Again solid state versus tube, some technical consideration of the truth

Discussion in 'Amps and Cabs [BG]' started by ThisBass, Dec 21, 2015.


  1. ThisBass

    ThisBass

    Aug 29, 2012
    Germany
    Inspiered by our TB member @bdwgml who enjoyed us with some polls of the tube versus ss amplifier thing on which (pardon) I had hardly no idea how to extract tube from ss. :)

    I think most of us are influenced by an imagine that tube does a more smooth (rounding) limiting to the signal thus the tonal feel becomes a warmer overall feel with enriched even Harmonics.

    LTspice is a very nice tool to simulate lots of different applications. Now, the idea was to simulate a pure tube preamp stage design versus a ss preamp stage designed by myself.

    Let me call the preamps preamp_1 and preamp_2. One of the two preamps is based on a more generic tube standard design to get some amount of overdrive/distortion. As is this tube preamp design is approved in a very lots of tube amplifiers all around the world. Here (in this case) I did some "tuning" to provide as much even Harmonic content as possible. The ss design is somewhat special thing I think because as is it's probably not very widespreaded at present.
    Never the less there are very different ways to design a well sounding emulation, so here we go.

    I did four kinds of "gaining" the preamp modellings:
    1) around 50% headroom remaining
    2) close at saturation or at least some amount of saturation
    3) input signal arond 5 times greater than saturation point
    4) both halfs of the output signal gained to "flat"


    1) around 50% headroom remaining

    preamp_1

    upload_2015-12-21_22-40-33.png
    upload_2015-12-21_22-42-0.png

    preamp_2

    upload_2015-12-21_22-43-55.png
    upload_2015-12-21_22-44-50.png


    2) close at saturation or at least some amount of saturation

    preamp_1

    upload_2015-12-21_22-46-10.png
    upload_2015-12-21_22-46-34.png

    preamp_2

    upload_2015-12-21_22-47-20.png
    upload_2015-12-21_22-47-52.png


    3) input signal arond 5 times greater than saturation point

    preamp_1

    upload_2015-12-21_22-50-52.png
    upload_2015-12-21_22-51-14.png

    preamp_2

    upload_2015-12-21_22-58-56.png
    upload_2015-12-21_22-59-26.png


    4) both halfs of the output signal gained to "flat"

    preamp_1

    upload_2015-12-21_23-0-33.png
    upload_2015-12-21_23-1-1.png



     

    Attached Files:

    Last edited: Dec 21, 2015
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  2. ThisBass

    ThisBass

    Aug 29, 2012
    Germany
    Sorry, something went wrong while creating the thread, here are the missing pics for amplifier_2

    4) both halfs of the output signal gained to "flat"

    preamp_2

    upload_2015-12-21_23-22-4.png
    upload_2015-12-21_23-22-24.png
     
    blindrabbit likes this.
  3. ThisBass

    ThisBass

    Aug 29, 2012
    Germany
    That's of course a very lot of pics I know. But I think it's the only way to contrast different topologies. And of course I know these charts are only Spice simulations but, I'm very pleased about the accuracy how close the simulation looks to a real oscilloscope tracing.

    So the question is, what do you think, which one is the ss state thing and which one the "real" tube.
    The tube Spice simulation was done for the JJ ECC83s.

    Note:
    one of the simulations I also did for the "real tube" was based on the Hiwatt OL drive stage. Because of remarkable dominant odd Harmonics I did a somewhat different schematic design, so to obtain more of even Harmonic content for this "battle":)
     
    Last edited: Dec 21, 2015
  4. BrBss

    BrBss

    Jul 9, 2010
    Albuquerque NM
    Preamp 1 is tube.
     
  5. BbbyBld

    BbbyBld

    Oct 13, 2005
    Meridian, MS
    Based solely on the waveform V(out_preamp_1) in section 3, I'd say that preamp_1 is SS, because it looks like there is some knee action happening.
     
    agedhorse likes this.
  6. seamonkey

    seamonkey

    Aug 6, 2004
    Hardly anybody plays sine waves :)
    LT SPice can take a wave file as input. How about taking a bass guitar track and record the output of both pre-amps?

    Be sure to gain match etc. as louder will always sound better. Before each sample be sure to add some silence or white noise, change blindness and all.
     
  7. ThisBass

    ThisBass

    Aug 29, 2012
    Germany
    sure of course, totally agree!
    The idea to use 100Hz for simulation, it's close to the 2nd Harmonic of an E1 string and besides a 2nd Harmonic is (most of the time) the most powerfull Harmonic with any bass guitar.
    The bass guitar is a very dynamicfull instrument and that's why I did such a lot of pics for very different input levels.

    I'd wish to have a tool to trace a bass guitar signal from the very beginning, starting with some fret noise and finger hiding the string, at the next step the monstrous excursion at just the moment a finger (or thumb) hits the string to force a swing of the string, a couple of msec later 50% of the amplitude is already gone while the tonal response is changing with every swing of the string, up to the nearly steady swing of the string we actually perceive as loudness.

    Because of we don't have a tool that fits those requirements we have to combine "dynamic" response properties to a conceptual "unique" response. Of course that was never easy nothing at all but, any amplifier design and any serious amp modelling isn't an "very" easy job.
     
    Last edited: Dec 21, 2015
  8. ThisBass

    ThisBass

    Aug 29, 2012
    Germany
    BTW both of the simulations were influenced to provide a firm tonal reponse with minor terz and major terz on a 6-string. While power chords are easy to design to provide a fat sound!
     
  9. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    Ah, so you'd like to figure out a way to feed something like this through your Spice model?

    [​IMG]
     
    Last edited: Dec 21, 2015
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  10. Interceptor

    Interceptor

    Mar 29, 2005
    Madison, WI
    I'd say #2 is the tube, the presence of DC in the output of #1 is the reason why. It is interesting how much less trash is in circuit 2.
     
  11. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    My guess is that the solid state is preamp #1 also,

    ...BUT it depends very much on the circuit application and even more-so, the amount of feedback applied. Global feedback can have a greater influence than the device itself depending on the particular topology, a good example of this is some of the early solid state amps like the old Acoustics, where there are 2 or even more transistor stages with a global loop. Same for any high gain cascaded circuit, be it tube or transistor.
     
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  12. seamonkey

    seamonkey

    Aug 6, 2004
    I meant just wave in, wave out, save it to soundcloud, see if people can "hear" a difference
    Using WAVE files as input/output in LTSpice

    Just compare the audio
     
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  13. ThisBass

    ThisBass

    Aug 29, 2012
    Germany
    Thanks a very lot for this very helpful link.
    The "dirty" sound files are ready for upload. It's late at night here in Germany. I hope I can manage to do the upload at soundcloud tomorrow
     
  14. ThisBass

    ThisBass

    Aug 29, 2012
    Germany
    There was some work to do to manage all that stuff. Sorry for beeing late here

    In descending order:

    At the top and first track the unprocessed sound file of a Yamaha rbx for note E1

    gain1: a kind of medium gain to obtain some compression/dirt (it depends)

    gain2: large gain to obtain remarkable distortion

    gain2 with C1 added: smallish C added to both to obtain some timbre shape voicing

    gain2 with C2 added: larger C added to both to obtain more of shape voicing

    I have to state that soundcloud does a noticable interference to the original sound quality. Remarkable accents (soundwise based at the schematics) to which I gave a lot of regards seem to be obsolete due to the upload. For instance the high-definition difference of C1 versus C2 is nearly ruined! Even the orginal unprecessed file sounds somewhat "boring"!

    Never the less, enjoy :)

    User 152612824

    I wish you all a merry Christmas :bassist:
     
    Last edited: Dec 23, 2015
  15. JimmyM

    JimmyM

    Apr 11, 2005
    Apopka, FL
    Endorsing: Yamaha, Ampeg, Line 6, EMG
    Ya, Soundcloud isn't invisible. It normalizes files. I don't know what else it does, but I know for sure it does that, and it does whatever you're talking about it doing.
     
  16. miiitch

    miiitch

    Nov 27, 2011
    Germany
    what kind of solid-state elements did you test? There´s several different technologies, some of which come remarkably close to that "tube" saturation characteristics (likely 98% or closer).
     
  17. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    What I do to get around that is just enable downloads, if you upload a .wav or .flac file it should come back bit-identical. I haven't actually checked that, but there are plenty of DAW programs that can. I can tell you that the files I've tried are exactly the same size going up and coming down though. My experience is that Soundcoud may normalize louder clips downward, but it does not make my quiet ones any louder.

    Not sure when I can get to listening, but I already know what I prefer in what passes for my "real world." [​IMG]
     
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  18. IMO, the 'blind/contest' aspect obfuscates and hinders progress on this issue. Why not just openly discuss tube & ss stereotypes, their basis in fact and any merit they have. Then illustrate your major points using your software/modeling tools? A schematic of each circuit would be helpful, perhaps even relying on a couple of examples that many are familiar with.
     
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  19. ThisBass

    ThisBass

    Aug 29, 2012
    Germany
    Totally agree,
    but it would mean to reveal a schematic design that is unique?
    There are many ways to design a nice voicing.
    I think one starting point could be a question of how to generate a nice voicing anyway, independent of tube characteristic.

    BTW the schematic designs were done "on paper" with LTspice with sine waves only. There was actually no "basically" alterations on the schematics for the "yamaha rbx" tracks.
     
    Last edited: Dec 24, 2015
    blindrabbit likes this.
  20. ThisBass

    ThisBass

    Aug 29, 2012
    Germany
    Clearly I was too picky with the uploaded tracks, and was hearing grass growing where is nothing but some normalisation.

    I enabled just now download permission to all tracks. There is a limitation to free users

    Free users have a download limit of 100 downloads per track,
     
  21. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
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