Tube boost + overdrive running off a 9 volt battery

[Krinor]

Thanks for the translations. Could I be so bold as to ask you to please translate the whole article and post it for the benefit of the DIY community ? I know a lot of people would be very gratefull. 

You're very welcome.

As for translating the rest, most of it isn't of much use as he makes lots of references to some obscure Japanese magazines and texts, and the rest is just some "shoulda/woulda" kind of brainstorming.

A few things that may be of interest - he said that he bought a tube socket with pcb pins - but the pins weren't sized for his board holes so he had to do a lot of bending and twisting to get the socket mounted. One thought he had was to just use a regular tube socket and attach the components directly to the base of the socket (ala DanO) or use a small turret board or lag board. He used some vintage ceramic caps in C1 and C4 as well as an oil capacitor for some extra "mojo". He did say that his layout wasn't too well thought out as he would have to remove knobs and unscrew the pots to get access to the tube 

He did give big props to Bancika's DIY layout creator and mentioned how much he appreciated the upgraded version.

There are so much incredible information on hi-fi and other such things in Japanese. I think I need to learn some of that language eventually! Right now I can only look at photos and sometimes I'm lucky enough to accidetally stumble across something that turns out to be a link to a schematic. Ha,ha. Please share more goodies with us if you come across something that might be of interest here. 

I'm using a regulated ac/dc adaptor capable of 500mA. It's switchable between 9 and 12 v. I tried it with everything maxed on the valve caster and the amp turned up loud. There is a subtle hiss at these extreme settings. Switching between 9 and 12 volts does not alter that rather faint hiss in my case. All in all I was actualy surprised at how quiet this circuit was.

Damn. Exactly the same power situation as me, but yours doesn't make the odd noise.

Now you have rewired the heaters for 12V operation, right? If you're running them in parallel (6,3V operation) at 12V, that can't be good.

If I had half a clue what that means, I'd respond appropriately...      

If he was running the heaters in parallel he would be sending 12 volts to pins 4 and 5 and use pin 9 for ground, right ? In this case pin 5 gets 12 volts and pin 4 goes to ground. Pin 9 is not used.

Are you suggesting that there should be a separate 6.3 volt heater circuit  on this one ?

[niopren]

If properly understanding the above, the 12.6 V could be connected without any changes, according to the wiring of this image?

[/quote]

[/quote]

[Renegadrian]

this is my version... dual overdrive

Niopren, or Dano, is it possible to have a layout for the dual valve schematic?! I'd like to have one as this one above for one valve only...Thank you...

[brett]

Hi
RE: dual tubes
My "Triode triode" circuit, which is similar, gave plenty of gain and distortion with just 1 12AU7 tube. (soundclip posted above)
If you want monster gain, just use a booster in front.

RE: series and parallel heater wiring

For those new to the 12**7 series and similar tubes, the element connects 4 and 9 and 9 and 5.
Serial connection runs from 4 thru 9 to 5, with 4 at 12.6V and 5 grounded. ( Or 5 at 12.6 V and 4 grounded).
Parralel runs from 4 to 9 AND 5 to 9, with 4 and 5 at 6.3 V, and 9 grounded.

For a circuit such as this I recommend using DC for the filaments.  Even better if it's a DC wall, wart, so that AC never gets near the circuit at all.  This is because those hum-inducing AC currents in heaters are so large (hundreds of mA) relative to the signal (thousandths of a mA) that hum will appear if your wiring setup is less than perfect.
cheers

[ItZaLLgOOd]

Has anyone tried clipping diodes yet?  I already use a tube amp and I am mainly looking for a tube distortion type of pedal.

[Krinor]

this is my version... dual overdrive

Niopren, or Dano, is it possible to have a layout for the dual valve schematic?! I'd like to have one as this one above for one valve only...Thank you...

The schematic for the dual version is posted on page 4 of this thread.

EDIT: Er... sorry. I didn't read that question properly. You probablu know where the schmo is.

Hi
RE: dual tubes
My "Triode triode" circuit, which is similar, gave plenty of gain and distortion with just 1 12AU7 tube. (soundclip posted above)
If you want monster gain, just use a booster in front.

RE: series and parallel heater wiring

For those new to the 12**7 series and similar tubes, the element connects 4 and 9 and 9 and 5.
Serial connection runs from 4 thru 9 to 5, with 4 at 12.6V and 5 grounded. ( Or 5 at 12.6 V and 4 grounded).
Parralel runs from 4 to 9 AND 5 to 9, with 4 and 5 at 6.3 V, and 9 grounded.

For a circuit such as this I recommend using DC for the filaments.  Even better if it's a DC wall, wart, so that AC never gets near the circuit at all.  This is because those hum-inducing AC currents in heaters are so large (hundreds of mA) relative to the signal (thousandths of a mA) that hum will appear if your wiring setup is less than perfect.
cheers

Thanks Brett! This thread is becoming a nice little tubenoob primer 

[Renegadrian]

Yes, Krinor, I'd like to have a LAYOUT based on the schem we have some ages ago...


EDIT: ooops, I meant "Pages"...This darn sylicon keyboard...

[mojo_hand]

Has anyone tried clipping diodes yet?  I already use a tube amp and I am mainly looking for a tube distortion type of pedal.

Can't say that I've ever used clipping diodes in a tube circuit.  Aside from extreme fuzz effects like the early germanium stuff, I think of diodes as a way to get around the fact that bipolar transistors often sound like crap when driven to clipping.  With the lovely sound of clipping tubes, I'm not sure why you'd want diodes, unless you were wanting to play a lot of "Satisfaction" or "In-A-Gadda-Da-Vida."

[ItZaLLgOOd]

I was curious about clipping diodes and tubes.  I was under the impression that this project didn't clip a whole lot.  I was looking for something with more distortion but "In-A-Gadda" was not the direction I wanted to head.

[mojo_hand]

Well, with a reported gain of around 30, and output that's somewhere between 8 and 11 volts (depending on whether you're doing it with 9 volts or 12), the most you'd need to drive it into clipping would be 11v/30 = 0.37 volts.  If that isn't enough gain for your pickups to drive it into clipping, more gain could easily be added -- switching from a 12AU7 to a 12AT7 might work, or you could just stick a single JFET in front of it and pick up additional gain of 4-5, boosting total gain to 120-150.

(Some people might cringe at the idea of "polluting" a tube effect with a solid state device, but I think that JFETs are just about perfect for this particular use.)

[earthtonesaudio]

What about tube diode clipping?  I have a few old 6AL5 tubes (twin diodes) lying around, but I don't know much about tubes in general.  You could do the same thing with tube diodes as you normally do with solid state, but I don't know how useful it would be.  Some things to consider:

-Would tube diodes clip like we are talking about here, or would the clipping voltage level be way too high? 
-For the 6AL5, the spec sheet says it drops 10 volts per plate... My guess is that would be way too much in a low-voltage effect such as this, but I just thought I'd throw it out there as food for thought.

[Caferacernoc]

A regular diode to ground clipper will work just fine in this circuit. See Marshall JCM900 schematic. Diode and tube distortion in the preamp. Whether that sounds better than just adding more gain at the front, I don't know.
As for tube diode, maybe try it with a AMZ saturation control.

[brett]

Hi
RE clipping.

As I said above, with a tad of boost I got this much clipping.



With lots of boost (to 2V p-p), the output was squarish.  It sounded similar to my JTM60 Marshall when fully cranked on the "vintage" channel. (a tone that's loved my many) Clipping diodes will be much coarser in tone, whether in this circuit or one such as the Distortion +, placed before it. 

As said above, a single JFET booster will do the job of overloading this circuit:

Well, with a reported gain of around 30, and output that's somewhere between 8 and 11 volts (depending on whether you're doing it with 9 volts or 12), the most you'd need to drive it into clipping would be 11v/30 = 0.37 volts.  If that isn't enough gain for your pickups to drive it into clipping, more gain could easily be added -- switching from a 12AU7 to a 12AT7 might work, or you could just stick a single JFET in front of it and pick up additional gain of 4-5, boosting total gain to 120-150.

cheers

[petemoore]

or you could just stick a single JFET in front of it and pick up additional gain of 4-5, boosting total gain to 120-150.
  Often we do, Jfet 'up front' is oft preferred, not that CMoS or..
  For just getting the signal level up to a point where the next stage or so can start distorting it, some fine Jfet dirt, or Mosfet clean, or...other non-tube active circuit as gain stage certainly makes sense, i
  If the first tube stage is only boosting and not distorting, well, that type of clean or even a touch of fine dirt leaves the subsequent tube stages to be used for producing the actual distorting properties we're looking for.
  Not to say "Don't let any non-tube light distortion introduced by non-tube active in" before tube gets it's chance to distort.
  @9vdc with 12a_7 tube providing boost and distortion, and not much headroom to work with, letting something else to much of the grunt work [many small signal device types bias @9v and sound great]...more tube distortion will be available as well as more output available which could be used for voicing options.
  You could use another tube for that, but with battery, I'd stick to one tube.
  There's probably a sweet spot for input level on the tube, adding preboost at least seems a logical way to find out if it's not preferred.
  First priority for new tube here is to get the right power supplied and see if they light up, a little off isn't bad, and as long as they light up the tube should work, I've run them like that, but between the data sheets and other data, the right voltage for the heaters is always recommended.

[Jered]

  Anybody tried 12AV7 in this circuit? I'm going to try it tomorrow and will post my results.
  Guys, if you have a power supply you can use for this, do it. Using batteries, they barely last long enough to do any tweaking. The circuit goes from sounding decent, to degrading quickly, trying to work on tone improvements with batteries for power, in this circuit, is tough.
  Jered

[Zben3129]

12AV6

IIRC - This tube was built to be driven (I believe in computer systems?)
Has roughly same gain as ax7
Would act the same as ax7 in this circuit if the above is correct

But why not try it, and tell us your results

Zach

[mojo_hand]

  For just getting the signal level up to a point where the next stage or so can start distorting it, some fine Jfet dirt, or Mosfet clean, or...other non-tube active circuit as gain stage certainly makes sense, i
  If the first tube stage is only boosting and not distorting, well, that type of clean or even a touch of fine dirt leaves the subsequent tube stages to be used for producing the actual distorting properties we're looking for.

Thanks for elaborating, those were exactly my thoughts.

[Jered]

  Were you talking to me Zach, about the 12AV6? I'll try it out. I'll have to go get the AV6's from the tube cabinet at the studio, I'll be down there Monday. The AV7's are right in front of me, going to run those first.
  Jered

[Zben3129]

Sorry, meant av7,

Fingers mind and eyes don't always line up after exam week 


Zach

[Jered]

  On the subject of tubes, here's a link to some tubes that have just been collecting dust.
http://www.diystompboxes.com/smfforum/index.php?topic=64670.0
Take a look, maybe there's some you guys might want.
  Jered