter depends on what was used. If an ideal match was used... it would be 1.0 like the Axe uses already. Doing math to pretend you didn't do a transformer swap wouldn't be any more "Authentic" than what it currently does since in real life that wouldn't be possible.

c) There's a lot of numbers and math involved in figuring out the transformer and power tube interactions. Specs of the transformer, specs of that particular power tube, and the fact that tubes had variance so sometimes they would be more or less of a match despite being biased (which could also be hotter or colder). My assumption is that a lot of those numbers don't actually have to make it to the model because in terms of simulating the effects all that stuff just boils down to "What's the Transformer match ratio?". So the current behavior isn't "Cliff is doing a bunch of changes I don't want behind the scenes to make the transformer match the new tubes", it's "I'm only changing the tube type so only the tube type changes". To set up this automatic calculation would involve adding a bunch of values to the different tube types, and a bunch of values to each model to use for calculation.

That, and I don't know if there's anything currently in the Axe FX where changing one value makes other values change for you (short of block type). Implementing this adds a whole class of UI functionality and bugs for both Axe Edit and the devices themselves, And confusion when you tweak one value and then tweaking another changes the first. Or a new UI paradigm where you can enable or disable the linking, and confuse users who haven't learned that yet.

I think where I've ended up on this issue is despite understanding how "nice it would be", practically I don't see how it could be done in a good way. It seems like the best answer is either a tech note or manual section explaining the process instead of a function in the code that does it for you. A calculator to give you a starting point also sounds nice, if you want to know the "authentic" value before tweaking.

But I think even that's a bit of a flawed concept: Some amps have a tube type switch that really do have an authentic value for those two types. But most amps the authentic value depended a lot on how the amp was modified to use a completely different tube type, so just using a calculator is really just answering the theoretical "what if I could somehow put this tube into an amp without changing anything else to make it work", where the Axe FX works like "What if this power amp was designed for this new tube type instead".
 
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