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6V6's Graded For Sooner Breakup??

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  • 6V6's Graded For Sooner Breakup??

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ID:	6082579 Howdy all~ Just as JJ has their EL844 for 'allegedly' earlier breakup, does any maker have the same thing going on for the venerable 6V6? The amp is one of my many fantastic homebrews, with this one having been pulled from an old Bell & Howell projector & brought back to life as a very solid amp, with 2x6V6, 1x6SC7, 1x6J7, & a 5Z4 recto that you could cook a Kobi steak on,,, Amp sounds fantastic w/that classic robust 6V6 sound w/some grain drive,,, BUT, short of having my tech ripping apart this overbuilt chassis again, if i could get the the amp to sound like it's '12' instead of like '9', & nudge up the gain just a smidgen, I'd happy as the day is long!! So again, what's out there in 6V6's that may get me 'there', that are 'rated' on a 1 to 5, or a
    1 to 10 scale, & not be a possible 'reject ala the EL844, & still sound good? Maybe a rectifier change & rebias would get me there as well? I don't use OD pedals other than my Barefoot Model G (Gibson) effect, but I don't want to color the sound at all, or get louder,, but just to get a extra tiny touch of drive....
    Thnx well, & be well~

  • #2
    I don't know of any particular 6V6 variants that advertise " sooner break up ", but you can probably find a lower grade version that simply has less output ( a 1 out of 5 as you mentioned ). Another way to play with getting power tube breakup vs PI or preamp breakup is to change the grid leak resistor/s for the power tube/s. Be sure to check the bias after messing with the grid leaks of the power tubes though. If you use larger grid leak resistors, more signal will go to the power tube causing it to break up earlier in your volume sweep. So if you don't have enough volume as it is currently to get appreciable power tube breakup, this is a way to push them harder. Conversely, if you have more than sufficient volume and you simply can't stand to be near the amp before it breaks up, you can reduce the grid leak resistance to make the preamp do more work. Reducing the grid leak value will reduce the amount of signal going to the power tubes, which will require you to turn your volume up. This will make the PI work harder perhaps getting it to distort. You can use the power tube grid leak to fine-tune the point where the power tubes and pi distorts, but it does not address how much output volume you will get. In theory, if you have enough volume sweep from your PI, you will achieve power tube distortion regardless, all you can do is adjust where in your volume sweep that occurs.

    I don't think you will find much gain by trying to change the rectifier. I am pretty sure it is already one of the lower-rated ones there are and has a pretty significant voltage drop.

    Changing the bias may get you somewhere, but come with downsides. Class A amps can only be biased so hot before you just start burning up tubes. And to be honest, the few watts you gain or lose either way will never change the output volume enough to go from intolerable to just right. Bias to make the tube happy while hitting the desired quality of sound within its range.

    Often times it is easier to reduce volume by finding a speaker that is simply less efficient or getting a power soak, The Two Notes Captor X is an amazing device and I am so glad I got one! I can listen to my amp silently if desired. Its attenuator circuit doesn't sound great but is good enough to take the edge off and allow you to play your amp at high volumes at closer to bedroom levels.


    • #3
      Or Fender GT's Red, White, & Blue rating?
      Thnx again~


      • #4
        I think you would need to change the amp circuit to use a different preamp with different a gain factor / transconductance.


        • #5
          Remove the negative feedback wire common in most amps of that era…breakup will happen sooner and and less abruptly…


          • #6
            Buy an OD pedal. It's literally what they were designed for!
            Join me in the fight against muscular atrophy!

            Originally posted by Douglas Adams
            This planet has - or rather had - a problem, which was this: most of the people living on it were unhappy for pretty much of the time. Many solutions were suggested for this problem, but most of these were largely concerned with the movements of small green pieces of paper, which is odd because on the whole it wasn't the small green pieces of paper that were unhappy.


            • #7
              Originally posted by justFred View Post
              Remove the negative feedback wire common in most amps of that era…breakup will happen sooner and and less abruptly…
              there will also be tonal changes. on my dr i used the old ground switch as a neg feedback defeat switch. when off, the amp is louder, brighter, more aggressive, and has more over all gain. i dont know if it breaks up at a lower perceived volume, even if the dial is maybe a touch lower.


              • #8
                The JJ EL844 is actually a lower wattage tube.
                There is no 6V6 that is like that. But somewhat ironically the JJ 6V6 is actually cleaner typically as it more resembles a 6L6 in operation.

                You're better off looking at either speakers, an attenuator, or as mentioned an OD pedal as a boost.


                • #9
                  The only other 'simple' option I can think of might be trying old 6V6 (either metal can or coke bottle types, if they fit), but you'll want to consult with the tube spec sheets and B&H schematic and your tech to make sure there are no issues with that.

                  Note, my understanding is pre-1960 6V6s were spec'd at design-center dissipation, which was 12W, and after about 1960 the industry standards changed to report design-max, which is 14W for the 6V6. So really 6V6s are 6V6s, they didn't actually change their output by model. However, some other characteristics did change, like heater warm-up time. Also, I've read the metal versions can be microphonic; but haven't tried them myself (except for my grandfather's old radio, which has never exhibited tube microphonics).