Tube thoughts from Ken..

[JoeCon]

Matt

So if I put in EL34's and bias it kinda hot lets say 80% thats gonna be a higher voltage than what 6V6's are gonna need. So how could you just swap tubes without adjusting the bias? Even when changing the same kinda tubes you readjust the bias, oui?

Unless it's biased hot for 6V6's and cool for EL34's?? Then just plug and play...

[matt h]

(deleted)

[Hogy]

A few things.

That "glitch" in the Express is real. Ken told me about it. No, I haven't heard it in person, but it is some kind of intermodulation gargle that only happens at a certain frequency, played a certain way. Apparently Ken never knew about it until an astute (read: OCD) Trainwreck owner pointed it out. Ken tried to chase it down and found it not to be a problem with one specific amp, but an inherent oddity in the circuit. Yes, I also remember him saying that it didn't happen with certain output tubes.


Ken recommended a bias voltage of -40V in the Express owner's manual. I asked him about it and he told me it was a reasonably good middle ground for both Siemens EL34s and RCA 6V6s without having to reset the bias when switching between them. A safe spot, if you will, allowing a new user to experiment with both tube types without doing damage. Ken was a Groove Tubes dealer at the time, and both these tubes were available through GT when the manual was written.

I know that Ken biased amps he tuned up for a specific set of tubes by ear.


Ken was not afraid to experiment with bias settings, in both directions. When I first sent him the original Komet 60 prototype for evaluation, it came back with GT/Tesla E34Ls. There was nail polish on the shaft of the bias pot so that it wouldn't move. The tubes were biased around 11mA per side. That's what he liked with this particular set of tubes, in this particular amp, on that particular day.


Hogy

[matt h]

(deleted)

[Richie]

A few things.

That "glitch" in the Express is real. Ken told me about it. No, I haven't heard it in person, but it is some kind of intermodulation gargle that only happens at a certain frequency, played a certain way. Apparently Ken never knew about it until an astute (read: OCD) Trainwreck owner pointed it out. Ken tried to chase it down and found it not to be a problem with one specific amp, but an inherent oddity in the circuit. Yes, I also remember him saying that it didn't happen with certain output tubes.


Ken recommended a bias voltage of -40V in the Express owner's manual. I asked him about it and he told me it was a reasonably good middle ground for both Siemens EL34s and RCA 6V6s without having to reset the bias when switching between them. A safe spot, if you will, allowing a new user to experiment with both tube types without doing damage. Ken was a Groove Tubes dealer at the time, and both these tubes were available through GT when the manual was written.

I know that Ken biased amps he tuned up for a specific set of tubes by ear.


Ken was not afraid to experiment with bias settings, in both directions. When I first sent him the original Komet 60 prototype for evaluation, it came back with GT/Tesla E34Ls. There was nail polish on the shaft of the bias pot so that it wouldn't move. The tubes were biased around 11mA per side. That's what he liked with this particular set of tubes, in this particular amp, on that particular day.


Hogy

I guess similar in a way Mesa,or GT does. If you know what tubes are that is going into the amp, and match those.. then you won't need to bias it, they should be the same..or close enough..

[njwrecks]

In response to Hi Tests article, specifically the statement about how Ken would just confirm standard beliefs rather than try to explain a new concept to a customer, I have a story.
I brought my BF Bandmaster head to ken's shop for repair. He asked if I liked/used the Vibrato and would I like the channel disconnected and turned into a high gain channel. So I agreed, picked up the amp, had a normal channel and a high gain channel that was just that , wild and over the top. He also replaced the power chord with one that was twice as thick. "I asked why the thicker chord ?" His answer - "I ran out of stock of the normal sizes." I still have that head and remember him saying that clear as day.

[rooster]

Hogy, thanks for this info. It's really mind-f'ing to consider 11ma, and yet this is what Gregg is suggesting, something much lower than 40ma. I have tried 20 ma on the XF2 Mullards (as Gregg suggested) and do not like them there. Eh, and I may be a weak player, or perhaps I am not prepared to turn the amp up to 12 o'clock every time I play. And I use pedals in clubs, for that matter, a modded TS9 or an Barbur LTD.

But back to the tube glitch. I hate to say this because I am not typically the one to get hung up on vintage gear, but they don't make tubes like they used to. And it's true for the TW amps, but also true for every other brand out there, IMO.

Changing subjects slightly, JM told me recently that he at one time, years ago, played some very quick (speed metal?) type riffing through a Fender BF amp so that Ken could hear how the amp was overwhelmed by the barrage of notes. JM said Ken seemed surprised to hear this as it happened, suggesting that this might have been a wheel-turning event for Ken.

OK, let me try to put this together.... somewhat. A guitar amp is a 'series' type thing, with the path of the guitar signal entering in one end (preamp) and exiting out the other as it reaches the 'end', in this case the speakers. If you wax visually for a moment, it's somewhat like a length of a continuous piece of wood - visualize a either a 3 foot long (dry) stick or a (dry) 20 foot log, or anything in between. If you were to strike one end of the stick or log with something like a hammer, you should feel the impact of it resonating through it and arriving at the other end. Hopefully. And it won't be amplified, the impact will be reduced. To build an amp - and to connect all the components as miraculously as God connects all the cells in a tree branch - is a daunting challenge - and - in the case of a guitar amp, the circuit/path needs to amplify the original signal AND make it sound deliciously compelling/inviting/inspiring. And some people believe that people like Ken and Alexander have done this. Maybe they have, too. But this is not the point of my revisit to this post.....

Today I'm asking anyone who's listening: Are you gonna do this with the wrong tubes? Are you going to do this with the wrong wire? Are you going to do this with the wrong caps?

[Plexified]

This is probably the same resistor that Ken made the change to in the Climax . I think it was the 100k in the pi to 150k . Pretty subtle difference actually . Funny trying to track down a hic cup heard by an ocd dude on a scope . I wonder if he was a monster player or just a froot loop .

What do you guys find are the best sounding of these tubes in current production now .

EL 34
RL 84
6L6
6CA7
6550
6V6
12ax7

Last thing is Ken suggested the 12ay7 in the PI and I liked it after a while .

[rooster]

Wow, the 12AY7 is a surprise. I have never tried this but I guess I should.

As to new tubes:

J/J E34L and the KT77, in that order.

I am using the Saratov EL84s in my personal Rocket and Reflector EL84s in two others. The Russian glass just seems a bit more transparent to my ear.


Everything else I use is NOS, sorry. And this would be in the TW amps. Being fair, there are different amps that the various tubes available today might sound really good in. It's kind of a hit or miss thing. Hey, but we'll all be using something new sooner or later.

[Plexified]

Thanks Rooster and all in advance ,
Yeah I was definitely thinking that we all are going to have to buy new stuff also and certainly for the TW circuits . When Ken suggested the 12AY7 it was not about gain , it was about the quality of the end signal . It was also around the time he was really digging the Crowther Hotcake and say a vintage wah . He was almost using the express like a Hendrix set up with this . Big bold tone , the Hotcake and the Wah interacted like a small lead boost and when the Wah was engaged with or without the cake it gave a noticeable lead boost . Was very resonant . I suspect a part of his secret sauce is circuitry resonance . Their is a synergy that happens with magnetics in this realm . You can even excite the magnetics with whats called an exciter that influences with capacitance . Its a hard concept to write about yet , I am still working it out myself . But I am almost sure of this . He would even talk of resonance in strange places like a head box or tube being irradiated with magnetism . Just some food for thought here . He was also so out their with magnetics he spoke of the earth having a signature and using it . Wha ? Thought it was him screwing with me , but he actually wasn't . I'll share it when I can explain what I'm working on later.

[rooster]

Wow, that's cool stuff. Really, I credit Gregg Levy with an eye opening experience for me in regards to tubes and bias, and then there's JM and you, too. All helpful and informative, all speaking to the uniqueness of Ken's thinking process and interests.

BTW, Gregg is all about the Liverpool and I think this is interesting all by itself. Frankly, as much as I like the Rocket, I like the Express better, and FWIW I have never built a Liverpool. How about you, Plexified? What's your favorite?

[Plexified]

Wow , good question . I will try to be as concrete as I can here . First I love the sound of EVH , SRV and a Swedish chap names Yngwie . Its what I love soundwise and I play it all . And I should not forget to mention guys like Rhoades with live King Biscuit Flour Hour tone and George Lynch live at Radio City Hall tone and Schon , Gilmour and bunch more . So I love a strat with the Liverpool . Its designed for it . The Rocket is the answer to the problems with a VOX like overheating and FIRE . And the Express was an answer to the hot plexi . A guy wanting a plexi mod . Like the plexi with a mod , well try this .... Express was the answer to that . And if its too loud put in some 6v6 TUBES with a 12ay7 . So I guess I love them all . Now to answer your question , Trem Rocket . Boom , the most rare and plus I can put goose bumps on the necks of hot chicks playing the Star spangled banner . Click on my hot cake pump up the wah and now I am a rock star . If I had a strat older than me I would go liverpoole . That's what Ken designed it for . A strat , of vintage to hear it all . The Express is a statement . Take your best plexi and now its deathmatch . Headcutting at its best . I put my head on the chopping block for pink slips . I think it says that on the inside of the Trainwreck and Vegas gives odds for the challengers as well . So you cannot loose here . Its just that you have to bring your A game . And expect to have every impurity in your playing amplified to entire embarrassment status . And after that trauma its good . But the Trainwreck recipe loves good tubes , good speakers and good feel or hands . I think you all feel me here . I will post the follow up to my statement on resonant circuits soon in the main page , because it is really mind numbing . I cannot explain what I have seen is the issue . So I will probably just post and maybe together it will be more . Peace , David

[Cameron]

If I remember right.....the glich.....was the swirl sound some amps do......the low tone ....when you hit a harmonic and pull the bar up.....if you are a VH guy you have probably heard this.....and it might sound like bad filtering.... but its not ...its the output tubes and P.I. combo
And some playing styles bring this out ....wammy stuff is when I get it to happen ...if no wammy bar noodling ..you probably won't notice it.