Another "mystery tube"- NoMeansNo's Rob Wright, help me make a tube pre?

[Earthscum]

So, this is the pentacle of what got me started in modding stompboxes... trying to find that sound. With my trusty Ibanez (GIO) GS205 and my Peavey TNT 115 BW, I could get just about any tone I wanted, but the distortions were eluding me. I have always dug on the sound of the basses in D.R.I., Wrathchild America, Megadeth... that nice punch, and the overall tones.

So, we get to one of my favorite bands, NoMeansNo. This is basically a bass-driven band, starting with Jon and Rob Wright (brothers) gigging a little punk band together, Jon on drums and Rob, as always, on Bass. Awesome band, overall. Things like this:

http://www.nomeanswhatever.com/press.html[/u]]http://www.nomeanswhatever.com/press.html
"Over the years, Nomeansno has created a sort of "Scavenger Hunt" for fans by leaving a piece of stage gear and/or musical equipment in a secluded spot in each Canadian city they play in. Elliott Marks of Nelson, BC, rejoiced upon finding a Tom Holliston Flying V axe behind the hippie bakery downtown. Mrs. Rodney Carthon of Red Deer reported finding Rob Wright's famous slide rule tuner outside her garden of petunias in 1997, the year of the infamous Rocket RV debacle on the Trans-Canada."

Gotta love that.

Anyways, back on topic, in a Bass Player Magazine article, archived in a thread on the Talk Bass Forums (hope they aren't on the sh*t list here), Rob says about his Sound:

"nomeansno's rob wright admits that much of his sound comes from sheer volume. "i don't think i could get away with my stage volume in any other band," he says. "that's my sound. but it's loud music and you can't fake loud music. loudness has a certain impact; it's got to have a visceral feeling. if it doesn't, you're just lip-syncing to your own music.""

I love that. And eventually the article says this:

"wright plays stock fender precision basses. " i like the new ones with the cheap mexican pickups. those pickups are the greatest- they're so hot they're microphonic. the trouble is i sweat so much on my bass that i kill it within a year, and i have to get all the guts replaced because they're completely corroded. i work my bass pretty hard but that's what a hammer is for." he drives a marshall 4x12 guitar cabinet with a 300 watt marshall 3530 solid state head, which includes one tube " to soften the waves". the amp is not common. "everyone else has trace elliots and gallien kruegers; they're great; but that's not my sound. i'm not looking for fat , clean lows.i'm looking for mid range growl- basically a lemmy tone." rob uses a pick on .045 - .105 rotosound strings. his only outboard effect is an eq pedal he sometimes steps on to cut all the highs, turning his sound into "a complete dub bass.""

Ok. So, he had a buddy like us that modded his head with a tube. I've searched, and this is all I get... it's about the same as the mystery tube in the Big Muff that gave Korn their super-thick sound.

This is about the amount of "grind" I am looking for (maybe variable so I can tune in a little less or more). http://www.myspace.com/myspaceiswrong#!/myspaceiswrong/music/songs/metronome-53856492

What I want to do is make a tube based interstage. I'm totally ok with hybrid stuff. Basically, I guess I want to make a tube distortion pedal, but it will be part of my pedal board. This is going to be a long project, but I figure since I'm going to have mains power going to a Spider PS already, I may as well plan me a nice sounding tube pre for some distortion.

I say I'm fine with hybrid design because I'm going to use this full time, and will be running a DI out, so the final output will probably be from a NE5532 or such.

As is, I have a "McTube" supply on a tube pre to tone to follower, I think. I may have tried bootstrapping, haven't looked... but the supply is fine, fairly quiet, about 110V B+. If I can re-use it, awesome... if not, oh well. I know the heater supply half will be fine, maybe step the voltage up from there? I have a 12AX7 LPS, the characheristics seem to be s bit off from most of the other 12AX7's, but that's not much of a problem. Thanks to Merlin's site, I understand how to read and bias for the better part of keeping myself out of trouble.

I think what I'm most looking for with the tube is the compression and the distortion when I really dig into the strings. I just don't know how to coax it out of the tube. With what I was trying before, I just kept making clean amps, unless I biased hot or cold, so I tried a mosfet pre-gain stage which I ran off the heater supply... needless to say, it worked a bit, sounded ok, but it hummmmmmmmmed. Yeah, this was about 2 years ago, and I really didn't get what I was doing (should've at least regulated  a 9V off the 12V to get rid of some of the hum, etc... separate supply).

So, any ideas on a design? If I can throw a tone stack in there, sweet... I have a "split muff" that sounds great, but consists of 2 50k pots to ground. Is this too low to run? Should I bump to 500k (and other components accordingly)? Or should I run a tone section after the tubes, before an op amp follower?

Thanks for the help, guys. This is gonna probably be a project for closer to the end of the year, but I figure if I get my head on it now, maybe I won't have to pack all my pedals in a bag for much longer. I'm getting laughed at by my multi-fx playing guitarists.  

[iccaros]

you can try this -->

I have had successes getting good distortion from it.. I am working on putting a unity gain opamp in the front of it, worked on breadboard, just not time to complete now..  you may want to add a volume pot at the end, as almost any effect after would be in pain, with that pentode out.. say a 1meg output pot

I replaced R2 with two 1meg trimmer pots, this way I could adjust for any tube, see the paper on the thread first post to see the goal of the first tube..

Its switchable so if you want a clean boost you get it, or switch to just the pentode for a little dirty boost and both for distortion.. 


the thread http://www.diystompboxes.com/smfforum/index.php?topic=91745.0

The submin version is cool, but no real distortion.

[John Lyons]

I don't have any leads for you but I also share and affection for No Means No and their sound, bass included.
I've seen them several times over the years and even have done sound for them as No Means No and
The Hanson Brothers (side project) at a cub I ran for a number of years.
Nice guys and many great records.

[glops]

NoMeansNo used to be one of my favorites.  I was so blown away when I heard Wrong.  I think I was 16 or 17 at the time.  I saw them for the first time in Dallas for that tour and it sounded just like the record.  Really full and really powerful. Years later, I opened for them with the band I was in.  Emos in Austin.  Great great sweet guys.  I love the sound of his bass. Our bass player used to get really close to that sound with a rickenbacker going into a dying Peavy solid state.  Good luck with your venture, that's a great sound....

[Johan]

Im not a bassplayer, but I allways encourage bassplayers I know to try 12inch speakers. deeper than 10's and more punch than 15's..most who try it end up with a 4x12 sooner or later..
just a thought
J

[Pigyboy]

I don't have any leads for you but I also share and affection for No Means No and their sound, bass included.
I've seen them several times over the years and even have done sound for them as No Means No and
The Hanson Brothers (side project) at a cub I ran for a number of years.
Nice guys and many great records.

I with John. Can't really help but we opened for them once at the SO36 in Berlin and it was one of the happiest days of my life.
They are the kind of guys you could probably get hold of and ask what they are using...

[Strange]

NoMeansNo are by far the best Canadian band ever. Needless to say they are my favourite band.

I have been lucky enough to share the stage with them as well. I agree with Rob in that sheer volume is an important part of his tone. He drives the hell out of those Celestion (75s?).

[Earthscum]

I don't know what dark corner of the earth I've been living in... I don't think I've met 5 people in my life who even knew who NoMeansNo were. Crazy!

So, I looked in my box and this is what I have right now. Everything is, for the most part, P2P, so it's all flexible. The mosfet stage is on it's own board. It works great, except for the hum. Would disconnecting tube pin 9 from Ground do any good or bad?

So, I built this over a year ago, and who knows what I was thinking. I'm not too convinced that if I got it all working right that the bootstrapped tubes will make much distortion on their own... maybe if I was driving another stage after. Is this right? If so, would I be better off doing 2 stages with a volume between?

[amptramp]

There are two "grounds" here that I would prefer to see connected: the ground at the junction of R5/R7/R8 and the ground at R14/R17/R19.  The effect of C10 and C11 is interesting in that the rectifier pulse hits the anode and cathode of C11 simultaneously but the cathode first of C10, then a delayed pulse to its anode.  The same thing happens with C12 and C13.  If you were to cut R20 in half and leave half where it is followed by the other half between the cathodes of C10 and C11 and do the same with R21, putting half between the positive and half between the negative terminals of C12 and C13, you  might eliminate some of the buzz.  It would be best if the time constants were similar (including the effect of the load).  As it is, your ground connection is through the resistance of the heater.  The resistive connection is essentially paralleled 42 ohm resistors giving 21 ohms; not good for what should be a solid ground.  Removing the pin 9 connection would result in a huge increase in noise because there would be no ground reference between the FET stage and the tube stage.

The tube stage looks to be quite linear - I see nothing that indicates that you are trying for distortion unless your plate voltages are low.

[MrTonesNZ]

Had to look it up. Cool sound, super punchy

[Earthscum]

I'd have to search around, but I think you just listed every problem mentioned about the RMII supply, Ron.
I do believe I'm going to be reconfiguring some things. As it is now, and you missed this, if I were to connect the 2 grounds, it would short out pin 9 and 5. The heater supply swings 6V +/- of the tube supply ground. As I understand it, I can get away with it here because of the 110V B+ being low enough.
Thanks for confirming that I probably won't be getting much distortion out of the tubes. That's really the whole point unless I just go for a driven stage like suggested earlier. That does look tasty, lol.

[amptramp]

Correct, once you make the changes I suggested, the pin 9 connection should be lifted.  (I didn't miss it - I thought it was obvious.)  I do like the connection between the output cathode follower and the R15/R16 junction.  It makes R15 look much larger than it is and should give you a bit more gain.  If both sides of R15 move up and down the same amount in voltage, it looks like there is infinite resistance, but you can still supply the B+ to the first triode.

[Earthscum]

So, I did the ground connection thing and a large portion of hum went away. I pulled the musfet out and hum virtually disappeared, so I'm gonna look into an entire reconfig of this. It sounded great, like a clean amp. The only overdriving I got was from the Mosfet.

So, think I should just do 2 gain stages, direct input to the tube (no pre-gain, buffer, etc)? I don't really need a tone section. I was going in a different direction with this, originally... more screwing around.

I gotta say, though... I'm considering just ripping out the pre-gain through the tone and just using this bootstrapped setup. I was running different distortions through it and, wow... it has a certain "honk" to it on bass. It turns the Bazz Fuss into a completely different beast altogether. I love it!

ETA: I noticed that when biasing, my cathode voltage was hardly changing through out the entire 10k range, getting the most gain with the cathode directly to ground. The cathode voltage would vary from about .3-.5V. Do I have something wrong here??? Or am I supposed to measure the actual Grid to Cathode voltage? I was just measuring cathode to ground, across the trimmer. At ground, it would drop to 0V, so I bumped it up just a hair and played with it there. I didn't even think to measure anything else, just making sure it fired up at the very least.

ETA, Again:

Not sure if this helps at all.

[mothercruncher]

Wrong had a huge impact on me too as a 15 year old hearing that outpouring of played and sung emotion. Had no idea they did little Easter egg hunts with their gear, that is too cool. Wonder how much has been lost over the years by some random fella picking something up and then sticking it in the garage to rot?

[Earthscum]

I was wondering about Grid Leak Bias... in reading through some of Merlin's stuff, it sounds like low enough voltage I could take advantage of that. Is 110V low enough, or does it have to drop lower, like 90 or 50V? When I was biasing by ear, I got the most gain from running straight to ground, but I gave it a couple hundred ohms or so because I didn't know if it was safe to run the Cathode straight to ground.

I've decided to yank the whole mosfet and tone stage out. Haven't got to it yet (probably Sunday evening). Do I need to put a 68k in front of the grid? And, again, can I bias my cathode to ground? If so, what do I need to watch out for? I want this to last a while and not be changing the tube every 3 months, lol. "Pack of D'Addario XL5's and a 12AX7LPS"... "That'll be $40 with tax" 

[amptramp]

Grid leak bias and contact potential bias are two separate items.  Grid leak bias depends on pulling grid current at the highest part of the input waveform and was used for early AM detectors, beginning with all the radios in my collection from the 1920's.  This introduces a certain amount of distortion and also provides a tendency toward "gulp distortion" where a high peak may bias the tube so heavily that there is a noticeable dropout in the signal intil the bias voltage leaks back to usable levels.

Contact potential has been used in the All-American Five, a radio design that started in the 1930's and continued until the end of the tube radio era in the early 1970's with a design that most collectors have memorized.  The first audio stage was often a 12AV6 or 12SQ7 which have identical characteristics to one half of a 12AX7.  The cathode was gounded since it was also shared with the detector diodes and grid bias was obtained through a 10 megohm resistor.  The cloud of electrons emitted by the cathode is intercepted by the grid so that the grid develops a negative bias of about one volt.  I prefer cathode bias since the high gain means you do not need a bypass capacitor and there is both DC and AC feedback via the cathode resistor - if the tube pulls more current, the bias becomes larger and stabilizes the gain.  The relative size of the plate and cathode resistors to obtain the small amount of bias needed means that you can get almost the same gain without bypassing the cathode resistor with a capacitor and this eliminates a gain drop at low frequencies.

[markie83]

just listened to a couple of you tube clips......since its the "sound" your chasing a pedal may or may not be what your after.

I listened to the clips before finishing your post and I was IMEDIATELY thinking use cheaper speakers.....then I finished your post and I saw that he is using a guitar cab......I think this is probobly the biggest part of his sound. Other than that I think its about passive pickups and alot of mids/highs to get there.

IMHO I would look at speakers and maybe even different/no tone cap in your bass (maybe a full bypass switch so you can run the pickups straight into the jack).....now if you have active pickups disregard the last part, I think you will have alot harder time getting "that" sound with actives anyway.

JMHO chase the sound not the gear.....I dont even think you'll have to have a tube(or overdrive) in the mix since it sounds pretty clean..........I know I keep saying it but it just sounds like pure jacked passive PU's(my warwick rock bass actually sounds alot like this when jacked and its passive) with cheaper speakers.

....good luck and keep rockin'

[PRR]

> again, can I bias my cathode to ground

Yes. Look at the plate resistor. 100K across 100V supply means you could have at-most 1mA. Worst dissipation is half voltage: 50V across 100K is 0.5mA, tube gets 50V*0.5mA or 0.025 Watts.

> Is 110V low enough, or does it have to drop lower, like 90

Depends on ratio of supply voltage to _signal_ voltage. A happy tube stage can make a clean signal about 15% of its supply voltage. Say 16V for a 110V supply. 5V after your 1Meg:500K divider. But you are feeding a guitar input. Anything over 1V or so is utter overload. So the tube is loafing, dead-clean, up to and past the point the guitar amp input overloads.

You need to "strain" the tube to have much tube-sound. You may have to turn the output pot WAY down, below 2.

[soggybag]

To be honest, after reading the article I get the impression the whole thing is made up. I don't believe that they leave their gear for people to find in various cities and, are you sitting down? I don't believe there is an extra tube in anyone's amp.

I saw Pelican last weekend. I accidentally happened to notice one of the pedal boards. I don't normally look at these things. Really, I could care less. Anyway, there was a tube type over driver in a box. Looked like it had two 12AX7 type tubes in it. He had a pretty good tone. Might be easiest to place your extra tube outside of the amp?

[Earthscum]

To be honest, after reading the article I get the impression the whole thing is made up. I don't believe that they leave their gear for people to find in various cities and, are you sitting down? I don't believe there is an extra tube in anyone's amp.

The myth is real, let's eat.

I have to ask... you aren't an ATS troll to follow me here just to debunk everything that comes from me, are you? What you believe and what is real are apparently 2 different things. If I told you that I saw a pic of a guitar with a tube in it, and it's claimed to work, would you believe me? If you can put  a tube in a guitar, why couldn't you put it in an amp as a pre? Jeez... already have power to run to it.

I saw Pelican last weekend. I accidentally happened to notice one of the pedal boards. I don't normally look at these things. Really, I could care less. Anyway, there was a tube type over driver in a box. Looked like it had two 12AX7 type tubes in it. He had a pretty good tone. Might be easiest to place your extra tube outside of the amp?

Thanks a bunch for reading everything. I appreciate your input, but c'mon...

What I want to do is make a tube based interstage. I'm totally ok with hybrid stuff. Basically, I guess I want to make a tube distortion pedal, but it will be part of my pedal board. This is going to be a long project, but I figure since I'm going to have mains power going to a Spider PS already, I may as well plan me a nice sounding tube pre for some distortion.

I am building this into a pedal board. I DO NOT want Rob's tone. I DO NOT want that fender sound. I DO want to get some grind from a tube. He says a single tube, but it could be anywhere in the chain, or even replacing part of the SS chain. That's inconsequential to my desires.

So, as an update, I tried pulling the Mosfet stage, grounds connected as per Ron's rec's. It sounds ok... volume is a little low at the 1M/500k, but I'm leaving that alone for the moment. I pretty much went stripped it down to the bare tube stage. I have to say, though... the mosfet stage really warmed things up, so I'm not sure what I want to do now, lol. I'm definitely thinking an input amp is necessary, and Paul and Ron's comments support that (or, told me so, lol).

Well, guess I'll get back to experimenting.