Gain, what it is, what it isn’t?

Discussion in 'Amp Tech Center' started by peteb, Jan 5, 2019.

  1. bftfender

    bftfender Friend of Leo's

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    yes that amp exists Marshall 6100..non MV plexi chan 1 with 3 flavors ....jc800 on 2 & jcm900 SLX on 3...from hendrix to meltdown..handles Gibson & fender .classic tones...can just add slight gain for nice note bloom or gut punch or sustain till next year...all set up on 3 buttons on a footswitch...hey in fact the DSL does this also...no pedals...no coloring..you and ya guitar and whatever finger talent you have coming out ya speakers for the whole world to experience
     
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  2. Wally

    Wally Telefied Ad Free Member

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    bffender, that amp exists in many amps, ime. Ime, any amp with a MV and the capability to create overdrive characteristics in the preamp can doe this with judicious adjustment of the controls.

    As for manufacturers using the term ‘gain’ when talking about distorti9n in these amps, perhaps Soldano has those controls labeled correctly???? He used ‘Normal’ for the clean mode and ‘Overdrive’ for the ‘distortion’ mode. He uses these labels for both the preamp and master adjustments in each mode.
    I have in the past used overdrive instead of gain when talking about this increased signal but have also used gain. After this thread, I suppose I may never use gain for that description. Terminology.......it can be tricky, it seems.
     
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  3. Doctorx33

    Doctorx33 Tele-Afflicted

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    Untrue, at least for me. I played loud, hard, rock and roll for twenty five years with a pair of silverface Bassmans and a Strat. Please don't make assumptions of people without any facts.
     
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  4. bftfender

    bftfender Friend of Leo's

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    my assumptions are from playing like your self..dont have to brag about how many years..but some people know what to do with gian without it being brootal..i have played with many a folks with twins, even owned one...and gain def does not equal brootal
     
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  5. Lynxtrap

    Lynxtrap Tele-Holic

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    If we're talking about the strict technical definition of distortion, it could be almost anything that makes the output signal different from the input signal. Non-linearity, phase, frequency response, compression, intermodulation, and not least harmonic buildup (measured as THD - Total Harmonic Distortion).

    And of course, distortion was defined long before anyone could imagine that one day some people would think it could be a good thing.

    To continue with the strict definitions of terms, this is overdrive you are talking about. Which is a form of distortion :)

    Take two Champs. One stock and one with a SLO100 preamp in it. These are extremely different setups with different levels of overdrive but both amps would still have about the same output.

    The SLO with all it's gain stages has the potential for a massive amount of gain, but it's of course attenuated throughout the circuit to make a usable sound. It still will have to have more gain than the Champ in the preamp to get a huge amount of preamp overdrive. But once it reaches the output, the magnitude of the signal will be limited to about the same amount of increase (gain) compared to input in both amps.

    I should maybe add that I personally think that we, being guitar players and amp tinkerers, should be able to talk about "high-gain amps" and such, as we all know what we mean by these terms.
     
    Last edited: Jan 8, 2019
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  6. peteb

    peteb Friend of Leo's

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    you are right Wally, the next step in the path is to understand how gain affects harmonics. I imagine that's a challenging subject.







    what is you had a foot switchable two channel amp with one nmv cahennel and one master volume channel. set the volume on the nmv channel to taste, and then the gain and then the master so that they had the same over all level. Wouldn't that be one amp with two setups, one with a gainy preamp and one without but both at the same over all gain between input to output.
     
  7. Wally

    Wally Telefied Ad Free Member

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    Yes, imho, Pete, that can be. It seems that just in MV ‘channel’, there could be two different set of settings that would very different breakup characteristics and yet have the same ratio on output to input gain.
     
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  8. PCollen

    PCollen Friend of Leo's

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    Agreed...depends on circuit topology and component values.
     
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  9. Bendyha

    Bendyha Tele-Afflicted Silver Supporter

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    I would argue that the use of harmonic distortion, especially one producing overtones through some form of drive sensitive overload, has been considered a disireable form of tonal modulation utilized by instrument makers and musicians for many hundreds of years.....maybe even thousands....Sitar, Hurdy-gurdy, Tromba Marina, Marimba.....
    Equally, accoustical/electronic technicians have long been aware of the capability of tube circuits to produce 1st,2nd,3rd....order harmonics, to clip and modulate wave forms, and that they are an important part of "TONE". Early attemps at reproducing the pallet of tones that a pipe organ can, (with pipe organs trying to mimic flutes, horns...) is well documented from the at least the early 1930's onwards, with many patents explaining the methods.

    That Fender may not have been aware of the potential may well be the case......but he was not a musician.
     
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  10. kelnet

    kelnet Telefied Ad Free Member

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    My Princeton Reverb doesn't have a Master Volume. Does that mean I have no gain?
     
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  11. kelnet

    kelnet Telefied Ad Free Member

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    Is a 20-speed bicycle a high-gain bike, and a single-speed bike a low-gain bike?
     
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  12. peteb

    peteb Friend of Leo's

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    first gear is low gain, 20th gears high gain, unless your output of interest is torque, then it would be the other way around
     
  13. peteb

    peteb Friend of Leo's

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    side question


    I see that the 15W criteria has its limitations.



    I would like to set the output as the max available power from a particular tube or tubes.





    lets say the output must be 6W from a single ended 6V6. No matter how much the gain you can only get 6 watts out. you could have high gain or low gain in the pre amp, but the max power out remains 6 watts.


    or does it? what does the tube spec mean when they say max power out? Is that max clean power out? what about beyond the clean power, can a single 6V6 put out more than 6 watts power? I think it can.





    how about a single ended amp with a master volume? Do they exist?





    what about disconnecting the bf tone stack? that unleashes a lot of gain in the preamp.

    it makes a champ twice as loud, if I remember right. twice as loud is ten times the power, right? maybe 4 times?




    the bf tone stack, even when dimed, cuts signal by a factor of 4. disconnecting the tone stack boosts the signal to the 2nd pre amp stage 4 X.



    How much power is the single 6V6 putting out now?
     
  14. kelnet

    kelnet Telefied Ad Free Member

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    If top gear in the 20-speed bike produces the same pedal-to-wheel drive ratio as the single-speed bike, then they would both have the same speed if the pedal speed is matched. Speed would be the equivalent of decibel output in amps.

    Your answer suggests that the idea of a low-gain amp or a high-gain amp is incorrect. An amp is neither high-gain OR low-gain. Gain is merely a setting on the amp, one that can be adjusted up or down. A low-powered amp can be set to a high level of gain and a high-powered amp can be set to a low level of gain.

    Doesn't that contradict the common usage of the term "high-gain amp"?
     
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  15. BigDaddyLH

    BigDaddyLH Telefied Ad Free Member

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    Next: vibrato or tremolo
     
  16. Wally

    Wally Telefied Ad Free Member

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    They are the opposite of what Leo called it because Leo could not possibly agree with either P. Bigsby or the Gibson people. Bigsby beat Leo to the vibrato, and Gibson produced tremolo-equipped amps before Leo did.

    And what in the world is the dog in your avatar upset about, Big Daddy?
     
  17. Lynxtrap

    Lynxtrap Tele-Holic

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    Yes, maybe I was thinking more along hifi-lines. And tube data sheets, circuits and applications in manuals etc were focused on utilizing tubes under "optimal" and linear circumstances, with minimal distortion. There is probably a reason it's called "distortion"...

    But of course people pretty early on also started to figure out ways to use tubes beyond optimal/intended design parameters to obtain certain effects.
    Others worked in the opposite direction, like coming up with negative feedback to minimize distortion.

    Fender and every other amp maker at the time. But Fender is a funny case, like the marketing for the 4x10" 1959 Bassman. My take on it is that Leo Fender himself and anyone working with him certainly knew it was all BS, but it might show what the selling points were for an amp back then. This is borrowed from the Tone Lizard site:

    The Fender Bassman Amp is a compact, portable musical instrument conservatively rated, with all necessary controls for handling complete High Fidelity music reproduction.
    Power Output: 60 watts at less than 5% distortion.
    Frequency Response: With optimum tone control settings +1 dB 20 to 20,000 cycles per second at 50 watts.


    …features the latest in electronic design, inasmuch as the inputs are so arranged that tremendous surges of voltage can be accommodated without overloading the first tubes, thereby eliminating a great source of distortion which is normal in all older type amplifiers.
    In addition to these many features is the fact that this amplifier has an over-size power supply employing an extremely heavy duty power transformer …
    The output transformer is also much heavier than is usually found in amplifiers of this size.
     
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  18. Bendyha

    Bendyha Tele-Afflicted Silver Supporter

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    Oh yes...lets get into Dynamical Analogies, that will help clear things up!
    upload_2019-1-8_22-38-1.png

    Maybe this book will help......
    upload_2019-1-8_22-41-5.png

    Just over 300 pages of very dryly presented mathmatical calculations, equivalent circuits & frequency/impedance responces of various triode topologies....one of the duller books I have.
     
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  19. clintj

    clintj Friend of Leo's

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    Perhaps we can all agree that this is gain?[​IMG]

    Sent from my Pixel 2 using Tapatalk
     
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  20. blowtorch

    blowtorch Telefied Ad Free Member

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    Gein
    upload_2019-1-8_18-46-17.jpeg
     
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