Axe-Fx III Firmware Release Version 19.00

FractalAudio said:
I could make the difference more pronounced. As it stands I don't change the transconductance when changing tubes. The problem is if I did change the transconductance things would change dramatically if, for example, going from a 6L6 to an EL84. An EL84 has around twice the transconductance.

In a real amp you can't put EL84s in an amp designed for 6L6s.

What I change are the parameters that control the frequency response and distortion.
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If the resulting sounds would be useable, I say go for it!
 
That would be awesome! To be able to change tubes you couldn't normally do. Yes please!
FractalAudio said:
I could make the difference more pronounced. As it stands I don't change the transconductance when changing tubes. The problem is if I did change the transconductance things would change dramatically if, for example, going from a 6L6 to an EL84. An EL84 has around twice the transconductance.

In a real amp you can't put EL84s in an amp designed for 6L6s.

What I change are the parameters that control the frequency response and distortion.
Click to expand...
 
FractalAudio said:
I could make the difference more pronounced. As it stands I don't change the transconductance when changing tubes. The problem is if I did change the transconductance things would change dramatically if, for example, going from a 6L6 to an EL84. An EL84 has around twice the transconductance.
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Tell you what, when I bought the AF2 (10 years ago) it replaced the rest of my gear and the heart of it was a custom made (my specs) Metro Super Lead (early '69 specs mainly) with several modifications to be able to swap power tubes easily. In my case I was using ancient Mullard EL34's, Winged C EL34's, old RFTs EL34's, JJE34Ls (never bonded with those), a quad of contemporary 6550 Tungsols classified as "late gain" and many more. I was swapping power tubes all the time as it was easy to bias them etc (very large external resistance range 10-turn bias pot etc).

The differences were instantly obvious at all volumes and under any condition. And back then the TS 6550s were my favorites, again at all volumes and I don't use distortions.

As much as I loved my AF2 (spent 9 whole years with it) and now my AF3, swapping tubes on these devices was never satisfactory for me as I had a real world experience with tube swapping on my Super Lead.

I would much prefer if the transconductance was put in the sound/behaviour equation of yours at least maybe the results would be more realistic. But, hey, what do I know. ;)

PS: with EL34s the differences were even more obvious when the volume was wide open, it was very easy to observe the differences in sound, behaviour, compression, how "controlled" the amp remains or not, how the bass frequencies were behaving or if they were all over the place etc. Going from any EL34 quad to a 6550 was night and day accross all volumes, frequently-wise, gain-wise etc. That's my experience.
 
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FractalAudio said:
I could make the difference more pronounced. As it stands I don't change the transconductance when changing tubes. The problem is if I did change the transconductance things would change dramatically if, for example, going from a 6L6 to an EL84. An EL84 has around twice the transconductance.

In a real amp you can't put EL84s in an amp designed for 6L6s.

What I change are the parameters that control the frequency response and distortion.
Click to expand...
Maybe an authentic/ideal switch to have both options?
 
Jupiter said:
As much as I loved my AF2 (spent 9 whole years with it) and now my AF3, swapping tubes on these devices was never satisfactory for me as I had a real world experience with tube swapping on my Super Lead.

I would much prefer if the transconductance was put in the sound/behaviour equation of yours at least maybe the results would be more realistic. But, hey, what do I know. ;)

PS: with EL34s the differences were even more obvious when the volume was wide open, it was very easy to observe the differences in sound, behaviour, compression, how "controlled" the amp remains or not, how the bass frequencies were behaving or if they were all over the place etc. Going from any EL34 quad to a 6550 was night and day accross all volumes, frequently-wise, gain-wise etc. That's my experience.
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what i understand is transconductance is constant, so transformer matching remains the same.

in real world different between the transconductance or plate current for the two tubes you mentioned above will be very very different. plate current affects the sound we get from the tube. so that is why what is happening in real world sounds more different to you for el34 vs 6550, but thats not ideal way of doing it, and what you are thinking is the tube sound is actually more or less plate current.

So the realistic results people talk about are actually something that arise out of erroneous practices, and if you bias thing rightly and set the transformer etc correctly, real world would be as close as what we hear on axe too.

every thing needs to be redesigned/recalibrated when making such a change.
 
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FractalAudio said:
I could make the difference more pronounced. As it stands I don't change the transconductance when changing tubes. The problem is if I did change the transconductance things would change dramatically if, for example, going from a 6L6 to an EL84. An EL84 has around twice the transconductance.

In a real amp you can't put EL84s in an amp designed for 6L6s.

What I change are the parameters that control the frequency response and distortion.
Click to expand...
Might it be possible to provide a parameter for how much of the real-world transconductance change gets applied? On zero it's like today, where it doesn't change, on 10 it varies with tube type like it would in the real world, in between, it varies, but not as much as in real life.

Not having experienced this, I have no idea if that'd be useful or not, but it does sound like tube swaps in real amps have more of an effect than they do in the Axe.
 
jin1995x said:
what i understand is transconductance is constant, so transformer matching remains the same.

in real world different between the transconductance or plate current for the two tubes you mentioned above will be very very different. plate current affects the sound we get from the tube. so that is why what is happening in real world sounds more different to you for el34 vs 6550, but thats not ideal way of doing it, and what you are thinking is the tube sound is actually more or less plate current.
every thing needs to be redesigned/recalibrated when making such a change.
Click to expand...

Tell you what, I had two (one for each pair of the quad) Compubias' so I could monitor everything and bias accordingly.

Between the same type of power tubes (say EL34s) the plate voltage differences were not a big deal. The difference of the plate voltage between any EL34 and my 6550s was massive. Talking about 475V (give or take 10-15V) with the EL34s and 420-430V with the 6550s. Was it a problem to me? No, as I could bias my amp accordingly, in fact I prefered my EL34s anywhere between 65-75% while I much prefered the 6550s at around 58%.

Although I am a programmer, I sure can't tell Cliff how he could do it, I am not qualified, not even close, not for that.

But my point is that the way the power tube swapping operates on these devices doesn't match my personal experience, that's all I am saying. So, personally, I stopped messing around with this feature long time ago.
 
Jupiter said:
Tell you what, I had two (one for each pair of the quad) Compubias' so I could monitor everything and bias accordingly.

Between the same type of power tubes (say EL34s) the plate voltage differences were not a big deal. The difference of the plate voltage between any EL34 and my 6550s was massive. Talking about 475V (give or take 10-15V) with the EL34s and 420-430V with the 6550s. Was it a problem to me? No, as I could bias my amp accordingly, in fact I prefered my EL34s anywhere between 65-75% while I much prefered the 6550s at around 58%.

Although I am a programmer, I sure can't tell Cliff how he could do it, I am not qualified, not even close, not for that.

But my point is that the way the power tube swapping operates on these devices doesn't match my personal experience, that's all I am saying. So, personally, I stopped messing around with this feature long time ago.
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Nice! yeah for different tubes the plate current can vary alot i guess unlike sametubes. but since switching them involves maybe alot more changes which no one does ias we also got to apparently change the transformer stuff which is too tedious for rl..



what i do on axe is i vary the bias to get the effect of more / less current after switching tubes, along with some other stuff
 
jin1995x said:
Nice! yeah for different tubes the plate current can vary alot i guess unlike sametubes. but since switching them involves maybe alot more changes which no one does ias we also got to apparently change the transformer stuff which is too tedious for rl..
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I don't know what to say mate. All I know is that Cliff has pretty much modelled the whole universe (lol) with great success, and that comes from an once upon a time hardcore tube-head who ditched tube amps forever for the FA devices loooong time ago.

I am pretty sure that if Cliff thinks it is worth the trouble, he will find a way and do it, after more than 10 years with the Fractal Audio, I have zero doubts about it.
 
Jupiter said:
I don't know what to say mate. All I know is that Cliff has pretty much modelled the whole universe (lol) with great success, and that comes from an once upon a time hardcore tube-head who ditched tube amps forever for the FA devices loooong time ago.

I am pretty sure that if Cliff thinks it is worth the trouble, he will find a way and do it, after more than 10 years with the Fractal Audio, I have zero doubts about it.
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yep fully agreed i was actually referring real world changes being a more half baked approach! he definitely can introduce this, but if he doesnt i guess it would be because he views how the approach in real world more erroneous than his current approach inthe axe,haha!
 
FractalAudio said:
I could make the difference more pronounced. As it stands I don't change the transconductance when changing tubes. The problem is if I did change the transconductance things would change dramatically if, for example, going from a 6L6 to an EL84. An EL84 has around twice the transconductance.

In a real amp you can't put EL84s in an amp designed for 6L6s.

What I change are the parameters that control the frequency response and distortion.
Click to expand...
That would actually be very welcome.

Changing between different EL34s wouldn't have this big of a difference, but going from EL34 to a rather different type of tube probably would (well, relatively speaking). Oftentimes it seems to be what people expect when changing tubes in axe fx, it seems to me..

Or there could he a switch that keeps transconductance the same or varies it according to tube choice.
 
sprint said:
I'll post this vid - just for balance along side those 2 (then I'll run for cover)

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Johan's preamp tubes vid clearly shows a lot of differences in real world amps. That's not the same as power amp tubes though.

Didn't have the patience to get through all of Joe's power amp ones, sorry, not that much difference, to my ear.

Didn't make it through Mud's either. Would have much preferred hearing the same riff on each tube, then another riff on each of them etc. It's hard to compare tubes with different riffs in between.

Gotta check it out for myself anyway, none of these sounded like me :)
 
Yeah, this firmware sounds and feels awesome. The the overall tight feel and the tightness in the low end is really pleasing among everything else! Great stuff!
 
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