Tube boost + overdrive running off a 9 volt battery

[karter2000]

Sorry if this was covered elsewhere in the thread, but is there a verified layout for a Subcaster?  Vero, perf, or otherwise?

[oneeyedog]

thanks renegadrian, I'll give it a try first chance I get .... where is your gallery?
john

[served]

Well yes, I did build the Valve earlier, and did build peppershredder with two 12AU7, but his Triple valvevaster made me really want it. So, I will go for it!

I thought on powering the pedal from 24VDC, so that I will regulate heater and LED voltage from 7812 and Anode voltage will go directly from the adaptor socket, but. Then It got me thinking, 7812 will not let 12V inputpower pass, it will lower it, so if I would like to power it from 12V adaptor then I am screwed and will have to remove 7812, but hey, that's why they invented switches.

At the moment I have some tubes in my storage, but I am afraid i dont have the right ones to make it sound good. So It will take some time to complete.

I have built several tube amps before and done some tube stuff, but I don't know everything about it, so I will stop by and maybe ask some questions.

One thing more, I have a Tube Driver somewhere. its not finished, because I didn't have the motivation to finish it. Has anybody done it? How would you compare it with this subject? I know its hybrid, but still.

I will go or at least try to build something out of these old Russian tubes:6N1P, 6N2P, 6N3P, 6N6P, 6N23P and so on. You could get them unused and really cheap. So that If anyone could get his hand on them, then you would know what to choose. But it will not happen in weeks, maybe after a month or so. Some research has to be done and there is not much time and finance to make it quickly.

So good luck to everyone!

One thing though. Could you all post the tubes you have used in this circuit and found it working and worth trying?

On more: if you look for oldschool rock sound, metal or something. Try Peppershredder from tubeTowns DIY section. This thing made me really enthusiastic about tubes. its not high-Gain or something, but its better than DS-1 and fun to build.

[zambo]

@ Served.....You could use a 24volt supply and a 7812. Run wires right from dc input to anodes ( to resistors at anodes). Run 7812 right from socket to heaters. Done. It works, you just end up having 3 24volt leads off the dc in as well as a 7812. I use 12au7 in all three spots on my latest triple tube build. I use a voltage multiplier I saw from Rick Holts Murder One design. Works quite well at 45volts.         http://www.youtube.com/watch?v=YhyyYjY5CgA   

[Renegadrian]

thanks renegadrian, I'll give it a try first chance I get .... where is your gallery?
john

http://www.aronnelson.com/gallery/main.php/v/Renegadrian/

[jcgss77]

Hello, I am sorry if this has already been covered, and if it is common knowledge, but I am new at this stuff, and am very excited to build myself a valvecaster.  I only have AC power converters, no AC to DC.  Do I need to rectify the AC to DC to have this work, or will the normal step-down AC adapter work?  Thank you.

[served]

Hello, I am sorry if this has already been covered, and if it is common knowledge, but I am new at this stuff, and am very excited to build myself a valvecaster.  I only have AC power converters, no AC to DC.  Do I need to rectify the AC to DC to have this work, or will the normal stepson AC adapter work?  Thank you.

No. You cant use AC to make it work. Heaters can do their job with AC but no amplifycation is possible with AC.
But rectification is actually so easy to perform. It will acquire only like 6 additional parts, or less. Diodes(or diode-bridge - don't know how its in English), el.caps and that should do the trick. Of course if you want something more, filtering and regulation, then its a bit more complex, but not much. So give it a try and if its not enough, add what ever is necessary.

[lowend]

Egads, so much info in this thread!

So here is what I think I have figured out from all my reading and researching:

This is the simplest overdrive valve circuit and any mug should be able to build it,

The schematic on the first page works. Blowed if I can make head nor tail of it corellating with another thread that says the valve heaters are pins 4 & 5. I assume a 9V power input works by virtue of resistor(s) feeding the tube with 6.3V twice so it's getting 12.6V in total just like its name 12AU7, not sure on the maths to verify that, I just take these things on faith.

It's a little bit noisy but will run fine with a wall wart style unregulated 9V.
It's a little dark toned for some but all the vids I saw sounded cool to me.

I want one and that means I have to buy some components which I don't have. Nobody seems to sell a kitset for it. How come? Does Mr Matsuwotshisname retain rights to it that nobody is allowed to profit off it?

Going shopping online I am struck by so many different capacitors it makes my head spin. Can somebody please point me at the right ones? Ceramic, monolithic, metal film, polyester??? Nothing as low as 9V so I guess a 50V works ok??? I think I've got the value scales figured out.

Pots I have found locally online don't specify if they are linear B or logarithmic A. Gee, you'd think I actually knew what I was talking about. I guess you learn a lot in a day when you have to.

I'm in New Zealand. We have a "Dick Smith" in town, a lot like radioshack, prolly copied from RS actually. Anyway, I should be able to get correct pots, resistors and capacitors off the shelf if I ask their guy the right questions? Any tips?

[zambo]

use a regulated dc power supply. I use a 1 spot 9 volt. You can run 9 volts to pin 5 and ground pin 4. Works great. 100k a pots and 50 k b pot are the right ones I believe. %0 volt caps are fine. I use poly or whatever is available and they all seem to work. Antique electronics was selling a kit that I believe is this pedal. You can build your own for about a quarter of the price. There are only 4 caps and 4 resistors 3 pots a tube a socket a dc jack and a box. An extra cap and 7812 on the dc jack make it quieter. Renegadrian has the cool vero layouts that are tried and true. Schematic on first page works as well. Welcome!

[lowend]

Thanks. Is that a typo, %0 V caps??

I tested my power supply with mulitimeter and it's putting out 9.2V with no load, rated at 1000mA so I could prolly run three off it, but it doesn't say anything about being regulated as such.

Valves are very pricey in New Zealand but I see some bargains on ebay so might have to go there. They all claim to be tested NOS but who really knows? I haven't found anyone selling the tubes and the sockets together yet. Stuff paying two lots of shipping.

I tracked down Renegadrian's layout and it appears same as the front page one but done on that stripped board stuff, might have to get some of that too, looks real handy to solder onto. Is that the vero or is that the drawing program name?? I'll find out shortly!

[oneeyedog]

IT WORKS!!!!!!!!!!!!  not that I ever doubted the advice, I got the 7812 and cap today and.. no noise. thank you kindly for the advice. I have it built in a cardboard box!!! but now that it works i will get a proper enclosure, and post pics when I'm done. thanks again

cheers
john

[jcgss77]

Thank you for the direct replies.

Just to ask-is it really a good idea to run the whole 9v to the filaments?  Don't they want 6.3v with 300mA, or 12.6 v with 150mA?  I thought I had read earlier in this thread that going more than 10% over or under was bad?

[zambo]

Sorry about the typo.....50 volt caps should be fine.yes the striped stuff is vero board on renegadrians layout. 9 volts on the heaters seems to be ok as well. I have been running them on 9 for a long time and they are still working great! Antique Electronic Supply sells tubes and sockets I believe. Small Bear Electronics is a great source as well. 16 bucks for a tube and 2.20 for a socket. They have all the caps enclosure etc. A good one spot shopping place to be sure. I recomend using 100 volt caps on these as once you build it you may want to start running on higher voltage.....it gets kind of addicting imho...good luck and hope this helps.

[lowend]

Just to ask-is it really a good idea to run the whole 9v to the filaments?  Don't they want 6.3v with 300mA, or 12.6 v with 150mA?  I thought I had read earlier in this thread that going more than 10% over or under was bad?

I read that too and it confuses me no end trying to figure it out off the schematic. I'm not even sure I got the good oil on which pin is which in the valve so it ended there for me.

wot I learned at highschool:
If you put resistances in series then then the voltage each part consumes in turn is in proportion to the resistances.
Power is voltage drop x current

So I can see how applying 6.3 volts to two heaters seperately is the same power consumption as 12.6 volts to them both if they were in series with each other. I just don't see how the wiring is doing that.

All the yap about shouldn't it be 12V is just guys who know even less than me messing with it, finding it makes more noise without going bang and then going "rarara it does need 12V", when they are now overpowering theirs if they kept the same circuit. Good luck to their valve if I'm reading it all right.

[lowend]

aarg, after more reading it looks like the pins 4 and 5 are indeed the heaters but they are connected together in series (via a disused pin 9) straight off the 9v to ground. So it looks like the heaters indeed being run at somewhat less than ideal power input after all! Any fool can see that! Apologies.

I have a multi voltage adaptor that does 12V so I guess that's a better bet. If I do that do I need to change anything else?

Is it possible to parallel the heaters off pin9 , ground 4 and 5 and get clever with that voltage regulating filter scheme to drop 9V down to 6V regulated. Anyone done it that way?

[served]

Well they will heat up, but I remember somewhere, that they don't actually like lower voltages. They last less or something like this.

[lowend]

Well they will heat up, but I remember somewhere, that they don't actually like lower voltages. They last less or something like this.

This concerns me, although nobody complains that their valve craps out prematurely on the 9V.

Can anyone confirm my very limited understanding of the circuit please? The way I read it the tube heaters are in series and they are parallel with the rest of the circuit off the power supply, meaning thay get the full supply voltage whatever that is, 9V being the original standard, 4.5V per heater plate.

My cunning plan, ( ref BlackAdder, Baldrick ) is to throw the 9v into a voltage dividing scheme for the heater side, onto pin 9 @ 6.3V and ground the pins 4 and 5. That could be a very bad idea if I misunderstand the nature of pin 9. Still need to get a grip on voltage division. I guess I need to know the internal resistance of the heaters when they are up to temp. Do I infer that off the power consumption? Sheesh, 5 days ago a valve was a thing that glows inside an amp and makes lots of noise.

Anyways, valves have been evilbayed, enough for another project or three if they are all good. I got a 4 pack of "tested" NOS Sylvania Baldwin organ 12AU7 for 16 buckeroo + a Raytheon just because the seller had it cheap and it didn't cost any more to ship.

EDIT, just looking up specsheet on 12AU7, they say one is good for a 5w, presumably clean, power amp. Mamamia, Valvecaster on 'roids. Doesn't tell me what the heater resistance is but it sure looks like pin9 is common to both plates.

RE EDIT Ok, 300mA at 6.3V makes for 6.3/0.3 = 21 0hm from the parallel pair of heaters. 9v @.3 amp needs 30 ohm so I need to put a 9 ohm resistor soaker into the heater circuit to deliver 6.3V.  Did I get that right?

btw The power supply has a doofer in the line about an inch long and thick as a finger. I'm guessing that's there to regulate and/or stop hum?

[lowend]

and by and by polishing off more of this monster thread.

Zambo, you RAWK. I'm a bassist but I love rock guitar and run a jam session at a bar. I'm building this thing for the guest artists to rock out with. I think your "triple rectifier" version will be next once I get my building chops.

[zambo]

@ Lowend. Thanks! I wouldnt worry to much about the heater voltage thing. Cathode stripping is what occurs if you run to low of a voltage and no one has reported a problem with it since I started reading the post. I have run quite a few versions of these for about a year now with no tube replacement and I gig with mine 4 to 6 times a month. 12.6 volts to pin 5 and pin 4 to ground is good. I rum 9 to pin 5 and 4 to ground. Havent tried using pin 9 yet. I think you put 6.3 volts to pin 4 and pin 5 and run 9 to ground? I think....but in not positive. I just do it the other way and never worry about it. Baldwin organ tubes work really well by the way. I use those all the time. The old organ speakers are awsome if you can find them too. I got some jensen 8 inch speaks from my tube guy. He said they are from an old balwin organ? Anyway, I love them. Good luck and rock on!

[lowend]

Thanks for the help. The vid where you were running a higher voltage one into a wee fender blues junior was tres cool. I've got a wee solid state combo that we mic up. It's got a very nice rich clean so hoping my valvecaster does something similar. With the same valve as yours that's a good start.

I think I have confirmed my own maths for the drop resistor in the heater by comparing it with the answer someone else got to 18V. Still not sure how to wire it though. Does it matter which is neg and pos on the heater? My guess is it shouldn't.