Analog SS amp should take pedals better than Digital right?

Discussion in 'Amp Central Station' started by Nashville-tele-19, Feb 18, 2020.

  1. Digital Larry

    Digital Larry Tele-Afflicted Gold Supporter

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    The Nextone uses all sorts of references to things which aren't physically there, such as the specific power tube types. Their ad copy was done by pros during the time between things I can't talk about here. All the tube amps in the pictures are "things they studied" or whatever, but do they ever show the circuit board of the Nextone? I don't think so. Is writing new firmware or selecting a new program "physically reconfiguring the circuit"? I'd argue that it is (with a roll of the eyes), although the phrase is likely to be misinterpreted just they way they want it to be.
     
  2. trxx

    trxx Tele-Afflicted

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    The person doing the modeling also has to have really good ears for what those circuits do under various operating conditions. DSP isn't lightweight in the programming world, so I have major doubts that anyone has the time to play simultaneous roles of being a DSP programmer, a really good audio engineer, and a really good guitarist, capable of bringing it all together. Just being a really good musician alone is a life-consuming endeavor. And a programmer has to really understand the problems involved, being capable of hearing the problems (audio engineer) and interacting with the models (musician), in order to effectively program them. Add on top of that the elephant in the room of aliasing / foldback distortion wreaking havoc in the audio spectrum of those math models.

    Digital modeling of great analog circuits is severely overestimated if you ask me. I think part of that is the amount of time that the geeks need to invest into it, so it must be sold as being accurate to the real deal if there is any hope of making money from it. And that requires heavy marketing and gear pimps, which kicks off the monkey hear monkey say of end users who don't have the experience or good taste to hear the difference. To me, the whole endeavor seems to be pretty perverse. I haven't even heard filters modeled really well yet, much less tubes, transformers, spring tanks, speakers, entire circuits, and how they interact. According to the marketing, every generation sounds more accurate than the last, yet the last gen was as good as the real deal or even better. Hoopla.

    Go back 70 years to some of the simplest classics. Show me a really well done tweed model that I can hear and feel as being the real deal, rather than a sterile and ugly clipping thing, and I'll start being a believer.
     
    Last edited: Feb 20, 2020
  3. trxx

    trxx Tele-Afflicted

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    Everyone knows that pushing the front end of a solid state amp isn't going to provide the same end goods as driving the front end of classic tube amps. So then, the best that can be hoped for there is not an interaction between a pedal and an amp, but rather, an amp combining the sound of a pedal in a rather linear way to what the amp is already doing. It's like making a Bolognese sauce by adding minced meat on top of a tomato sauce. It's never going to be the same sort of thing. So then, the same holds for a digital amp, because it is a sort of solid state amp. But a digital amp also has a set of converters that must not be clipped and the aliasing problem. A pedal in front of it now becomes something like a Bolognese sauce with very finely chopped meat that has been heavily brazed on top of the sauce, with the side of effect of a little charring added in that shouldn't be there.
     
    Last edited: Feb 20, 2020
  4. Digital Larry

    Digital Larry Tele-Afflicted Gold Supporter

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    I've worked on a fair number of engineering teams during my (now waning) career. Emphasis on the word team. Marketing comes in with a request (e.g. make a sound card). Engineer designs a schematic. PCB layout person lays it out. Tech builds it. Engineer turns it on and demos to marketing person.

    I've worked on a lot of audio oriented products as well, including a few for musicians or audiophiles. The success of a product is not based on one person doing all of it, nor is it based on fooling all the people all the time. Now if you can't fool anybody, that's going to be a problem.

    Marketing departments all over the place are working to get you to buy things that you don't need using all of the same sorts of psychological tricks that have been used for centuries because by and large, they work. Amp modeling seems to be somewhat unique in that the yardstick of quality continues to generally be references to things which were originally designed a really long time ago, that most people (including me) have never spent any significant amount of time actually listening to.

    It's a good thing you can still buy tube amps because some people still want them.
     
  5. printer2

    printer2 Poster Extraordinaire

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    You are wrong about the transistors in the picture, that is not the power amp. That is the Switched Mode Power Supply (SMPS for short). I give Fender credit for using one,( now lets see them use one for tube amps). The transformer is tiny because the frequency going through it is in the hundreds of kHz, 60 Hz from the wall requires much more iron. The Mosfet on the left, two linear regulators on the right for the +/- supplies. The metal plate on the lower left corner of that board would hold the power section chip.

    The chip is a TDA7294, from the datasheet, I snipped the relevant parts.

    Texas Instruments, the chip maker, has designed a class H amplifier and calls it a class AB. The difference in power dissipation curves shows why I did not feel a simple lightweight chassis could dissipate the power of a 40W Class AB amp. Class H was invented by a company called Carver in the 70's and brought out an amplifier called the Carver Cube without the bulky power supply and heatsinks. (Yes I have been involved in electronics for a while)

    While the plot shows the amp at a higher wattage of the Champion the same curves apply but at a lower wattage. Just cut the power figures in half. The difference between this chip's power dissipation curve and a real class AB amp is heat that the chassis does not have to get rid of. As you can see, the class AB amp puts out twice the heat in the normal operating range of the amp (the average wattage rather than the peak). TI calls it a Class AB amp because that is what sells. Not that there is anything wrong with the amp being Class H, it still is a linear output.

    Not to be a jerk, but I gave you the benefit of the doubt as far as your electronic knowledge. But your analysis of the Champion picture shows that you are not well versed as I gave credit for. Given that, comparatively speaking, I will say, yeah, I know a bit about electronics.
     
    Last edited: Feb 20, 2020
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  6. cyclopean

    cyclopean Friend of Leo's

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    it's an hd. i usually have a dimed spark mini as the last thing in my chain.
     
  7. Blrfl

    Blrfl Tele-Holic

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    Real engineers don't do that by ear, they do it by measurement. They might take the results to people with ears and ask what they think, and if the people with the ears don't like it, they'll go back and figure out what they didn't measure correctly. That goes to what Larry said about it being a team effort.

    I've done signal processing for RF, but these days I make my living in the research computing world. Pretty much every endeavor there is about understanding and modeling the behavior of things in the real world. If we're capable if figuring out how much deflection an airplane wing will take before it snaps and where the break will occur, I have lots of confidence that we can develop and refine a model of the the behavior of something as simple as a vacuum tube.

    Your take on this seems to be that if it can't be done 100% perfect the first time, it shouldn't be done at all. It would be naive to think there weren't any awful tube designs early on, which is why I remind my interns that experience is what you get when things don't go as expected.

    If you're skeptical of the marketing copy, you should be. The first few iterations of anything rarely live up to the hype. R&D usually knows where the bodies are buried; marketing's job is to try and convince buyers that there are no bodies.
     
  8. trxx

    trxx Tele-Afflicted

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    I'm actually pretty interested in modeling technology and have been following (and sometimes using it) over the past 20 years or so. But I also think that every gen is way overestimated and marketed as being as good as the real deal while at the same time better than the last gen (the big contradiction). Modeling has come a very long way, but it also has a good way to go before being fully there. I have said it here and elsewhere. Once 70 year old tweed amps and speakers are done very well in sound and feel, I will be a believer in the final arriving of modeling. Despite the inherent distortions of tweed amps, they can at the same time have a tremendous amount of clarity and rich harmonics. I haven't heard any digital models yet approach that. And doing speakers right isn't nearly as simple as single impulse responses. But once tweeds and speakers are there, the rest should be cake by comparison. And I wouldn't discount tubes as being so simplistic. That is likely where much of the problem lies. Tubes are significantly faster than transistors. I have wondered whether so-called 'vacuum' transistors might end up playing a role in the final arriving of modeling amps, but something that I read about their behavior in the past iindicated that they wouldn't be.
     
    Last edited: Feb 20, 2020
  9. reckless toboggan

    reckless toboggan Tele-Holic

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    Heres my collection of tweed modellers...

    [​IMG]

    [​IMG]

    [​IMG]
    ...light weight, easy to carry, sound amazing: clear, articulate, rich, fat, dynamic, harmonic, musical.


    The future is now.
     
    Last edited: Feb 21, 2020
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