Analog SS amp should take pedals better than Digital right?

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

  1. dswo

    dswo Tele-Holic

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    It wasn't clear, when the Katana first came out, what connection it had with the GT gear. Then someone discovered "Sneaky Amps," and we realized that a bunch of the GT amps were hidden in the firmware.
     
  2. ICTRock

    ICTRock Tele-Afflicted

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    go all in, kustom 200
     
  3. Frodebro

    Frodebro Doctor of Teleocity Ad Free Member

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    Makes you wonder if the software was ported directly over from the GTs, or if it was a hidden Easter Egg that Roland did intentionally.
     
  4. DougM

    DougM Friend of Leo's

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    This may have been true in the past with early Peavey Bandits or similar SS amps, but the SS amps and digital modeling amps made today are designed to replicate the behavior of tube amps, including how they react when their input stage is overdriven by a boost or overdrive pedal.
     
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  5. Frodebro

    Frodebro Doctor of Teleocity Ad Free Member

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    Yep, although the input (actually the A/D converter) isn't being overdriven at all in a technical sense. There is enough headroom on the better units that they WON'T be overdriven by hot signals-the software 'sees' the increased amplitude and 'reacts' accordingly. All of the overdrive/distortion sounds exist solely in the digital domain, at no point is the analog signal overdriving any components.
     
  6. DougM

    DougM Friend of Leo's

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    There's a lot of misunderstanding here. With the incredibly fast and powerful processing power available today designers can analyze in real time every aspect of how any tube amp's (or any anp's) circuitry, from input to speaker, react to a guitar signal, and are then able to emulate every aspect of those circuits reactions using digital modeling platforms. This is why a modeling amp can have a very convincing model of a Twin, a Plexi, an AC30, or any other tube amp the designer wishes to emulate. The Kemper takes it a step further, allowing the end user to "record and store", or "profile" the sound of any amp into the Kemper, to be recalled on demand. The Boss Nextone and Blackstar ID-TVP technology that are used to simulate different power tubes do the same thing, with a powerful simulation of every aspect of how each particular tube reacts to the guitar signal. Remember, digital technology had become so advanced that your smartphone has more processing power than the banks of computers NASA used to send men to the moon!
     
    Last edited: Feb 19, 2020
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  7. cyclopean

    cyclopean Friend of Leo's

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    i like how a musicman amp sounds if you slam the preamp aggressively, and that's a solid state preamp.
     
  8. printer2

    printer2 Poster Extraordinaire

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    So, is it a solid state module that they would have four of, or is it real tubes? I have not heard of the company advertising they had modules to do output tube. But then again, I don't get out as often as I like.
     
  9. PCollen

    PCollen Friend of Leo's Silver Supporter

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    To each his own.....and some MM amps did have a 12AX7 in the preamp circuit..the RD series.
     
  10. Frodebro

    Frodebro Doctor of Teleocity Ad Free Member

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    No tubes in them, it's just a sound modifier.
     
  11. printer2

    printer2 Poster Extraordinaire

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    I plan to waste more hours of my time and design a dual triode preamp going into a Class D amp that the average tdpri'er could put together themselves.


    A sound modifier. I wonder what that would be.

    "physically changes the complete output circuitry, as well as the way the preamp and speaker interacts with it."

    Not really sure why the preamp would react to the power amp, not really a thing in tube amps, but maybe you are getting a bargain with it thrown in. On changing the speaker interacts with the power amp, easily done with current feedback, SS amps have been doing it for the past 15-20 years. Now, to first get a SS circuit to sound like a particular tube, that is an interesting feat. Hove not heard of anyone doing that yet. And I guess if you know how, then changing the circuit to 'model' its behavior to get it to sound like the other tubes, all in transistors or Fets in the analog domain, pretty impressive.
     
  12. DougM

    DougM Friend of Leo's

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    I would venture to say that, as I stated in my previous post, the Boss Nextone amps, and the Blackstar ID-TVP (now the Silver Series) which came first, and Boss copied, don't have separate analog circuits emulating each power amp tube type, but instead are simulating the response of each tube to the guitar signal using digital modeling.Has anyone here heard of amp sims and IRs?
    https://music.tutsplus.com/tutorials/using-guitar-amp-simulators-101-part1--audio-6598
     
    Last edited: Feb 19, 2020
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  13. printer2

    printer2 Poster Extraordinaire

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    Just stopped by their website and watched the video. At 1:04 he says that the amp can be tailored by software on your computer for changes in bias, power supply sag, eEQ and other things. The 2.0 software gives you a whole whack more amp types as options. I am starting to think this is a modeling amp.

    https://www.boss.info/ca/products/nextone_stage/



    Sorry for the big picture.

    [​IMG]

    I wanted to find a picture of the back to see the heatsinks of the class AB amp. There does not seem to be any. I wonder how they are getting rid of the heat, at best SS Class AB amps are about 40% efficient. I can see them using switching technology to power the amp, lighter weight than lugging around a 100W transformer, but running an analog out stage takes power devices that dissipate heat.

    But of course they are using a switcher for the power supply. The vid says that you can modify the amp parameters like sag. But no heatsinks. I guess they must have low powered modules that mimic the four different tubes and feed the signal through them, then send that to a Class d amp. But I am just guessing.



    Anyone want to pop their amp out and take the lid off and take a picture?
     
    Last edited: Feb 19, 2020
  14. The Angle

    The Angle Tele-Holic

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    Why is one amp "digital" and another isn't?

    A digital amp takes the analog AC signal from your guitar and converts it to a stream of 1s and 0s, just like the music on a CD or in an MP3 file. Software then manipulates those 1s and 0s in mysterious and wonderful ways - adding and subtracting 1s and 0s and changing 0s to 1s and vice versa. When the software is done solving math problems on the signal, it's converted back into analog AC current for the speaker.

    Digital has nothing to do inherently with amp modeling. Software can make a guitar sound like a saxophone or like an elephant as easily as it can make it sound like it's coming from a '57 Deluxe. Amp modeling is just one possible thing the software can do to the 1s and 0s.

    In short, if the amp converts the signal to 1s and 0s, it's digital. If it doesn't, it's analog.
     
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  15. DougM

    DougM Friend of Leo's

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    There are plenty of class AB amps without giant heatsinks vsisble. The power devices can be mounted to heat sinks that aren't vsisble from the outside of the chassis. I've seen it many times in guitar amps and in stereo and pro audio equipment. Here's a Peavey Bandit 112. Where are the heatsinks on it? You can't see them, because they don't need giant finned external heatsinks. peavey-bandit-112-2263932.jpg
     
    Last edited: Feb 20, 2020
  16. BelairPlayer

    BelairPlayer Tele-Afflicted

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    All of my pedals have 1/4” outputs and all of my amps, whether solid state (digital or analog) or tube, have 1/4” inputs. So my amps all “take pedals well”.
     
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  17. printer2

    printer2 Poster Extraordinaire

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    Yes, I realize I generally have no idea what I am talking about. But I was talking about the Nextone, and the picture above does not look like the Peavey. The cooling slots punched into the back panel would not have been that practical to do on an aluminum plate as thick as the back panel of the Peavey (0.120"). How do I know it is this thick? It is only a sample size of one, but that is how thick the plate is on my Bandit downstairs. On whether I know what is practical to stamp as cooling slots of the size in the Nextone, I worked in the test lab of a metal shop (well, we did composites also) and stamping those slots in aluminum thick enough to be an effective heatsink for the amp (would not be practical). Don't know where that last bit went.

    I still do not see the Nextone being a class AB amp, what would be the point? The writeup just sounds like a way to sell the different tube models, electrically it does not make much sense. Even you with your vast background in electronics can see that.
     
    Last edited: Feb 20, 2020
  18. Stratguy70

    Stratguy70 TDPRI Member

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    Yikes!

    What's a "heatsink"? A device that takes the heat from vital components?Why should I care about them?

    :)
     
  19. DougM

    DougM Friend of Leo's

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    Sorry for being a jerk. Apparently it's in my nature to be an obnoxious DB. I'm not sure how many guitar amps use class D power amps, because I think the cost of the high frequency switching power supply might cost more than using a simple class AB power amp circuit. Here's the inside of the Fender Champion 40, which I'm pretty sure is a standard class AB power amp, and see the small finned heatsinks on the board, next to the yellow power transformer? I'm pretty sure the one on the right is the voltage regulator, and the two on the left are the two power transistors for the push pull power amp. That's all that's needed to keep the power transistors from overheating. It's not the same as a class AB tube amp that needs big iron for its power transformer and output transformer, and produces a lot of heat from the tubes. Solid state amps don't need 300-400 volts from their power transformer, only about 25 volts, and they have no output transformer, only a power transformer, as the output transistors drive the speaker directly. So, the power transistors only need small heatsinks for cooling. maxresdefault.jpg I've only seen large exterior finned heat sinks on high power stereo power amps, 200 watts per channel and above, with 8 or more power transistors per channel. Even 100 watt per channel amps usually have the power transistors mounted to smaller heat sinks inside the chassis.
     
  20. Blrfl

    Blrfl Tele-Holic

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    It also leaves open the possibility that the power amp section is also modeled and that what makes the output of the DSP loud is an analog section that's either FRFR or has been characterized. Having seen the innards of the Blues Cube and Katana, I'm inclined to think that the analog parts of those amps (and the Nextone, which sits between them) are there because they're a necessary evil. Analog, solid-state circuits that try to behave like tubes tend not to do a good job of it; I'm sure it can be done, but not practically enough to put into at a consumer product at a price point where it will sell. The four power tube emulations offered in the Nextone when it was introduced (6L6, 6V6, EL84, EL34) were already available in the Blues Cube either in the stock firmware or as an add-on. I can't see a good reason to build up new analog circuits when there are already digital models on the shelf that will run on the chip that underpins virtually everything computerized that Roland makes.

    The TubeLogic moniker has been used twice: once in the 1990s for FET designs that used some clever tricks to give them some tubey properties and again in the late 2010s for the DSP version.

    You revoice the Blues Cube Stage, Artist and Tour by plugging in a tone capsule, which isn't anything more than a serial ROM and a couple of LEDs to make it light up. The only thing that circuit provides is data, likely in the form of new firmware. I would be very surprised if the switch on the Nextone does anything other than telling the computer to run a different model on the DSP.
     
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