Graded 6V6's For Earlier Breakup ??

[ksl]

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~
kenny 
🕉🎶

[WRGKMC]

That's a single ended amp running a single power tube.  Changing its bias level by changing the fixed resistance is the only thing that's going to change the amount of drive.  You can try different brands of tubes but I doubt it will have much effect on an amp that simple.  

Given its age Its also a very dangerous method of changing the sound you want.  The caps in that amp are likely original and have values that have drifted far out of specs and also seeing its still got metal can type army surplus tubes from the 40's (The Military used metal tubes instead of glass so they didn't damaged in combat so easily) If you go and monkey with its specs you may wind up smoking the thing.  Besides its far cheaper to simply buy another amp then to pay someone with enough engineering knowledge to do the work correctly and safely.  

Beyond that, if you want more drive and punch try an Electro Harmonix tube instead of a JJ. They are much higher quality and have fuller frequency response with less noise.  It will likely get louder too which gives you more headroom.  

Anything beyond that I'd focus on either a different amp speaker which has a huge impact on tone and drive, or you can change the guitar pickups (or both) to achieve the changes you want.  Pickups mostly affect the amps front end and change how much dig and drive you get from the strings.  Frequency response and preamp drive are affected too.  Just remember the Hotter the pickups, the narrower the frequency respose. You may get more drive but you also loose top and bottom end.  

Speaker changes since that amp was original built are like night and day. Not only are they far more efficiency, (more sound for less watts) the types of materials used are going to give you the best tone vs drive, vs loudness.  I wouldn't be surprised if the original speaker has an efficiency of a Hi Fi speaker in the 70/80dB range.  A new speaker can have an SPL of 90 ~ 110dB and not only give you better tone but make the amp 2~4X louder.  Of course knowing which speaker  (or pickups) that might give you what you need is not going to be an easy decision.  I've been an electronic tech and musician for over 50 years and I cant tell you what might be best for you.  If I had the amp in hand using your guitar I could "instinctually" find better accessory choices based on my experience but there is nothing to say my choices would be anything you'd prefer. 

This is why we are all mostly left to using the trial and error method of getting what you want.  In short you roll the dice, spend the money and hope you don't get burned too badly if you make a poor choice.  The best you can do is educate yourself as much as possible like you're doing here before buying something. This should at least help you avoid making complete failures by not diligently investigating what you buy/  Believe me, I could have retired on all the money I've spent on stuff I failed to study thoroughly. Then again you don't learn those lessons without someone looking out for your best interest that has the wisdom to help you choose. When it comes to tubes, they quit designing new tubes 60 years ago.  The guys like myself who were trained in tube technology are a dying breed now. Few even mess with them any more because there is so little profit in it.  You cant earn a living at it.  Companies that make amps simply recycle classic designs. Since the tube choices for audio are limited so are the amp designs.

Fact is, there isn't much difference between tubes. On top of that you can only wire a tube so many ways to get decent tone while remaining within a safe range of tolerance.  The more you push them to be unique the more likely you wind up having catastrophic failure. If you can afford huge repairs or do those repairs yourself then  maybe you can risk running them out of specs to obtain some small measure of difference.

In your case I'd recommend the K.I.S.S. method.  You have a simple amp, Keep all mods simple and reversible.  Try some a different speakers so you at least have some idea of what might sound best, then save the original speaker in case you sell the amp.  take it to a music store and try different guitars through it then note the pickup type. Most amps have an ideal match. The pickups, the amp circuitry and the speaker all complement each other.  It only takes one of those things to be out of specs and the tone goes to crap.