1959SLP without power amp modeling ques

chrisjnyc

chrisjnyc

Power User
I tried using the 1959SLP amp block with my tube amp, and as soon as I turn off the power amp modeling and sag it looses all its mojo. The obvious answer is to leave it on, but how do I get the amp drive\distortion back without using a drive block in front?
 
To the best of my knowledge, a good part of the distortion on Plexis does come from the power amp.. so if you turn that off in the AxeFx, you would need to turn your tube amp way up to get the power amp distortion from that. Probably NOT what you want.
 
chrisjnyc said:
I tried using the 1959SLP amp block with my tube amp, and as soon as I turn off the power amp modeling and sag it looses all its mojo. The obvious answer is to leave it on, but how do I get the amp drive\distortion back without using a drive block in front?
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Regarding your actual question: Use the input trim. You'll get more distortion again, but it won't sound the same as it's preamp vs power amp distortion.
 
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A Plexi-style amp needs to be turned up to get power-amp distortion. My guess is your tube power-amp isn’t running loud enough to provide it, so you need to use power-amp modeling to compensate. If you can get the tube power-amp loud enough you will find it starting to get thicker sounding and then will want to turn off the compensating modeling. P. 26 in the manual covers some of this. The Wiki entry and Yek’s discussion are good reading.

The speaker impedance curve in the AMP block can affect this as the power amp reacts to the speakers and that’s a large part of the tone.

I hope that all makes sense. It’s the reason why you use your ears, not your eyes to find the right tone, and what works in one situation can change in another. It’s also why solid-state power-amps are often preferred over tubes when modeling, for consistency, whereas without modeling people want the tube-powered power-amp to soften and sweeten the sound; guitarists expect and want that softer power-amp distortion and sustaining sound.

See https://wiki.fractalaudio.com/wiki/index.php?title=Amp_block#Preamp_and_power_amp_modeling and the sections following it… heck, read the entire page a couple times, because this is important to understand for your type of rig.

PS - moving air, having enough volume to begin to shake your guitar, is important too. The acoustic coupling from the speaker to the guitar into the strings and through the pickups back into the amp, out the speaker… adds some gain to the sound and helps add thickness and sustain. Without that volume you have to adjust the tone controls, and/or the master volume setting in the AMP block, and, if you later turn your tube amp louder, you’ll unbalance the settings you tweaked to compensate. Then frustration sets in, because it’s all so simple when using only a tube combo amp, we intuitively compensate by twiddling knobs, but they’re somewhat hidden by the modeler. Setting up the per-preset and global performance knobs on the modeler can help ease that problem, but adjusting the preset at stage volume is the real solution, which loops back to making sure the tube power-amp is running loudly enough.

PPS - <soapbox> A second problem with tube powered amps and their need to be turned up to get a good sound, is that too many people have no idea how loud a tube amp can be. They don’t select the amp for the size of room they need to fill considering stage volume and a FOH system. They buy 100 watt amps into 4x12 cabinets and turn the amp only up to 1.5 because it’s fricken’ loud and the club manager comes out yelling that it’s too loud… so they buy pedals and stick them in front of the amp “to get that sound”, or cheap load boxes to force the amp to work harder, reducing tube and component life, or stick the cabinets in isolation, or switch to amps with complicated switching, or any number of other solutions, when buying a small amp to start would have solved the problem. I use a ToneKing Imperial Mk II, which puts out about 20 watts, for 99% of the times I need an amp. It’s running flat out, the power-amp is hardwired at 10, and it has a great built-in attenuator. I can stand a couple feet in front of it, it’s tipped back so I can hear exactly what it sounds like, the “amp in the room” sound is very close to what my modeled “Imperial” preset sounds like. Yeah, back to pushing air and making the power-amp work. </soapbox>
 
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To piggy back on @Greg Ferguson‘s excellent post, to simulate the loud volume of a real Plexi I’d also fiddle with adding Speaker Compression from the Speaker page, as well as the Gain Enhancer from the Output Compressor section of the amp block. With those parameters in addition to the accuracy of the power amp modeling, you don’t need any actual volume at all to make it sound like you’re peeling the paint off the walls. Cliff recommends using the Speaker Compression sparingly.
 
sprint said:
Oh boy - another "just use your ears" year eh! - how bout a "+just understand how the amp works" year for a change 😖
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The problem is people don’t want to learn that. They like doorknobs and rotary dial phones, simple things like toothpicks and two-knob water faucets and single lever toilets, things that invite jiggling a lever or turning something … heaven forbid being faced with a Japanese toilet with push buttons. They don’t want to read. “Read… is too hard.” They don’t even want to interpret iconography in an interface… the “Snapshot” tool, what’s that?

A modeler isn’t as intuitive as a combo amp, where we’re much more likely to twist the knobs, see where they end up, and remember them. Most of the details and changes that occurred in that circuit was hidden. But the modeler, even when using the authentic page in the cab block, still presents a much more complex and intimidating experience because of the front panel, and too many people have brains that rebel well before they drop into a submenu or pane.

So, to counter people getting exploded brains, Cliff started telling people to use their ears to help overcome the fear of twisting knobs. They can’t permanently break the modeler by doing so, and in the meantime they learn to experiment.
 
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Greg Ferguson said:
The problem is people don’t want to learn that. They like doorknobs and rotary dial phones, simple things like toothpicks and two-knob water faucets and single lever toilets, things that invite jiggling a lever or turning something … heaven forbid being faced with a Japanese toilet with push buttons. They don’t want to read. “Read… is too hard.” They don’t even want to interpret iconography in an interface… the “Snapshot” tool, what’s that?

A modeler isn’t as intuitive as a combo amp, where we’re much more likely to twist the knobs, see where they end up, and remember them. Most of the details and changes that occurred in that circuit was hidden. But the modeler, even when using the authentic page in the cab block, still presents a much more complex and intimidating experience because of the front panel, and too many people have brains that rebel well before they drop into a submenu or pane.

So, to counter people getting exploded brains, Cliff started telling people to use their ears, to help overcome the fear of twisting knobs. They can’t permanently break the modeler by doing so, and in the meantime they learn to experiment.
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agreed, and not saying using your ears is not important, or best advice in some circumstances, or a good way to explore the more advanced pages - it just seems to have become so much of a catch all mantra round here + suggested to solve any tonal search, but leaves out half the essential story which can sometimes be meaningfully explained with a little effort as you did above and as I often see you and a precious few others do well in other posts. I find it most amusing to see "just use your ears" in threads that are discussing advanced controls - ya, like I'm gonna use "just use my ears" while adjusting Bias Excursion without having the faintest clue what it does and how it operates in a real amp - maybe I'll luck into finding a sound I like while adjusting that control and maybe that's good enough for some, but, given the number of controls in the amp block, and the exponential number of inter-control-relationships, navigating to a tone I seek seems almost impossible with a "just your ears" / twist knobs / hope for the best method. I'll have a much easier time following my ears if I understand what it is my ears are hearing. The simple case above (no MV amp) is a perfect example as the answer to "why is there no gain here with PA off" could be puzzling with just ears for someone unaware of the conceptual difference, but obvious after adding in your explanation of the basic difference between a Plexi/other MV amp... - without some concepts being grasped it's like one giant blob of compiled code and no source code or decompiler to get me some logical ability to make changes. Even taking the example of simple real tube combos: if I have a specific sound in my head and I "just use my ears", I may, unless lucky, buy and sell a whack of tube combos (as many do) before happening onto the one that clicks to that tone I seek (the magic one). I could have likely navigated to that "magic" tube combo a lot faster and cheaper if I had understood more about how those different tube combos worked conceptually as they passed thru my hands - ie when I first started playing I owned 2 fender style tube amps and a couple of mid gain tube amps and went through a bunch of pickup changes before understanding that the higher gain sounds I wanted were mostly determined by preamp in some specific families/brands/models of amps - feels silly to admit now, but, my ears alone were far less efficient than ears+knowledge.
 
sprint said:
agreed, and not saying using your ears is not important, or best advice in some circumstances, or a good way to explore the more advanced pages - it just seems to have become so much of a catch all mantra round here + suggested to solve any tonal search, but leaves out half the essential story which can sometimes be meaningfully explained with a little effort as you did above and as I often see you and a precious few others do well in other posts. I find it most amusing to see "just use your ears" in threads that are discussing advanced controls - ya, like I'm gonna use "just use my ears" while adjusting Bias Excursion without having the faintest clue what it does and how it operates in a real amp - maybe I'll luck into finding a sound I like while adjusting that control and maybe that's good enough for some, but, given the number of controls in the amp block, and the exponential number of inter-control-relationships, navigating to a tone I seek seems almost impossible with a "just your ears" / twist knobs / hope for the best method. I'll have a much easier time following my ears if I understand what it is my ears are hearing. The simple case above (no MV amp) is a perfect example as the answer to "why is there no gain here with PA off" could be puzzling with just ears for someone unaware of the conceptual difference, but obvious after adding in your explanation of the basic difference between a Plexi/other MV amp... - without some concepts being grasped it's like one giant blob of compiled code and no source code or decompiler to get me some logical ability to make changes. Even taking the example of simple real tube combos: if I have a specific sound in my head and I "just use my ears", I may, unless lucky, buy and sell a whack of tube combos (as many do) before happening onto the one that clicks to that tone I seek (the magic one). I could have likely navigated to that "magic" tube combo a lot faster and cheaper if I had understood more about how those different tube combos worked conceptually as they passed thru my hands - ie when I first started playing I owned 2 fender style tube amps and a couple of mid gain tube amps and went through a bunch of pickup changes before understanding that the higher gain sounds I wanted were mostly determined by preamp in some specific families/brands/models of amps - feels silly to admit now, but, my ears alone were far less efficient than ears+knowledge.
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I agree with you VERY MUCH, it is a mantra, and is a fallback, because trying to explain what is actually happening is mind-boggling, and the myriad of ways to tweak controls is overwhelming and we can’t explain how they interact without chapters of background. So, yeah, “turn it until it happens for you”, in theory, works but we actually could do better.

In a simple real-world analog tube amp, like a Fender Champ, the component values are fixed, and turning a dial has an effect we immediately hear. We’re not sure why though. When we get a tool like the Fractals, which expose the adjustments that an amp tech or designer understands, then it’s overwhelming. Perhaps what we, or Fractal, needs, is an amplifier theory course that is explained in terms of the modelers. If you do “this”, then “that” will happen, a cause and effect situation where we can explore, turn knobs and explore. Move from a Champ, to more complex designs, so, as we go, we understand the theory of amp design.

Maybe @Cooper Carter wants to take this on? It needs to be someone who knows the hardware really well, and how amp designs work, to explain turn X and Y happens and here’s why, but if Z is set then that will happen. Charge us, because it’s a great class, and, especially in Cooper’s case, it could intersect with his regular class.
 
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I started my effort toward understanding a while ago - definitely not easy but worthwhile for me so far. After some trial and error I found the vid below (and the Part2) which were the best I could find on tube amps 101 in a presentation style that I could get along with. Still a long way to go / looking for a good book or 2. This site is also useful, as well as Cliff's tech notes, but ya, if someone like Cooper Carter could do a session or series on advanced controls that taught: 1.) The Underlying Tube Amp Concepts, 2.) Critical listening techniques / ear training for isolating and hearing the tonal nuances that advanced controls make 3.) Inter-ralationships between advanced controls 4.) Methodology for dialing in very specific tones - I'd be down for it for sure.
 
Fwiw "use your ears not your eyes" is not unique to this forum (nor is "rtfm" either). I agree that further explanation of the Why can help a lot, but in some cases it is the best starting point. This forum is fortunate to have users who do take the time to explain things. Hopefully those asking questions actually use the resources.
 
sprint said:
I started my effort toward understanding a while ago - definitely not easy but worthwhile for me so far. After some trial and error I found the vid below (and the Part2) which were the best I could find on tube amps 101 in a presentation style that I could get along with. Still a long way to go / looking for a good book or 2. This site is also useful, as well as Cliff's tech notes, but ya, if someone like Cooper Carter could do a session or series on advanced controls that taught: 1.) The Underlying Tube Amp Concepts, 2.) Critical listening techniques / ear training for isolating and hearing the tonal nuances that advanced controls make 3.) Inter-ralationships between advanced controls 4.) Methodology for dialing in very specific tones - I'd be down for it for sure.
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They'd definitely be good to know because it'd be practical, applicable, information. It'd also make Fractal and the community a major force in the music market.
 
sprint said:
Oh boy - another "just use your ears" year eh! - how bout a "+just understand how the amp works" year for a change 😖
Click to expand...
So without ears as the judge, please tell me "tone-wise" knowing how an amp works would help you?
OTOH, one idea does go well with the other. ;)
 
sprint said:
agreed, and not saying using your ears is not important, or best advice in some circumstances, or a good way to explore the more advanced pages - it just seems to have become so much of a catch all mantra round here + suggested to solve any tonal search, but leaves out half the essential story which can sometimes be meaningfully explained with a little effort as you did above and as I often see you and a precious few others do well in other posts. I find it most amusing to see "just use your ears" in threads that are discussing advanced controls - ya, like I'm gonna use "just use my ears" while adjusting Bias Excursion without having the faintest clue what it does and how it operates in a real amp - maybe I'll luck into finding a sound I like while adjusting that control and maybe that's good enough for some, but, given the number of controls in the amp block, and the exponential number of inter-control-relationships, navigating to a tone I seek seems almost impossible with a "just your ears" / twist knobs / hope for the best method. I'll have a much easier time following my ears if I understand what it is my ears are hearing. The simple case above (no MV amp) is a perfect example as the answer to "why is there no gain here with PA off" could be puzzling with just ears for someone unaware of the conceptual difference, but obvious after adding in your explanation of the basic difference between a Plexi/other MV amp... - without some concepts being grasped it's like one giant blob of compiled code and no source code or decompiler to get me some logical ability to make changes. Even taking the example of simple real tube combos: if I have a specific sound in my head and I "just use my ears", I may, unless lucky, buy and sell a whack of tube combos (as many do) before happening onto the one that clicks to that tone I seek (the magic one). I could have likely navigated to that "magic" tube combo a lot faster and cheaper if I had understood more about how those different tube combos worked conceptually as they passed thru my hands - ie when I first started playing I owned 2 fender style tube amps and a couple of mid gain tube amps and went through a bunch of pickup changes before understanding that the higher gain sounds I wanted were mostly determined by preamp in some specific families/brands/models of amps - feels silly to admit now, but, my ears alone were far less efficient than ears+knowledge.
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What people do you hang out with? Spent time with some Gen~Z kids over the break. They are smart, focused and hardworking. There were a couple of people in their 70’s and one in her late 80’s. Same thing. And all did a lot of reading BTW (the older ones were part of a book club, GenZ deep in taking extra courses over the break). If you are the smartest guy in the room you are in the wrong room. If you get out of the everyone is lazy and get off my lawn rooms there are a lot of other rooms to be in!
 
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